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Allemand R, Abdul-Sater J, Macrì S, Di-Poï N, Daghfous G, Silcox MT. Endocast, brain, and bones: Correspondences and spatial relationships in squamates. Anat Rec (Hoboken) 2023; 306:2443-2465. [PMID: 36602153 DOI: 10.1002/ar.25142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023]
Abstract
Vertebrate endocasts are widely used in the fields of paleoneurology and comparative neuroanatomy. The validity of endocranial studies is dependent upon the extent to which an endocast reflects brain morphology. Due to the variable neuroanatomical resolution of vertebrate endocasts, direct information about the brain morphology can be sometimes difficult to assess and needs to be investigated across lineages. Here, we employ X-ray computed tomography (CT), including diffusible iodine-based contrast-enhanced CT, to qualitatively compare brains and endocasts in different species of squamates. The relative position of the squamate brain within the skull, as well as the variability that may exist in such spatial relationships, was examined to help clarify the neurological regions evidence on their endocasts. Our results indicate that squamate endocasts provide variable representation of the brain, depending on species and neuroanatomical regions. The olfactory bulbs and peduncles, cerebral hemispheres, as well as the medulla oblongata represent the most easily discernable brain regions from squamate endocasts. In contrast, the position of the optic lobes, the ventral diencephalon and the pituitary may be difficult to determine depending on species. Finally, squamate endocasts provide very limited or no information about the cerebellum. The spatial relationships revealed here between the brain and the surrounding bones may help to identify each of the endocranial region. However, as one-to-one correspondences between a bone and a specific region appear limited, the exact delimitation of these regions may remain challenging according to species. This study provides a basis for further examination and interpretation of squamate endocast disparity.
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Affiliation(s)
- Rémi Allemand
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Jade Abdul-Sater
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Simone Macrì
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | | | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
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2
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Broeckhoven C, du Plessis A. Osteoderms as calcium reservoirs: Insights from the lizard Ouroborus cataphractus. J Anat 2022; 241:635-640. [PMID: 35502528 DOI: 10.1111/joa.13683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/13/2022] [Accepted: 04/13/2022] [Indexed: 11/27/2022] Open
Abstract
The functional significance of osteoderms-bony elements embedded in the dermis-remains a topic of much debate. Although many hypotheses have been put forward in the past, the idea that osteoderms can serve as calcium reservoirs has received little experimental attention thus far. In this study, we use micro-computed tomography to investigate inter- and intrasexual variation in osteoderm density in the viviparous lizard Ouroborus cataphractus and conduct histochemical analyses to unravel the potential mechanism involved in mineral resorption from the osteoderms. Our results show that females have denser, more compact osteoderms than males of similar body sizes, regardless of the season during which they were collected and their reproductive state. Furthermore, a histochemical study demonstrates the presence of mononucleated TRAP-positive cells in the vascular canals of the osteoderms. Based on the findings of this study, we suggest that the mineral storage hypothesis merits further attention as a candidate explanation for osteoderm evolution.
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Affiliation(s)
- Chris Broeckhoven
- Laboratory of Functional Morphology, University of Antwerp, Wilrijk, Belgium
| | - Anton du Plessis
- Object Research Systems, Montreal, Canada.,Research group 3D Innovation, Stellenbosch University, Stellenbosch, South Africa
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3
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Sakai O. One or two eggs: what underlies clutch size variation within a gecko species? ZOOLOGY 2021; 146:125911. [PMID: 33711783 DOI: 10.1016/j.zool.2021.125911] [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: 09/26/2020] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 12/01/2022]
Abstract
Although the majority of reptiles show variable clutch sizes, geckos have a fixed clutch size (one or two eggs) and modify reproductive output by changing the offspring size or clutch frequency. However, the clutch size of several geckos is not strictly fixed at the species level; they actually lay both single- and double-egg clutches. We still do not fully understand if clutch size variation within a gecko species is due to adaptive control or reproductive failure like accidental absorption of one of two eggs. This study investigated differences between single- and double-egg clutches of a gecko species in terms of reproductive frequency, egg size, and offspring trait. I housed mourning geckos Lepidodactylus lugubris in a controlled environment and observed their reproduction for seven years. No large differences between single- and double-egg clutches were detected in reproductive frequency and egg size, indicating that life-history trade-offs do not explain much about clutch size variation. Single-egg was comparable in egg size to double-egg, but hatchlings from single-egg showed significantly lower body condition than did those from double-egg. These results suggest that the single-egg is not only a reduction of reproductive output per clutch, but it may provide negative effect on ontogeny.
