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Khannoon ER, Borczyk B, Alahmadi BA, Aloufi A, Skawiński T. Ontogeny of the autopodial skeleton of the gecko Tarentola (Squamata: Phyllodactylidae). ZOOLOGY 2024; 164:126160. [PMID: 38574691 DOI: 10.1016/j.zool.2024.126160] [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: 09/22/2023] [Revised: 03/24/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Squamates exhibit evident diversity in their limb morphology. Gekkotans are a particularly diverse group in this respect. The appearance of toepads in gekkotans usually cooccurs with the reduction or loss of claws. The gecko Tarentola (Phyllodactylidae) shows a unique combination of features among geckos, with toepads, hyperphalangy, and dimorphism of claw expression (claws are retained on digits III and IV, but lost (manus) or strongly reduced (pes) on the remaining digits). Despite being a candidate model for studying embryonic skeletal development of the autopodium, no studies have investigated the autopodial development of the gecko Tarentola in detail. Here, we aim to follow up the development of the autopodial skeleton in T. annularis and T. mauritanica using acid-free double staining. The results indicate that the terminal phalanges of claw-bearing digits III and IV ossify earlier than in the remaining digits. This confirms the differential ossification as a result of claw regression in Tarentola. The strongly reduced second phalanges of digits IV in both the fore- and hindlimbs are the last ossifying phalanges. Such late ossification may precede the evolutionary loss of this phalanx. If this is correct, the autopodia of Tarentola would be an interesting example of both the hyperphalangy in digit I and the process of phalanx loss in digit IV. Delay in ossification of the miniaturised phalanx probably represents an example of paedomorphosis.
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Affiliation(s)
- Eraqi R Khannoon
- Department of Biology, College of Science, Taibah University, Al-Madinah, Al-Munawwarah 344, Saudi Arabia; Department of Zoology, Faculty of Science, Fayoum University, Fayoum 63514, Egypt.
| | - Bartosz Borczyk
- Department of Evolutionary Biology and Conservation of Vertebrates, Faculty of Biological Sciences, University of Wrocław, Sienkiewicza 21, Wrocław 50-335, Poland
| | - Bassam A Alahmadi
- Department of Biology, College of Science, Taibah University, Al-Madinah, Al-Munawwarah 344, Saudi Arabia
| | - Abdulhadi Aloufi
- Department of Biology, College of Science, Taibah University, Al-Madinah, Al-Munawwarah 344, Saudi Arabia
| | - Tomasz Skawiński
- Museum of Natural History, Faculty of Biological Sciences, University of Wrocław,, Sienkiewicza 21, Wrocław 50-335, Poland
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Ollonen J, Khannoon ER, Macrì S, Vergilov V, Kuurne J, Saarikivi J, Soukainen A, Aalto IM, Werneburg I, Diaz RE, Di-Poï N. Dynamic evolutionary interplay between ontogenetic skull patterning and whole-head integration. Nat Ecol Evol 2024; 8:536-551. [PMID: 38200368 DOI: 10.1038/s41559-023-02295-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/29/2023] [Indexed: 01/12/2024]
Abstract
The arrangement and morphology of the vertebrate skull reflect functional and ecological demands, making it a highly adaptable structure. However, the fundamental developmental and macroevolutionary mechanisms leading to different vertebrate skull phenotypes remain unclear. Here we exploit the morphological diversity of squamate reptiles to assess the developmental and evolutionary patterns of skull variation and covariation in the whole head. Our geometric morphometric analysis of a complex squamate ontogenetic dataset (209 specimens, 169 embryos, 44 species), covering stages from craniofacial primordia to fully ossified bones, reveals that morphological differences between snake and lizard skulls arose gradually through changes in spatial relationships (heterotopy) followed by alterations in developmental timing or rate (heterochrony). Along with dynamic spatiotemporal changes in the integration pattern of skull bone shape and topology with surrounding brain tissues and sensory organs, we identify a relatively higher phenotypic integration of the developing snake head compared with lizards. The eye, nasal cavity and Jacobson's organ are pivotal in skull morphogenesis, highlighting the importance of sensory rearrangements in snake evolution. Furthermore, our findings demonstrate the importance of early embryonic, ontogenetic and tissue interactions in shaping craniofacial evolution and ecological diversification in squamates, with implications for the nature of cranio-cerebral relations across vertebrates.
