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Montoya-Sanhueza G, Bennett NC, Šumbera R. Functional and morphological divergence in the forelimb musculoskeletal system of scratch-digging subterranean mammals (Rodentia: Bathyergidae). J Anat 2024. [PMID: 38760952 DOI: 10.1111/joa.14058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 05/20/2024] Open
Abstract
Whether the forelimb-digging apparatus of tooth-digging subterranean mammals has similar levels of specialization as compared to scratch-diggers is still unknown. We assessed the scapular morphology and forelimb musculature of all four solitary African mole rats (Bathyergidae): two scratch-diggers, Bathyergus suillus and Bathyergus janetta, and two chisel-tooth diggers, Heliophobius argenteocinereus and Georychus capensis. Remarkable differences were detected: Bathyergus have more robust neck, shoulder, and forearm muscles as compared to the other genera. Some muscles in Bathyergus were also fused and often showing wider attachment areas to bones, which correlate well with its more robust and larger scapula, and its wider and medially oriented olecranon. This suggests that shoulder, elbow, and wrist work in synergy in Bathyergus for generating greater out-forces and that the scapula and proximal ulna play fundamental roles as pivots to maximize and accommodate specialized muscles for better (i) glenohumeral and scapular stabilization, (ii) powerful shoulder flexion, (iii) extension of the elbow and (iv) flexion of the manus and digits. Moreover, although all bathyergids showed a similar set of muscles, Heliophobius lacked the m. tensor fasciae antebrachii (aiding with elbow extension and humeral retraction), and Heliophobius and Georychus lacked the m. articularis humeri (aiding with humeral adduction), indicating deeper morphogenetic differences among digging groups and suggesting a relatively less specialized scratch-digging ability. Nevertheless, Heliophobius and Bathyergus shared some similar adaptations allowing scratch-digging. Our results provide new information about the morphological divergence within this family associated with the specialization to distinct functions and digging behaviors, thus contributing to understand the mosaic of adaptations emerging in phylogenetically and ecologically closer subterranean taxa. This and previous anatomical studies on the Bathyergidae will provide researchers with a substantial basis on the form and function of the musculoskeletal system for future kinematic investigations of digging behavior, as well as to define potential indicators of scratch-digging ability.
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Affiliation(s)
- Germán Montoya-Sanhueza
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Hamidi K, Matin MM, Pérez MJ, Kilpatrick CW, Darvish J. Postcranial skeleton of Goodwin's brush-tailed mouse (Calomyscus elburzensis Goodwin, 1939) (Rodentia: Calomyscidae): Shape, size, function, and locomotor adaptation. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:1059-1101. [PMID: 37698162 DOI: 10.1002/jez.2755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023]
Abstract
Goodwin's brush-tailed mouse (Calomyscus elburzensis Goodwin, 1939) is a poorly known small rodent that occupies rocky habitats in Iran, Turkmenistan, Afghanistan, Pakistan, Azerbaijan, and Syria. Herein, a detailed description of the shape, size, and function of the postcranial skeleton of this species is presented for the first time. Trapping was carried out in eastern Iran between the years 2013 and 2015. Skeletal parts of 24 adult male specimens were removed using the papain digestion protocol, and several postcranial morphological characteristics and measurements were examined. We attempted to achieve a morpho-functional characterization of Goodwin's brush-tailed mouse and to match morphological specializations with previous information on the ecology, behavior, and phylogenetic inferences of this rodent. Goodwin's brush-tailed mouse has extended transverse processes and long zygapophyses in the first five caudal vertebrae along with a good innervation of the caudal vertebrae, which has resulted in a well-developed basal musculature of the tail. It has extended forelimb, long ilium, and short post-acetabular part of the innominate bone, loose hip joint with high degree of lateral movement of the hindlimb, and long distal elements of the hindlimb. These features have resulted in fast terrestrial movements in open microhabitats, including climbing and jumping. Although superficial scratching of the ground is observed, the species is incapable of digging burrows. Evaluation of postcranial morphological characteristics and character states further indicated the basal radiation of the genus Calomyscus among other Muroidea. Findings constitute a source of information for morpho-functional and phylogenetic comparisons between Calomyscidae and other mouse-like muroids.
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Affiliation(s)
- Kordiyeh Hamidi
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Maryam M Matin
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
- Novel Diagnostics and Therapeutics Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - M Julieta Pérez
- Instituto de Investigaciones de Biodiversidad Argentina (PIDBA) y Programa de Conservación de los Murciélagos de Argentina (PCMA), Facultad de Ciencias Naturales e Instituto Miguel Lillo, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina
| | | | - Jamshid Darvish
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
- Research Group of Rodentology, Institute of Applied Zoology, Ferdowsi University of Mashhad, Mashhad, Iran
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Mills KK, Everson KM, Hildebrandt KPB, Brandler OV, Steppan SJ, Olson LE. Ultraconserved elements improve resolution of marmot phylogeny and offer insights into biogeographic history. Mol Phylogenet Evol 2023; 184:107785. [PMID: 37085130 DOI: 10.1016/j.ympev.2023.107785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/01/2023] [Accepted: 04/13/2023] [Indexed: 04/23/2023]
Abstract
Marmots (Marmota spp.) comprise a lineage of large-bodied ground squirrels that diversified rapidly in the Pleistocene, when the planet quickly transitioned to a drier, colder, and highly seasonal climate-particularly at high latitudes. Fossil evidence indicates the genus spread from North America, across Beringia, and into the European Alps over the course of only a few million years, beginning in the late Pliocene. Marmots are highly adapted to survive long and severely cold winters, and this likely favored their expansion and diversification over this time period. Previous phylogenetic studies have identified two major subgenera of marmots, but the timing of important speciation events and some species relationships have been difficult to resolve. Here we use ultraconserved elements and mitogenomes, with samples from all 15 extant species, to more precisely retrace how and when marmots came to inhabit a vast Holarctic range. Our results indicate marmots arose in North America in the mid Miocene (∼16.3 Mya) and dispersed across the Bering Land Bridge in the late Pliocene (∼3-4 Mya); in addition, our fossil-calibrated timeline is suggestive of the rise and spread of open grasslands as being particularly important to marmot diversification. The woodchuck (M. monax) and the Alaska marmot (M. broweri) are found to be more closely related to the Eurasian species than to the other North American species. Paraphyly is evident in the bobak marmot (M. bobak) and the hoary marmot (M. caligata), and in the case of the latter the data are highly suggestive of a second, cryptic species in the Cascade Mountains of Washington.
