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Iijima M, Mayerl CJ, Munteanu VD, Blob RW. Forelimb muscle activation patterns in American alligators: Insights into the evolution of limb posture and powered flight in archosaurs. J Anat 2024. [PMID: 38242862 DOI: 10.1111/joa.14011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/21/2024] Open
Abstract
The evolution of archosaurs provides an important context for understanding the mechanisms behind major functional transformations in vertebrates, such as shifts from sprawling to erect limb posture and the acquisition of powered flight. While comparative anatomy and ichnology of extinct archosaurs have offered insights into musculoskeletal and gait changes associated with locomotor transitions, reconstructing the evolution of motor control requires data from extant species. However, the scarcity of electromyography (EMG) data from the forelimb, especially of crocodylians, has hindered understanding of neuromuscular evolution in archosaurs. Here, we present EMG data for nine forelimb muscles from American alligators during terrestrial locomotion. Our aim was to investigate the modulation of motor control across different limb postures and examine variations in motor control across phylogeny and locomotor modes. Among the nine muscles examined, m. pectoralis, the largest forelimb muscle and primary shoulder adductor, exhibited significantly smaller mean EMG amplitudes for steps in which the shoulder was more adducted (i.e., upright). This suggests that using a more adducted limb posture helps to reduce forelimb muscle force and work during stance. As larger alligators use a more adducted shoulder and hip posture, the sprawling to erect postural transition that occurred in the Triassic could be either the cause or consequence of the evolution of larger body size in archosaurs. Comparisons of EMG burst phases among tetrapods revealed that a bird and turtle, which have experienced major musculoskeletal transformations, displayed distinctive burst phases in comparison to those from an alligator and lizard. These results support the notion that major shifts in body plan and locomotor modes among sauropsid lineages were associated with significant changes in muscle activation patterns.
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Affiliation(s)
- Masaya Iijima
- Structure and Motion Lab, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hertfordshire, UK
- Nagoya University Museum, Nagoya, Japan
| | - Christopher J Mayerl
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - V David Munteanu
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Richard W Blob
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
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2
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Sales-Oliveira V, Altmanová M, Gvoždík V, Kretschmer R, Ezaz T, Liehr T, Padutsch N, Badjedjea G, Utsunomia R, Tanomtong A, Cioffi M. Cross-species chromosome painting and repetitive DNA mapping illuminate the karyotype evolution in true crocodiles (Crocodylidae). Chromosoma 2023; 132:289-303. [PMID: 37493806 DOI: 10.1007/s00412-023-00806-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/23/2023] [Accepted: 07/14/2023] [Indexed: 07/27/2023]
Abstract
Crocodilians have maintained very similar karyotype structures and diploid chromosome numbers for around 100 million years, with only minor variations in collinearity. Why this karyotype structure has largely stayed unaltered for so long is unclear. In this study, we analyzed the karyotypes of six species belonging to the genera Crocodylus and Osteolaemus (Crocodylidae, true crocodiles), among which the Congolian endemic O. osborni was included and investigated. We utilized various techniques (differential staining, fluorescence in situ hybridization with repetitive DNA and rDNA probes, whole chromosome painting, and comparative genomic hybridization) to better understand how crocodile chromosomes evolved. We studied representatives of three of the four main diploid chromosome numbers found in crocodiles (2n = 30/32/38). Our data provided new information about the species studied, including the identification of four major chromosomal rearrangements that occurred during the karyotype diversification process in crocodiles. These changes led to the current diploid chromosome numbers of 2n = 30 (fusion) and 2n = 38 (fissions), derived from the ancestral state of 2n = 32. The conserved cytogenetic tendency in crocodilians, where extant species keep near-ancestral state, contrasts with the more dynamic karyotype evolution seen in other major reptile groups.
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Affiliation(s)
- Vanessa Sales-Oliveira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | - Marie Altmanová
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721, Liběchov, Czech Republic
- Department of Ecology, Faculty of Science, Charles University, 12844, Prague, Czech Republic
| | - Václav Gvoždík
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
- Department of Zoology, National Museum of the Czech Republic, Prague, Czech Republic
| | - Rafael Kretschmer
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
| | - Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Jena, Germany
| | - Niklas Padutsch
- Institute of Human Genetics, Jena University Hospital, Jena, Germany
| | - Gabriel Badjedjea
- Department of Aquatic Ecology, Biodiversity Monitoring Center, University of Kisangani, Kisangani, Democratic Republic of the Congo
| | | | - Alongklod Tanomtong
- Department of Biology Faculty of Science, Khon Kaen University, Muang, Khon Kaen, 40002, Thailand
| | - Marcelo Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil.
- Institute of Human Genetics, Jena University Hospital, Jena, Germany.
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Fernandez Blanco MV, Cassini GH, Bona P. A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny. PeerJ 2023; 11:e15548. [PMID: 37456902 PMCID: PMC10349558 DOI: 10.7717/peerj.15548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/22/2023] [Indexed: 07/18/2023] Open
Abstract
Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris, respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris. The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements (e.g., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris, whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare.
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Affiliation(s)
- María Victoria Fernandez Blanco
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Guillermo Hernán Cassini
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- División Mastozoología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina
| | - Paula Bona
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
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4
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Booth W, Levine BA, Corush JB, Davis MA, Dwyer Q, De Plecker R, Schuett GW. Discovery of facultative parthenogenesis in a new world crocodile. Biol Lett 2023; 19:20230129. [PMID: 37282490 DOI: 10.1098/rsbl.2023.0129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Over the past two decades, there has been an astounding growth in the documentation of vertebrate facultative parthenogenesis (FP). This unusual reproductive mode has been documented in birds, non-avian reptiles-specifically lizards and snakes-and elasmobranch fishes. Part of this growth among vertebrate taxa is attributable to awareness of the phenomenon itself and advances in molecular genetics/genomics and bioinformatics, and as such our understanding has developed considerably. Nonetheless, questions remain as to its occurrence outside of these vertebrate lineages, most notably in Chelonia (turtles) and Crocodylia (crocodiles, alligators and gharials). The latter group is particularly interesting because unlike all previously documented cases of FP in vertebrates, crocodilians lack sex chromosomes and sex determination is controlled by temperature. Here, using whole-genome sequencing data, we provide, to our knowledge, the first evidence of FP in a crocodilian, the American crocodile, Crocodylus acutus. The data support terminal fusion automixis as the reproductive mechanism; a finding which suggests a common evolutionary origin of FP across reptiles, crocodilians and birds. With FP now documented in the two main branches of extant archosaurs, this discovery offers tantalizing insights into the possible reproductive capabilities of the extinct archosaurian relatives of crocodilians and birds, notably members of Pterosauria and Dinosauria.
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Affiliation(s)
- Warren Booth
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Chiricahua Desert Museum, Rodeo, NM 88056, USA
| | - Brenna A Levine
- Chiricahua Desert Museum, Rodeo, NM 88056, USA
- Department of Biology, Kean University, Union, NJ 07083, USA
| | - Joel B Corush
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign, Illinois, IL 61820, USA
| | - Mark A Davis
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana-Champaign, Illinois, IL 61820, USA
| | - Quetzal Dwyer
- Reptilandia Reptile Lagoon, Johnson City, TX 78636, USA
| | - Roel De Plecker
- Parque Reptilandia, Dominical 5000, Puntarenas Province, 11902, Costa Rica
| | - Gordon W Schuett
- Chiricahua Desert Museum, Rodeo, NM 88056, USA
- Department of Biology, Neuroscience Institute, Georgia State University, Atlanta, GA 30302, USA
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5
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Puértolas-Pascual E, Kuzmin IT, Serrano-Martínez A, Mateus O. Neuroanatomy of the crocodylomorph Portugalosuchus azenhae from the late cretaceous of Portugal. J Anat 2023; 242:1146-1171. [PMID: 36732084 PMCID: PMC10184551 DOI: 10.1111/joa.13836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
We present the first detailed braincase anatomical description and neuroanatomical study of Portugalosuchus azenhae, from the Cenomanian (Late Cretaceous) of Portugal. This eusuchian crocodylomorph was originally described as a putative Crocodylia and one of the oldest representatives of this clade; however, its phylogenetic position remains controversial. Based on new data obtained from high resolution Computed Tomography images (by micro-CT scan), this study aims to improve the original description of this taxon and also update the scarce neuroanatomical knowledge of Eusuchia and Crocodylia from this time interval, a key period to understand the origin and evolution of these clades. The resulting three-dimensional models from the CT data allowed a detailed description of its well-preserved neurocranium and internal cavities. Therefore, it was possible to reconstruct the cavities of the olfactory region, nasopharyngeal ducts, brain, nerves, carotid arteries, blood vessels, paratympanic sinus system and inner ear, which allowed to estimate some neurosensorial capabilities. By comparison with other crocodylomorphs, these analyses showed that Portugalosuchus, back in the Cenomanian, already displayed an olfactive acuity, sight, hearing and cognitive skills within the range of that observed in other basal eusuchians and crocodylians, including extant species. In addition, and in order to test its disputed phylogenetic position, these new anatomical data, which helped to correct and complete some of the original observations, were included in one of the most recent morphology-based phylogenies. The position of Portugalosuchus differs slightly from the original publication since it is now located as a "thoracosaurid" within Gavialoidea, but still as a crocodylian. Despite all this, to better contrast these results, additional phylogenetic analyses including this new morphological character coding together with DNA data should be performed.