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Affiliation(s)
- Joni Ollonen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Al Madinah Al Munawwarah, Saudi Arabia
- Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - Simone Macrì
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Vladislav Vergilov
- National Museum of Natural History, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Jaakko Kuurne
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jarmo Saarikivi
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Arttu Soukainen
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ida-Maria Aalto
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ingmar Werneburg
- Senckenberg Centre for Human Evolution and Palaeoenvironment, Eberhard Karls Universität, Tübingen, Germany
- Fachbereich Geowissenschaften, Eberhard Karls Universität, Tübingen, Germany
| | - Raul E Diaz
- Department of Biological Sciences, California State University, Los Angeles, CA, USA
- Department of Herpetology, Natural History Museum of Los Angeles County, Los Angeles, CA, USA
| | - Nicolas Di-Poï
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.
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Usui K, Yamamoto T, Khannoon ER, Tokita M. Musculoskeletal morphogenesis supports the convergent evolution of bat laryngeal echolocation. Proc Biol Sci 2024; 291:20232196. [PMID: 38290542 PMCID: PMC10827442 DOI: 10.1098/rspb.2023.2196] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 12/18/2023] [Indexed: 02/01/2024] Open
Abstract
The order Chiroptera (bats) is the second largest group of mammals. One of the essential adaptations that have allowed bats to dominate the night skies is laryngeal echolocation, where bats emit ultrasonic pulses and listen to the returned echo to produce high-resolution 'images' of their surroundings. There are two possible scenarios for the evolutionary origin of laryngeal echolocation in bats: (1) a single origin in a common ancestor followed by the secondary loss in Pteropodidae, or (2) two convergent origins in Rhinolophoidea and Yangochiroptera. Although data from palaeontological, anatomical, developmental and genomic studies of auditory apparatuses exist, they remain inconclusive concerning the evolutionary origin of bat laryngeal echolocation. Here we compared musculoskeletal morphogenesis of the larynx in several chiropteran lineages and found distinct laryngeal modifications in two echolocating lineages, rhinolophoids and yangochiropterans. Our findings support the second scenario that rhinolophoids and yangochiropterans convergently evolved advanced laryngeal echolocation through anatomical modifications of the larynx for ultrasonic sound generation and refinement of the auditory apparatuses for more detailed sound perception.
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Affiliation(s)
- Kaoru Usui
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Tomoki Yamamoto
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Eraqi R. Khannoon
- Biology Department, College of Science, Taibah University, Al Madinah Al Munawwarah, PO Box 30002, Saudi Arabia
- Zoology Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
| | - Masayoshi Tokita
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
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Khannoon ER, Alvarado C, Poveda R, de Bellard ME. Description of trunk neural crest migration and peripheral nervous system formation in the Egyptian cobra Naja haje haje. Differentiation 2023; 133:40-50. [PMID: 37473561 DOI: 10.1016/j.diff.2023.06.002] [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: 02/02/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/22/2023]
Abstract
The neural crest is a stem cell population that forms in the neurectoderm of all vertebrates and gives rise to a diverse set of cells such as sensory neurons, Schwann cells and melanocytes. Neural crest development in snakes is still poorly understood. From the point of view of evolutionary and comparative anatomy is an interesting topic given the unique anatomy of snakes. The aim of the study was to characterize how trunk neural crest cells (TNCC) migrate in the developing elapid snake Naja haje haje and consequently, look at the beginnings of development of neural crest derived sensory ganglia (DRG) and spinal nerves. We found that trunk neural crest and DRG development in Naja haje haje is like what has been described in other vertebrates and the colubrid snake strengthening our knowledge on the conserved mechanisms of neural crest development across species. Here we use the marker HNK1 to follow the migratory behavior of TNCC in the elapid snake Naja haje haje through stages 1-6 (1-9 days postoviposition). We observed that the TNCC of both snake species migrate through the rostral portion of the somite, a pattern also conserved in birds and mammals. The development of cobra peripheral nervous system, using neuronal and glial markers, showed the presence of spectrin in Schwann cell precursors and of axonal plexus along the length of the cobra embryos. In conclusion, cobra embryos show strong conserved patterns in TNCC and PNS development among vertebrates.