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Affiliation(s)
- Kendall K Mills
- Department of Biology and Wildlife, University of Alaska Fairbanks, 982 North Koyukuk Drive, Fairbanks, AK 99775, USA; Department of Mammalogy, University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK 99775, USA.
| | - Kathryn M Everson
- Department of Mammalogy, University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK 99775, USA; Department of Integrative Biology, Oregon State University, 2701 SW Campus Way, Corvallis, OR 97331, USA
| | - Kyndall P B Hildebrandt
- Department of Mammalogy, University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK 99775, USA
| | - Oleg V Brandler
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Vavilova 26, Moscow, Russia
| | - Scott J Steppan
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Link E Olson
- Department of Mammalogy, University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK 99775, USA
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Gomes Rodrigues H, Damette M. Incipient morphological specializations associated with fossorial life in the skull of ground squirrels (Sciuridae, Rodentia). J Morphol 2023; 284:e21540. [PMID: 36533735 PMCID: PMC10107104 DOI: 10.1002/jmor.21540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 09/01/2022] [Accepted: 11/26/2022] [Indexed: 12/14/2022]
Abstract
Anatomical and biological specializations have been studied extensively in fossorial rodents, especially in subterranean species, such as mole-rats or pocket-gophers. Sciurids (i.e., squirrels) are mostly known for their diverse locomotory behaviors, and encompass many arboreal species. They also include less specialized fossorial species, such as ground squirrels that are mainly scratch diggers. The skull of ground squirrels remains poorly investigated in a fossorial context, while it may reflect incipient morphological specializations associated with fossorial life, especially due to the putative use of incisors for digging in some taxa. Here, we present the results of a comparative analysis of the skull of five fossorial sciurid species, and compare those to four arboreal sciurids, one arboreal/fossorial sciurid and one specialized fossorial aplodontiid. The quantification of both cranial and mandibular shapes, using three dimensional geometric morphometrics, reveals that fossorial species clearly depart from arboreal species. Fossorial species from the Marmotini tribe, and also Xerini to a lesser extent, show widened zygomatic arches and occipital plate on the cranium, and a wide mandible with reduced condyles. These shared characteristics, which are present in the aplodontiid species, likely represent fossorial specializations rather than relaxed selection on traits related to the ancestral arboreal condition of sciurids. Such cranial and mandibular configurations combined with proodont incisors might also be related to the frequent use of incisors for digging (added to forelimbs), especially in Marmotini evolving in soft to hard soil conditions. This study provides some clues to understand the evolutionary mechanisms shaping the skull of fossorial rodents, in relation to the time spent underground and to the nature of the soil.
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Affiliation(s)
- Helder Gomes Rodrigues
- Centre de Recherche en Paléontologie-Paris (CR2P), UMR CNRS 7207, CP38, Muséum national d'Histoire naturelle, Sorbonne Université, Paris, France
| | - Mathilde Damette
- Centre de Recherche en Paléontologie-Paris (CR2P), UMR CNRS 7207, CP38, Muséum national d'Histoire naturelle, Sorbonne Université, Paris, France
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Hofmann R, Lehmann T, Warren DL, Ruf I. The squirrel is in the detail: Anatomy and morphometry of the tail in Sciuromorpha (Rodentia, Mammalia). J Morphol 2021; 282:1659-1682. [PMID: 34549832 DOI: 10.1002/jmor.21412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 09/09/2021] [Accepted: 09/15/2021] [Indexed: 11/07/2022]
Abstract
In mammals, the caudal vertebrae are certainly among the least studied elements of their skeleton. However, the tail plays an important role in locomotion (e.g., balance, prehensility) and behavior (e.g., signaling). Previous studies largely focused on prehensile tails in Primates and Carnivora, in which certain osteological features were selected and used to define tail regions (proximal, transitional, distal). Interestingly, the distribution pattern of these anatomical characters and the relative proportions of the tail regions were similar in both orders. In order to test if such tail regionalization can be applied to Rodentia, we investigated the caudal vertebrae of 20 Sciuridae and six Gliridae species. Furthermore, we examined relationships between tail anatomy/morphometry and locomotion. The position of selected characters along the tail was recorded and their distribution was compared statistically using Spearman rank correlation. Vertebral body length (VBL) was measured to calculate the proportions of each tail region and to perform procrustes analysis on the shape of relative vertebral body length (rVBL) progressions. Our results show that tail regionalization, as defined for Primates and Carnivora, can be applied to almost all investigated squirrels, regardless of their locomotor category. Moreover, major locomotor categories can be distinguished by rVBL progression and tail region proportions. In particular, the small flying squirrels Glaucomys volans and Hylopetes sagitta show an extremely short transitional region. Likewise, several semifossorial taxa can be distinguished by their short distal region. Moreover, among flying squirrels, Petaurista petaurista shows differences with the small flying squirrels, mirroring previous observations on locomotory adaptations based on their inner ear morphometry. Our results show furthermore that the tail region proportions of P. petaurista, phylogenetically more basal than the small flying squirrels, are similar to those of bauplan-conservative arboreal squirrels.
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Affiliation(s)
- Rebecca Hofmann
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany.,Institut für Geowissenschaften, Goethe-Universität, Frankfurt am Main, Germany
| | - Thomas Lehmann
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany
| | - Dan L Warren
- Senckenberg Biodiversität und Klima Forschungszentrum, Frankfurt am Main, Germany.,Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Irina Ruf
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Frankfurt am Main, Germany.,Institut für Geowissenschaften, Goethe-Universität, Frankfurt am Main, Germany
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Youlatos D, He G, Guo S, Li B. Positional behavior, habitat use, and forelimb morphology of Père David’s Rock Squirrels Sciurotamias davidianus (Milne-Edwards, 1867) (Sciuridae, Rodentia) in the Qinling Mountains, Shaanxi, China. Mamm Biol 2021. [DOI: 10.1007/s42991-021-00116-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Marshall SK, Superina M, Spainhower KB, Butcher MT. Forelimb myology of armadillos (Xenarthra: Cingulata, Chlamyphoridae): Anatomical correlates with fossorial ability. J Anat 2021; 238:551-575. [PMID: 33111984 PMCID: PMC7855086 DOI: 10.1111/joa.13326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/31/2020] [Accepted: 09/10/2020] [Indexed: 11/27/2022] Open
Abstract
Descriptions of myology reflect adaptations of the post-cranium and are essential for understanding the functional morphology of animal limbs. Armadillos (Cingulata) are the most species-rich group of the basal superorder Xenarthra, which is evident by their various lifestyles (subterranean vs. terrestrial) and levels of fossoriality (fossorial vs. semi-fossorial). While there have been several studies on limb bone proportions in numerous armadillos, limb myology has been reported for a limited number of species. Many of these descriptions need updating, and detailed quantitative muscle data are available only for nine-banded armadillos. The main objective of this study is to assess the forelimb myology of the pichi (Zaedyus pichiy), screaming hairy (Chaetophractus vellerosus), large hairy (Chaetophractus villosus), and pink fairy (Chlamyphorus truncatus) armadillos with comparisons to previous observations to specify muscle traits that indicate scratch-digging specializations in cingulates. Several myological features are variable among the species studied, including the origin of m. trapezius pars cervicalis, presence of a distinct m. rhomboideus profundus and m. omotransversarius, and number of heads present for m. triceps brachii and m. flexor digitorum profundus, all of which can be associated with variability in their respective habitats and functional habits. These traits are consistently observed in the members of the Euphractinae, whereas they are slightly divergent (i.e., reduced complexity) in the pink fairy armadillo despite a similar distribution of muscle mass in the limb retractors, elbow extensors, and carpal/digital flexors across species. The ecomorphology observed here among cingulates also confirms their recent reorganization into separate families and subfamilies.
