Scale-able defense

Fish-scale geckos, Geckolepis spp., are small and arboreal lizards endemic to Madagascar and the Comoro Islands. The base coloration of the fish-scaled gecko is generally chestnut-cream with darker/black bands or mottling. Their appearance may vary by locality and individual, allowing excellent camouflage on tree bark and rocky surfaces. Its scales are large, overlapping, and partially ossified, giving the lizard a distinctive “fish scale” appearance.

First described more than 150 years ago, Geckolepis maculata (Peters, 1880), is

commonly known as Peters’s spotted gecko or fish-scale gecko. Five species of Geckolepis are

currently recognized: G. typica (Grandidier, 1867), G. maculata (Peters, 1880), G. polylepis

(Boettger, 1893), G. humbloti (Vaillant, 1887), and G. megalepis (Scherz et al., 2017). However, morphological features (scale counts, pattern, size) show variation among populations and from animals in different localities, and molecular analyses suggest that several additional cryptic species may be hidden within the genus (Lemme et al., 2013).

Photo: Fish-scaled gecko (Geckolepis spp.) Provided by Marina Saito, DVM, PhD and George Eisenhoffer, PhD

Today, we share the chromosome-length genome assembly and Hi-C data for Geckolepis

maculata. This genome assembly was done in collaboration with Dr. George Eisenhoffer and team at the Department of Genetics at the MD Anderson Cancer Center using PacBio HiFi data and Hi-C.

Unlike most lizards, which are best known for their ability to drop and regenerate their tails, fish-scale geckos take autotomy to the next level. When threatened by predators—such as birds, snakes or larger lizards—they can shed large patches of skin to facilitate escape and avoid being consumed. This skin loss leaves much of the body surface exposed and unprotected (Scherz et al., 2017).

A unique attribute of the integument (a tough outer protective layer) of G. maculata is the presence of osteoderms, which are mineralized dermal deposits that are embedded in the scales (Paluh et al., 2017). The presence of osteoderms gives G. maculata a kind of protective dermal ossification, which is unusual among geckos. These osteoderms within scales likely contribute to both physical protection and may influence how scales detach. The ability to create a protective layer and then rapidly lose it has lead to the concept of “sheddable armor” (Paluh et al., 2017).

The genome of fish-scaled geckos stands to provide new insights into their striking appearance, unique defensive strategies, and taxonomy uncertainties.

Explore the interactive Hi-C contact map for the fish-scale gecko below, and check out more details about the assembly here.

References:

• A.M. Bauer & A. P. Russell (1992) The evolutionary significance of regional integumentary loss in island geckos: a complement to caudal autotomy, Ethology Ecology & Evolution, 4:4, 343-358, DOI: 10.1080/08927014.1992.9523127

• Lemme, I., Erbacher, M., Kaffenberger, N. et al. Molecules and morphology suggest cryptic species diversity and an overall complex taxonomy of fish scale geckos, genus Geckolepis . Org Divers Evol 13, 87–95 (2013). https://doi.org/10.1007/s13127-012-0098-y

• Paluh, D. J., Griffing, A. H., & Bauer, A. M. (2017). Sheddable armour: identification of osteoderms in the integument of Geckolepis maculata (Gekkota). African Journal of Herpetology, 66(1), 12–24. https://doi.org/10.1080/21564574.2017.1281172

• Scherz MD, Daza JD, Köhler J, Vences M, Glaw F. 2017. Off the scale: a new species of fish-scale gecko (Squamata: Gekkonidae: Geckolepis) with exceptionally large scales. PeerJ 5:e2955. https://doi.org/10.7717/peerj.2955

• Uetz, P.; Freed, P.; Hošek, J. The Reptile Database. 2022. Available online: http://www.reptile-database.org