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Affiliation(s)
- Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Al-Madinah Al-Munawwarah, 344, Saudi Arabia; Zoology Department, Faculty of Science, Fayoum University, Fayoum, 63514, Egypt
| | - Christian Alvarado
- California State University Northridge, Biology Dept., MC 8303, 18111 Nordhoff Street, Northridge, CA, 91330, USA
| | - Rafael Poveda
- Department of Biology. Moorpark College, Moorpark, CA, 93021, USA
| | - Maria Elena de Bellard
- California State University Northridge, Biology Dept., MC 8303, 18111 Nordhoff Street, Northridge, CA, 91330, USA.
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Usui K, Khannoon ER, Tokita M. Facial muscle modification associated with chiropteran noseleaf development: insights into the developmental basis of a movable rostral appendage in mammals. Dev Dyn 2022; 251:1368-1379. [DOI: 10.1002/dvdy.472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/12/2022] [Accepted: 03/17/2022] [Indexed: 11/05/2022] Open
Affiliation(s)
- Kaoru Usui
- Department of Biology, Faculty of Science Toho University, 2‐2‐1 Miyama, Funabashi Chiba JAPAN
| | - Eraqi R. Khannoon
- Biology Department College of Science, Taibah University, Al Madinah Al Munawwarah KSA
- Zoology Department, Faculty of Science Fayoum University Fayoum Egypt
| | - Masayoshi Tokita
- Department of Biology, Faculty of Science Toho University, 2‐2‐1 Miyama, Funabashi Chiba JAPAN
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Khannoon ER, Evans SE. Embryonic skull development in the gecko, Tarentola annularis (Squamata: Gekkota: Phyllodactylidae). J Anat 2020; 237:504-519. [PMID: 32485010 DOI: 10.1111/joa.13213] [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: 02/28/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 11/29/2022] Open
Abstract
Tarentola annularis is a climbing gecko with a wide distribution in Africa north of the equator. In the present paper, we describe the development of the osteocranium of this lizard, from the first appearance of the cranial elements up to the point of hatching. This is based on a combination of histology and cleared and stained specimens. This is the first comprehensive account of gekkotan pre-hatching skull development based on a comprehensive series of embryos, rather than a few selected stages. Given that Gekkota is now widely regarded as representing the sister group to other squamates, this account helps to fill a significant gap in the literature. Moreover, as many authors have considered features of the gekkotan skull and skeleton to be indicative of paedomorphosis, it is important to know whether this hypothesis is supported by delays in the onset of cranial ossification. In fact, we found the sequence of cranial bone ossification to be broadly comparable to that of other squamates studied to date, with no significant lags in development.
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Affiliation(s)
- Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Al-Madinah Al-Munawwarah, Saudi Arabia.,Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - Susan E Evans
- Department of Cell and Developmental Biology, Centre for Integrated Anatomy, University College London, London, UK
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Alturk WIM, Khannoon ER. Ontogeny of the Moorish gecko Tarentola mauritanica with emphasis on morphogenesis of the skin and its derivatives. J Exp Zool B Mol Dev Evol 2020; 334:294-310. [PMID: 32410344 DOI: 10.1002/jez.b.22951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 04/05/2020] [Accepted: 04/27/2020] [Indexed: 01/08/2023]
Abstract
Studying reptilian embryonic development provides answers to many questions related to the development of tetrapods. Reptilian skin has been recently considered in studies at the evo-devo level. The lizard epidermis has to be shed periodically. At the embryonic level, contention exists regarding the first layers to appear, whether the oberhautchen or the clear layer, and whether the shedding complex develops before hatching. Geckos exhibit diverse morphologies independently evolved multiple times within the clade, such as subdigital pad lamellae. Here we investigate the embryonic development of Tarentola mauritanica and establishing its embryonic table. Primarily we follow the development of the integument. This is a closely related species to Tarentola annularis and it is crucial to investigate whether it has the same derived digital condition of claw regression. Eleven embryonic stages are described according to the external morphological characteristics of the embryos. Interestingly, the oviposition stage appears earlier than its close relative T. annularis, and the total incubation time is less. We also describe skin development, adding clear evidence to the debate on the development of the shedding complex, which we found is developed before hatching. We describe one layer of periderm and the clear layer as the first embryonic epidermal layers. Generally, our results show the genus Tarentola to have the advantage of being a unique taxon, easily breed at the laboratory, with multiple clutches per year, and with an earlier stage at oviposition. That could be a model animal for embryonic development and experimental embryology studies.