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Affiliation(s)
- Sarah K. Marshall
- Department of Biological SciencesYoungstown State UniversityYoungstownOHUSA
| | - Mariella Superina
- Instituto de Medicina y Biología Experimental de CuyoUNCuyo—CONICETMendozaArgentina
| | - Kyle B. Spainhower
- Department of Biological SciencesYoungstown State UniversityYoungstownOHUSA
| | - Michael T. Butcher
- Department of Biological SciencesYoungstown State UniversityYoungstownOHUSA
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Locomotor Behavior and Body Mass of Paramys delicatus (Ischyromyidae, Rodentia) and Commentary on Other Early North American Paramyines. J MAMM EVOL 2020. [DOI: 10.1007/s10914-020-09523-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Doubell NS, Sahd L, Kotzé SH. Comparative forelimb morphology of scratch-digging and chisel-tooth digging African mole-rat species. J Morphol 2020; 281:1029-1046. [PMID: 32589809 DOI: 10.1002/jmor.21229] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 01/09/2023]
Abstract
Bathyergus suillus (Cape dune mole-rat) and Heterocephalus glaber (naked mole-rat) are two species of subterranean burrowing rodents. Bathyergus suillus occurs in soft sandy soils and is regarded as a scratch-digger, while H. glaber is found in hard, compact soils and is a chisel-tooth digging species. The present study aimed to determine musculoskeletal differences in the forelimb of these two species. The muscles of the forelimb, back and neck were dissected to the points of origin and insertion in the left and right forelimbs, B. suillus (n = 7) and H. glaber (n = 5). Dissected muscles were photographed before maceration to demonstrate muscle attachments. The scapular spine, acromion process and clavicle were relatively straight in B. suillus. In comparison a curved scapular spine, acromion process and clavicle were observed in H. glaber. In both species, the clavicle rested on the greater tuberosity of the humerus. In B. suillus, the deltoid tuberosity was prominent and situated more distally on the humeral shaft compared to the indistinct, more proximally situated deltoid tuberosity in H. glaber. A prominent bony structure underlying the thenar pad as well as a cartilaginous protrusion beneath the hypothenar pad were observed on the palmar surface of the manus in B. suillus. Prominent claws were observed in B. suillus. A robust m. sternohyoideus was observed in H. glaber while mm. tensor fasciae antebrachii and coracobrachialis were absent. The flexors of the antebrachium of B. suillus had additional and enlarged attachment sites. The forelimb of B. suillus may be morphologically adapted for scratch-digging with relatively large and additional forelimb muscles and robust bones. In comparison, H. glaber had a reduction in the relative size, amount of muscles as well as number of attachment sites in the forelimb muscles, while the well-developed ventral neck muscles may facilitate neck and head stabilisation during chisel-tooth digging.
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Affiliation(s)
- Narusa S Doubell
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Lauren Sahd
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Sanet H Kotzé
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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Nyakatura JA, Baumgarten R, Baum D, Stark H, Youlatos D. Muscle internal structure revealed by contrast-enhanced μCT and fibre recognition: The hindlimb extensors of an arboreal and a fossorial squirrel. Mamm Biol 2019. [DOI: 10.1016/j.mambio.2019.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wölfer J, Arnold P, Nyakatura JA. Effects of scaling and locomotor ecology suggest a complex evolution of scapular morphology in sciuromorph rodents. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jan Wölfer
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
- Bild Wissen Gestaltung. Ein Interdisziplinäres Labor, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Patrick Arnold
- Institut für Anatomie I, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena, Germany
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, Friedrich-Schiller-Universität Jena, Jena, Germany
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - John A Nyakatura
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
- Bild Wissen Gestaltung. Ein Interdisziplinäres Labor, Humboldt-Universität zu Berlin, Berlin, Germany
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12
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Guignard ML, Martinelli AG, Soares MB. The postcranial anatomy of Brasilodon quadrangularis and the acquisition of mammaliaform traits among non-mammaliaform cynodonts. PLoS One 2019; 14:e0216672. [PMID: 31075140 PMCID: PMC6510408 DOI: 10.1371/journal.pone.0216672] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/25/2019] [Indexed: 11/20/2022] Open
Abstract
Brasilodon quadrangularis (Cynodontia, Probainognathia) is an iconic non-mammaliaform cynodont from the Late Triassic of Brazil (Riograndia Assemblage Zone, Candelária Sequence), being considered as the sister taxon of Mammaliaformes. Although its phylogenetic position is very important, several aspects of its postcranial anatomy remain unclear or unstudied. Here, we present a detailed description of the postcranial elements referred to Brasilodon, including previously mentioned specimens and new ones, which add relevant information about its postcranial morphology and provide a new insight into the anatomical transition between advanced non-mammaliaform cynodonts and early mammaliaforms. Functional and ecological implications are also investigated, based on the postcranial morphology and muscular reconstructions. The postcranium of Brasilodon differs from most non-mammaliaform cynodonts and presents similarities with tritylodontids, early mammaliaforms and extant therians, such as a ventrally oriented scapular glenoid facet, a distinct and ossified greater humeral tubercle, lack of ectepicondylar foramen, olecranon process, hemispherical humeral and femoral heads and a prominent intertrochanteric crest. The humeral torsion, the length of the deltopectoral crest, the large bicipital groove and the well-developed lesser tubercle, indicate that the forelimb of Brasilodon was hold in a semi-sprawling position, with well-developed adductor muscles to maintain the body off the ground. The short femoral neck and the strong medial projection of the femoral head indicate the femur was held in a more erect posture than in basal non-mammaliaform cynodonts. The anterodorsally projected iliac blade with reduced postacetabular process, reduction of the anterior part of the pubis, medially located lesser trochanter indicate a basically mammalian pattern of pelvic musculature, able to swing the femur in a nearly parasagittal plane.
