The Development of Cephalic Armor in The Tokay Gecko (Squamata: Gekkonidae: Gekko gecko)

Authors

Rebecca J. Laver, Australian National University
Cristian H. Morales, Sam Houston State University
Matthew P. Heinicke, University of Michigan - Dearborn
Tony Gamble, Marquette UniversityFollow
Kristin Longoria, Sam Houston State University
Aaron M. Bauer, Villanova UniversityFollow
Juan D. Daza, Sam Houston State University - Huntsville, TXFollow

Document Type

Article

Language

eng

Publication Date

2-1-2020

Publisher

Wiley

Source Publication

Journal of Morphology

Source ISSN

0362-2525

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, and Tarentola. The Tokay gecko (Gekko gecko LINNAEUS 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 broader Gekko clade 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 of G. gecko, using X-rays and high-resolution computed tomography for visualizing and quantifying the dermal armor in situ. Results from this survey confirm the presence of osteoderms in a second species within this genus, Gekko reevesii GRAY 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 that G. gecko and 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.

Comments

Accepted version. Journal of Morphology, Vol. 281, No. 2 (February 1, 2020): 213-228. DOI. © 2020 Wiley. Used with permission.

Recommended Citation

Laver, Rebecca J.; Morales, Cristian H.; Heinicke, Matthew P.; Gamble, Tony; Longoria, Kristin; Bauer, Aaron M.; and Daza, Juan D., "The Development of Cephalic Armor in The Tokay Gecko (Squamata: Gekkonidae: Gekko gecko)" (2020). Biological Sciences Faculty Research and Publications. 810.
https://epublications.marquette.edu/bio_fac/810