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Affiliation(s)
- Eduardo Puértolas-Pascual
- Aragosaurus-IUCA, Departamento de Ciencias de la Tierra, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.,GeoBioTec, Departamento de Ciências da Terra FCT, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, Lourinhã, Portugal
| | - Ivan T Kuzmin
- Department of Vertebrate Zoology, Saint Petersburg State University, St. Petersburg, Russian Federation
| | | | - Octávio Mateus
- GeoBioTec, Departamento de Ciências da Terra FCT, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, Lourinhã, Portugal
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6
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Ristevski J, Weisbecker V, Scanlon JD, Price GJ, Salisbury SW. Cranial anatomy of the mekosuchine crocodylian Trilophosuchus rackhami Willis, 1993. Anat Rec (Hoboken) 2023; 306:239-297. [PMID: 36054424 PMCID: PMC10086963 DOI: 10.1002/ar.25050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 01/25/2023]
Abstract
One of the best-preserved crocodylian fossil specimens from the Cenozoic of Australia is the holotype of the mekosuchine Trilophosuchus rackhami, from the middle Miocene (13.56 ± 0.67 Ma) Ringtail Site at Riversleigh, northwestern Queensland. Although lacking most of the snout, the holotype skull of T. rackhami (QMF16856) has an exceptionally well-preserved cranium. Micro-CT scanning of the holotype has allowed for all the preserved cranial bones to be digitally disarticulated, facilitating an unprecedented insight into the cranial anatomy of not just T. rackhami, but any mekosuchine. Trilophosuchus rackhami was a small-bodied crocodylian and one of the most morphologically distinct mekosuchines, characterized by a unique combination of cranial characteristics several of which are exclusive to the species. Fossil material that is definitively referrable to the species T. rackhami is currently known solely from the middle Miocene Ringtail Site. However, an isolated parietal from Hiatus Site at Riversleigh demonstrates that Trilophosuchus also occurred during the late Oligocene (~25 Ma), extending the range of the genus by more than 10 million years. The new description of T. rackhami also allowed for a reevaluation of its phylogenetic relationships. Our results reaffirm the placement of T. rackhami as a member of Mekosuchinae within the subclade Mekosuchini. In all analyses, Mekosuchinae was consistently found to be monophyletic and part of the larger crocodylian clade Longirostres. However, the assignment of Mekosuchinae as a subset of Crocodylidae is brought into question, suggesting that the status of Mekosuchinae as a subfamily should be reconsidered.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.,College of Science and Engineering, Flinders University, Bedford Park, South Australia, Australia
| | - John D Scanlon
- Phoenix Environmental Sciences, Osborne Park, Western Australia, Australia
| | - Gilbert J Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Perrichon G, Hautier L, Pochat-Cottilloux Y, Raselli I, Salaviale C, Dailh B, Rinder N, Fernandez V, Adrien J, Lachambre J, Martin JE. Ontogenetic variability of the intertympanic sinus distinguishes lineages within Crocodylia. J Anat 2023; 242:1096-1123. [PMID: 36709416 PMCID: PMC10184552 DOI: 10.1111/joa.13830] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/30/2023] Open
Abstract
The phylogenetic relationships within crown Crocodylia remain contentious due to conflicts between molecular and morphological hypotheses. However, morphology-based datasets are mostly constructed on external characters, overlooking internal structures. Here, we use 3D geometric morphometrics to study the shape of the intertympanic sinus system in crown crocodylians during ontogeny, in order to assess its significance in a taxonomic context. Intertympanic sinus shape was found to be highly correlated with size and modulated by cranial shape during development. Still, adult sinus morphology distinguishes specimens at the family, genus and species level. We observe a clear distinction between Alligatoridae and Longirostres, a separation of different Crocodylus species and the subfossil Malagasy genus Voay, and a distinction between the Tomistoma and Gavialis lineages. Our approach is independent of molecular methods but concurs with the molecular topologies. Therefore, sinus characters could add significantly to morphological datasets, offering an alternative viewpoint to resolve problems in crocodylian relationships.
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Affiliation(s)
- Gwendal Perrichon
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Lionel Hautier
- Institut des Sciences de l'Évolution, Université Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Mammal Section, Life Sciences, Vertebrate Division, The Natural History Museum, London, UK
| | - Yohan Pochat-Cottilloux
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Irena Raselli
- Geoscience Department, Chemin de Musée 6, University of Fribourg, Jurassica Museum, Porrentruy, Switzerland
| | - Céline Salaviale
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Benjamin Dailh
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Nicolas Rinder
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | | | - Jérôme Adrien
- Laboratoire Matériaux, Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France
| | - Joël Lachambre
- Laboratoire Matériaux, Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France
| | - Jeremy E Martin
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
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Massonne T, Böhme M. Re-evaluation of the morphology and phylogeny of Diplocynodon levantinicum Huene & Nikoloff, 1963 and the stratigraphic age of the West Maritsa coal field (Upper Thrace Basin, Bulgaria). PeerJ 2022; 10:e14167. [PMID: 36389401 PMCID: PMC9653056 DOI: 10.7717/peerj.14167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/12/2022] [Indexed: 11/11/2022] Open
Abstract
Diplocynodon levantinicum Huene & Nikoloff, 1963 was described based on few bone fragments from the West-Maritsa lignite basin of Central Bulgaria. Huene & Nikoloff, 1963 assumed a late Pliocene age, implying that this species represents the stratigraphically youngest crocodilian of Europe. In this current study, we re-evaluate the stratigraphy of the West-Maritsa Basin and conclude a late Oligocene age of ~26 Ma for the Kipra coal-seam, the fossiliferous horizon. Furthermore, topotypical and undescribed D. levantinicum specimens are accessible now and allowed for a deeper taxonomic and phylogenetic analysis. A comparison with other Diplocynodon species reveals D. levantinicum as a valid species, having (1) a long suborbital fenestra, (2) a very short dentary symphysis, (3) a large gap between the first and second dentary alveolus, (4) an occlusion pit in line with the tooth row posterior to the 14th dentary alveolus, (5) a sulcus lateral to the glenoid fossa and, (6) a lingual foramen for the articular artery situated entirely on the surangular. The phylogenetic analyses find D. levantinicum deeply nested inside the Diplocynodontinae subfamily. After the disappearance of the Paratethyan influence (Solenovian regional stage) in the Upper Thrace Basin this species has roamed during the late Oligocene extensive freshwater lake and swamp ecosystems represented by the Maritsa Formation. Diplocynodon levantinicum represents the only nominal Diplocynodon taxon of late Oligocene (Chattian) age.
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Affiliation(s)
- Tobias Massonne
- Senckenberg Center of Human Evolution and Palaeoecology, Tübingen, Germany,Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Madelaine Böhme
- Senckenberg Center of Human Evolution and Palaeoecology, Tübingen, Germany,Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
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9
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Ristevski J. Neuroanatomy of the mekosuchine crocodylian Trilophosuchus rackhami Willis, 1993. J Anat 2022; 241:981-1013. [PMID: 36037801 PMCID: PMC9482699 DOI: 10.1111/joa.13732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/15/2022] [Accepted: 07/17/2022] [Indexed: 12/03/2022] Open
Abstract
Although our knowledge on crocodylomorph palaeoneurology has experienced considerable growth in recent years, the neuroanatomy of many crocodylomorph taxa has yet to be studied. This is true for Australian taxa, where thus far only two crocodylian crocodylomorphs have had aspects of their neuroanatomy explored. Here, the neuroanatomy of the Australian mekosuchine crocodylian Trilophosuchus rackhami is described for the first time, which significantly increases our understanding on the palaeoneurology of Australian crocodylians. The palaeoneurological description is based on the taxon's holotype specimen (QMF16856), which was subjected to a μCT scan. Because of the exceptional preservation of QMF16856, most neuroanatomical elements could be digitally reconstructed and described in detail. Therefore, the palaeoneurological assessment presented here is hitherto the most in‐depth study of this kind for an extinct Australian crocodylomorph. Trilophosuchus rackhami has a brain endocast with a distinctive morphology that is characterized by an acute dural peak over the hindbrain region. While the overall morphology of the brain endocast is unique to T. rackhami, it does share certain similarities with the notosuchian crocodyliforms Araripesuchus wegeneri and Sebecus icaeorhinus. The endosseous labyrinth displays a morphology that is typical for crocodylians, although a stand‐out feature is the unusually tall common crus. Indeed, the common crus of T. rackhami has one of the greatest height ratios among crocodylomorphs with currently known endosseous labyrinths. The paratympanic pneumatic system of T. rackhami is greatly developed and most similar to those of the extant crocodylians Osteolaemus tetraspis and Paleosuchus palpebrosus. The observations on the neuroanatomy of T. rackhami are also discussed in the context of Crocodylomorpha. The comparative palaeoneurology reinforces previous evaluations that the neuroanatomy of crocodylomorphs is complex and diverse among species, and T. rackhami has a peculiar neuromorphology, particularly among eusuchian crocodyliforms.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
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10
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Brochu CA, de Celis A, Adams AJ, Drumheller SK, Nestler JH, Benefit BR, Grossman A, Kirera F, Lehmann T, Liutkus-Pierce C, Manthi FK, McCrossin ML, McNulty KP, Nyaboke Juma R. Giant dwarf crocodiles from the Miocene of Kenya and crocodylid faunal dynamics in the late Cenozoic of East Africa. Anat Rec (Hoboken) 2022; 305:2729-2765. [PMID: 35674271 PMCID: PMC9541231 DOI: 10.1002/ar.25005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 12/03/2022]
Abstract
We describe two new osteolaemine crocodylids from the Early and early Middle Miocene of Kenya: Kinyang mabokoensis tax. nov. (Maboko, 15 Ma) and Kinyang tchernovi tax. nov. (Karungu and Loperot, 18 Ma). Additional material referable to Kinyang is known from Chianda and Moruorot. The skull was broad and dorsoventrally deep, and the genus can be diagnosed based on the combined presence of a partial overbite, a subdivided fossa for the lateral collateral ligament on the surangular, and a maxilla with no more than 13 alveoli. Phylogenetic analyses based on morphological and combined morphological and molecular data support a referral of Kinyang to Osteolaeminae, and morphological data alone put the new taxon at the base of Euthecodontini. Some Kinyang maxillae preserve blind pits on the medial caviconchal recess wall. Kinyang co‐occurs with the osteolaemine Brochuchus at some localities, and together, they reinforce the phylogenetic disparity between early Neogene osteolaemine‐dominated faunas and faunas dominated by crocodylines beginning in the Late Miocene in the Kenya Rift. The causes of this turnover remain unclear, though changes in prevailing vegetation resulting from tectonic and climatic drivers may provide a partial explanation.
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Affiliation(s)
- Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Ane de Celis
- Grupo de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Amanda J Adams
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA.,Department of Biological Sciences, Fort Hays State University, Hays, Kansas, USA
| | - Stephanie K Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - Jennifer H Nestler
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Brenda R Benefit
- Department of Anthropology, New Mexico State University, Las Cruces, New Mexico, USA
| | - Aryeh Grossman
- Department of Anatomy, College of Graduate Studies, Midwestern University, Glendale, Arizona, USA.,Arizona College of Veterinary Medicine, Midwestern University, Glendale, Arizona, USA.,Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona, USA
| | - Francis Kirera
- Mercer University School of Medicine, Macon, Georgia, USA
| | - Thomas Lehmann
- Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
| | - Cynthia Liutkus-Pierce
- Department of Geological and Environmental Sciences, Appalachian State University, Boone, North Carolina, USA
| | - Fredrick K Manthi
- Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
| | - Monte L McCrossin
- Department of Anthropology, New Mexico State University, Las Cruces, New Mexico, USA
| | - Kieran P McNulty
- Department of Anthropology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Rose Nyaboke Juma
- Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
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11
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Sellers KC, Nieto MN, Degrange FJ, Pol D, Clark JM, Middleton KM, Holliday CM. The effects of skull flattening on suchian jaw muscle evolution. Anat Rec (Hoboken) 2022; 305:2791-2822. [PMID: 35661427 DOI: 10.1002/ar.24912] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/20/2022]
Abstract
Jaw muscles are key features of the vertebrate feeding apparatus. The jaw musculature is housed in the skull whose morphology reflects a compromise between multiple functions, including feeding, housing sensory structures, and defense, and the skull constrains jaw muscle geometry. Thus, jaw muscle anatomy may be suboptimally oriented for the production of bite force. Crocodylians are a group of vertebrates that generate the highest bite forces ever measured with a flat skull suited to their aquatic ambush predatory style. However, basal members of the crocodylian line (e.g., Prestosuchus) were terrestrial predators with plesiomorphically tall skulls, and thus the origin of modern crocodylians involved a substantial reorganization of the feeding apparatus and its jaw muscles. Here, we reconstruct jaw muscles across a phylogenetic range of crocodylians and fossil suchians to investigate the impact of skull flattening on muscle anatomy. We used imaging data to create 3D models of extant and fossil suchians that demonstrate the evolution of the crocodylian skull, using osteological correlates to reconstruct muscle attachment sites. We found that jaw muscle anatomy in early fossil suchians reflected the ancestral archosaur condition but experienced progressive shifts in the lineage leading to Metasuchia. In early fossil suchians, musculus adductor mandibulae posterior and musculus pterygoideus (mPT) were of comparable size, but by Metasuchia, the jaw musculature is dominated by mPT. As predicted, we found that taxa with flatter skulls have less efficient muscle orientations for the production of high bite force. This study highlights the diversity and evolution of jaw muscles in one of the great transformations in vertebrate evolution.