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Affiliation(s)
- Morgan L. Guignard
- Programa de Pós-Graduação em Geociências, Universidade Federal do Rio Grande do Sul, Agronomia, Porto Alegre, Rio Grande do Sul, Brazil
- * E-mail:
| | - Agustin G. Martinelli
- CONICET-Sección Paleontología de Vertebrados, Museo Argentino de Ciencias Naturales ’Bernardino Rivadavia', Buenos Aires, Argentina
- Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Agronomia, Porto Alegre, Rio Grande do Sul, Brazil
| | - Marina B. Soares
- Programa de Pós-Graduação em Geociências, Universidade Federal do Rio Grande do Sul, Agronomia, Porto Alegre, Rio Grande do Sul, Brazil
- CONICET-Sección Paleontología de Vertebrados, Museo Argentino de Ciencias Naturales ’Bernardino Rivadavia', Buenos Aires, Argentina
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Mendes CP, Koprowski JL, Galetti M. NEOSQUIRREL: a data set of ecological knowledge on Neotropical squirrels. Mamm Rev 2019. [DOI: 10.1111/mam.12152] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Calebe Pereira Mendes
- Laboratório de Biologia da Conservação (LABIC)Departamento de EcologiaInstituto de BiociênciasUniversidade Estadual Paulista (UNESP) Avenida 24A,1515, ZIP 13506‐900, Rio Claro São Paulo Brazil
| | - John L. Koprowski
- School of Natural Resources and the EnvironmentUniversity of Arizona Tucson AZ 85721 USA
| | - Mauro Galetti
- Departamento de EcologiaInstituto de BiociênciasUniversidade Estadual Paulista (UNESP) Rio Claro São Paulo Brazil
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14
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Calede JJM, Samuels JX, Chen M. Locomotory adaptations in entoptychine gophers (Rodentia: Geomyidae) and the mosaic evolution of fossoriality. J Morphol 2019; 280:879-907. [PMID: 31006903 DOI: 10.1002/jmor.20990] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 03/28/2019] [Accepted: 03/30/2019] [Indexed: 12/20/2022]
Abstract
Pocket gophers (family Geomyidae) are the dominant burrowing rodents in North America today. Their fossil record is also incredibly rich; in particular, entoptychine gophers, a diverse extinct subfamily of the Geomyidae, are known from countless teeth and jaws from Oligocene and Miocene-aged deposits of the western United States and Mexico. Their postcranial remains, however, are much rarer and little studied. Yet, they offer the opportunity to investigate the locomotion of fossil gophers, shed light on the evolution of fossoriality, and enable ecomorphological comparisons with contemporaneous rodents. We present herein a quantitative study of the cranial and postcranial remains of eight different species of entoptychine gophers as well as many contemporary rodent species. We find a range of burrowing capabilities within Entoptychinae, including semifossorial scratch-digging animals and fossorial taxa with cranial adaptations to burrowing. Our results suggest the repeated evolution of chisel-tooth digging across genera. Comparisons between entoptychine gophers and contemporaneous rodent taxa show little ecomorphological overlap and suggest that the succession of burrowing rodent taxa on the landscape may have had more to do with habitat partitioning than competition.
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Affiliation(s)
- Jonathan J M Calede
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University at Marion, Marion, Ohio
| | - Joshua X Samuels
- Department of Geosciences, Don Sundquist Center of Excellence in Paleontology, East Tennessee State University, Johnson City, Tennessee
| | - Meng Chen
- Nanjing University, School of Earth Sciences and Engineering, Centre for Research and Education on Biological Evolution and Environment, Qixia District, Nanjing, China.,State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Academy of Sciences, Nanjing, China
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15
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Wölfer J, Amson E, Arnold P, Botton-Divet L, Fabre AC, van Heteren AH, Nyakatura JA. Femoral morphology of sciuromorph rodents in light of scaling and locomotor ecology. J Anat 2019; 234:731-747. [PMID: 30957252 DOI: 10.1111/joa.12980] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2019] [Indexed: 11/26/2022] Open
Abstract
Sciuromorph rodents are a monophyletic group comprising about 300 species with a body mass range spanning three orders of magnitude and various locomotor behaviors that we categorized into arboreal, fossorial and aerial. The purpose of this study was to investigate how the interplay of locomotor ecology and body mass affects the morphology of the sciuromorph locomotor apparatus. The most proximal skeletal element of the hind limb, i.e. the femur, was selected, because it was shown to reflect a functional signal in various mammalian taxa. We analyzed univariate traits (effective femoral length, various robustness variables and the in-levers of the muscles attaching to the greater, third and lesser trochanters) as well as femoral shape, representing a multivariate trait. An ordinary least-squares regression including 177 species was used to test for a significant interaction effect between body mass and locomotor ecology on the variables. Specifically, it tested whether the scaling patterns of the fossorial and aerial groups differ when compared with the arboreal, because the latter was identified as the ancestral sciuromorph condition via stochastic character mapping. We expected aerial species to display the highest trait values for a given body mass as well as the steepest slopes, followed by the arboreal and fossorial species along this order. An Ornstein-Uhlenbeck regression fitted to a phylogenetically pruned dataset of 140 species revealed the phylogenetic inertia to be very low in the univariate traits, hence justifying the utilization of standard regressions. These variables generally scaled close to isometry, suggesting that scaling adjustments might not have played a major role for most of the femoral features. Nevertheless, the low phylogenetic inertia indicates that the observed scaling patterns needed to be maintained during sciuromorph evolution. Significant interaction effects were discovered in the femoral length, the centroid size of the condyles, and the in-levers of the greater and third trochanters. Additionally, adjustments in various femoral traits reflect the acquisitions of fossorial and aerial behaviors from arboreal ancestors. Using sciuromorphs as a focal clade, our findings exemplify the importance of statistically accounting for potential interaction effects of different environmental factors in studies relating morphology to ecology.
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Affiliation(s)
- Jan Wölfer
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany.,Bild Wissen Gestaltung, Ein Interdisziplinäres Labor, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Eli Amson
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany.,Bild Wissen Gestaltung, Ein Interdisziplinäres Labor, Humboldt-Universität zu Berlin, Berlin, Germany.,Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Patrick Arnold
- Institut für Anatomie I, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena, Germany.,Institut für Zoologie und Evolutionsforschung, mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, Friedrich-Schiller-Universität Jena, Jena, Germany.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Léo Botton-Divet
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany.,UMR 7179, Centre National de la Recherche Scientifique, Pavillon d'Anatomie Comparée, Muséum national d'Histoire naturelle, Paris, France
| | - Anne-Claire Fabre
- UMR 7179, Centre National de la Recherche Scientifique, Pavillon d'Anatomie Comparée, Muséum national d'Histoire naturelle, Paris, France.,Life Sciences Department, The Natural History Museum, London, UK
| | - Anneke H van Heteren
- Sektion Mammalogie, Zoologische Staatssammlung München, Staatliche Naturwissenschaftliche Sammlungen Bayerns, München, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, München, Germany.,Department Biologie II, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - John A Nyakatura
- AG Morphologie und Formengeschichte, Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany.,Bild Wissen Gestaltung, Ein Interdisziplinäres Labor, Humboldt-Universität zu Berlin, Berlin, Germany
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16
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Legendre LJ, Botha-Brink J. Digging the compromise: investigating the link between limb bone histology and fossoriality in the aardvark ( Orycteropus afer). PeerJ 2018; 6:e5216. [PMID: 30018860 PMCID: PMC6045922 DOI: 10.7717/peerj.5216] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 06/21/2018] [Indexed: 01/07/2023] Open
Abstract
Bone microstructure has long been known as a powerful tool to investigate lifestyle-related biomechanical constraints, and many studies have focused on identifying such constraints in the limb bones of aquatic or arboreal mammals in recent years. The limb bone microstructure of fossorial mammals, however, has not been extensively described. Furthermore, so far, studies on this subject have always focused on the bone histology of small burrowers, such as subterranean rodents or true moles. Physiological constraints associated with digging, however, are known to be strongly influenced by body size, and larger burrowers are likely to exhibit a histological profile more conspicuously influenced by fossorial activity. Here, we describe for the first time the limb bone histology of the aardvark (Orycteropus afer), the largest extant burrowing mammal. The general pattern is very similar for all six sampled limb bones (i.e., humerus, radius, ulna, femur, tibia, and fibula). Most of the cortex at midshaft is comprised of compacted coarse cancellous bone (CCCB), an endosteal tissue formed in the metaphyses through the compaction of bony trabeculae. Conversely, the periosteal bone is highly resorbed in all sections, and is reduced to a thin outer layer, suggesting a pattern of strong cortical drift. This pattern contrasts with that of most large mammals, in which cortical bone is of mostly periosteal origin, and CCCB, being a very compliant bone tissue type, is usually resorbed or remodeled during ontogeny. The link between histology and muscle attachment sites, as well as the influence of the semi-arid environment and ant-eating habits of the aardvark on its bone microstructure, are discussed. We hypothesize that the unusual histological profile of the aardvark is likely the outcome of physiological constraints due to both extensive digging behavior and strong metabolic restrictions. Adaptations to fossoriality are thus the result of a physiological compromise between limited food availability, an environment with high temperature variability, and the need for biomechanical resistance during digging. These results highlight the difficulties of deciphering all factors potentially involved in bone formation in fossorial mammals. Even though the formation and maintaining of CCCB through ontogeny in the aardvark cannot be unambiguously linked with its fossorial habits, a high amount of CCCB has been observed in the limb bones of other large burrowing mammals. The inclusion of such large burrowers in future histological studies is thus likely to improve our understanding of the functional link between bone growth and fossorial lifestyle in an evolutionary context.
