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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] [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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Denny KL, Huskey S, Anderson CV, Smith ME. Communication via Biotremors in the Veiled Chameleon (Chamaeleo calyptratus): Part II-Social Contexts. Integr Comp Biol 2023; 63:498-514. [PMID: 37365686 DOI: 10.1093/icb/icad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/01/2023] [Accepted: 06/11/2023] [Indexed: 06/28/2023] Open
Abstract
This study extends recent research demonstrating that the veiled chameleon (Chamaeleo calyptratus) can produce and detect biotremors. Chameleons were paired in various social contexts: dominance (male-male; female-female C. calyptratus); courtship (male-female C. calyptratus); heterospecific (C. calyptratus + C. gracilis); and inter-size class dominance (adult + juvenile C. calyptratus). Simultaneous video and accelerometer recordings were used to monitor their behavior and record a total of 398 biotremors. Chamaeleo calyptratus produced biotremors primarily in conspecific dominance and courtship contexts, accounting for 84.7% of the total biotremors recorded, with biotremor production varying greatly between individuals. Biotremors were elicited by visual contact with another conspecific or heterospecific, and trials in which chameleons exhibited visual displays and aggressive behaviors were more likely to record biotremors. Three classes of biotremor were identified-hoots, mini-hoots, and rumbles, which differed significantly in fundamental frequency, duration, and relative intensity. Biotremor frequency decreased with increasing signal duration, and frequency modulation was evident, especially in hoots. Overall, the data show that C. calyptratus utilizes substrate-borne vibrational communication during conspecific and possibly heterospecific interactions.
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Affiliation(s)
- Kathryn L Denny
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
| | - Steve Huskey
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
| | | | - Michael E Smith
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA
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3
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Shylo NA, Smith SE, Price AJ, Guo F, McClain M, Trainor PA. Morphological changes and two Nodal paralogs drive left-right asymmetry in the squamate veiled chameleon ( C. calyptratus). Front Cell Dev Biol 2023; 11:1132166. [PMID: 37113765 PMCID: PMC10126504 DOI: 10.3389/fcell.2023.1132166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 02/23/2023] [Indexed: 04/29/2023] Open
Abstract
The ancestral mode of left-right (L-R) patterning involves cilia in the L-R organizer. However, the mechanisms regulating L-R patterning in non-avian reptiles remains an enigma, since most squamate embryos are undergoing organogenesis at oviposition. In contrast, veiled chameleon (Chamaeleo calyptratus) embryos are pre-gastrula at oviposition, making them an excellent organism for studying L-R patterning evolution. Here we show that veiled chameleon embryos lack motile cilia at the time of L-R asymmetry establishment. Thus, the loss of motile cilia in the L-R organizers is a synapomorphy of all reptiles. Furthermore, in contrast to avians, geckos and turtles, which have one Nodal gene, veiled chameleon exhibits expression of two paralogs of Nodal in the left lateral plate mesoderm, albeit in non-identical patterns. Using live imaging, we observed asymmetric morphological changes that precede, and likely trigger, asymmetric expression of the Nodal cascade. Thus, veiled chameleons are a new and unique model for studying the evolution of L-R patterning.
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Affiliation(s)
- Natalia A. Shylo
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Sarah E. Smith
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Andrew J. Price
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Fengli Guo
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Melainia McClain
- Stowers Institute for Medical Research, Kansas City, MO, United States
| | - Paul A. Trainor
- Stowers Institute for Medical Research, Kansas City, MO, United States
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO, United States
- *Correspondence: Paul A. Trainor,
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Diaz RE, Taylor-Diaz EA, Trainor PA, Diogo R, Molnar JL. Comparative development of limb musculature in phylogenetically and ecologically divergent lizards. Dev Dyn 2021; 251:1576-1612. [PMID: 34927301 DOI: 10.1002/dvdy.447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Squamate reptiles (lizards, snakes, and amphisbaenians) exhibit incredible diversity in their locomotion, behavior, morphology, and ecological breadth. Although they often are used as models of locomotor diversity, surprisingly little attention has been given to muscle development in squamate reptiles. In fact, the most detailed examination was conducted almost 80 years ago and solely focused on the proximal limb regions. Herein, we present forelimb and hindlimb muscle morphogenesis data for three lizard species with different locomotion and feeding strategies: the desert grassland whiptail lizard, the central bearded dragon, and the veiled chameleon. This study fills critical gaps in our understanding of muscle morphogenesis in squamate reptiles and presents a comparative and temporospatial analysis of muscle development. RESULTS Our results reveal a conserved pattern of early muscle development among lizards with different adult morphologies and ecologies. The variations that exist are concentrated in distal regions, particularly the specialized autopodia of chameleons, where differentiation of muscles associated with the digits is delayed. CONCLUSIONS The chameleon autopod provides an example of major evolutionary modifications to the skeleton with only minor disruption of the conserved order and pattern of limb muscle development. This robustness of muscle patterning facilitates the evolution of extreme yet functional phenotypes.