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Affiliation(s)
- Wafaa I M Alturk
- Biology Department, College of Science, Taibah University, Medina, Saudi Arabia
| | - Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Medina, Saudi Arabia.,Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
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Khannoon ER, Ollonen J, Di-Poï N. Embryonic development of skull bones in the Sahara horned viper (Cerastes cerastes), with new insights into structures related to the basicranium and braincase roof. J Anat 2020; 237:1-19. [PMID: 32242931 DOI: 10.1111/joa.13182] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 11/04/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 01/14/2023] Open
Abstract
Ontogenetic studies are crucial for understanding functional morphology, origin and adaptation of skulls in vertebrates. However, very few studies have so far released complete embryonic series focusing on skull embryonic development in species showing diverse and extreme cranial morphologies such as snakes. The wide distribution and unique reproductive and ecological behaviors of venomous vipers, including the heterogeneity in breeding and egg incubation periods in oviparous species, make this group an excellent new model for studying the diversity of skull developmental processes in snakes. Here we present the first complete description of osteocranium development in a viperine snake, Cerastes cerastes, using detailed analysis of the ossification pattern of individual bones across different embryonic stages based on high-resolution micro-computed tomography data. Particularly, we describe in detail the development of the laterosphenoid from its dorsal and ventral components, dividing the trigeminal foramen into maxillary and mandibular foramina. Furthermore, our data help clarify some controversy concerning the presence and/or origin of structures related to the snake basicranium and braincase roof. For example, our detailed description of supraoccipital development suggests that this bone derived, at least in part, from the tectum posterius, although the involvement of the tectum synoticum cannot be totally excluded. Similarly, the epiotic centers of supraoccipital ossification are confirmed during braincase development, and the ancestral lacrimal bone primordium is observed as a ventral element at the early stages of prefrontal development. Finally, our embryonic C. cerastes data highlight a plausible asymmetry in snake skull development, mostly occurring in the basicranium region, but further investigations of embryonic samples and viper species would be required to confirm such phenomenon.
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Affiliation(s)
- Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Saudi Arabia.,Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - Joni Ollonen
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Program in Developmental Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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Khannoon ER, Usui K, Tokita M. Embryonic Development of the Egyptian Fruit Bat Rousettus aegyptiacus (Mammalia: Chiroptera: Pteropodidae). Acta Chiropterologica 2020. [DOI: 10.3161/15081109acc2019.21.2.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Eraqi R. Khannoon
- Biology Department, College of Science, Taibah University, Al Madinah Al Munawwarah, PO Box 30002, Saudi Arabia
| | - Kaoru Usui
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
| | - Masayoshi Tokita
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
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Fons JM, Gaete M, Zahradnicek O, Landova M, Bandali H, Khannoon ER, Richman JM, Buchtova M, Tucker AS. Getting out of an egg: Merging of tooth germs to create an egg tooth in the snake. Dev Dyn 2019; 249:199-208. [PMID: 31587402 DOI: 10.1002/dvdy.120] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 02/25/2019] [Revised: 08/02/2019] [Accepted: 08/24/2019] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The egg tooth is a vital structure allowing hatchlings to escape from the egg. In squamates (snakes and lizards), the egg tooth is a real tooth that develops within the oral cavity at the top of the upper jaw. Most squamates have a single large midline egg tooth at hatching, but a few families, such as Gekkonidae, have two egg teeth. In snakes the egg tooth is significantly larger than the rest of the dentition and is one of the first teeth to develop. RESULTS We follow the development of the egg tooth in four snake species and show that the single egg tooth is formed by two tooth germs. These two tooth germs are united at the midline and grow together to produce a single tooth. In culture, this merging can be perturbed to give rise to separate smaller teeth, confirming the potential of the developing egg tooth to form two teeth. CONCLUSIONS Our data agrees with previous hypotheses that during evolution one potential mechanism to generate a large tooth is through congrescence of multiple tooth germs and suggests that the ancestors of snakes could have had two egg teeth.