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Affiliation(s)
- Lucas J Legendre
- Karoo Palaeontology Department, National Museum, Bloemfontein, South Africa
| | - Jennifer Botha-Brink
- Karoo Palaeontology Department, National Museum, Bloemfontein, South Africa.,Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa
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17
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Calede JJM, Orcutt JD, Kehl WA, Richards BD. The first tetrapod from the mid-Miocene Clarkia lagerstätte (Idaho, USA). PeerJ 2018; 6:e4880. [PMID: 29900070 PMCID: PMC5995101 DOI: 10.7717/peerj.4880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/10/2018] [Indexed: 11/24/2022] Open
Abstract
The Clarkia lagerstätte (Latah Formation) of Idaho is well known for its beautifully preserved plant fossils as well as a fauna of insects and fish. Here we present the first known tetrapod fossil from these deposits. This specimen, recovered from the lower anoxic zone of the beds, is preserved as a carbonaceous film of a partial skeleton associated with a partial lower incisor and some tooth fragments. The morphology of the teeth indicates that the first tetrapod reported from Clarkia is a rodent. Its skeletal morphology as well as its bunodont and brachydont dentition suggests that it is a member of the squirrel family (Sciuridae). It is a large specimen that cannot be assigned to a known genus. Instead, it appears to represent the first occurrence of a new taxon with particularly gracile postcranial morphology likely indicative of an arboreal ecology. This new specimen is a rare glimpse into the poorly known arboreal mammal fossil record of the Neogene. It supports a greater taxonomic and ecological diversity of Miocene Sciuridae than previously recognized and offers new lines of inquiry in the paleoecological research enabled by the unique preservation conditions of the Clarkia biota.
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Affiliation(s)
- Jonathan J M Calede
- Department of Evolution, Ecology & Organismal Biology, Ohio State University, Marion, OH, USA
| | - John D Orcutt
- Department of Biology, Gonzaga University, Spokane, WA, USA
| | | | - Bill D Richards
- Department of Geology & Geography, North Idaho College, Coeur d'Alene, ID, USA
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18
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Perry JMG, Prufrock KA. Muscle Functional Morphology in Paleobiology: The Past, Present, and Future of “Paleomyology”. Anat Rec (Hoboken) 2018; 301:538-555. [DOI: 10.1002/ar.23772] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Jonathan M. G. Perry
- Center for Functional Anatomy and Evolution; The Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Kristen A. Prufrock
- Center for Functional Anatomy and Evolution; The Johns Hopkins University School of Medicine; Baltimore Maryland
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19
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McLean BS, Helgen KM, Goodwin HT, Cook JA. Trait‐specific processes of convergence and conservatism shape ecomorphological evolution in ground‐dwelling squirrels. Evolution 2018; 72:473-489. [DOI: 10.1111/evo.13422] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/18/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Bryan S. McLean
- Department of Biology and Museum of Southwestern Biology University of New Mexico Albuquerque New Mexico 87131
- Florida Museum of Natural History University of Florida Gainesville Florida 32611
| | - Kristofer M. Helgen
- School of Biological Sciences University of Adelaide Adelaide SA 5005 Australia
| | - H. Thomas Goodwin
- Department of Biology Andrews University Berrien Springs Michigan 49104
| | - Joseph A. Cook
- Department of Biology and Museum of Southwestern Biology University of New Mexico Albuquerque New Mexico 87131
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20
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Bertrand OC, Amador‐Mughal F, Silcox MT. Virtual endocast of the early Oligocene Cedromus wilsoni (Cedromurinae) and brain evolution in squirrels. J Anat 2017; 230:128-151. [PMID: 27580644 PMCID: PMC5192888 DOI: 10.1111/joa.12537] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2016] [Indexed: 01/21/2023] Open
Abstract
Extant squirrels exhibit extensive variation in brain size and shape, but published endocranial data for living squirrels are limited, and no study has ever examined brain evolution in Sciuridae from the perspective of the fossil record to understand how this diversity emerged. We describe the first virtual endocast for a fossil sciurid, Cedromus wilsoni, which is known from a complete cranium from Wyoming (Orellan, Oligocene), and make comparisons to a diverse sample of virtual endocasts for living sciurids (N = 20). The virtual endocasts were obtained from high-resolution X-ray micro-computed tomography data. Comparisons were also made with endocasts of extinct ischyromyid rodents, the most primitive rodents known from an endocranial record, which provide the opportunity to study the neuroanatomical changes occurring near the base of Sciuridae. The encephalization quotient of C. wilsoni is higher than that of Ischyromys typus from the same epoch, and falls within the range of modern terrestrial squirrel variation, but below the range of extant scansorial, arboreal and gliding sciurids when using cheek-tooth area for the estimation of body mass. In a principal components analysis, the shape of the endocast of C. wilsoni is found to be intermediate between that of primitive fossil taxa and the modern sample. Cedromus wilsoni has a more expanded neocortical surface area, especially the caudal region of the cerebrum, compared with ischyromyid rodents. Furthermore, C. wilsoni had proportionally larger paraflocculi and a more complex cerebellar morphology compared with ischyromyid rodents. These neurological differences may be associated with improvements in vision, although it is worth noting that the size of the parts of the brain most directly involved with vision [the rostral (superior) colliculi and the primary visual cortex] cannot be directly assessed on endocasts. The changes observed could also relate to balance and limb coordination. Ultimately, the available evidence suggests that early squirrels were more agile and visually oriented animals compared with more primitive rodents, which may relate to the process of becoming arboreal. Extant sciurids have an even more expanded neocortical surface area, while exhibiting proportionally smaller paraflocculi, compared with C. wilsoni. This suggests that the neocortex may continue increasing in size in more recent sciurid rodents in relation to other factors than arboreality. Despite the fact that both Primates and Rodentia exhibit neocortical expansion through time, since the adoption of arboreality preceded major increases in the neocortex in Primates, those neurological changes may be related to different ecological factors, underlining the complexity of the inter-relationship between time and ecology in shaping the brain in even closely related clades.