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Affiliation(s)
- Raul E Diaz
- Department of Biological Sciences, California State University, Los Angeles, California, USA.,Department of Herpetology, Natural History Museum of Los Angeles County, Los Angeles, California, USA
| | - Elizabeth A Taylor-Diaz
- Department of Biological Sciences, California State University, Los Angeles, California, USA
| | - Paul A Trainor
- Investigator, Stowers Institute for Medical Research, Kansas City, Missouri, USA.,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Rui Diogo
- Department of Anatomy, Howard University College of Medicine, Washington, District of Columbia, USA
| | - Julia L Molnar
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York, USA
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Rasys AM, Pau SH, Irwin KE, Luo S, Kim HQ, Wahle MA, Trainor PA, Menke DB, Lauderdale JD. Ocular elongation and retraction in foveated reptiles. Dev Dyn 2021; 250:1584-1599. [PMID: 33866663 PMCID: PMC10731578 DOI: 10.1002/dvdy.348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Pronounced asymmetric changes in ocular globe size during eye development have been observed in a number of species ranging from humans to lizards. In contrast, largely symmetric changes in globe size have been described for other species like rodents. We propose that asymmetric changes in the three-dimensional structure of the developing eye correlate with the types of retinal remodeling needed to produce areas of high photoreceptor density. To test this idea, we systematically examined three-dimensional aspects of globe size as a function of eye development in the bifoveated brown anole, Anolis sagrei. RESULTS During embryonic development, the anole eye undergoes dynamic changes in ocular shape. Initially spherical, the eye elongates in the presumptive foveal regions of the retina and then proceeds through a period of retraction that returns the eye to its spherical shape. During this period of retraction, pit formation and photoreceptor cell packing are observed. We found a similar pattern of elongation and retraction associated with the single fovea of the veiled chameleon, Chamaeleo calyptratus. CONCLUSIONS These results, together with those reported for other foveated species, support the idea that areas of high photoreceptor packing occur in regions where the ocular globe asymmetrically elongates and retracts during development.
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Affiliation(s)
- Ashley M. Rasys
- Department of Cellular Biology, The University of Georgia, Athens, Georgia
| | - Shana H. Pau
- Department of Genetics, The University of Georgia, Athens, Georgia
| | - Katherine E. Irwin
- Department of Cellular Biology, The University of Georgia, Athens, Georgia
| | - Sherry Luo
- Department of Genetics, The University of Georgia, Athens, Georgia
| | - Hannah Q. Kim
- Department of Cellular Biology, The University of Georgia, Athens, Georgia
| | | | - Paul A. Trainor
- Stowers Institute for Medical Research, Kansas City, Missouri
- Department of Anatomy & Cell Biology, The University of Kansas School of Medicine, Kansas City, Kansas
| | - Douglas B. Menke
- Department of Genetics, The University of Georgia, Athens, Georgia
| | - James D. Lauderdale
- Department of Cellular Biology, The University of Georgia, Athens, Georgia
- Neuroscience Division of the Biomedical and Translational Sciences Institute, The University of Georgia, Athens, Georgia
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Charles van Zanten T, Craig Simpson S. Managing the Health of Captive Groups of Reptiles and Amphibians. Vet Clin North Am Exot Anim Pract 2021; 24:609-645. [PMID: 34366012 DOI: 10.1016/j.cvex.2021.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Managing the health of reptile and amphibian collections is centered on providing appropriate environmental parameters, husbandry conditions, and nutrition as well as maintaining good welfare and careful collection planning. Disease transmission is reduced through quarantine, appropriate diagnostic testing, and annual veterinary health assessment."