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Affiliation(s)
- Juan M Fons
- Centre for Craniofacial and Regenerative Biology, Floor 27 Guy's Tower, Guy's Hospital, King's College London, London Bridge, London, UK
| | - Marcia Gaete
- Centre for Craniofacial and Regenerative Biology, Floor 27 Guy's Tower, Guy's Hospital, King's College London, London Bridge, London, UK.,Department of Anatomy, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Oldrich Zahradnicek
- Department of Developmental Biology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
| | - Marie Landova
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Hussein Bandali
- Centre for Craniofacial and Regenerative Biology, Floor 27 Guy's Tower, Guy's Hospital, King's College London, London Bridge, London, UK
| | - Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Al-Madinah Al-Munawwarah, Kingdom of Saudi Arabia.,Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - Joy M Richman
- Department of Oral Health Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Marcela Buchtova
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Brno, Czech Republic.,Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, Floor 27 Guy's Tower, Guy's Hospital, King's College London, London Bridge, London, UK.,Department of Developmental Biology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czech Republic
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Al Mohammadi AGA, Khannoon ER, Evans SE. The development of the osteocranium in the snake Psammophis sibilans (Serpentes: Lamprophiidae). J Anat 2019; 236:117-131. [PMID: 31475358 DOI: 10.1111/joa.13081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2019] [Indexed: 11/29/2022] Open
Abstract
Non-avian reptiles are good models to investigate structural and developmental differences between amniotes. Investigations of craniofacial development in a complete series of embryos from oviposition up to hatching are still relatively rare. Consideration of a complete series can reveal developmental events that were previously missed, and thus correct or confirm theories about developmental events. The Egyptian Sand snake, Psammophis sibilans, has been a key species in descriptions of the snake skull development. However, published work was based on a limited sample of specimens collected from the wild. Here, we supplement previous descriptions with an illustrated account of skull development in P. sibilans based on a staged series of embryos and histological sections. Our findings largely agree with those of previous authors, although we record differences in developmental timing, confirming the presence of an egg tooth in this species. We add further observations on the enigmatic fenestra X, showing that it closes rather than merging with the prootic notch. Our observations revealed the likely contribution of the tectum posterius to the occipital roof, the presence of an internal carotid foramen (possibly transitory or variable), and the formation of the initial laterosphenoid pillar.
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Affiliation(s)
- Ameera G A Al Mohammadi
- Biology Department, College of Science, Taibah University, Al-Madinah Al-Munawwarah, Saudi Arabia
| | - Eraqi R Khannoon
- Biology Department, College of Science, Taibah University, Al-Madinah Al-Munawwarah, Saudi Arabia.,Zoology Department, Faculty of Science, Fayoum University, Fayoum, Egypt
| | - Susan E Evans
- Department of Cell and Developmental Biology, University College London, London, UK
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Khannoon ER, Rupik W, Lewandowski D, Dubińska-Magiera M, Swadźba E, Daczewska M. Unique features of myogenesis in Egyptian cobra (Naja haje) (Squamata: Serpentes: Elapidae). Protoplasma 2016; 253:625-33. [PMID: 26025263 PMCID: PMC4783446 DOI: 10.1007/s00709-015-0840-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/21/2015] [Indexed: 06/04/2023]
Abstract
During early stages of myotomal myogenesis, the myotome of Egyptian cobra (Naja haje) is composed of homogenous populations of mononucleated primary myotubes. At later developmental phase, primary myotubes are accompanied by closely adhering mononucleated cells. Based on localization and morphology, we assume that mononucleated cells share features with satellite cells involved in muscle growth. An indirect morphological evidence of the fusion of mononucleated cells with myotubes is the presence of numerous vesicles in the subsarcolemmal region of myotubes adjacent to mononucleated cell. As differentiation proceeded, secondary muscle fibres appeared with considerably smaller diameter as compared to primary muscle fibre. Studies on N. haje myotomal myogenesis revealed some unique features of muscle differentiation. TEM analysis showed in the N. haje myotomes two classes of muscle fibres. The first class was characterized by typical for fast muscle fibres regular distribution of myofibrils which fill the whole volume of muscle fibre sarcoplasm. White muscle fibres in studied species were a prominent group of muscles in the myotome. The second class showed tightly paced myofibrils surrounding the centrally located nucleus accompanied by numerous vesicles of different diameter. The sarcoplasm of these cells was characterized by numerous lipid droplets. Based on morphological features, we believe that muscle capable of lipid storage belong to slow muscle fibres and the presence of lipid droplets in the sarcoplasm of these muscles during myogenesis might be a crucial adaptive mechanisms for subsequent hibernation in adults. This phenomenon was, for the first time, described in studies on N. haje myogenesis.