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Affiliation(s)
- Kaleb C Sellers
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA.,Department of Clinical Anatomy and Osteopathic Principles and Practice, Rocky Vista University, Parker, Colorado, USA
| | - Mauro Nicolas Nieto
- Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), UNC, CONICET, Córdoba, Argentina
| | - Federico J Degrange
- Centro de Investigaciones en Ciencias de la Tierra (CICTERRA), UNC, CONICET, Córdoba, Argentina
| | - Diego Pol
- CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Argentina
| | - James M Clark
- Department of Biological Sciences, The George Washington University, Washington, District of Columbia, USA
| | - Kevin M Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA
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12
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Matsumoto R, Fujiwara S, Evans SE. Feeding behaviour and functional morphology of the neck in the long-snouted aquatic fossil reptile Champsosaurus (Reptilia: Diapsida) in comparison with the modern crocodilian Gavialis gangeticus. J Anat 2022; 240:893-913. [PMID: 34865223 PMCID: PMC9005684 DOI: 10.1111/joa.13600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 10/19/2022] Open
Abstract
The extinct freshwater choristoderan reptiles Champsosaurus and Simoedosaurus are characterised by large body size and an elongated snout. They have often been considered as eco-analogues of crocodilians based on superficial similarities. The slender-snouted Champsosaurus has been described as a 'gavial-like reptile', which implies it feeds underwater with a lateral swipe of the head and neck, as in the living slender-snouted crocodilians such as Gavialis gangeticus. In contrast, the short-snouted Simoedosaurus is often compared with short-snouted living crocodilians and is considered to take single prey items. However, the neck mobility and flexibility needed for feeding movements are poorly understood even in extant crocodilians. This study explores the relationship between cervical morphology and neck flexion, focusing particularly on lateral and dorsal movements in G. gangeticus by comparison with shorter-snouted crocodilians. The paper also describes a method to estimate the maximum angle of neck dorsiflexion in choristoderes based on the cervical morphology of extant crocodilian species. Three indices were used in this study, of which Index 3 is newly proposed, to compare cervical morphology and intervertebral joint flexibility: (1) Enclosed zygapophyseal angles (EZA) as an index of dorsoventral/ bilateral flexibility, (2) moment arm (M) of dorsiflexor muscles as an Index of resistance against ventroflexion and (3) the orientations of zygapophysial facets for a maximum angle of dorsiflexion. These Indices were validated using µCT scanning of fresh specimens of G. gangeticus and Caiman latirostris in lateral and dorsal flexion. A unique mechanism of lateral flexion was identified in G. gangeticus that uses a combination of the following features: (1) lateral flexion mainly restricted to the anterior cervical vertebrae (v2/v3: high EZA, with more horizontal zygapophyses) and (2) high degree of dorsiflexion at the v3/v4 and v4/v5 joints with potential for dorsal flexibility through the middle-posterior neck, which is used in inertial feeding. In contrast, Champsosaurus and Simoedosaurus possess relatively short cervical vertebrae, as in short-snouted crocodilians. The middle-posterior cervical vertebrae of Champsosaurus are specialised for lateral flexion (high EZA), and there is only limited capacity for dorsiflexion throughout the neck. Like G. gangeticus, therefore, Champsosaurus may have used its slender snout to grab fish from shoals using lateral sweeping motions of the head and neck, but the movement is through the neck, not the craniocervical joint. However, inertial feeding is less likely to have occurred in this genus, and the aligned palatal dentition may have aided the lingual transport of prey into the mouth. Simoedosaurus, on the other hand, appears to have been less specialised, with a neck that combined lateral and dorsolateral flexion, a move that could have been effective in catching both terrestrial and aquatic prey. Where these two choristoderan genera occurred in the same place, they may have divided their niche by prey types.
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Affiliation(s)
- Ryoko Matsumoto
- Kanagawa Prefectural Museum of Natural HistoryOdawaraKanagawaJapan
| | | | - Susan E. Evans
- Centre for Integrative AnatomyDepartment of Cell and Developmental BiologyUCLUniversity College LondonLondonUK
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13
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Greer S, Cramberg MJ, Young BA. Morphometrics of the Spinal Cord and Surrounding Structures in Alligator mississippiensis. Biology (Basel) 2022; 11:514. [PMID: 35453713 DOI: 10.3390/biology11040514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023]
Abstract
Simple Summary Morphometric analysis of the spinal cord and surrounding tissue of the American alligator (Alligator mississippiensis) reveals that there are four significantly discrete regions; cervical, thoracic, lumbar, and caudal. Crocodylians, unlike mammals, have a caudal spinal cord that extends throughout the length of their tail (which accounts for roughly 50% of their total body length). Alligator mississippiensis has one of the largest ranges of body sizes among terrestrial vertebrates, this study documents how the different spinal structures change with increasing body size. Though most of the structures exhibit slightly positive allometry, a few exhibit slightly negative allometry; these differences mean that there are significant relational changes as hatchlings grow into large adults. This study provides the first documentation that A. mississippiensis has an expansive subdural space, a lumbar cistern, at the pelvis. Abstract Understanding the fluid dynamics of the cerebrospinal fluid requires a quantitative description of the spaces in which it flows, including the spinal cord and surrounding meninges. The morphometrics of the spinal cord and surrounding tissues were studied in specimens of the American alligator (Alligator mississippiensis) ranging from hatchlings through adults. Within any size class of alligators (i.e., hatchlings), along the axial length there are significant differences in the size of the spinal cord, meninges, and vertebral canal; these differences can be used to define discrete cervical, thoracic, lumbar and caudal regions. When compared across the range of body sizes in Alligator, every structure in each spinal region had a distinctive growth rate; thus, the physical arrangements between the structures changed as the alligator grew. The combination of regional differentiation and differential growth rates was particularly apparent in the lumbar meninges where a unique form of lumbar cistern could be identified and shown to decrease in relative size as the alligator ages. This analysis of the spinal cord and surrounding tissues was undertaken to develop a data set that could be used for computational flow dynamics of the crocodilian cerebrospinal fluid, and also to assist in the analysis of fossil archosaurs.
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14
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Darlim G, Lee MSY, Walter J, Rabi M. The impact of molecular data on the phylogenetic position of the putative oldest crown crocodilian and the age of the clade. Biol Lett 2022; 18:20210603. [PMID: 35135314 PMCID: PMC8825999 DOI: 10.1098/rsbl.2021.0603] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The use of molecular data for living groups is vital for interpreting fossils, especially when morphology-only analyses retrieve problematic phylogenies for living forms. These topological discrepancies impact on the inferred phylogenetic position of many fossil taxa. In Crocodylia, morphology-based phylogenetic inferences differ fundamentally in placing Gavialis basal to all other living forms, whereas molecular data consistently unite it with crocodylids. The Cenomanian Portugalosuchus azenhae was recently described as the oldest crown crocodilian, with affinities to Gavialis, based on morphology-only analyses, thus representing a potentially important new molecular clock calibration. Here, we performed analyses incorporating DNA data into these morphological datasets, using scaffold and supermatrix (total evidence) approaches, in order to evaluate the position of basal crocodylians, including Portugalosuchus. Our analyses incorporating DNA data robustly recovered Portugalosuchus outside Crocodylia (as well as thoracosaurs, planocraniids and Borealosuchus spp.), questioning the status of Portugalosuchus as crown crocodilian and any future use as a node calibration in molecular clock studies. Finally, we discuss the impact of ambiguous fossil calibration and how, with the increasing size of phylogenomic datasets, the molecular scaffold might be an efficient (though imperfect) approximation of more rigorous but demanding supermatrix analyses.
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Affiliation(s)
- Gustavo Darlim
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany
| | - Michael S. Y. Lee
- School of Biological Sciences, Flinders University, GPO Box 2100, South Australia 5001, Australia,Australia Earth Sciences Section, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - Jules Walter
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany,Dipartimento di Scienze della Terra, Universitàt degli Studi di Torino, Via Valperga Caluso 35, 10125 Torino, Italy
| | - Márton Rabi
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany,Central Natural Science Collections, Martin-Luther University Halle-Wittenberg, D-06108 Halle (Saale), Germany
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15
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Cossette AP, Grass AD, DeGuzman T. The contribution of ontogenetic growth trajectories on the divergent evolution of the crocodylian skull table. Anat Rec (Hoboken) 2021; 305:2904-2925. [PMID: 34779584 DOI: 10.1002/ar.24824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 08/05/2021] [Accepted: 08/18/2021] [Indexed: 11/07/2022]
Abstract
To explore shape variability among crocodylian skull tables, an analysis using geometric morphometric methods is conducted with the inclusion of extant and fossil taxa. Skull tables are variable and the differences likely play a role in hydrodynamics, species recognition, and biomechanical adaptations. Comparisons of allometric change within taxa are explored revealing that adults significantly diverge from juvenile skull table morphologies in most species and these changes happen in a stereotyped way. In all analyses, adults of the smallest extant taxa plot alongside the juveniles of related taxa and heterochrony may explain the maintenance of these morphologies into adulthood. When landmarks representing the supratemporal fenestrae are included, longirostrine taxa are broadly separated from one another due to variation in the size of the supratemporal fenestrae. The hypotheses of previous studies suggesting that the size of the supratemporal fenestrae is influenced by snout length-with longer snouts corresponding to larger fenestrae-must be re-evaluated. Although species of the crocodyloids Tomistoma and Euthecodon approach or exceed the length of the snout in gavialoids, their supratemporal fenestrae are proportionally smaller-this suggests a phylogenetic constraint in crocodyloids regardless of snout length.
