Pachydactylus Explained

Pachydactylus is a genus of insectivorous geckos, lizards in the family Gekkonidae. The genus is endemic to Africa, and member species are commonly known as thick-toed geckos. The genus also displays rich speciation, having 58 distinct species identified when compared to other closely related gecko genera like Rhoptropus, most of which have emerged since 35Ma.^[1] It has been suggested that the reason for this rich speciation not from adaptive radiation nor nonadaptive radiation, but that the genus represents a clade somewhere between the two drivers of speciation.^[2] P. bibronii geckos have been used by NASA as animal models for experimentation.^[3]

Description of the Pachydactylus genus

The genus Pachydactylus is characterized by dilated toe tips, usually with undivided scansors. Body scales are small, granular and non-overlapping, with scattered, large keeled tubercles.

Coloration of Pachydactylus species varies, but is generally drab in color.

Presence of adhesive toe pads varies by species and habitat, with rock dwelling species of Pachydactylus retaining adhesive pads, but unambiguous independent loss of toe pads in sand dwelling and burrowing species like P. rangei.

Body size in Pachydactylus varies across the 58 species, ranging from 35 to 115mm Snout-Vent Length (SVL)^[4] with the ancestral condition of a larger body size with adhesive toe pads to suit a generalist habitat.

Behavior

All observed species of Pachydactylus are strictly nocturnal. Wikibooks

Habitat of Pachydactylus geckos

Pachydactylus species live in a diverse range of habitats across Southern Africa. Habitat varies by species, with some species preferring generalist habitats, human dwellings, rock-dwellings, and sand dwellings. Habitat preference typically varies by body size and retention of toe pads, which varies across the genus. The body size of Pachydactylus geckos has been shown to correlate with their habitat range.^[5]

Diet

Lizards of the genus Pachydactylus feed mainly on arthropods, but have been observed eating small vertebrates.^[6]

Geographic range

The geographic range of the genus Pachydactylus is centered on Southern Africa, with some species reaching East Africa, the northernmost limit of their distribution. In South Africa's rugged Richtersveld region, Pachydactylus geckos comprised 13 of 18 all gecko species surveyed.^[7]

Species

There are 58 species that are recognized as being valid:^[8]

• Pachydactylus acuminatus
• Pachydactylus affinis – Transvaal thick-toed gecko
• Pachydactylus amoenus
• Pachydactylus angolensis – Angola large-scaled gecko, Angolan thick-toed gecko
• Pachydactylus atorquatus
• Pachydactylus austeni – Austen's thick-toed gecko
• Pachydactylus barnardi – Barnard's thick-toed gecko^[9]
• Pachydactylus bicolor – velvety thick-toed gecko
• Pachydactylus boehmei
• Pachydactylus capensis – Cape thick-toed gecko
• Pachydactylus caraculicus – Angola banded thick-toed gecko
• Pachydactylus carinatus
• Pachydactylus etultra
• Pachydactylus fasciatus – banded thick-toed gecko
• Pachydactylus formosus – Smith's thick-toed gecko
• Pachydactylus gaiasensis – Brandberg thick-toed gecko
• Pachydactylus geitje – ocellated thick-toed gecko
• Pachydactylus griffini
• Pachydactylus haackei – Haacke's thick-toed gecko
• Pachydactylus katanganus
• Pachydactylus kladaroderma – thin-skinned thick-toed gecko
• Pachydactylus kobosensis
• Pachydactylus kochii
• Pachydactylus labialis – Calvinia thick-toed gecko
• Pachydactylus latirostris – quartz gecko
• Pachydactylus macrolepis – large-scaled banded gecko
• Pachydactylus maculatus – spotted thick-toed gecko
• Pachydactylus maiatoi – Maiato's thick-toed gecko
• Pachydactylus maraisi
• Pachydactylus mariquensis – Marico thick-toed gecko
• Pachydactylus mclachlani
• Pachydactylus monicae
• Pachydactylus montanus
• Pachydactylus namaquensis – Namaqua thick-toed gecko
• Pachydactylus oculatus – golden spotted thick-toed gecko
• Pachydactylus oreophilus – Kaokoveld thick-toed gecko
• Pachydactylus oshaughnessyi
• Pachydactylus otaviensis
• Pachydactylus parascutatus
• Pachydactylus punctatus – speckled thick-toed gecko
• Pachydactylus purcelli
• Pachydactylus rangei – Namib sand gecko
• Pachydactylus reconditus
• Pachydactylus robertsi
• Pachydactylus rugosus – rough thick-toed gecko
• Pachydactylus sansteynae – San Steyn's thick-toed gecko
• Pachydactylus scherzi – Sherz's thick-toed gecko
• Pachydactylus scutatus – large-scaled thick-toed gecko
• Pachydactylus serval – western spotted thick-toed gecko
• Pachydactylus tigrinus – tiger thick-toed gecko
• Pachydactylus tsodiloensis – Tsodilo thick-toed gecko
• Pachydactylus vansoni – Van Son's thick-toed gecko
• Pachydactylus vanzyli
• Pachydactylus visseri
• Pachydactylus wahlbergii
• Pachydactylus waterbergensis
• Pachydactylus weberi – Weber's thick-toed gecko^[9]
• Pachydactylus werneri

Nota bene

A binomial authority in parentheses indicates that the species was originally described in a genus other than Pachydactylus.

