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| Diplodactylus fyfei sp. nov. from foothills of Mt Beddome on New Crown Station, NT; D. tjoritjarinya sp. nov. from Tjoritja National Park, Northern Territory. McDonald, Fenner, Torkkola & Oliver, 2024 photos by P. McDonald & A. Fenner |
Abstract
Stable upland habitats in arid zone biomes are often characterised by locally endemic lineages. Explanations for this pattern include habitat or substrate specialisation (ecological specialisation) or intensifying aridity driving retreat into climatically buffered habitats (climatic refugia). Here we present an analysis of these alternative models using genetic, morphological and climate data for Diplodactylus galeatus, a gecko from central Australia that occurs in a series of isolated populations associated with dissected tablelands and mountain ranges. Analyses of mtDNA and SNP data support four distinct lineages, and dating analyses suggest divergence through the Pliocene. Morphological data show slight differences across lineages. Investigation of climate niche shows that two lineages are restricted to areas more arid than the intervening uninhabited region. These data suggest that specialisation to rocky substrates, potentially with subsequent paleo-erosion of dissected tablelands after a Pliocene wet pulse, was the key driver of divergence in this clade. Based on their deep genetic divergence, and differences in morphology and pattern, we recognise two isolated populations as new species.
Keywords: Aridfication, Diplodactylus fyfei sp. nov, Diplodactylus galeatus, Diplodactylus tjoritjarinya sp. nov., paleo-erosion, stony deserts, vicariance
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| Colour-pattern variation in the Diplodactylus galeatus species complex: A, B Diplodactylus galeatus from Coober Pedy, SA (P. McDonald, A. Fenner), C, D Diplodactylus fyfei sp. nov. from foothills of Mt Beddome on New Crown Station, NT (P. McDonald, A. Fenner); E, F D. tjoritjarinya sp. nov. from Tjoritja National Park, Northern Territory (P. McDonald). |
Genus Diplodactylus Gray, 1832
Type species: Diplodactylus vittatus Gray, 1832
Diplodactylus galeatus Kluge, 1973
Southern mesa gecko
Etymology: Derived from the Latin word galea meaning covered with a helmet in reference to the dark occipital cap.
Diplodactylus fyfei sp. nov.
Fyfe’s mesa gecko
Etymology: Named for the pioneering herpetologist Greg Fyfe in recognition of his substantial contribution to the knowledge and conservation of central Australia’s reptile fauna.
Diplodactylus tjoritjarinya sp. nov.
Tjoritja gecko
Etymology: Tjoritja is a Western and Central Aranda name for the MacDonnell Ranges. Aranda people sometimes refer to themselves as Tjoritja-rinya (pronounced ‘choor-it-ja-rin-ya’) – meaning belonging to Tjoritja. This name respects that Tjoritja is a living cultural landscape to which this gecko belongs and was suggested as a name for this gecko by the Traditional Owners of Tjoritja National Park. Used as a noun in apposition.
Peter J. McDonald, Aaron L. Fenner, Janne Torkkola, Paul M. Oliver. 2024. Vicars in the Desert: Substrate Specialisation and Paleo-erosion underpin Cryptic Speciation in An Australian Arid-zone Lizard Lineage (Diplodactylidae: Diplodactylus). Vertebrate Zoology. 74: 577-594. DOI: doi.org/10.3897/vz.74.e128775