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Affiliation(s)
- Adam P Cossette
- Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, Arkansas, USA.,Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Andy D Grass
- A.T. Still University School of Osteopathic Medicine in Arizona, Mesa, Arizona, USA
| | - Thomas DeGuzman
- Department of Basic Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, Arkansas, USA
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16
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Kuzmin IT, Boitsova EA, Gombolevskiy VA, Mazur EV, Morozov SP, Sennikov AG, Skutschas PP, Sues H. Braincase anatomy of extant Crocodylia, with new insights into the development and evolution of the neurocranium in crocodylomorphs. J Anat 2021; 239:983-1038. [PMID: 34176132 PMCID: PMC8546529 DOI: 10.1111/joa.13490] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/30/2022] Open
Abstract
Present-day crocodylians exhibit a remarkably akinetic skull with a highly modified braincase. We present a comprehensive description of the neurocranial osteology of extant crocodylians, with notes on the development of individual skeletal elements and a discussion of the terminology used for this project. The quadrate is rigidly fixed by multiple contacts with most braincase elements. The parabasisphenoid is sutured to the pterygoids (palate) and the quadrate (suspensorium); as a result, the basipterygoid joint is completely immobilized. The prootic is reduced and externally concealed by the quadrate. It has a verticalized buttress that participates in the canal for the temporal vasculature. The ventrolateral processes of the otoccipitals completely cover the posteroventral region of the braincase, enclose the occipital nerves and blood vessels in narrow bony canals and also provide additional sutural contacts between the braincase elements and further consolidate the posterior portion of the crocodylian skull. The otic capsule of crocodylians has a characteristic cochlear prominence that corresponds to the lateral route of the perilymphatic sac. Complex internal structures of the otoccipital (extracapsular buttress) additionally arrange the neurovascular structures of the periotic space of the cranium. Most of the braincase elements of crocodylians are excavated by the paratympanic pneumatic sinuses. The braincase in various extant crocodylians has an overall similar structure with some consistent variation between taxa. Several newly observed features of the braincase are present in Gavialis gangeticus and extant members of Crocodylidae to the exclusion of alligatorids: the reduced exposure of the prootic buttress on the floor of the temporal canal, the sagittal nuchal crest of the supraoccipital projecting posteriorly beyond the postoccipital processes and the reduced paratympanic pneumaticity. The most distinctive features of the crocodylian braincase (fixed quadrate and basipterygoid joint, consolidated occiput) evolved relatively rapidly at the base of Crocodylomorpha and accompanied the initial diversification of this clade during the Late Triassic and Early Jurassic. We hypothesize that profound rearrangements in the individual development of the braincases of basal crocodylomorphs underlie these rapid evolutionary modifications. These rearrangements are likely reflected in the embryonic development of extant crocodylians and include the involvement of neomorphic dermal anlagen in different portions of the developing chondrocranium, the extensive ossification of the palatoquadrate cartilage as a single expanded quadrate and the anteromedial inclination of the quadrate.
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Affiliation(s)
- Ivan T. Kuzmin
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Elizaveta A. Boitsova
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Victor A. Gombolevskiy
- Research and Practical Clinical Center of Diagnostics and Telemedicine TechnologiesMoscowRussian Federation
| | - Evgeniia V. Mazur
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Sergey P. Morozov
- Research and Practical Clinical Center of Diagnostics and Telemedicine TechnologiesMoscowRussian Federation
| | | | - Pavel P. Skutschas
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Hans‐Dieter Sues
- Department of PaleobiologyNational Museum of Natural HistorySmithsonian InstitutionWashingtonDCUSA
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17
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Morris ZS, Vliet KA, Abzhanov A, Pierce SE. Developmental origins of the crocodylian skull table and platyrostral face. Anat Rec (Hoboken) 2021; 305:2838-2853. [PMID: 34694063 DOI: 10.1002/ar.24802] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/13/2021] [Indexed: 11/10/2022]
Abstract
The dorsoventrally flattened skull typifies extant Crocodylia perhaps more than any other anatomical feature and is generally considered an adaptation for semi-aquatic feeding. Although the evolutionary origins of caniofacial flattening have been extensively studied, the developmental origins have yet to be explored. To understand how the skull table and platyrostral snout develop, we quantified embryonic development and post-hatching growth (ontogeny) of the crocodylian skull in lateral view using geometric morphometrics. Our dataset (n = 103) includes all but one extant genus and all of the major ecomorphs, including the extremely slender-snouted Gavialis and Tomistoma. Our analysis reveals that the embryonic development of the flattened skull is remarkably similar across ecomorphs, including the presence of a conserved initial embryonic skull shape, similar to prior analysis of dorsal snout shape. Although differences during posthatching ontogeny are recovered among ecomorphs, embryonic patterns are not distinct, revealing an important shift in developmental rate near hatching. In particular, the flattened skull table is achieved by the end of embryonic development with no changes after hatching. Further, the rotation of skull roof and facial bones during development is critical for the stereotypical flatness of the crocodylian skull. Our results suggest selection on hatchling performance and constraints on embryonic skull shape may have been important in this pattern of developmental conservation. The appearance of aspects of cranial flatness among Jurassic stem crocodylians suggests key aspects of these cranial developmental patterns may have been conserved for over 200 million years.
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Affiliation(s)
- Zachary S Morris
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Arhat Abzhanov
- Department of Life Sciences, Imperial College London, Berkshire, UK.,Natural History Museum, Cromwell Road, London, UK
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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18
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Gignac PM, Smaers JB, O'Brien HD. Unexpected bite-force conservatism as a stable performance foundation across mesoeu crocodylian historical diversity. Anat Rec (Hoboken) 2021; 305:2823-2837. [PMID: 34555273 DOI: 10.1002/ar.24768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 07/07/2021] [Accepted: 08/09/2021] [Indexed: 12/29/2022]
Abstract
Effective interpretation of historical selective regimes requires comprehensive in vivo performance evaluations and well-constrained ecomorphological proxies. The feeding apparatus is a frequent target of such evolutionary studies due to a direct relationship between feeding and survivorship, and the durability of craniodental elements in the fossil record. Among vertebrates, behaviors such as bite force have been central to evaluation of clade dynamics; yet, in the absence of detailed performance studies, such evaluations can misidentify potential selective factors and their roles. Here, we combine the results of a total-clade performance study with fossil-inclusive, phylogenetically informed methods to assess bite-force proxies throughout mesoeucrocodylian evolution. Although bite-force shifts were previously thought to respond to changing rostrodental selective regimes, we find body-size dependent conservation of performance proxies throughout the history of the clade, indicating stabilizing selection for bite-force potential. Such stasis reveals that mesoeucrocodylians with dietary ecologies as disparate as herbivory and hypercarnivory maintain similar bite-force-to-body-size relationships, a pattern which contrasts the precept that vertebrate bite forces should vary most strongly by diet. Furthermore, it may signal that bite-force conservation supported mesoeucrocodylian craniodental disparity by providing a stable performance foundation for the exploration of novel ecomorphospace.
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Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Jeroen B Smaers
- Department of Anthropology, Stony Brook University, Circle Road, Social & Behavioral Sciences Building, Stony Brook, New York, USA
| | - Haley D O'Brien
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
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19
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Rio JP, Mannion PD. Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem. PeerJ 2021; 9:e12094. [PMID: 34567843 PMCID: PMC8428266 DOI: 10.7717/peerj.12094] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 08/09/2021] [Indexed: 12/16/2022] Open
Abstract
First appearing in the latest Cretaceous, Crocodylia is a clade of semi-aquatic, predatory reptiles, defined by the last common ancestor of extant alligators, caimans, crocodiles, and gharials. Despite large strides in resolving crocodylian interrelationships over the last three decades, several outstanding problems persist in crocodylian systematics. Most notably, there has been persistent discordance between morphological and molecular datasets surrounding the affinities of the extant gharials, Gavialis gangeticus and Tomistoma schlegelii. Whereas molecular data consistently support a sister taxon relationship, in which they are more closely related to crocodylids than to alligatorids, morphological data indicate that Gavialis is the sister taxon to all other extant crocodylians. Here we present a new morphological dataset for Crocodylia based on a critical reappraisal of published crocodylian character data matrices and extensive firsthand observations of a global sample of crocodylians. This comprises the most taxonomically comprehensive crocodylian dataset to date (144 OTUs scored for 330 characters) and includes a new, illustrated character list with modifications to the construction and scoring of characters, and 46 novel characters. Under a maximum parsimony framework, our analyses robustly recover Gavialis as more closely related to Tomistoma than to other extant crocodylians for the first time based on morphology alone. This result is recovered regardless of the weighting strategy and treatment of quantitative characters. However, analyses using continuous characters and extended implied weighting (with high k-values) produced the most resolved, well-supported, and stratigraphically congruent topologies overall. Resolution of the gharial problem reveals that: (1) several gavialoids lack plesiomorphic features that formerly drew them towards the stem of Crocodylia; and (2) more widespread similarities occur between species traditionally divided into tomistomines and gavialoids, with these interpreted here as homology rather than homoplasy. There remains significant temporal incongruence regarding the inferred divergence timing of the extant gharials, indicating that several putative gavialids ('thoracosaurs') are incorrectly placed and require future re-appraisal. New alligatoroid interrelationships include: (1) support for a North American origin of Caimaninae in the latest Cretaceous; (2) the recovery of the early Paleogene South American taxon Eocaiman as a 'basal' alligatoroid; and (3) the paraphyly of the Cenozoic European taxon Diplocynodon. Among crocodyloids, notable results include modifications to the taxonomic content of Mekosuchinae, including biogeographic affinities of this clade with latest Cretaceous-early Paleogene Asian crocodyloids. In light of our new results, we provide a comprehensive review of the evolutionary and biogeographic history of Crocodylia, which included multiple instances of transoceanic and continental dispersal.
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Affiliation(s)
- Jonathan P. Rio
- Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, London, United Kingdom
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20
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Scavezzoni I, Fischer V. The postcranial skeleton of Cerrejonisuchus improcerus (Crocodyliformes: Dyrosauridae) and the unusual anatomy of dyrosaurids. PeerJ 2021; 9:e11222. [PMID: 34026348 PMCID: PMC8117932 DOI: 10.7717/peerj.11222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/15/2021] [Indexed: 01/11/2023] Open
Abstract
Dyrosauridae is a clade of neosuchian crocodyliforms that diversified in terrestrial and aquatic environments across the Cretaceous-Paleogene transition. The postcranial anatomy of dyrosaurids has long been overlooked, obscuring both their disparity and their locomotive adaptations. Here we thoroughly describe of the postcranial remains of an unusually small dyrosaurid, Cerrejonisuchus improcerus, from the middle-late Paleocene Cerrejón Formation of Colombia, and we provide a wealth of new data concerning the postcranial anatomy of the key dyrosaurids: Congosaurus bequaerti and Hyposaurus rogersii. We identify a series of postcranial autapomorphies in Cerrejonisuchus improcerus (an elliptic-shaped odontoid laterally wide, a ulna possessing a double concavity, a fibula bearing a widely flattened proximal end, a pubis showing a large non-triangular distal surface) as well as functionally-important traits such as a relatively long ulna (85% of the humerus’ length), short forelimb (83% of hindlimb’s length), or thoracic vertebra bearing comparatively large lateral process (with widened parapophysis and diapophysis) along with strongly arched thoracic ribs allowing a more sturdy and cylindrical rib cage. These indicate a more terrestrial lifestyle for Cerrejonisuchus compared to the derived members of the clade. We also built a dataset of 187 traits on 27 taxa, that extensively samples the cranial and postcranial architectures of exemplar crocodyliforms. We analyze these data in via Principal Coordinate Analysis (PCoA) to visualize the postcranial morphospace occupation of Dyrosauridae, Thalattosuchia, and Crocodylia. Our data reveal the existence of a distinctive postcranial anatomy for Dyrosauridae that is markedly distinct from that of crocodylians. As a result, modern crocodylians are probably not good functional analog for extinct crocodyliformes. Postcranial data should also be more widely used in phylogenetic and disparity analyses of Crocodyliformes.
