The Diplodactylidae are a family in the suborder Gekkota (geckos), with over 150 species in 25 genera. These geckos occur in Australia, New Zealand, and New Caledonia. Diplodactylids are the most ecologically diverse and widespread family of geckos in both Australia and New Caledonia, and are the only family of geckos found in New Zealand. Three diplodactylid genera (Oedura, Rhacodactylus, and Hoplodactylus) have recently been split into multiple new genera.
In previous classifications, the family Diplodactylidae is equivalent to the subfamily Diplodactylinae.Goin CJ, Goin OB, Zug GR. 1978. Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman and Company. xi + 378 pp. . ("Subfamily Diplodactylinae", p. 284).
Habitat Like other geckos, Diplodactylidae often live in warm areas that are around the temperature of . They mostly live in rain forests, up in the trees for protection. However, they are also found in cooler climates such as those found in southern New Zealand, where they have been found to be active in temperatures ranging from 1.4 to 31.9C.Chukwuka, C. O. (2020). Microhabitat use by the nocturnal, cool-climate gecko Woodworthia 'Otago/Southland' in the context of global climate change (Thesis, Doctor of Philosophy). University of Otago. Retrieved from http://hdl.handle.net/10523/10412
Reproduction Viviparity is notable as a trait unique to diplodactylids within Gekkota, with two species in New Caledonia from the genus Rhacodactylus and all species in New Zealand exhibiting this form of reproduction.
Common traits
Adhesion and climbing ability All species in this family possess some form of toepad, except for Lucasium damaeum, which shows strong evidence of toepads being secondarily lost. The ability for geckos to climb vertical surfaces is made possible by the hundreds of microscopic, hair-like fibers present on their toes, which are so fine and densely concentrated as to trap air between the gecko's toes and the surface they are adhering to. Effectively, the geckos do not "stick" or "adhere" to a surface, rather, they are able to utilize compressed air to grip. With the help of this ability they have on their feet, they are able to grip on to surfaces, making it easier for them to travel from one place to another.
Based on a study, captive geckos like to grip onto coarser, sandpaper- or bark-like surfaces, as opposed to smooth glass or plastic, as this material is similar to the type of surfaces they grip on to in their natural habitats. It was concluded that Diplodactylidae, in particular, like to grip-on to rough surfaces.
Classification While diplodactylid geckos have been relatively well-studied, the family's placement and composition has experienced several revisions, with the systematics continuing to evolve. Recent molecular work has helped to clarify phylogeny that was historically based primarily on morphological traits, justifying the monophyly of Diplodactylidae, revising intergeneric relationships between several genera, and uncovering significant cryptic diversity within the family. However, the current understanding of the systematics and evolution of diplodactylid geckos remains limited, with certain genera and taxa still largely unstudied and significant underestimates in diversity at the species level left to resolve.
Placement within Gekkota Underwood completed the first comprehensive systematics analysis of geckos in 1954, using morphological features like pupil shape and inferences around biogeography to establish three major families within Gekkota (or Gekkonoidea as it was also known): the Eublepharidae, the Sphaerodactylidae, and the Gekkonidae. He designated Gekkoninae and Diplodactylinae as subfamilies within Gekkonidae. Underwood's Diplodactylinae comprised 22 genera from Australian regions and South Africa, including many of the diplodactylid and carphodactylid species known at the time. Kluge disputed Underwood's classification, instead recognizing a single family, Gekkonidae (later equivalent to Gekkota) with four subfamilies that included the Eublepharinae, Sphaerodactylinae, Gekkoninae and Diplodactylinae. He subdivided Diplodactylinae into two tribes, Diplodactylini with four genera, and Carphodactylini with nine. As Kluge believed pupil shape alone to be too variable a diagnostic character, his classification was based on 18 morphological characters, as well as geologic and geographical origins. This necessitated the reallocation of several Diplodactylinae genera (e.g., those from South Africa, those with "non-parchment-like" shelled eggs) to the Gekkoninae.
In subsequent years, Kluge's classifications of genera, which built off Underwood's original groupings, were generally accepted. However, Kluge's subfamilial allocations—including his subdivision of Diplodactylinae—and his apparent assumptions around their respective monophyly proved problematic for some (e.g., Moffatt 1973, Hecht 1976), who suggested alternative or expanded hypotheses. Kluge's 1987 publication continued to build on his earlier work by examining the relationship of the limbless Pygopodidae to the Gekkonidae. He used a simple phylogenetic analysis of synapomorphies to place the pygopods within Gekkonidae as sisters to the Diplodactylinae, and delineated this clade as Pygopodoidea. This grouping also made more sense biogeographically, as Kluge modified his earlier assumptions of gekkotan origins from fixed continents, landbridges, and oceanic dispersal, to lie more in line with the emerging plate-tectonics Gondwanan hypothesis. While these revisions helped advance systematics closer to the contemporary understanding of Diplodactylidae, inconsistencies around how Carphodactylini were then defined and how they fit within the Australia-New Zealand vicariance left questions that required more sophisticated genetic analyses to answer.
