skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Notes on patagium morphology in the Gliding Flat-tailed House Gecko (Hemidactylus platyurus)
Several species of geckos have independently evolved patagia, membranous features that facilitate gliding.Detailed morphological investigations of gecko patagia have largely been limited to gliding members of the genus Gekko(formerly in the genus Ptychozoon). Herein we describe the morphology of gliding patagia of the Flat-tailed HouseGecko (Hemidactylus platyurus), a species with an independent evolutionary origin of gliding patagia from Gekko andan important species for researching gliding biomechanics. We compared morphology of H. platyurus with a closelyrelated non-gliding species, the Common House Gecko (Hemidactylus frenatus). Using external examination and histologicaltechniques, we compared and contrasted three regions that exhibit patagia (trunk, femoral region, and tail)in H. platyurus but not in H. frenatus. We find that patagia in a gliding Hemidactylus, like patagia in gliding membersof the genus Gekko, are derived from expansion of lateral fat bodies, suggesting analogous processes to achieve similarphenotypic outcomes.  more » « less
Award ID(s):
2209090
PAR ID:
10637584
Author(s) / Creator(s):
; ;
Publisher / Repository:
Reptiles and Amphibians
Date Published:
Journal Name:
Reptiles & Amphibians
Volume:
31
Issue:
1
ISSN:
2330-3956
Page Range / eLocation ID:
e22398
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    Lizards and snakes (squamates) are known for their varied sex determining systems, and gecko lizards are especially diverse, having evolved sex chromosomes independently multiple times. While sex chromosomes frequently turnover among gecko genera, intrageneric turnovers are known only from Gekko and Hemidactylus. Here, we used RADseq to identify sex-specific markers in two species of Burmese bent-toed geckos. We uncovered XX/XY sex chromosomes in Cyrtodactylus chaunghanakwaensis and ZZ/ZW sex chromosomes in Cyrtodactylus pharbaungensis. This is the third instance of intrageneric turnover of sex chromosomes in geckos. Additionally, Cyrtodactylus are closely related to another genus with intrageneric turnover, Hemidactylus. Together, these data suggest that sex chromosome turnover may be common in this clade, setting them apart as exceptionally diverse in a group already known for diverse sex determination systems. 
    more » « less
  2. Abstract Armored skin resulting from the presence of bony dermal structures, osteoderms, is an exceptional phenotype in gekkotans (geckos and flap‐footed lizards) only known to occur in three genera:Geckolepis,Gekko, andTarentola. The Tokay gecko (Gekko geckoLINNAEUS 1758) is among the best‐studied geckos due to its large size and wide range of occurrence, and although cranial dermal bone development has previously been investigated, details of osteoderm development along a size gradient remain less well‐known. Likewise, a comparative survey of additional species within the broaderGekkoclade to determine the uniqueness of this trait has not yet been completed. Here, we studied a large sample of gekkotans (38 spp.), including 18 specimens ofG. gecko, using X‐rays and high‐resolution computed tomography for visualizing and quantifying the dermal armorin situ. Results from this survey confirm the presence of osteoderms in a second species within this genus,GekkoreevesiiGRAY 1831, which exhibits discordance in timing and pattern of osteoderm development when compared with its sister taxon,G. gecko. We discuss the developmental sequence of osteoderms in these two species and explore in detail the formation and functionality of these enigmatic dermal ossifications. Finally, we conducted a comparative analysis of endolymphatic sacs in a wide array of gekkotans to explore previous ideas regarding the role of osteoderms as calcium reservoirs. We found thatG. geckoand other gecko species with osteoderms have highly enlarged endolymphatic sacs relative to their body size, when compared to species without osteoderms, which implies that these membranous structures might fulfill a major role of calcium storage even in species with osteoderms. 
    more » « less
  3. Squamate remains from fossil-bearing deposits are difficult to identify on the basis of their morphology, because their modern relatives lack osteological description. In addition, intraspecific morphological variability of modern taxa is mostly understudied, making taxonomic identification of subfossil bones even more difficult. The aim of this study was to investigate osteological differences between two sympatric gecko species, Thecadactylus rapicauda and Hemidactylus mabouia, both currently occurring in the Lesser Antilles and in the subfossil assemblages of the region. Comparison of several modern museum specimens reveals the intraspecific osteological variability of these lizards and how difficult it is to distinguish between their bones, even though they are from two distant families. This study presents nine osteological characters, allowing for a fully reliable distinction of these two gecko species. These characters are applied to the specific identification of gecko species subfossil remains unearthed from the Pointe Gros Rempart 6 Hole (La De´sirade Island, Guadeloupe). Our results confirm the past occurrence of T. rapicauda as well as the historical introduction of H. mabouia on La De´sirade Island. 
    more » « less
  4. Abstract Gekkotan lizards of the genusHemidactylusexhibit derived digital morphologies. These include heavily reduced antepenultimate phalanges of digits III and IV of the manus and digits III–V of the pes, as well as enigmatic cartilaginous structures called paraphalanges. Despite this well‐known morphological derivation, no studies have investigated the development of these structures. We aimed to determine if heterochrony underlies the derived antepenultimate phalanges ofHemidactylus. Furthermore, we aimed to determine if convergently evolved paraphalanges exhibit similar or divergent developmental patterns. Herein we describe embryonic skeletal development in the hands and feet of four gekkonid species, exhibiting a range of digital morphologies. We determined that the derived antepenultimate phalanges ofHemidactylusare the products of paedomorphosis. Furthermore, we found divergent developmental patterns between convergently evolved paraphalanges. 
    more » « less
  5. ABSTRACT The extinct nonavian dinosaurTyrannosaurus rex, considered one of the hardest biting animals ever, is often hypothesized to have exhibited cranial kinesis, or, mobility of cranial joints relative to the braincase. Cranial kinesis inT.rexis a biomechanical paradox in that forcefully biting tetrapods usually possess rigid skulls instead of skulls with movable joints. We tested the biomechanical performance of a tyrannosaur skull using a series of static positions mimicking possible excursions of the palate to evaluate Postural Kinetic Competency inTyrannosaurus. A functional extant phylogenetic bracket was employed using taxa, which exhibit measurable palatal excursions:Psittacus erithacus(fore–aft movement) andGekko gecko(mediolateral movement). Static finite element models ofPsittacus,Gekko, andTyrannosauruswere constructed and tested with different palatal postures using anatomically informed material properties, loaded with muscle forces derived from dissection, phylogenetic bracketing, and a sensitivity analysis of muscle architecture and tested in orthal biting simulations using element strain as a proxy for model performance. Extant species models showed lower strains in naturally occurring postures compared to alternatives. We found that fore–aft and neutral models ofTyrannosaurusexperienced lower overall strains than mediolaterally shifted models. Protractor muscles dampened palatal strains, while occipital constraints increased strains about palatocranial joints compared to jaw joint constraints. These loading behaviors suggest that even small excursions can strain elements beyond structural failure. Thus, these postural tests of kinesis, along with the robusticity of other cranial features, suggest that the skull ofTyrannosauruswas functionally akinetic. Anat Rec, 303:999–1017, 2020. © 2019 Wiley Periodicals, Inc. 
    more » « less