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Affiliation(s)
- Isaure Scavezzoni
- Evolution and Diversity Dynamics Lab, University of Liège, Liège, Belgium
| | - Valentin Fischer
- Evolution and Diversity Dynamics Lab, University of Liège, Liège, Belgium
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21
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Dos Santos RL, de Sousa Correia JM, Paim APS, da Silva Selva de Oliveira LL, Diniz GTN, Dos Santos EM. Metallic elements in aquatic herpetofauna ( Crocodylia; Testudines) from a lentic Atlantic rainforest environment in northeastern Brazil. Environ Monit Assess 2021; 193:314. [PMID: 33914196 DOI: 10.1007/s10661-021-09076-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
In the present study, Fe, Cu, Cr, Cd, Pb, Ni, and Al concentrations in Caiman latirostris and Testudines blood from the Tapacurá reservoir, Pernambuco, Brazil, were investigated. Blood was acid digested with HNO3, and metals were determined by ICP-OES and FAAS. Lead showed concentrations below the established limit of detection. Eighty animals were evaluated, forty from each group. The levels of all elements were statistically significant when compared between the two studied taxa (p < 0.05). In caimans, significant differences between young and adults were observed for chromium (p = 0.0539) and aluminum (p = 0.0515). Testudines showed no statistically significant differences for the variable age structure. Gender did not influence metal concentrations detected in the present study for either group. Differences between species of testudines were significant for Fe between Mesoclemmys tuberculata vs Phrynops geoffroanus (p = 0.0932) and Kinosternon scorpioides vs Phrynops geoffroanus (p = 0.063). The inter-elementary correlations showed statistically significant differences between the elements Cr vs Al (R2 = 0.52), Cr vs Cd (0.43), Cd vs Cu (R2 = 0.41), Ni vs Cu (R2 = 0.31), Ni vs Cr (R2 = 0.30), Al vs Cd (R2 = 0.27), and Cd vs Fe (R2 = 0.26). It is concluded that blood is an excellent predictor of metals in crocodilians and testudines in the Tapacurá reservoir, with statistically significant differences when correlated to concentrations such as size and species studied. In addition, it evidenced data that prove the exposure of these animals to metals, with strong inter-elementary correlations and opening doors for future studies that seek to understand possible biological effects caused in the studied taxa.
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Affiliation(s)
- Rayssa Lima Dos Santos
- Programa de Pós-gradução em Biodiversidade e Conservação, Universidade Federal Rural de Pernambuco, Av. Gregório Ferraz Nogueira, Serra Talhada, PE, Brasil.
| | | | - Ana Paula Silveira Paim
- Departamento de Química Fundamental, Universidade Federal Pernambuco, Av. Prof. Moraes Rego, Recife, PE, Brasil
| | | | - George Tadeu Nunes Diniz
- Centro de Pesquisa Aggeu Magalhães/FIOCRUZ, Fundação Oswaldo Cruz, Av. Prof. Moraes Rego, Recife, PE, Brasil
| | - Ednilza Maranhão Dos Santos
- Departamento de Biologia, Universidade Federal Rural de Pernambuco, Rua Manoel de Medeiros, Recife, PE, Brasil
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22
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Duszynski DW. Biodiversity of the Coccidia (Apicomplexa: Conoidasida) in vertebrates: what we know, what we do not know, and what needs to be done. Folia Parasitol (Praha) 2021; 68. [PMID: 33527909 DOI: 10.14411/fp.2021.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022]
Abstract
Over the last two decades my colleagues and I have assembled the literature on a good percentage of most of the coccidians (Conoidasida) known, to date, to parasitise: Amphibia, four major lineages of Reptilia (Amphisbaenia, Chelonia, Crocodylia, Serpentes), and seven major orders in the Mammalia (Carnivora, Chiroptera, Lagomorpha, Insectivora, Marsupialia, Primates, Scandentia). These vertebrates, combined, comprise about 15,225 species; only about 899 (5.8%) of them have been surveyed for coccidia and 1,946 apicomplexan valid species names or other forms are recorded in the literature. Based on these compilations and other factors, I extrapolated that there yet may be an additional 31,381 new apicomplexans still to be discovered in just these 12 vertebrate groups. Extending the concept to all of the other extant vertebrates on Earth; i.e. lizards (6,300 spp.), rodents plus 12 minor orders of mammals (3,180 spp.), birds (10,000 spp.), and fishes (33,000 spp.) and, conservatively assuming only two unique apicomplexan species per each vertebrate host species, I extrapolate and extend my prediction that we may eventually find 135,000 new apicomplexans that still need discovery and to be described in and from those vertebrates that have not yet been examined for them! Even doubling that number is a significant underestimation in my opinion.
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23
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Ristevski J, Yates AM, Price GJ, Molnar RE, Weisbecker V, Salisbury SW. Australia's prehistoric 'swamp king': revision of the Plio-Pleistocene crocodylian genus Pallimnarchus de Vis, 1886. PeerJ 2020; 8:e10466. [PMID: 33391869 PMCID: PMC7759136 DOI: 10.7717/peerj.10466] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
The crocodylian fossil record from the Cenozoic of Australasia is notable for its rich taxonomic diversity, and is primarily represented by members of the clade Mekosuchinae. Reports of crocodylian fossils from Australia date back to the late nineteenth century. In 1886, Charles Walter de Vis proposed the name Pallimnarchus pollens for crocodylian fossils from southeast Queensland-the first binomen given to an extinct crocodylian taxon from Australia. Pallimnarchus has come to be regarded as a large, broad-snouted crocodylian from Australia's Plio-Pleistocene, and numerous specimens, few of which are sufficiently complete, have been assigned to it by several authors throughout the twentieth century. In the late 1990s, the genus was expanded to include a second species, Pallimnarchus gracilis. Unfortunately, the original syntype series described as Pallimnarchus pollens is very fragmentary and derives from more than one taxon, while a large part of the subsequently selected lectotype specimen is missing. Because descriptions and illustrations of the complete lectotype do not reveal any autapomorphic features, we propose that Pallimnarchus pollens should be regarded as a nomen dubium. Following this decision, the fossil material previously referred to Pallimnarchus is of uncertain taxonomic placement. A partial skull, formerly assigned to Pallimnarchus pollens and known as 'Geoff Vincent's specimen', possesses many features of diagnostic value and is therefore used as basis to erect a new genus and species-Paludirex vincenti gen. et sp. nov. A comprehensive description is given for the osteology of 'Geoff Vincent's specimen' as well as aspects of its palaeoneurology, the latter being a first for an extinct Australian crocodyliform. The newly named genus is characterized by a unique combination of premaxillary features such as a distinctive arching of the anterior alveolar processes of the premaxillae, a peculiar arrangement of the first two premaxillary alveoli and a large size disparity between the 3rd and 4th premaxillary alveoli. These features presently allow formal recognition of two species within the genus, Paludirex vincenti and Paludirex gracilis comb. nov., with the former having comparatively more robust rostral proportions than the latter. The Paludirex vincenti holotype comes from the Pliocene Chinchilla Sand of the Darling Downs, south-eastern Queensland, whereas the material assigned to Paludirex gracilis is from the Pleistocene of Terrace Site Local Fauna, Riversleigh, northwest Queensland. Phylogenetic analyses recover Paludirex vincenti as a mekosuchine, although further cladistic assessments are needed to better understand the relationships within the clade.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
| | - Adam M. Yates
- Museum of Central Australia, Museum and Art Gallery of the Northern Territory, Alice Springs, NT, Australia
| | - Gilbert J. Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Ralph E. Molnar
- University of California Museum of Paleontology, Berkeley, CA, USA
| | - Vera Weisbecker
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
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24
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Schachner ER, Hedrick BP, Richbourg HA, Hutchinson JR, Farmer CG. Anatomy, ontogeny, and evolution of the archosaurian respiratory system: A case study on Alligator mississippiensis and Struthio camelus. J Anat 2020; 238:845-873. [PMID: 33345301 DOI: 10.1111/joa.13358] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/13/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
The avian lung is highly specialized and is both functionally and morphologically distinct from that of their closest extant relatives, the crocodilians. It is highly partitioned, with a unidirectionally ventilated and immobilized gas-exchanging lung, and functionally decoupled, compliant, poorly vascularized ventilatory air-sacs. To understand the evolutionary history of the archosaurian respiratory system, it is essential to determine which anatomical characteristics are shared between birds and crocodilians and the role these shared traits play in their respective respiratory biology. To begin to address this larger question, we examined the anatomy of the lung and bronchial tree of 10 American alligators (Alligator mississippiensis) and 11 ostriches (Struthio camelus) across an ontogenetic series using traditional and micro-computed tomography (µCT), three-dimensional (3D) digital models, and morphometry. Intraspecific variation and left to right asymmetry were present in certain aspects of the bronchial tree of both taxa but was particularly evident in the cardiac (medial) region of the lungs of alligators and the caudal aspect of the bronchial tree in both species. The cross-sectional area of the primary bronchus at the level of the major secondary airways and cross-sectional area of ostia scaled either isometrically or negatively allometrically in alligators and isometrically or positively allometrically in ostriches with respect to body mass. Of 15 lung metrics, five were significantly different between the alligator and ostrich, suggesting that these aspects of the lung are more interspecifically plastic in archosaurs. One metric, the distances between the carina and each of the major secondary airways, had minimal intraspecific or ontogenetic variation in both alligators and ostriches, and thus may be a conserved trait in both taxa. In contrast to previous descriptions, the 3D digital models and CT scan data demonstrate that the pulmonary diverticula pneumatize the axial skeleton of the ostrich directly from the gas-exchanging pulmonary tissues instead of the air sacs. Global and specific comparisons between the bronchial topography of the alligator and ostrich reveal multiple possible homologies, suggesting that certain structural aspects of the bronchial tree are likely conserved across Archosauria, and may have been present in the ancestral archosaurian lung.
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Affiliation(s)
- Emma R Schachner
- Department of Cell Biology & Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Brandon P Hedrick
- Department of Cell Biology & Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Heather A Richbourg
- Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, CA, USA
| | - John R Hutchinson
- Department of Comparative Biomedical Sciences, Structure & Motion Laboratory, Royal Veterinary College, University of London, Hatfield, UK
| | - C G Farmer
- Department of Biology, University of Utah, Salt Lake City, UT, USA
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25
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Souza RBBD, Bonfim VMG, Rios VP, Klein W. Allometric relations of respiratory variables in Amniota: Effects of phylogeny, form, and function. Comp Biochem Physiol A Mol Integr Physiol 2020; 252:110845. [PMID: 33197562 DOI: 10.1016/j.cbpa.2020.110845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 10/23/2022]
Abstract
Biological variables are frequently described by analyzing scaling relationships of the variable against body mass (MB). Respiratory variables are no exception and allometric relations for oxygen consumption, pulmonary ventilation, tidal volume, breathing frequency, and lung volume have been described in the literature. While the allometric relations of respiratory variables given for mammals and birds are very consistent among different studies, scaling relationships for non-avian reptiles have only been scarcely described and show considerable variation between studies. Since no comprehensive study of allometric relations of respiratory variables has been carried out comparing the different groups of non-avian reptiles, we analyzed morphological and physiological variables of the respiratory system of crocodilians, chelonians, lizards, snakes, birds, and mammals, regarding the allometric relations of each variable from a phylogenetic perspective as well as related to lung morphology. Our results indicated that few respiratory variables possess significant phylogenetic signals and that tidal volume, breathing frequency (except mammals), and air convection requirement were independent of phylogeny. Contrary to the literature, lung volume of amniotes scaled isometrically to MB, with the exception of lizards (MB0.78). Air convection requirement scaled isometrically in mammals and birds, but was more variable among non-avian reptiles, from a taxonomic perspective and in regard to different lung structures. In conclusion, respiratory variables among non-avian reptiles scaled more variably than previously expected, both according to phylogeny and to lung type, warranting future studies to explore structure-function relations of the reptilian respiratory system, especially regarding snakes and crocodilians, since these groups had very few data available for analysis.