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Affiliation(s)
- Eraqi R Khannoon
- Zoology Department, Faculty of Science, Fayoum University, Fayoum, 63514, Egypt
| | - Weronika Rupik
- Department of Animal Histology and Embryology, University of Silesia, 9 Bankowa Str., 40-007, Katowice, Poland
| | - Damian Lewandowski
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wrocław, 21 Sienkiewicza Str., 53-335, Wrocław, Poland
| | - Magda Dubińska-Magiera
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wrocław, 21 Sienkiewicza Str., 53-335, Wrocław, Poland
| | - Elwira Swadźba
- Department of Animal Histology and Embryology, University of Silesia, 9 Bankowa Str., 40-007, Katowice, Poland
| | - Małgorzata Daczewska
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wrocław, 21 Sienkiewicza Str., 53-335, Wrocław, Poland.
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Khannoon ER, Zahradnicek O. Postovipositional development of the sand snakePsammophis sibilans(Serpentes:Lamprophiidae) in comparison with other snake species. ACTA ZOOL-STOCKHOLM 2016. [DOI: 10.1111/azo.12157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Eraqi R. Khannoon
- Department of Biology; Faculty of Science; Taibah University; PO Box 30002, Al Madinah Al Munawarah Saudi Arabia
- Zoology Department; Faculty of Science; Fayoum University; Fayoum 63514 Egypt
| | - Oldrich Zahradnicek
- Department of Teratology; Institute of Experimental Medicine; Academy of Sciences of the Czech Republic; Vídeňská, 1083 Prague 4 142 20 Czech Republic
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Khannoon ER, Mohammed KK, Dakrory AI. Skin-derived semiochemicals of the lacertid lizard Acanthodactylus boskianus. AMPHIBIA-REPTILIA 2016. [DOI: 10.1163/15685381-00003074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Skin lipids impede transcutaneous water loss in several species of squamate reptiles and act as a barrier to harmful microorganisms; they play an additional role as chemical cues involved in chemical communication eliciting behavioral responses in intra- and interspecific interactions. While studies till now give little detailed information on the nature of skin slough, the femoral gland secretions of the lacertid lizardAcanthodactylus boskianushave been analyzed and the chemical profile is known for the species. In the present study we use GC-MS analysis of skin slough to focus on the chemical composition of skin in the xeric-adapted lacertid lizardA. boskianusand compare this to its femoral secretions. In the shed skin we detected steroids, alcohols, carboxylic acids, alkanes, aldehydes, carboxylic acid esters, squalene, monoglycerides of fatty acids, glycerol monoethers of long chain alcohols, and 1,3 alkanediol, which are the same chemical groups already found in the femoral secretions of this species. However, the relative percentages of these compounds in skin slough differ from those known for femoral secretions. While the compounds characterizing skin slough are qualitatively similar to femoral secretions, they could represent an adaptation to hot and dry habitats ofA. boskianus. With regard to the characteristic chemical profiles for different sexes, there is not enough evidence to support their possible role as chemosignals, and behavioral experiments should be performed to test the possible use of skin shedding in intraspecific communication.