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Affiliation(s)
- Osamu Sakai
- Department of Zoology, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake, Sakyo, Kyoto, 606-8502, Japan.
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Laver RJ, Morales CH, Heinicke MP, Gamble T, Longoria K, Bauer AM, Daza JD. The development of cephalic armor in the tokay gecko (Squamata: Gekkonidae:
Gekko gecko
). J Morphol 2019; 281:213-228. [DOI: 10.1002/jmor.21092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Rebecca J. Laver
- Research School of Biology Australian National University Canberra Australia
| | - Cristian H. Morales
- Department of Biological Sciences Sam Houston State University Huntsville Texas
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Matthew P. Heinicke
- Department of Natural Sciences University of Michigan‐Dearborn Dearborn Michigan
| | - Tony Gamble
- Department of Biological Sciences Marquette University Milwaukee Wisconsin
- Milwaukee Public Museum Milwaukee Wisconsin
- Bell Museum of Natural History University of Minnesota Saint Paul Minnesota
| | - Kristin Longoria
- Department of Biological Sciences Sam Houston State University Huntsville Texas
| | - Aaron M. Bauer
- Department of Biology Villanova University Villanova Pennsylvania
| | - Juan D. Daza
- Department of Biological Sciences Sam Houston State University Huntsville Texas
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Diaz RE, Shylo NA, Roellig D, Bronner M, Trainor PA. Filling in the phylogenetic gaps: Induction, migration, and differentiation of neural crest cells in a squamate reptile, the veiled chameleon (Chamaeleo calyptratus). Dev Dyn 2019; 248:709-727. [DOI: 10.1002/dvdy.38] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 12/13/2022] Open
Affiliation(s)
- Raul E. Diaz
- Department of Biological Sciences, Southeastern Louisiana University Hammond Louisiana
- Natural History Museum of Los Angeles CountyDivision of Herpetology Los Angeles California
| | | | - Daniela Roellig
- Division of Biology and Biological Engineering, California Institute of Technology Pasadena California
| | - Marianne Bronner
- Division of Biology and Biological Engineering, California Institute of Technology Pasadena California
| | - Paul A. Trainor
- Stowers Institute for Medical Research Kansas City Missouri
- Department of Anatomy and Cell Biology, University of Kansas Medical Center Kansas City Kansas
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Dornburg A, Lamb AD, Warren D, Watkins-Colwell GJ, Lewbart GA, Flowers J. Are Geckos Paratenic Hosts for Caribbean Island Acanthocephalans? Evidence from Gonatodes antillensis and a Global Review of Squamate Reptiles Acting as Transport Hosts. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2019. [DOI: 10.3374/014.060.0103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - April D. Lamb
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695 USA
| | - Dan Warren
- Senckenberg Biodiversity and Climate Research Institute, Frankfurt am Main 60325 Germany
| | - Gregory J. Watkins-Colwell
- Division of Vertebrate Zoology, Peabody Museum of Natural History, Yale University, New Haven, CT 06520 USA
| | - Gregory A. Lewbart
- College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607 USA
| | - James Flowers
- College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607 USA
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7
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Suzuki Y, Kurakata E, Yoshida A, Kobayashi A, Park MK. Molecular identification of single hormone-encoding proglucagon cDNA isoforms from squamates and their abundant expression. Gene 2018; 675:322-331. [PMID: 29981418 DOI: 10.1016/j.gene.2018.07.011] [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: 01/25/2018] [Revised: 06/29/2018] [Accepted: 07/03/2018] [Indexed: 11/15/2022]
Abstract