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Affiliation(s)
- Ornella C. Bertrand
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
| | | | - Mary T. Silcox
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
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21
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Kawashima T, Thorington RW, Bohaska PW, Sato F. Evolutionary Transformation of the Palmaris Longus Muscle in Flying Squirrels (Pteromyini: Sciuridae): An Anatomical Consideration of the Origin of the Uniquely Specialized Styliform Cartilage. Anat Rec (Hoboken) 2016; 300:340-352. [PMID: 27611816 DOI: 10.1002/ar.23471] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 06/20/2016] [Accepted: 07/01/2016] [Indexed: 11/06/2022]
Abstract
A long-standing issue in squirrel evolution and development is the origin of the styliform cartilage of flying squirrels, which extends laterally from the carpus to support the gliding membrane (patagium). Because the styliform cartilage is one of the uniquely specialized structures permitting gliding locomotion, the knowledge of its origin and surrounding transformation is key for understanding their aerodynamic evolution. The developmental study that would definitely answer this question would be difficult due to the rarity of embryological material. Instead, anatomical examinations have suggested two major hypotheses on the homology of the styliform cartilage: the pisiform bone of other mammals, or an additional carpal structure, such as the ulnar sesamoid of some of the other mammals or the hypothenar cartilage of the non-gliding squirrels. To test these hypotheses, a detailed examination of the anatomy of the carpus of gliding and non-gliding squirrels, and the colugo were undertaken. Based on physical and virtual dissections of the carpus, this study showed that both the pisiform bone and styliform cartilage were present in flying squirrels. This finding is further supported by demonstration that a "true Palmaris longus," with innervation typical for this muscle, inserts on the styliform cartilage. Taken together, our osteological, muscular, and neurological results suggest that the styliform cartilage was transformed in flying squirrels from an initially superficial and ulnar-derived anlagen into its current form. Anat Rec, 300:340-352, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Tomokazu Kawashima
- Department of Anatomy, School of Medicine, Toho University, Tokyo, Japan
| | - Richard W Thorington
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
| | - Paula W Bohaska
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
| | - Fumi Sato
- Department of Anatomy, School of Medicine, Toho University, Tokyo, Japan
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22
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Pfaff C, Martin T, Ruf I. Bony labyrinth morphometry indicates locomotor adaptations in the squirrel-related clade (Rodentia, Mammalia). Proc Biol Sci 2016; 282:20150744. [PMID: 26019162 DOI: 10.1098/rspb.2015.0744] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The semicircular canals (SCs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. Based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. Our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. The morphometric anatomy of the SCs was correlated to the locomotion mode. Even if the phylogenetic signal cannot entirely be excluded, the main significance for functional morphological studies has been found in the diameter of the SCs, whereas the radius of curvature is of minor interest. Additionally, we found clear differences in the bias angle of the canals between subterranean and gliding taxa, but also between sciurids and glirids. The sensitivity of the inner ear correlates with the locomotion mode, with a higher sensitivity of the SCs in fossorial species than in flying taxa. We conclude that the inner ear of flying and gliding mammals is less sensitive due to the large information flow into this sense organ during locomotion.
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Affiliation(s)
- Cathrin Pfaff
- Department of Palaeontology, Geozentrum, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
| | - Thomas Martin
- Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 8, Bonn 53115, Germany
| | - Irina Ruf
- Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, Abteilung Paläoanthropologie und Messelforschung, Senckenberganlage 25, Frankfurt am Main 60325, Germany
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23
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Pečnerová P, Moravec JC, Martínková N. A Skull Might Lie: Modeling Ancestral Ranges and Diet from Genes and Shape of Tree Squirrels. Syst Biol 2015; 64:1074-88. [PMID: 26254670 DOI: 10.1093/sysbio/syv054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 07/29/2015] [Indexed: 11/12/2022] Open
Abstract
Tropical forests of Central and South America represent hotspots of biological diversity. Tree squirrels of the tribe Sciurini are an excellent model system for the study of tropical biodiversity as these squirrels disperse exceptional distances, and after colonizing the tropics of the Central and South America, they have diversified rapidly. Here, we compare signals from DNA sequences with morphological signals using pictures of skulls and computational simulations. Phylogenetic analyses reveal step-wise geographic divergence across the Northern Hemisphere. In Central and South America, tree squirrels form two separate clades, which split from a common ancestor. Simulations of ancestral distributions show western Amazonia as the epicenter of speciation in South America. This finding suggests that wet tropical forests on the foothills of Andes possibly served as refugia of squirrel diversification during Pleistocene climatic oscillations. Comparison of phylogeny and morphology reveals one major discrepancy: Microsciurus species are a single clade morphologically but are polyphyletic genetically. Modeling of morphology-diet relationships shows that the only group of species with a direct link between skull shape and diet are the bark-gleaning insectivorous species of Microsciurus. This finding suggests that the current designation of Microsciurus as a genus is based on convergent ecologically driven changes in morphology.