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Affiliation(s)
- Eraqi R. Khannoon
- Zoology Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
- Department of Biology, Faculty of Science, Taibah University, PO Box 30002, Al Madinah Al Munawwarah, Saudi Arabia
| | - Kamar K.H. Mohammed
- Zoology Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
| | - Ahmed I. Dakrory
- Department of Biology, Faculty of Science, Taif University, Saudi Arabia
- Zoology Department, Faculty of Science, Cairo University, Egypt
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Khannoon ER. Developmental stages of the climbing geckoTarentola annulariswith special reference to the claws, pad lamellae, and subdigital setae. J Exp Zool (Mol Dev Evol ) 2015; 324:450-64. [DOI: 10.1002/jez.b.22630] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 04/18/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Eraqi R. Khannoon
- Department of Zoology; Faculty of Science; Fayoum University; Fayoum 63514 Egypt
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Khannoon ER, Russell AP, Tucker AS. Developmental mechanisms underlying differential claw expression in the autopodia of geckos. EvoDevo 2015; 6:8. [PMID: 25878768 PMCID: PMC4397723 DOI: 10.1186/s13227-015-0003-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 01/21/2015] [Accepted: 03/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The limb and autopodium are frequently employed to study pattern formation during embryonic development, providing insights into how cells give rise to complex anatomical structures. With regard to the differentiation of structures at the distal tips of digits, geckos constitute an attractive clade, because within their ranks they exhibit multiple independent occurrences of claw loss and reduction, these being linked to the development of adhesive pads. The developmental patterns that lead to claw loss, however, remain undescribed. Among geckos, Tarentola is a genus characterized by large claws on digits III and IV of the manus and pes, with digits I, II, and V bearing only vestigial claws, or lacking them entirely. The variable expression of claws on different digits provides the opportunity to investigate the processes leading to claw reduction and loss within a single species. RESULTS Here, we document the embryonic developmental dynamics that lead to this intraspecifically variable pattern, focusing on the cellular processes of proliferation and cell death. We find that claws initially develop on all digits of all autopodia, but, later in development, those of digits I, II, and V regress, leading to the adult condition in which robust claws are evident only on digits III and IV. Early apoptotic activity at the digit tips, followed by apoptosis of the claw primordium, premature ossification of the terminal phalanges, and later differential proliferative activity are collectively responsible for claw regression in particular digits. CONCLUSIONS Claw reduction and loss in Tarentola result from differential intensities of apoptosis and cellular proliferation in different digits, and these processes have already had some effect before visible signs of claw development are evident. The differential processes persist through later developmental stages. Variable expression of iteratively homologous structures between digits within autopodia makes claw reduction and loss in Tarentola an excellent vehicle for exploring the developmental mechanisms that lead to evolutionary reduction and loss of structures.
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Affiliation(s)
- Eraqi R Khannoon
- Zoology Department, Faculty of Science, Fayoum University, Fayoum, 63514 Egypt ; King's College London, Floor 27 Guy's Tower, Guy's Hospital, Great Maze Pond, London Bridge, London, SE1 9RT UK
| | - Anthony P Russell
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 Canada
| | - Abigail S Tucker
- King's College London, Floor 27 Guy's Tower, Guy's Hospital, Great Maze Pond, London Bridge, London, SE1 9RT UK
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Khannoon ER, Evans SE. The development of the skull of the Egyptian Cobra Naja h. haje (Squamata: Serpentes: Elapidae). PLoS One 2015; 10:e0122185. [PMID: 25860015 PMCID: PMC4393244 DOI: 10.1371/journal.pone.0122185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/08/2015] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The study of craniofacial development is important in understanding the ontogenetic processes behind morphological diversity. A complete morphological description of the embryonic skull development of the Egyptian cobra, Naja h. haje, is lacking and there has been little comparative discussion of skull development either among elapid snakes or between them and other snakes. METHODOLOGY/PRINCIPAL FINDINGS We present a description of skull development through a full sequence of developmental stages of the Egyptian cobra, and compare it to other snakes. Associated soft tissues of the head are noted where relevant. The first visible ossification centres are in the supratemporal, prearticular and surangular, with slight ossification visible in parts of the maxilla, prefrontal, and dentary. Epiotic centres of ossification are present in the supraoccipital, and the body of the supraoccipital forms from the tectum posterior not the tectum synoticum. The venom glands are visible as distinct bodies as early at stage 5 and enlarge later to extend from the otic capsule to the maxilla level with the anterior margin of the eye. The gland becomes more prominent shortly before hatching, concomitant with the development of the fangs. The tongue shows incipient forking at stage 5, and becomes fully bifid at stage 6. CONCLUSIONS/SIGNIFICANCE We present the first detailed staging series of cranial development for the Egyptian cobra, Naja h. haje. This is one of the first studies since the classical works of G. de Beer and W. Parker that provides a detailed description of cranial development in an advanced snake species. It allows us to correct errors and misinterpretations in previous accounts which were based on a small sample of specimens of uncertain age. Our results highlight potentially significant variation in supraoccipital formation among squamates and the need for further research in this area.