Many early assumptions of diplodactylid systematics have either been supported or invalidated with the improvement of phylogenetic analyses and more comprehensive sampling. Nuclear loci in particular have been helpful for resolving intergeneric relationships and origin questions. C-mos loci and 12S rRNA gene sequences to construct a molecular phylogeny helped to confirm the pygopods' placement as a monophyletic sister lineage to the Diplodactylinae. These results also corroborated that both the Diplodactylinae and its Diplodactylini subdivision were monophyletic, although monophyly of the Carphodactylini was not supported. In the first gecko-wide genetic analysis by Han et al. (2004), c-mos loci again helped clarify placement within the Pygopodoidea. Results showed evidence of paraphyly for Kluge's Diplodactylinae with Diplodactylini genera and padded carphodactylines instead supported as the sister group to pygopods and padless carphodactylines, which was upheld in later analyses. These new pairings led Han et al. (2004) to reorder membership within the Diplodactylini and Carphodactylini and to propose a new taxonomy of geckos at the family level to reflect their findings. The five new families proposed were the limbless Pygopodidae; Carphodactylidae, which included only padless Carphodactylini; Diplodactylidae, which now included all Kluge's Diplodactylini together with all pad-bearing Carphodactylini; Eublepharidae; and Gekkonidae. This was a significant revision to Kluge's proposed order, and, excepting minor movement of genera and more extensive movement at the species level, is generally representative of the modern monophyletic Diplodactylidae.
Genera List of genera Genus Image Type species Taxon author Common name Species Amalosia A. jacovae A. lesueruii Wells & Wellington, 1984 Velvet geckos 4 Bavayia B. septuiclavis B. cyclura Roux, 1913 Bavayias 41 Correlophus C. ciliatus C. ciliatus Guichenot, 1866 Crested geckos 3 Crenadactylus C. ocellatus C. ocellatus Dixon & Kluge, 1964 Clawless geckos 7 Dactylocnemis D. pacificus D. pacificus Steindachner, 1867 Pacific gecko 1+ Dierogekko D. nehoueensis D. validiclavis Bauer, Jackman, Sadlier, & A. Whitaker, 2006 Striped geckos 9 Diplodactylus D. vittatus D. vittatus Gray, 1832 Stone geckos and fat-tailed geckos 27 Eurydactylodes E. vieillardi E. vieillardi Wermuth, 1965 Chameleon geckos 4 Hesperoedura H. reticulata Oliver, Bauer, Greenbaum, Jackman & Hobbie, 2012 Reticulated velvet gecko 1 Hoplodactylus H. duvaucelii H. duvaucelii Fitzinger, 1843 New Zealand giant geckos 2+GigarcanumG. delcourtiG. delcourti (Bauer & Russell, 1986)Heinicke, et al. 2023Delcourt's giant gecko1 Lucasium L. stenodactylum L. damaeum Wermuth, 1965 Ground geckos 14 Mniarogekko M. chahoua M. chahoua Bauer, Whitaker, Sadlier & Jackman, 2012 Mossy geckos 2 Mokopirirakau M. cryptozoicus M. granulatus Nielsen, Bauer, Jackman, Hitchmough & Daugherty, 2011 New Zealand geckos 5+ Naultinus N. punctatus N. elegans Gray, 1842 Green geckos 9 Nebulifera N. robusta N. robusta Oliver, Bauer, Greenbaum, Jackman & Hobbie, 2012 Robust velvet gecko 1 Oedodera O. marmorata Bauer, Jackman, Sadlier, & Whitaker, 2006 Marbled gecko 1 Oedura O. cincta O. marmorata Gray, 1842 Velvet geckos 19 Paniegekko P. madjo Bauer, Jackman, Sadlier, & Whitaker, 2000 1 Pseudothecadactylus P. lindneri P. australis Brongersma, 1936 3 Rhacodactylus R. leachianus R. leachianus Fitzinger, 1843 Giant Geckos 4 Rhynchoedura R. ormsbyi R. ornata Günther, 1867 Beaked Geckos 6 Strophurus R. taenicauda S. strophurus Fitzinger, 1843 Spiny-tailed geckos 20 Toropuku T. stephensi T. stephensi Nielsen, Bauer, Jackman, Hitchmough & Daugherty, 2011 Striped geckos 2 Tukutuku T. rakiurae T. rakiurae Nielsen, Bauer, Jackman, Hitchmough & Daugherty, 2011 Harlequin gecko 1 Woodworthia W. brunnea W. maculata Garman, 1901 New Zealand geckos 3+
Intergeneric systematics The Australian endemic diplodactylids excepting Pseudothecadactylus, the New Caledonia diplodactylids together with the Australian Pseudothecadactylus, and the New Zealand endemics comprise the three well-supported clades within current-day Diplodactylidae. Due to their closer divergence, the New Zealand and Australian endemics (without Pseudothecadactylus) form a sister clade, while the New Caledonian diplodactylids show evidence of their more recent and rapid radiation in short branch lengths. Because the quick succession of genera can complicate phylogenetic reconstruction, it may remain difficult to produce well-supported intergeneric relationships for the eight New Caledonian diplodactylids in spite of a growing number of studies investigating them. New Zealand genera have proved somewhat easier to analyze. The group has correspondingly gone through several taxonomic revisions to reach the current order of genera proposed by Nielson et al. in 2011. Yet, a high amount of cryptic diversity remains unresolved, especially within Hoplodactylus. Australia genera such as Diplodactylus, Lucasium, Rhynchoedura and Strophurus are generally considered well-studied, with many of their intergeneric relationships strongly supported and resolved. The Pseudothecadactylus affinity to New Caledonian geckos has been informative and is under study, while Oedura are being increasingly examined. However, more work is still needed to understand the basal relationships and divergence of other "non-core" genera like Nebulifera, Amalosia, Hespeodura and Crenadactylus.