Among ectothermic reptiles, the order Squamata has adapted most successfully to the terrestrial environment. However, the physiological background of this success remains unknown. Since the regulation of energy metabolism provides an important insight into terrestrial adaption by ectothermic animals, we focused on proglucagon-derived peptides (PGDPs). In the process of cloning proglucagon mRNA in geckos, we identified several novel proglucagon (PG) cDNA isoforms. They were tissue-specifically and strongly expressed in the pancreas and small intestine of the geckos, suggesting their biological relevance. Therefore, in order to clarify whether these novel cDNA isoforms are phylogenetically conserved, we performed the additional molecular characterization of proglucagon cDNAs from several representative species of the Squamata and Testudine clade and examined the expression of proglucagon mRNAs in the small intestine and pancreas. In the present study, a total of 7 proglucagon cDNA isoforms were identified and divided into two groups (Classes A and B) based on the 3'-UTR sequence of each isoform. The longest isoform of each group (named PG-A1 and PG-B1, respectively) had the same molecular characteristics as those previously reported from chickens and reptiles, namely, PG-A and PG-B. Other 5 isoforms were novel-type cDNAs, and were the products of exon skipping (named PG-A2, PG-A2s, PG-B2, PG-B2s, and PG-B3). Some of these isoforms coded for only one peptide hormone (GLP-1 or GLP-2). This is the first identification of single hormone-encoding proglucagon cDNAs in vertebrates. Moreover, an expression analysis of these isoforms revealed that single hormone-encoding proglucagon mRNAs were predominantly expressed with tissue and lineage specificities in the reptile clade. Collectively, the present results suggest an independent regulatory system for GLP-1 and GLP-2 secretion and indicate the plasticity of proglucagon genes in expressing different isoforms in different tissues in Squamata. These results also provide insights into the plastic energy metabolic system of Squamata in accordance with various habitats in the terrestrial environment, supporting their successful prosperity.
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Affiliation(s)
- Yudai Suzuki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - Erina Kurakata
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - Ayaka Yoshida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - Aya Kobayashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - Min Kyun Park
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
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Dornburg A, Warren DL, Zapfe KL, Morris R, Iglesias TL, Lamb A, Hogue G, Lukas L, Wong R. Testing ontogenetic patterns of sexual size dimorphism against expectations of the expensive tissue hypothesis, an intraspecific example using oyster toadfish ( Opsanus tau). Ecol Evol 2018; 8:3609-3616. [PMID: 29686842 PMCID: PMC5901164 DOI: 10.1002/ece3.3835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 11/09/2022] Open
Abstract
Trade‐offs associated with sexual size dimorphism (SSD) are well documented across the Tree of Life. However, studies of SSD often do not consider potential investment trade‐offs between metabolically expensive structures under sexual selection and other morphological modules. Based on the expectations of the expensive tissue hypothesis, investment in one metabolically expensive structure should come at the direct cost of investment in another. Here, we examine allometric trends in the ontogeny of oyster toadfish (Opsanus tau) to test whether investment in structures known to have been influenced by strong sexual selection conform to these expectations. Despite recovering clear changes in the ontogeny of a sexually selected trait between males and females, we find no evidence for predicted ontogenetic trade‐offs with metabolically expensive organs. Our results are part of a growing body of work demonstrating that increased investment in one structure does not necessarily drive a wholesale loss of mass in one or more organs.
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Affiliation(s)
- Alex Dornburg
- North Carolina Museum of Natural Sciences Raleigh NC USA
| | - Dan L Warren
- Senckenberg Institute for Biodiversity and Climate Frankfurt am Main Germany
| | | | - Richard Morris
- North Carolina Museum of Natural Sciences Raleigh NC USA
| | - Teresa L Iglesias
- Physics and Biology Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - April Lamb
- North Carolina Museum of Natural Sciences Raleigh NC USA.,Department of Applied Ecology North Carolina State University Raleigh NC USA
| | - Gabriela Hogue
- North Carolina Museum of Natural Sciences Raleigh NC USA
| | - Laura Lukas
- North Carolina Museum of Natural Sciences Raleigh NC USA
| | - Richard Wong
- Delaware Division of Fish and Wildlife Dover DE USA
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