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.
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.
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 genus 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.