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Affiliation(s)
- Patrícia Pečnerová
- Department of Botany and Zoology, Masaryk University, Kotlářská 2, 602 00 Brno, Czech Republic; Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Květná 8, 603 65 Brno, Czech Republic; Department of Zoology, Stockholm University, 10691 Stockholm, Sweden; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, PO Box 50007, 10405 Stockholm, Sweden;
| | - Jiří C Moravec
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Květná 8, 603 65 Brno, Czech Republic; Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand; and
| | - Natália Martínková
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Květná 8, 603 65 Brno, Czech Republic; Institute of Biostatistics and Analyses, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
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24
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“Septal compass” and “septal formula”: a new method for phylogenetic investigations of the middle ear region in the squirrel-related clade (Rodentia: Mammalia). ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0222-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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25
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Olson RA, Womble MD, Thomas DR, Glenn ZD, Butcher MT. Functional Morphology of the Forelimb of the Nine-Banded Armadillo (Dasypus novemcinctus): Comparative Perspectives on the Myology of Dasypodidae. J MAMM EVOL 2015. [DOI: 10.1007/s10914-015-9299-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Kawashima T, Thorington RW, Bohaska PW, Chen YJ, Sato F. Anatomy of Shoulder Girdle Muscle Modifications and Walking Adaptation in the Scaly Chinese Pangolin (Manis Pentadactyla Pentadactyla: Pholidota) Compared with the Partially Osteoderm-Clad Armadillos (Dasypodidae). Anat Rec (Hoboken) 2015; 298:1217-36. [DOI: 10.1002/ar.23170] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 04/02/2015] [Accepted: 04/13/2015] [Indexed: 11/10/2022]
Affiliation(s)
| | - Richard W. Thorington
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History; Smithsonian Institution; District of Columbia
| | - Paula W. Bohaska
- Division of Mammals, Department of Vertebrate Zoology, National Museum of Natural History; Smithsonian Institution; District of Columbia
| | - Yen-Jean Chen
- Division of Bird and Mammal, Department of Zoology, National Museum of Natural Science; Taichung Taiwan
| | - Fumi Sato
- Department of Anatomy, School of Medicine; Toho University; Tokyo Japan
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27
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Carrizo LV, Tulli MJ, Abdala V. An ecomorphological analysis of forelimb musculotendinous system in sigmodontine rodents (Rodentia, Cricetidae, Sigmodontinae). J Mammal 2014. [DOI: 10.1644/13-mamm-a-232] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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28
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Youlatos D, Panyutina AA. Habitual Bark Gleaning by Cambodian Striped Squirrels Tamiops rodolphii (Rodentia: Sciuridae) in Cat Tien National Park, South Vietnam. MAMMAL STUDY 2014. [DOI: 10.3106/041.039.0202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Dionisios Youlatos
- Aristotle University of Thessaloniki, School of Biology, Department of Zoology, GR-54124 Thessaloniki, Greece
| | - Aleksandra A. Panyutina
- Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskii pr. 33, Moscow 119071, Russian Federation
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29
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Rupert JE, Rose JA, Organ JM, Butcher MT. Forelimb muscle architecture and myosin isoform composition in the groundhog (Marmota monax). J Exp Biol 2014; 218:194-205. [DOI: 10.1242/jeb.107128] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Scratch-digging mammals are commonly described as having large, powerful forelimb muscles for applying high force to excavate earth, yet studies quantifying the architectural properties of the musculature are largely unavailable. To further test hypotheses about traits that represent specializations for scratch-digging, we quantified muscle architectural properties and fiber type in the forelimb of the groundhog (Marmota monax), a digger that constructs semi-complex burrows. Architectural properties measured were muscle moment arm, muscle mass (MM), belly length (ML), fascicle length (lF), pennation angle, and physiological cross-sectional area (PCSA), and these metrics were used to estimate maximum isometric force, joint torque, and power. Myosin heavy chain (MHC) isoform composition was determined in selected forelimb muscles by SDS-PAGE and densitometry analysis. Groundhogs have large limb retractors and elbow extensors that are capable of applying moderately high torque at the shoulder and elbow joints, respectively. Most of these muscles (e.g., latissimus dorsi and pectoralis superficialis) have high lF/ML ratios, indicating substantial shortening ability and moderate power. The unipennate triceps brachii long head has the largest PCSA and is capable of the highest joint torque at both the shoulder and elbow joints. The carpal and digital flexors show greater pennation and shorter fascicle lengths than the limb retractors and elbow extensors, resulting in higher PCSA:MM ratios and force production capacity. Moreover, the digital flexors have the capacity for both appreciable fascicle shortening and force production indicating high muscle work potential. Overall, the forelimb musculature of the groundhog is capable of relatively low sustained force and power, and these properties are consistent with the findings of a predominant expression of the MHC-2A isoform. Aside from the apparent modifications to the digital flexors, the collective muscle properties observed are consistent with its behavioral classification as a less specialized burrower and these may be more representative of traits common to numerous rodents with burrowing habits or mammals with some fossorial ability.
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30
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Wilson LAB. Allometric disparity in rodent evolution. Ecol Evol 2013; 3:971-84. [PMID: 23610638 PMCID: PMC3631408 DOI: 10.1002/ece3.521] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 01/31/2013] [Accepted: 02/04/2013] [Indexed: 11/11/2022] Open
Abstract
In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents.
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Affiliation(s)
- Laura A B Wilson
- Kyoto University Museum, Kyoto University Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan
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31
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Arboreal locomotor and postural behaviour of European red squirrels (Sciurus vulgaris L.) in northern Greece. J ETHOL 2010. [DOI: 10.1007/s10164-010-0248-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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STEINER-SOUZA FRANCISCO, DE FREITAS THALESRO, CORDEIRO-ESTRELA PEDRO. Inferring adaptation within shape diversity of the humerus of subterranean rodent Ctenomys. Biol J Linn Soc Lond 2010. [DOI: 10.1111/j.1095-8312.2010.01400.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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33
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SALESA MANUELJ, ANTÓN MAURICIO, PEIGNÉ STÉPHANE, MORALES JORGE. Functional anatomy and biomechanics of the postcranial skeleton of Simocyon batalleri (Viret, 1929) (Carnivora, Ailuridae) from the Late Miocene of Spain. Zool J Linn Soc 2008. [DOI: 10.1111/j.1096-3642.2007.00370.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thorington RW, Santana EM. How to Make a Flying Squirrel:GlaucomysAnatomy in Phylogenetic Perspective. J Mammal 2007. [DOI: 10.1644/06-mamm-s-325r2.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Rocha-Barbosa O, Loguercio MFC, Renous S, Gasc JP. Comparative study on the forefoot and hindfoot intrinsic muscles of some cavioidea rodents (Mammalia, Rodentia). ZOOLOGY 2007; 110:58-65. [PMID: 17008077 DOI: 10.1016/j.zool.2006.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 04/06/2006] [Accepted: 05/03/2006] [Indexed: 11/30/2022]
Abstract
The present study compares the forefoot and hindfoot musculature of five representative species of Cavioidea rodents. In all species, the musculature of both forefeet and hindfeet have the same array regardless of the absence of digit I in the manus of Hydrochaeris hydrochaeris and Cavia porcellus. Our results suggest a tendency in these species towards a three-digit system, with a functional loss of digit V and a predominance of digit III in their forefeet. In the same way, the muscular reduction of digit I in the other rodents analyzed indicates a four-digit system with predominance of digit II in Myoprocta acouchy and Dasyprocta leporina and of digit V in Agouti paca. There seems to be an association between the muscular arrangement and functional axis of the foot, raising the general question why this axis runs between the third and forth digit, or along the third digit.
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Affiliation(s)
- Oscar Rocha-Barbosa
- Laboratório de Zoologia de Vertebrados (Tetrapoda), Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, 524, Maracanã 20550-013, Rio de Janeiro, RJ, Brazil.
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Lagaria A, Youlatos D. ANATOMICAL CORRELATES TO SCRATCH DIGGING IN THE FORELIMB OF EUROPEAN GROUND SQUIRRELS (SPERMOPHILUS CITELLUS). J Mammal 2006. [DOI: 10.1644/05-mamm-a-251r1.1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
The authors report a presumably unusual bony attachment of the pectoralis minor muscle in an adult cadaver. The specimen's left pectoralis minor had no attachment to the coracoid process of the scapula but attached directly to the fibrous capsule of the glenohumeral joint. Some have theorized that the coracohumeral ligament represents fibers of the pectoralis minor that attach to this bone in some animals but that has degenerated in man. This case report seems to support this possibility.