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Affiliation(s)
- Trent Charles van Zanten
- Conservation, Research and Veterinary Services, Wildlife Reserves Singapore, Jurong Bird Park, 2 Jurong Hill, Singapore 628925.
| | - Shane Craig Simpson
- The Unusual Pet Vets, 210 Karingal Drive, Frankston, Victoria 3199, Australia
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Serpentovirus (Nidovirus) and Orthoreovirus Coinfection in Captive Veiled Chameleons ( Chamaeleo calyptratus) with Respiratory Disease. Viruses 2020; 12:v12111329. [PMID: 33228135 PMCID: PMC7699425 DOI: 10.3390/v12111329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/05/2020] [Accepted: 11/11/2020] [Indexed: 12/24/2022] Open
Abstract
Serpentoviruses are an emerging group of nidoviruses known to cause respiratory disease in snakes and have been associated with disease in other non-avian reptile species (lizards and turtles). This study describes multiple episodes of respiratory disease-associated mortalities in a collection of juvenile veiled chameleons (Chamaeleo calyptratus). Histopathologic lesions included rhinitis and interstitial pneumonia with epithelial proliferation and abundant mucus. Metagenomic sequencing detected coinfection with two novel serpentoviruses and a novel orthoreovirus. Veiled chameleon serpentoviruses are most closely related to serpentoviruses identified in snakes, lizards, and turtles (approximately 40–50% nucleotide and amino acid identity of ORF1b). Veiled chameleon orthoreovirus is most closely related to reptilian orthoreoviruses identified in snakes (approximately 80–90% nucleotide and amino acid identity of the RNA-dependent RNA polymerase). A high prevalence of serpentovirus infection (>80%) was found in clinically healthy subadult and adult veiled chameleons, suggesting the potential for chronic subclinical carriers. Juvenile veiled chameleons typically exhibited a more rapid progression compared to subadults and adults, indicating a possible age association with morbidity and mortality. This is the first description of a serpentovirus infection in any chameleon species. A causal relationship between serpentovirus infection and respiratory disease in chameleons is suspected. The significance of orthoreovirus coinfection remains unknown.
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Yang C, Zhao J, Diaz RE, Lyu N. Development of sexual dimorphism in two sympatric skinks with different growth rates. Ecol Evol 2019; 9:7752-7760. [PMID: 31346437 PMCID: PMC6636199 DOI: 10.1002/ece3.5358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 05/07/2019] [Accepted: 05/14/2019] [Indexed: 11/18/2022] Open
Abstract
Sexual size dimorphism (SSD) is widespread in animals, especially in lizards (Reptilia: Squamata), and is driven by fecundity selection, male-male competition, or other adaptive hypotheses. However, these selective pressures may vary through different life history periods; thus, it is essential to assess the relationship between growth and SSD. In this study, we tracked SSD dynamics between a "fading-tail color skink" (blue tail skink whose tail is only blue during its juvenile stage: Plestiodon elegans) and a "nonfade color" tail skink (retains a blue tail throughout life: Plestiodon quadrilineatus) under a controlled experimental environment. We fitted growth curves of morphological traits (body mass, SVL, and TL) using three growth models (Logistic, Gompertz, and von Bertalanffy). We found that both skinks have male-biased SSD as adults. Body mass has a higher goodness of fit (as represented by very high R 2 values) using the von Bertalanffy model than the other two models. In contrast, SVL and TL for both skinks had higher goodness of fit when using the Gompertz model. Two lizards displayed divergent life history tactics: P. elegans grows faster, matures earlier (at 65 weeks), and presents an allometric growth rate, whereas P. quadrilineatus grows slower, matures later (at 106 weeks), and presents an isometric growth rate. Our findings imply that species- and sex-specific trade-offs in the allocation of energy to growth and reproduction may cause the growth patterns to diverge, ultimately resulting in the dissimilar patterns of SSD.