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Affiliation(s)
- Ray Brasil Bueno de Souza
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Vanessa Maria Gomes Bonfim
- Programa de Pós-graduação em Biologia Comparada, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil
| | - Vitor Passos Rios
- Programa de Pós-graduação em Biologia Comparada, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil; Universidade do Estado de Minas Gerais, Passos 37900-106, Minas Gerais, Brazil
| | - Wilfried Klein
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, São Paulo, Brazil.
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26
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Russell AP, Bauer AM. Vocalization by extant nonavian reptiles: A synthetic overview of phonation and the vocal apparatus. Anat Rec (Hoboken) 2020; 304:1478-1528. [PMID: 33099849 DOI: 10.1002/ar.24553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/13/2020] [Accepted: 09/16/2020] [Indexed: 12/19/2022]
Abstract
Among amniote vertebrates, nonavian reptiles (chelonians, crocodilians, and lepidosaurs) are regarded as using vocal signals rarely (compared to birds and mammals). In all three reptilian clades, however, certain taxa emit distress calls and advertisement calls using modifications of regions of the upper respiratory tract. There is no central tendency in either acoustic mechanisms or the structure of the vocal apparatus, and many taxa that vocalize emit only relatively simple sounds. Available evidence indicates multiple origins of true vocal abilities within these lineages. Reptiles thus provide opportunities for studying the early evolutionary stages of vocalization. The early literature on the diversity of form of the laryngotracheal apparatus of reptiles boded well for the study of form-function relationships, but this potential was not extensively explored. Emphasis shifted away from anatomy, however, and centered instead on acoustic analysis of the sounds that are produced. New investigative techniques have provided novel ways of studying the form-function aspects of the structures involved in phonation and have brought anatomical investigation to the forefront again. In this review we summarize what is known about hearing in reptiles in order to contextualize the vocal signals they generate and the sound-producing mechanisms responsible for them. The diversity of form of the sound producing apparatus and the increasing evidence that reptiles are more dependent upon vocalization as a communication medium than previously thought indicates that they have a significant role to play in the understanding of the evolution of vocalization in amniotes.
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Affiliation(s)
- Anthony P Russell
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Aaron M Bauer
- Department of Biology and Center for Biodiversity and Ecosystem Stewardship, Villanova University, Villanova, Pennsylvania, USA
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Szabo B, Noble DWA, Whiting MJ. Learning in non-avian reptiles 40 years on: advances and promising new directions. Biol Rev Camb Philos Soc 2020; 96:331-356. [PMID: 33073470 DOI: 10.1111/brv.12658] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 01/06/2023]
Abstract
Recently, there has been a surge in cognition research using non-avian reptile systems. As a diverse group of animals, non-avian reptiles [turtles, the tuatara, crocodylians, and squamates (lizards, snakes and amphisbaenids)] are good model systems for answering questions related to cognitive ecology, from the role of the environment on the brain, behaviour and learning, to how social and life-history factors correlate with learning ability. Furthermore, given their variable social structure and degree of sociality, studies on reptiles have shown that group living is not a pre-condition for social learning. Past research has demonstrated that non-avian reptiles are capable of more than just instinctive reactions and basic cognition. Despite their ability to provide answers to fundamental questions in cognitive ecology, and a growing literature, there have been no recent systematic syntheses of research in this group. Here, we systematically, and comprehensively review studies on reptile learning. We identify 92 new studies investigating learning in reptiles not included in previous reviews on this topic - affording a unique opportunity to provide a more in-depth synthesis of existing work, its taxonomic distribution, the types of cognitive domains tested and methodologies that have been used. Our review therefore provides a major update on our current state of knowledge and ties the collective evidence together under nine umbrella research areas: (i) habituation of behaviour, (ii) animal training through conditioning, (iii) avoiding aversive stimuli, (iv) spatial learning and memory, (v) learning during foraging, (vi) quality and quantity discrimination, (vii) responding to change, (viii) solving novel problems, and (ix) social learning. Importantly, we identify knowledge gaps and propose themes which offer important future research opportunities including how cognitive ability might influence fitness and survival, testing cognition in ecologically relevant situations, comparing cognition in invasive and non-invasive populations of species, and social learning. To move the field forward, it will be immensely important to build upon the descriptive approach of testing whether a species can learn a task with experimental studies elucidating causal reasons for cognitive variation within and among species. With the appropriate methodology, this young but rapidly growing field of research should advance greatly in the coming years providing significant opportunities for addressing general questions in cognitive ecology and beyond.
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Affiliation(s)
- Birgit Szabo
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.,Division of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Wohlenstrasse 50a, Bern, 3032, Switzerland
| | - Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Martin J Whiting
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
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28
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Drumheller SK, Nestler JH, Hackett Farris CE, Farris SC, Mazzotti FJ. Crocodylus acutus (American crocodile) bite marks on a nest data logger. PeerJ 2020; 8:e8577. [PMID: 32110490 PMCID: PMC7032054 DOI: 10.7717/peerj.8577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/16/2020] [Indexed: 11/30/2022] Open
Abstract
Several data loggers deployed to monitor temperature and humidity of Crocodylus acutus (American crocodile) nests in South Florida could not be located after hatching. One badly damaged data logger was retrieved, providing insight into the possible fate of the others. Using a taphonomic approach, we identified numerous indentations, consistent with crocodylian bite marks, and inconsistent with potential mammalian or squamate bites. It seems most likely that the data logger was damaged by the nesting C. acutus rather than during attempted nest predation. Estimated bite forces for reproductive age, female C. acutus exceed the predicted material properties of the data logger’s housing, suggesting that the bites were exploratory in nature. We suggest that data loggers be removed prior to hatching or permit remote data storage.
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Affiliation(s)
- Stephanie K Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, United States of America
| | - Jennifer H Nestler
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States of America
| | - Caitlin E Hackett Farris
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States of America
| | - Seth C Farris
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States of America
| | - Frank J Mazzotti
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States of America
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29
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Duszynski DW, McAllister CT, Tellez M. The Coccidia (Apicomplexa) of the Archosauria ( Crocodylia: Eusuchia) of the World. J Parasitol 2020; 106:90-122. [PMID: 31999218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023] Open
Abstract
The order Crocodylia (suborder Eusuchia) includes 27 species of alligators, caimans, crocodiles, and gharials that are cosmopolitan in distribution, inhabiting subtropical and tropical locations. Numerous surveys (many of them trivial, with small sample sizes) have reported a wide variety of blood and intestinal apicomplexans from 17/27 (63%) crocodilian hosts, but neither a summation for the group nor a revisionary systematic approach to species evaluation has ever been provided. Herein, we summarize information on the 16 species of apicomplexans that we consider to be valid, including 8 Eimeria, 1 Haemogregarina (that eventually may be transferred to Hepatozoon), 4 Hepatozoon, 2 Isospora, and 1 Progarnia species. In addition, there are 46 apicomplexan forms that we have relegated to species inquirendae and/or only partially identified forms that await further study. We hope this review provides a foundation for future research between parasitologists and herpetologists on parasitism of all reptiles and their relatives. Since many apicomplexans seem to be reasonably host-specific, knowledge of shared species and/or genera may assist herpetologists to better understand the phylogenetic relationships among the New World crocodilians and the direction of their dispersal in the New World.
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Affiliation(s)
- Donald W Duszynski
- Professor Emeritus of Biology, 76 Homesteads Road, Placitas, New Mexico 87043
| | - Chris T McAllister
- Science and Mathematics Division, Eastern Oklahoma State College, Idabel, Oklahoma 74745
| | - Marisa Tellez
- Crocodile Research Coalition, Belize and Marine Science Institute, University of California-Santa Barbara, Santa Barbara, California 93106
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30
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Abstract
A complex pelvic morphology has been discovered in the fossils of one of the largest crocodylians.
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31
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Scheyer TM, Hutchinson JR, Strauss O, Delfino M, Carrillo-Briceño JD, Sánchez R, Sánchez-Villagra MR. Giant extinct caiman breaks constraint on the axial skeleton of extant crocodylians. eLife 2019; 8:e49972. [PMID: 31843051 PMCID: PMC6917493 DOI: 10.7554/elife.49972] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
The number of precaudal vertebrae in all extant crocodylians is remarkably conservative, with nine cervicals, 15 dorsals and two sacrals, a pattern present also in their closest extinct relatives. The consistent vertebral count indicates a tight control of axial patterning by Hox genes during development. Here we report on a deviation from this pattern based on an associated skeleton of the giant caimanine Purussaurus, a member of crown Crocodylia, and several other specimens from the Neogene of the northern neotropics. P. mirandai is the first crown-crocodylian to have three sacrals, two true sacral vertebrae and one non-pathological and functional dorsosacral, to articulate with the ilium (pelvis). The giant body size of this caiman relates to locomotory and postural changes. The iliosacral configuration, a more vertically oriented pectoral girdle, and low torsion of the femoral head relative to the condyles are hypothesized specializations for more upright limb orientation or weight support.
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Affiliation(s)
- Torsten M Scheyer
- University of Zurich, Palaeontological Institute and MuseumZurichSwitzerland
| | - John R Hutchinson
- Structure & Motion LaboratoryDepartment of Comparative Biomedical Sciences, The Royal Veterinary CollegeHatfieldUnited Kingdom
| | - Olivier Strauss
- University of Zurich, Palaeontological Institute and MuseumZurichSwitzerland
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di TorinoTorinoItaly
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de BarcelonaBarcelonaSpain
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Massonne T, Vasilyan D, Rabi M, Böhme M. A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis. PeerJ 2019; 7:e7562. [PMID: 31720094 PMCID: PMC6839522 DOI: 10.7717/peerj.7562] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/27/2019] [Indexed: 11/20/2022] Open
Abstract
During systematic paleontological surveys in the Na Duong Basin in North Vietnam between 2009 and 2012, well-preserved fossilized cranial and postcranial remains belonging to at least 29 individuals of a middle to late Eocene (late Bartonian to Priabonian age (39–35 Ma)) alligatoroid were collected. Comparative anatomical study of the material warrants the diagnosis of a new taxon, Orientalosuchus naduongensis gen. et sp. nov. The combined presence of an enlarged fifth maxillary tooth, prominent preorbital ridges, a large supraoccipital exposure on the skull table, a palatine-pterygoid suture anterior to the posterior end of the suborbital fenestra, and a pterygoid forming a neck surrounding the choana is unique to this species. Unlike previous phylogenies, our parsimony analysis recovers a monophyletic Late Cretaceous to Paleogene East to Southeastern Asian alligatoroid group, here named Orientalosuchina. The group includes Orientalosuchus naduongensis, Krabisuchus siamogallicus, Eoalligator chunyii, Jiangxisuchus nankangensis and Protoalligator huiningensis, all of them sharing a medial shifted quadrate foramen aerum. The recognition of this clade indicates at least two separate dispersal events from North America to Asia: one during the Late Cretaceous by Orientalosuchina and one by the ancestor of Alligator sinensis during the Paleogene or Neogene, the timing of which is poorly constrained.