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Affiliation(s)
- Eraqi R. Khannoon
- Zoology Department, Faculty of Science, Fayoum University, Fayoum, 63514, Egypt
| | - Susan E. Evans
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, England, United Kingdom
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Khannoon ER, Endlein T, Russell AP, Autumn K. Experimental evidence for friction-enhancing integumentary modifications of chameleons and associated functional and evolutionary implications. Proc Biol Sci 2013; 281:20132334. [PMID: 24285195 DOI: 10.1098/rspb.2013.2334] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [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: 11/12/2022] Open
Abstract
The striking morphological convergence of hair-like integumentary derivatives of lizards and arthropods (spiders and insects) demonstrates the importance of such features for enhancing purchase on the locomotor substrate. These pilose structures are responsible for the unique tractive abilities of these groups of animals, enabling them to move with seeming ease on overhanging and inverted surfaces, and to traverse inclined smooth substrates. Three groups of lizards are well known for bearing adhesion-promoting setae on their digits: geckos, anoles and skinks. Similar features are also found on the ventral subdigital and distal caudal skin of chameleons. These have only recently been described in any detail, and structurally and functionally are much less well understood than are the setae of geckos and anoles. The seta-like structures of chameleons are not branched (a characteristic of many geckos), nor do they terminate in spatulate tips (which is characteristic of geckos, anoles and skinks). They are densely packed and have attenuated blunt, globose tips or broad, blade-like shafts that are flattened for much of their length. Using a force transducer, we tested the hypothesis that these structures enhance friction and demonstrate that the pilose skin has a greater frictional coefficient than does the smooth skin of these animals. Our results are consistent with friction being generated as a result of side contact of the integumentary filaments. We discuss the evolutionary and functional implications of these seta-like structures in comparison with those typical of other lizard groups and with the properties of seta-mimicking synthetic structures.
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Affiliation(s)
- Eraqi R Khannoon
- Faculty of Science, Department of Zoology, Fayoum University, , Fayoum 63514, Egypt, Centre for Cell Engineering, University of Glasgow, , Joseph Black Building, University Avenue, Glasgow G12 8QQ, UK, Department of Biological Sciences, University of Calgary, , 2500 University Drive NW, Calgary, Alberta, Canada , T2N 1 N4, Department of Biology, Lewis and Clark College, , 0615 Palatine Hill Road, Portland, OR 97219-7899, USA
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Affiliation(s)
- Eraqi R. Khannoon
- Zoology Department; Faculty of Science; Fayoum University; Fayoum 63514 Egypt
| | - Susan E. Evans
- Department of Cell and Developmental Biology; University College London; Gower Street London WC1E 6BT UK
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Khannoon ER, Lunt DH, Schulz S, Hardege JD. Divergence of Scent Pheromones in Allopatric Populations ofAcanthodactylus boskianus(Squamata: Lacertidae). Zoolog Sci 2013; 30:380-5. [DOI: 10.2108/zsj.30.380] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Khannoon ER, El-Gendy A, Hardege JD. Scent marking pheromones in lizards: cholesterol and long chain alcohols elicit avoidance and aggression in male Acanthodactylus boskianus (Squamata: Lacertidae). CHEMOECOLOGY 2011. [DOI: 10.1007/s00049-011-0076-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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