Further reading

• Bauer AM, Lamb T, Branch WR . species:Aaron Matthew Bauer . species:Trip Lamb . William Roy Branch . A revision of the Pachydactylus serval and P. weberi groups (Reptilia: Gekkota: Gekkonidae) of Southern Africa, and with the description of eight new species. . Proceedings of the California Academy of Sciences . 2006 . 57 . 23 . 595–709 .
• Book: Boulenger GA . George Albert Boulenger . 1885 . Catalogue of the Lizards in the British Museum (Natural History). Second Edition. Volume I. Geckonidæ .... . London . Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xii + 436 pp. + Plates I–XXXII. (Genus Pachydactylus, p. 200).
• Book: Branch, Bill . 2004 . Field Guide to Snakes and other Reptiles of Southern Africa . Sanibel Island, Florida . Ralph Curtis Books . 0-88359-042-5 . (Third Revised edition, Second impression). 399 pp. (Genus Pachydactylus, pp. 249–250).
• Book: Wiegmann AF . Arend Friedrich August Wiegmann . 1834 . Herpetologia Mexicana, seu descriptio amphibiorum Novae Hispaniae, quae itineribus comitis de Sack, Ferdinandi Deppe et Chr. Guil. Schiede in Museum Zoologicum Berolinense pervenerunt. Pars prima, saurorum species amplectens. Adiecto systematis saurorum prodromo, additisque multis in hunc amphibiorum ordinem observationibus . Berlin . C.G. Lüderitz . vi + 54 pp. + Plates I–X . (Pachydactylus, new genus, p. 19). (in Latin).

Notes and References

1. Gamble T, Greenbaum E, Jackman TR, Russell AP, Bauer AM . species:Tony Gamble . species:Eli Greenbaum . species:Todd R. Jackman . species:Anthony Patrick Russell . species:Aaron Matthew Bauer . Repeated origin and loss of adhesive toepads in geckos . PLoS ONE . 7 . 6 . e39429 . 2012-06-27 . 22761794 . 3384654 . 10.1371/journal.pone.0039429 . 2012PLoSO...739429G . free.
2. Heinicke MP, Jackman TR, Bauer AM . species:Matthew Paul Heinicke . The measure of success: geographic isolation promotes diversification in Pachydactylus geckos . BMC Evolutionary Biology . 17 . 1 . 9 . January 2017 . 28077086 . 5225572 . 10.1186/s12862-016-0846-2 . free . 2017BMCEE..17....9H.
3. NASA Technical Reports Server (NTRS). 2021-04-16. Journal of Gravitational Physiology . 13 . 1. July 2006. Gulimova. V. I.. Nikitin. V. B.. Asadchikov. V. E.. Buzmakov. A. V.. Okshtein. I. L.. Almeida. E. a. C.. Ilyin. E. A.. Tairbekov. M. G.. Saveliev. S. V..
4. Book: Branch, Bill . William Roy Branch . Field Guide to Snakes and other Reptiles of Southern Africa . Third . Struik . 1998 . 1-86872-040-3 . Cape Town, South Africa.
5. Gaston, Kevin J. . Blackburn, Tim M. . 1996 . Global Scale Macroecology: Interactions between Population Size, Geographic Range Size and Body Size in the Anseriformes . 5669 . Journal of Animal Ecology . 65 . 6 . 701–714 . 10.2307/5669 . 1996JAnEc..65..701G . 0021-8790.
6. Pianka ER, Huey RB . Eric Pianka . Raymond B. Huey . 1978 . Comparative Ecology, Resource Utilization and Niche Segregation among Gekkonid Lizards in the Southern Kalahari . Copeia . 1978 . 4 . 691–701 . 10.2307/1443698 . 1443698 . 0045-8511.
7. Bauer AM . 2001 . The herpetofauna of the Richtersveld National Park and the adjacent northern Richtersveld, Northern Cape Province, Republic of South Africa. Herpetological Natural History. 8. 111–160. Researchgate.
8. www.reptile-database.org.
9. Book: Beolens B, Watkins M, Grayson M . species:Bo Beolens . species:Michael Watkins . species:Michael Grayson . 2011 . The Eponym Dictionary of Reptiles . Baltimore . Johns Hopkins University Press . 978-1-4214-0135-5. xiii + 296 pp. (Pachydactylus barnardi, p. 17; P. weberi, p. 280).