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Affiliation(s)
- Tobias Massonne
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Senckenberg Center for Human Evolution and Palaeoecology, Tuebingen, Germany
| | - Davit Vasilyan
- JURASSICA Museum, Porrentruy, Switzerland.,Department of Geosciences, University of Fribourg, Fribourg, Switzerland
| | - Márton Rabi
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Central Natural Science Collections, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Madelaine Böhme
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Senckenberg Center for Human Evolution and Palaeoecology, Tuebingen, Germany
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Valverde A, Madrigal-Valverde M, Castro-Morales O, Gadea-Rivas A, Johnston S, Soler C. Kinematic and head morphometric characterisation of spermatozoa from the Brown Caiman (Caiman crocodilus fuscus). Anim Reprod Sci 2019; 207:9-20. [PMID: 31266600 DOI: 10.1016/j.anireprosci.2019.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/23/2019] [Accepted: 06/11/2019] [Indexed: 01/18/2023]
Abstract
The development of analytical methods for the evaluation of crocodilian semen is an important component for the assessment of male breeding soundness and the development of assisted breeding technology in this taxon. Computer-Assisted Semen Analysis (CASA) technology is becoming an increasingly common technique in seminal evaluations for animals but there has been no application of this technique for reptilian spermatozoa. The aim of this study was to analyse sperm kinematic and morphometric variables in Caiman crocodilus fuscus semen samples and to determine whether there were sperm subpopulations. Four ejaculates from four sexually mature captive caimans were used for this study. A CASA-Mot and CASA-Morph system was used with an image acquisition rate of 50 Hz for 2 s of capture. The ISAS®D4C20 counting chambers were used and spermatozoa incubated at 25 °C. Total and progressive motilities did not differ among animals (P > 0.05). There was a significant animal effect in the model with respect to sperm morphometry, and kinematic indices including linearity (LIN) and straightness (STR) (P < 0.05). Results for principal component (PC) analysis indicated variables were grouped into four components: PC1 related to velocity, PC2 to progressivity, PC3 to oscillation and PC4 to sperm path cross-linking. Subpopulation (SP) structure analysis indicated there were four groups, namely, rapid non-progressive (SP1), slow non-progressive (SP2), rapid progressive (SP3) and medium progressive (SP4), representing 14.5%, 45.4%, 18.7%, and 21.4% respectively. Findings in the present study indicate the importance of continuing development of reliable protocols regarding the standardisation of computer-based semen analyses in reptilian species.
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Affiliation(s)
- Anthony Valverde
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica; University of Valencia, Department of Cellular Biology, Functional Biology and Physical Anthropology, Campus Burjassot, C/ Dr Moliner, 50, 46100, Burjassot, Spain.
| | - Mónica Madrigal-Valverde
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica; Federal University of Bahia, School of Veterinary Medicine and Animal Science, 40170-110, Salvador, Bahia, Brazil
| | - Olivier Castro-Morales
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica
| | - Arnoldo Gadea-Rivas
- Costa Rica Institute of Technology, School of Agronomy, San Carlos Campus, 223-21001, Alajuela, Costa Rica
| | - Stephen Johnston
- School of Agriculture and Food Science, The University of Queensland, Gatton, Qld, 4343, Australia
| | - Carles Soler
- University of Valencia, Department of Cellular Biology, Functional Biology and Physical Anthropology, Campus Burjassot, C/ Dr Moliner, 50, 46100, Burjassot, Spain; Proiser R+D, Scientific Park, University of Valencia, C/ Catedràtic Agustín Escardino, 9, Building 3 (CUE), Floor 1, 46980, Paterna, Valencia, Spain
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Morris ZS, Vliet KA, Abzhanov A, Pierce SE. Heterochronic shifts and conserved embryonic shape underlie crocodylian craniofacial disparity and convergence. Proc Biol Sci 2019; 286:20182389. [PMID: 30963831 PMCID: PMC6408887 DOI: 10.1098/rspb.2018.2389] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/25/2019] [Indexed: 12/29/2022] Open
Abstract
The distinctive anatomy of the crocodylian skull is intimately linked with dietary ecology, resulting in repeated convergence on blunt- and slender-snouted ecomorphs. These evolutionary shifts depend upon modifications of the developmental processes which direct growth and morphogenesis. Here we examine the evolution of cranial ontogenetic trajectories to shed light on the mechanisms underlying convergent snout evolution. We use geometric morphometrics to quantify skeletogenesis in an evolutionary context and reconstruct ancestral patterns of ontogenetic allometry to understand the developmental drivers of craniofacial diversity within Crocodylia. Our analyses uncovered a conserved embryonic region of morphospace (CER) shared by all non-gavialid crocodylians regardless of their eventual adult ecomorph. This observation suggests the presence of conserved developmental processes during early development (before Ferguson stage 20) across most of Crocodylia. Ancestral state reconstruction of ontogenetic trajectories revealed heterochrony, developmental constraint, and developmental systems drift have all played essential roles in the evolution of ecomorphs. Based on these observations, we conclude that two separate, but interconnected, developmental programmes controlling craniofacial morphogenesis and growth enabled the evolutionary plasticity of skull shape in crocodylians.
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Affiliation(s)
- Zachary S. Morris
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Kent A. Vliet
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, FL 32611, USA
| | - Arhat Abzhanov
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
- Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Stephanie E. Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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Clarac F, Quilhac A. The crocodylian skull and osteoderms: A functional exaptation to ectothermy? ZOOLOGY 2019; 132:31-40. [PMID: 30736927 DOI: 10.1016/j.zool.2018.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 12/08/2018] [Accepted: 12/11/2018] [Indexed: 10/27/2022]
Abstract
The crocodylians are ectothermic semi-aquatic vertebrates which are assessed to have evolved from endothermic terrestrial forms during the Mesozoic. Such a physiological transition should have involved modifications in their cardio-vascular system allowing to increase the heat transfers with the surrounding environment by growing a peripheral vascularization which would be mainly located in the dermal skeleton: the dermatocranium and the osteoderms. In order to assess the implication of these anatomical regions in thermal exchanges, we have recorded the temperature above a set of representative skin areas in order to draw comparisons between the skull, the osteoderms, and the rest of the body parts which present either none or residual dermal ossification. We computed the data after the specimens were successively laid in different stereotyped environmental conditions which involved significant variations in the environmental temperature. Our results show that the osteoderms collect the external heat during the basking periods as they become significantly warmer than the surrounding skin; they further release the heat into the core of the organism as they turn out to be colder than the surrounding skin after a significant cooling period. In disregard of the environmental temperature variations, the skull table (which encloses the braincase) remains warmer than the rest of the cranial regions and shows less temperature variations than the osteoderms; a result which has lead us to think that the braincase temperature is monitored and controlled by a thermoregulatory system. Therefore, as hypothesized by previous authors regarding the ectothermic diapsids, we assume that the crocodylian skull possesses shunting blood pathways which tend to maintain both the braincase and the main sensory organs at the nearest to the optimal physiological temperature depending on the external temperature variations. Concerning the skin vascularization, the study of an albino Alligator mississippiensis specimen permitted to observe the repartition of the superficial blood vessels by transparency through the skin. We thus testify that the skin which covers either the skull or the osteoderms is more vascularized than the skin which does not present any subjacent dermal ossification. We consequently deduce that the significant contrast in the thermal behavior between the dermal skeleton and the rest of the body is indeed correlated with a difference in the relative degree of skin vascularization. This last assessment confirms that the development of the dermal skeleton should have played a functional role in the crocodylian transition from endothermy to ectothermy through the set-up of a peripheral vessel network.
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Brocklehurst RJ, Moritz S, Codd J, Sellers WI, Brainerd EL. Rib kinematics during lung ventilation in the American alligator ( Alligator mississippiensis): an XROMM analysis. ACTA ACUST UNITED AC 2018; 220:3181-3190. [PMID: 28855323 PMCID: PMC5612015 DOI: 10.1242/jeb.156166] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/15/2017] [Indexed: 11/20/2022]
Abstract
The current hypothesis regarding the mechanics of breathing in crocodylians is that the double-headed ribs, with both a capitulum and tuberculum, rotate about a constrained axis passing through the two articulations; moreover, this axis shifts in the caudal thoracic ribs, as the vertebral parapophysis moves from the centrum to the transverse process. Additionally, the ventral ribcage in crocodylians is thought to possess additional degrees of freedom through mobile intermediate ribs. In this study, X-ray reconstruction of moving morphology (XROMM) was used to quantify rib rotation during breathing in American alligators. Whilst costovertebral joint anatomy predicted overall patterns of motion across the ribcage (decreased bucket handle motion and increased calliper motion), there were significant deviations: anatomical axes overestimated pump handle motion and, generally, ribs in vivo rotate about all three body axes more equally than predicted. The intermediate ribs are mobile, with a high degree of rotation measured about the dorsal intracostal joints, especially in the more caudal ribs. Motion of the sternal ribs became increasingly complex caudally, owing to a combination of the movements of the vertebral and intermediate segments. As the crocodylian ribcage is sometimes used as a model for the ancestral archosaur, these results have important implications for how rib motion is reconstructed in fossil taxa, and illustrate the difficulties in reconstructing rib movement based on osteology alone. Summary: Using XROMM to test how well joint anatomy predicts rib motion during breathing in crocodylians, our best living model for the earliest archosaurs.