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Affiliation(s)
- R Shane Tubbs
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
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Steppan SJ, Storz BL, Hoffmann RS. Nuclear DNA phylogeny of the squirrels (Mammalia: Rodentia) and the evolution of arboreality from c-myc and RAG1. Mol Phylogenet Evol 2004; 30:703-19. [PMID: 15012949 DOI: 10.1016/s1055-7903(03)00204-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2003] [Revised: 05/15/2003] [Indexed: 10/27/2022]
Abstract
Although the family Sciuridae is large and well known, phylogenetic analyses are scarce. We report on a comprehensive molecular phylogeny for the family. Two nuclear genes (c-myc and RAG1) comprising approximately 4500 bp of data (most in exons) are applied for the first time to rodent phylogenetics. Parsimony, likelihood, and Bayesian analyses of the separate gene regions and combined data reveal five major lineages and refute the conventional elevation of the flying squirrels (Pteromyinae) to subfamily status. Instead, flying squirrels are derived from one of the tree squirrel lineages. C-myc indels corroborate the sequence-based topologies. The common ancestor of extant squirrels appears to have been arboreal, confirming the fossil evidence. The results also reveal an unexpected clade of mostly terrestrial squirrels with African and Holarctic centers of diversity. We present a revised classification of squirrels. Our results demonstrate the phylogenetic utility of relatively slowly evolving nuclear exonic data even for relatively recent clades.
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Affiliation(s)
- Scott J Steppan
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100, USA.
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Swiderski DL. SEPARATING SIZE FROM ALLOMETRY: ANALYSIS OF LOWER JAW MORPHOLOGY IN THE FOX SQUIRREL, SCIURUS NIGER. J Mammal 2003. [DOI: 10.1644/brb-025] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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42
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MENG JIN, HU YAOMING, LI CHUANKUI. THE OSTEOLOGY OF RHOMBOMYLUS (MAMMALIA, GLIRES): IMPLICATIONS FOR PHYLOGENY AND EVOLUTION OF GLIRES. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2003. [DOI: 10.1206/0003-0090(2003)275<0001:toormg>2.0.co;2] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
SUMMARY
Leaping, parachuting and gliding are the primary means by which arboreal squirrels negotiate gaps in the canopy. There are notable differences among the three locomotor modes with respect to mid-air postures and aerodynamics,yet it is unclear whether variation should also be expected during the launch phase of locomotion. To address this question, launch kinematic profiles were compared in leaping (Tamias striatus), parachuting (Tamiasciurus hudsonicus) and gliding (Glaucomys volans) squirrels. Animals were filmed launching to the ground from a platform using high-speed video. Statistical comparisons among taxa indicated that only six out of 23 variables were significantly different among the three species. Two were associated with tail kinematics and were a consequence of tail morphology. Two were forelimb-related and discriminated gliding from non-gliding taxa. The remaining two variables were performance attributes, indicating significant variation among the species in take-off velocity and horizontal range. The absence of significant differences in hindlimb kinematics indicates that propulsion is essentially identical in leaping, parachuting and gliding squirrels.
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Affiliation(s)
- Richard L Essner
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
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Argot C. Functional‐adaptive anatomy of the forelimb in the didelphidae, and the paleobiology of the paleocene marsupials
Mayulestes ferox
and
Pucadelphys andinus. J Morphol 2001. [DOI: 10.1002/1097-4687(200101)247:1<51::aid-jmor1003>3.0.co;2-%23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Christine Argot
- Laboratoire de Paléontologie, Muséum national d'Histoire naturelle, Paris, France
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Argot C. Functional-adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus. J Morphol 2001; 247:51-79. [PMID: 11124686 DOI: 10.1002/1097-4687(200101)247:1<51::aid-jmor1003>3.0.co;2-#] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An attempt to determine the locomotor activities of Mayulestes ferox (Borhyaenoidea) and Pucadelphys andinus (Didelphoidea) from the early Paleocene site of Tiupampa (Bolivia) is presented. The functional anatomy of the forelimbs of these South American marsupials is compared to that of some living didelphids: Caluromys philander, Micoureus demerarae, Marmosa murina, Didelphis marsupialis, Monodelphis brevicaudata and Metachirus nudicaudatus. Deductions from bone morphology to myology and locomotor behavior in the fossils are inferred from the comparisons with living forms. Some features of the postcranial skeleton, indicative of arboreal adaptations, are found in the extinct marsupials: anteriorly projected acromion, hemispherical head of the humerus, extended humeral lateral epicondylar ridge, medially protruding humeral entepicondyle, proximal ulnar posterior convexity, and deep flexor fossa on the medial side of the ulna. But other features are related to a more terrestrial pattern: the well-developed tubercles of the humeral head, the elongated olecranon process of the ulna, and the oval shape of the radial head. Mayulestes had clear arboreal abilities, but, as a predaceous mammal, probably hunted on the ground. Pucadelphys was less specialized, close to the living Monodelphis, a terrestrial insectivorous form with some skeletal features related to arboreal locomotion that are probably plesiomorphic for marsupials.
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Affiliation(s)
- C Argot
- Laboratoire de Paléontologie, Muséum national d'Histoire naturelle, Paris, France
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46
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Thorington, Jr. RW, Stafford BJ. Homologies of the carpal bones in flying squirrels (Pteromyinae): A review. MAMMAL STUDY 2001. [DOI: 10.3106/mammalstudy.26.61] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Anatomical differences among squirrels are usually most evident in the comparison of flying squirrels and nongliding squirrels. This is true of wrist anatomy, probably reflecting the specializations of flying squirrels for the extension of the wing tip and control of it during gliding. In the proximal row of carpals of most squirrels, the pisiform articulates only with the triquetrum, but in flying squirrels there is also a prominent articulation between the pisiform and the scapholunate, providing a more stable base for the styliform cartilage, which supports the wing tip. In the proximal wrist joint, between these carpals and the radius and ulna, differences in curvature of articular surfaces and in the location of ligaments also correlate with differences in degree and kind of movement occurring at this joint, principally reflecting the extreme dorsal flexion and radial deviation of the wrist in flying squirrels when gliding. The distal wrist joint, between the proximal and distal rows of carpals, also shows most variation among flying squirrels, principally in the articulations of the centrale with the other carpal bones, probably causing the distal row of carpal bones to function more like a single unit in some animals. There is little variation in wrist musculature, suggesting only minor evolutionary modification since the tribal radiation of squirrels, probably in the early Oligocene. Variation in the carpal bones, particularly the articulation of the pisiform with the triquetrum and the scapholunate, suggests a different suprageneric grouping of flying squirrels than previously proposed by McKenna (1962) and Mein (1970). J. Morphol. 246:85-102, 2000. Published 2000 Wiley-Liss, Inc.
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Affiliation(s)
- R W Thorington
- Department of Vertebrate Zoology, Smithsonian Institution, Washington, DC 20560-0108, USA.
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