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Affiliation(s)
- Chen Yang
- Chengdu Institute of BiologyChinese Academy of SciencesChengduChina
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education)China West Normal UniversityNanchongChina
| | - Jinming Zhao
- School of Resources and Environmental EngineeringAnhui UniversityHefeiChina
| | - Raul E. Diaz
- Department of Biological SciencesSoutheastern Louisiana UniversityHammondLouisiana
| | - Nan Lyu
- Ministry of Education Key Laboratory for Biodiversity and Ecological EngineeringCollege of Life SciencesBeijing Normal UniversityBeijingChina
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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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Diaz RE, Trainor PA. Hand/foot splitting and the 're-evolution' of mesopodial skeletal elements during the evolution and radiation of chameleons. BMC Evol Biol 2015; 15:184. [PMID: 26382964 PMCID: PMC4574539 DOI: 10.1186/s12862-015-0464-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/21/2015] [Indexed: 01/07/2023] Open
Abstract
Background One of the most distinctive traits found within Chamaeleonidae is their split/cleft autopodia and the simplified and divergent morphology of the mesopodial skeleton. These anatomical characteristics have facilitated the adaptive radiation of chameleons to arboreal niches. To better understand the homology of chameleon carpal and tarsal elements, the process of syndactyly, cleft formation, and how modification of the mesopodial skeleton has played a role in the evolution and diversification of chameleons, we have studied the Veiled Chameleon (Chamaeleo calyptratus). We analysed limb patterning and morphogenesis through in situ hybridization, in vitro whole embryo culture and pharmacological perturbation, scoring for apoptosis, clefting, and skeletogenesis. Furthermore, we framed our data within a phylogenetic context by performing comparative skeletal analyses in 8 of the 12 currently recognized genera of extant chameleons. Results Our study uncovered a previously underappreciated degree of mesopodial skeletal diversity in chameleons. Phylogenetically derived chameleons exhibit a ‘typical’ outgroup complement of mesopodial elements (with the exception of centralia), with twice the number of currently recognized carpal and tarsal elements considered for this clade. In contrast to avians and rodents, mesenchymal clefting in chameleons commences in spite of the maintenance of a robust apical ectodermal ridge (AER). Furthermore, Bmp signaling appears to be important for cleft initiation but not for maintenance of apoptosis. Interdigital cell death therefore may be an ancestral characteristic of the autopodium, however syndactyly is an evolutionary novelty. In addition, we find that the pisiform segments from the ulnare and that chameleons lack an astragalus-calcaneum complex typical of amniotes and have evolved an ankle architecture convergent with amphibians in phylogenetically higher chameleons. Conclusion Our data underscores the importance of comparative and phylogenetic approaches when studying development. Body size may have played a role in the characteristic mesopodial skeletal architecture of chameleons by constraining deployment of the skeletogenic program in the smaller and earliest diverged and basal taxa. Our study challenges the ‘re-evolution’ of osteological features by showing that ‘re-evolving’ a ‘lost’ feature de novo (contrary to Dollo’s Law) may instead be due to so called ‘missing structures’ being present but underdeveloped and/or fused to other adjacent elements (cryptic features) whose independence may be re-established under changes in adaptive selective pressure. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0464-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Raul E Diaz
- Department of Biology, La Sierra University, Riverside, CA, 92515, USA. .,Natural History Museum of Los Angeles County, Los Angeles, CA, 90007, USA.
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA. .,Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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Diaz RE, Anderson CV, Baumann DP, Kupronis R, Jewell D, Piraquive C, Kupronis J, Winter K, Bertocchini F, Trainor PA. The Veiled Chameleon (Chamaeleo calyptratus Duméril and Duméril 1851): A Model for Studying Reptile Body Plan Development and Evolution. Cold Spring Harb Protoc 2015; 2015:889-894. [PMID: 26310903 DOI: 10.1101/pdb.emo087700] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vertebrate model organisms have facilitated the discovery and exploration of morphogenetic events and developmental pathways that underpin normal and pathological embryological events. In contrast to amniotes such as Mus musculus (Mammalia) and Gallus gallus (Aves), our understanding of early patterning and developmental events in reptiles (particularly nonavians) remains weak. Squamate reptiles (lizards, snakes, and amphisbaenians) comprise approximately one-third of all living amniotes. But studies of early squamate development have been limited because, in most members of this lineage, embryo development at the time of oviposition is very advanced (limb bud stages and older). In many cases, squamates give birth to fully developed offspring. However, in the veiled chameleon (Chamaeleo calyptratus), embryos have progressed only to a primitive pregastrula stage at the time of oviposition. Furthermore, the body plan of the veiled chameleon is highly specialized for climbing in an arboreal environment. It possesses an entire suite of skeletal and soft anatomical modifications, including cranioskeletal ornamentation, lingual anatomy and biomechanics for projection, autopodial clefting for grasping, adaptations for rapid integumental color changes, a prehensile tail with a lack of caudal autotomy, the loss of the tympanum in the middle ear, and the acquisition of turreted eyes. Thus, C. calyptratus is an important model organism for studying the role of ecological niche specialization, as well as genetic and morphological evolution within an adaptive framework. More importantly, this species is easily bred in captivity, with only a small colony (<10 individuals) needed to obtain hundreds of embryos every year.
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Affiliation(s)
- Raul E Diaz
- Department of Biology, La Sierra University, Riverside, California 92515; Natural History Museum of Los Angeles County, Los Angeles, California 90007
| | - Christopher V Anderson
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912
| | - Diana P Baumann
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Richard Kupronis
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - David Jewell
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | | | - Jill Kupronis
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Kristy Winter
- Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Federica Bertocchini
- Instituto de Biomedicina y Biotechnologia de Cantabria-CSIC-Universidad de Cantabria-Sodercan, Santander, Spain 39012
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, Missouri 64110; Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas 66160
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