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Affiliation(s)
- Robert J Brocklehurst
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Sabine Moritz
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Jonathan Codd
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - William I Sellers
- School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Elizabeth L Brainerd
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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Otero A, Allen V, Pol D, Hutchinson JR. Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha). PeerJ 2017; 5:e3976. [PMID: 29188140 PMCID: PMC5703147 DOI: 10.7717/peerj.3976] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 10/10/2017] [Indexed: 01/04/2023] Open
Abstract
Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages, including sauropodomorph dinosaurs. We present biomechanical computer models of two locomotor extremes within Archosauria in an analysis of joint ranges of motion and the moment arms of the major forelimb muscles in order to quantify biomechanical differences between more sprawling, pseudosuchian (represented the crocodile Crocodylus johnstoni) and more erect, dinosaurian (represented by the sauropodomorph Mussaurus patagonicus) modes of forelimb function. We compare these two locomotor extremes in terms of the reconstructed musculoskeletal anatomy, ranges of motion of the forelimb joints and the moment arm patterns of muscles across those ranges of joint motion. We reconstructed the three-dimensional paths of 30 muscles acting around the shoulder, elbow and wrist joints. We explicitly evaluate how forelimb joint mobility and muscle actions may have changed with postural and anatomical alterations from basal archosaurs to early sauropodomorphs. We thus evaluate in which ways forelimb posture was correlated with muscle leverage, and how such differences fit into a broader evolutionary context (i.e. transition from sprawling quadrupedalism to erect bipedalism and then shifting to graviportal quadrupedalism). Our analysis reveals major differences of muscle actions between the more sprawling and erect models at the shoulder joint. These differences are related not only to the articular surfaces but also to the orientation of the scapula, in which extension/flexion movements in Crocodylus (e.g. protraction of the humerus) correspond to elevation/depression in Mussaurus. Muscle action is highly influenced by limb posture, more so than morphology. Habitual quadrupedalism in Mussaurus is not supported by our analysis of joint range of motion, which indicates that glenohumeral protraction was severely restricted. Additionally, some active pronation of the manus may have been possible in Mussaurus, allowing semi-pronation by a rearranging of the whole antebrachium (not the radius against the ulna, as previously thought) via long-axis rotation at the elbow joint. However, the muscles acting around this joint to actively pronate it may have been too weak to drive or maintain such orientations as opposed to a neutral position in between pronation and supination. Regardless, the origin of quadrupedalism in Sauropoda is not only linked to manus pronation but also to multiple shifts of forelimb morphology, allowing greater flexion movements of the glenohumeral joint and a more columnar forelimb posture.
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Affiliation(s)
- Alejandro Otero
- División Paleontología de Vertebrados, Museo de la Plata, La Plata, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Vivian Allen
- Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, London, UK
| | - Diego Pol
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Museo Egidio Feruglio, Trelew, Chubut, Argentina
| | - John R Hutchinson
- Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, London, UK
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Abstract
Vertebrate color vision has evolved partly through the modification of five ancestral visual opsin proteins via gene duplication, loss, and shifts in spectral sensitivity. While many vertebrates, particularly mammals, birds, and fishes, have had their visual opsin repertoires studied in great detail, testudines (turtles) and crocodylians have largely been neglected. Here I examine the genomic basis for color vision in four species of turtles and four species of crocodylians, and demonstrate that while turtles appear to vary in their number of visual opsins, crocodylians experienced a reduction in their color discrimination capacity after their divergence from Aves. Based on the opsin sequences present in their genomes and previous measurements of crocodylian cones, I provide evidence that crocodylians have co-opted the rod opsin (RH1) for cone function. This suggests that some crocodylians might have reinvented trichromatic color vision in a novel way, analogous to several primate lineages. The loss of visual opsins in crocodylians paralleled the loss of various anatomical features associated with photoreception, attributed to a "nocturnal bottleneck" similar to that hypothesized for Mesozoic mammals. I further queried crocodylian genomes for nonvisual opsins and genes associated with protection from ultraviolet light, and found evidence for gene inactivation or loss for several of these genes. Two genes, encoding parietopsin and parapinopsin, were additionally inactivated in birds and turtles, likely co-occurring with the loss of the parietal eye in these lineages.
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Abstract
New records of the Oligo–Miocene mekosuchine crocodylian, Baru, from Queensland and the Northern Territory are described. Baru wickeni and Baru darrowi are accepted as valid species in the genus and their diagnoses are revised. Both species are present in Queensland and the Northern Territory but are restricted in time, with B. wickeni known from the late Oligocene and B. darrowi from the middle Miocene. The broad geographic distributions and restricted time spans of these species indicate that this genus is useful for biochronology. The record of B. wickeni from the Pwerte Marnte Marnte Local Fauna in the Northern Territory establishes that the species inhabited the north-western margin of the Lake Eyre Basin (LEB) drainage system. More southerly Oligo–Miocene sites in the LEB contain only one crocodylian species, Australosuchus clarkae. The Pwerte Marnte Marnte occurrence of B. wickeni indicates that the separation of Baru and Australosuchus did not correspond with the boundaries of drainage basins and that palaeolatitude was a more likely segregating factor.
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Affiliation(s)
- Adam M Yates
- Museum of Central Australia, Museum and Art Gallery of the Northern Territory, Alice Springs, NT, Australia
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40
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Drumheller SK, Wilberg EW, Sadleir RW. The utility of captive animals in actualistic research: A geometric morphometric exploration of the tooth row of Alligator mississippiensis suggesting ecophenotypic influences and functional constraints. J Morphol 2016; 277:866-78. [PMID: 27098092 DOI: 10.1002/jmor.20540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/10/2016] [Accepted: 03/19/2016] [Indexed: 11/07/2022]
Abstract
Captive broad snouted crocodylians are generally thought to have wider, shorter rostra than their wild counterparts. Interpreted to reflect morphological change in response to the conditions of captivity, this qualitative pattern could affect the utility of these animals in a variety of fields of research. However, due to relative ease of access and availability of life history data, captive animals are often utilized in actualistic research. Thus, this issue should be addressed in more detail. Here we explore snout shape variation between captive and wild members of Alligator mississippiensis using two-dimensional (2D) morphometric techniques. Several landmark schemesare used to assess the utility of different aspects of morphology in distinguishing the groups. While statistical analyses consistently differentiated between the groups, the area of morphospace occupied by wild members of A. mississippiensis generally overlapped with the larger area encompassing the captive specimens. This indicates that the captive condition is not as uniform as previously thought and instead encompasses a large spectrum of morphologies, ranging from the stereotypical broad, shortened snouts to outlines that are indistinguishable from the wild morphotype. These results align well with the interpretation that this change reflects an extreme example of ecophenotypy, since ranched, farmed, or zoo organisms are held in an array of enclosures, ranging from indoor, climate controlled pens to outdoor, more natural areas. This variation in environments should be reflected in different reactions to the animals' surroundings, resulting in a broad spectrum of morphotypes. While wild specimens are still preferred, especially for fine scale analyses, these results indicate that not all captive members of A. mississippiensis exhibit the extreme morphological alterations often cited in the literature. Weighing the conditions in which the animals are held and exploring the possibility of morphological differences against the benefits of using captive specimens should be part of any actualistic study. J. Morphol. 277:866-878, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Stephanie K Drumheller
- Department of Earth and Planetary Sciences, The University of Tennessee, Knoxville, Tennessee, 37996
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York, 11794
| | - Rudyard W Sadleir
- Department of Biological Sciences, Saint Xavier University, Chicago, Illinois, 60655.,Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois, 60605
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Blanco A, Fortuny J, Vicente A, Luján ÀH, García-Marçà JA, Sellés AG. A new species of Allodaposuchus (Eusuchia, Crocodylia) from the Maastrichtian (Late Cretaceous) of Spain: phylogenetic and paleobiological implications. PeerJ 2015; 3:e1171. [PMID: 26339549 PMCID: PMC4558081 DOI: 10.7717/peerj.1171] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/20/2015] [Indexed: 11/20/2022] Open
Abstract
Background. The Late Cretaceous is a keystone period to understand the origin and early radiation of Crocodylia, the group containing all extant lineages of crocodilians. Among the taxa described from the latest Cretaceous of Europe, the genus Allodaposuchus is one of the most common but also one of the most controversial. However, because of its fragmentary record, several issues regarding its phylogenetic emplacement and its ecology remain unsolved or unknown. The discovery of a single specimen attributed to Allodaposuchus, represented by both cranial and postcranial remains, from the Casa Fabà site (Tremp Basin, NE Spain) in the lower red unit of the Tremp Fm. (early Maastrichtian, Late Cretaceous) offers a unique opportunity to deepen in the phylogenetic relationships of the group and its ecological features. Methods. The specimen is described in detail, and CT scan of the skull is performed in order to study the endocranial morphology as well as paratympanic sinuses configuration. In addition, myological and phylogenetic analyses are also carried out on the specimen for to shed light in ecological and phylogenetic issues, respectively. Results. The specimen described herein represents a new species, Allodaposuchus hulki sp. nov., closely related to the Romanian A. precedens. The CT scan of the skull revealed an unexpected paratympanic sinuses configuration. Allosaposuchus hulki exhibits an “anterodorsal tympanic sinus” not observed in any other extant or extinct crocodilian. The caudal tympanic recesses are extremely enlarged, and the expanded quadratic sinus seems to be connected to the middle-ear channel. Phylogenetic analyses confirm the emplacement of the informal taxonomic group ‘Allodaposuchia’ at the base of Crocodylia, being considered the sister group of Borealosuchus and Planocraniidae. Discussion. Although this is a preliminary hypothesis, the unique paratympanic configuration displayed by A. hulki suggests that it could possess a high-specialized auditory system. Further, the large cranial cavities could help to reduce the weight of the cranium. Concerning the postcranial skeleton, Allodaposuchus hulki shows massive and robust vertebrae and forelimb bones, suggesting it could have a bulky body. The myological study performed on the anterior limb elements supports this interpretation. In addition, several bone and muscular features seem to point at a semi-erected position of the forelimbs during terrestrial locomotion. Taking all the above results into consideration, it seems plausible to suggest that A. hulki could conduct large incursions out of the water and have a semi-terrestrial lifestyle.
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Affiliation(s)
- Alejandro Blanco
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Josep Fortuny
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Alba Vicente
- Departament d'Estratigrafia, Paleontologia i Geociències marines, Facultat de Geologia, Universitat de Barcelona, Carrer de Martí i Franquès s/n , Barcelona, Catalonia , Spain
| | - Àngel H Luján
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Jordi Alexis García-Marçà
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
| | - Albert G Sellés
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona , Sabadell, Catalonia , Spain
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42
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Schachner ER, Hutchinson JR, Farmer C. Pulmonary anatomy in the Nile crocodile and the evolution of unidirectional airflow in Archosauria. PeerJ 2013; 1:e60. [PMID: 23638399 PMCID: PMC3628916 DOI: 10.7717/peerj.60] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/10/2013] [Indexed: 11/20/2022] Open
Abstract
The lungs of birds have long been known to move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi). Recently a similar pattern of airflow has been observed in American alligators, a sister taxon to birds. The pattern of flow appears to be due to the arrangement of the primary and secondary bronchi, which, via their branching angles, generate inspiratory and expiratory aerodynamic valves. Both the anatomical similarity of the avian and alligator lung and the similarity in the patterns of airflow raise the possibility that these features are plesiomorphic for Archosauria and therefore did not evolve in response to selection for flapping flight or an endothermic metabolism, as has been generally assumed. To further test the hypothesis that unidirectional airflow is ancestral for Archosauria, we measured airflow in the lungs of the Nile crocodile (Crocodylus niloticus). As in birds and alligators, air flows cranially to caudally in the cervical ventral bronchus, and caudally to cranially in the dorsobronchi in the lungs of Nile crocodiles. We also visualized the gross anatomy of the primary, secondary and tertiary pulmonary bronchi of C. niloticus using computed tomography (CT) and microCT. The cervical ventral bronchus, cranial dorsobronchi and cranial medial bronchi display similar characteristics to their proposed homologues in the alligator, while there is considerable variation in the tertiary and caudal group bronchi. Our data indicate that the aspects of the crocodilian bronchial tree that maintain the aerodynamic valves and thus generate unidirectional airflow, are ancestral for Archosauria.
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Affiliation(s)
- Emma R Schachner
- Department of Biology, University of Utah , Salt Lake City, UT , USA
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