New Caledonia: Evolution, Diversity and Endemism in a South Pacific Gecko Hotspot

Bauer, Aaron M.

aaron.bauer@villanova.edu

Department of Biology

Villanova University

Villanova, Pennsylvania, USA

The European “discovery” of the New Caledonian lizard fauna began with the description of Rhacodactylus leachianus in 1829 but only a few species were recognized prior to the 1869 monographic treatment of the New Caledonian herpetofauna by Arthur Bavay, in which some of the island’s most iconic geckos were described. Collections later in the 19th century were small and few new species were described, but the important Swiss expedition of Fritz Sarasin and Jean Roux (1911–1912) collected broadly across the Grande Terre and the Loyalty Islands. Although little herpetological work took place over the next 50 years, by the 1970s both academic and terrarium-based studies on geckos began to appear. Since 1998 fifty species and four new genera of geckos have been described from New Caledonia (29 in 2022 alone) and at least another eight remain to be described. Species rich genera like Bavayia reveal some of the likely evolutionary dynamics that have generated New Caledonia’s outstanding lizard diversity over the relatively short period of about 20 million years. Exciting recent discoveries include an extinct gecko from owl pellets more than 1000 years old, new biological data, a new genus of giant gecko with partly aquatic habits, and the revelation that the extinct giant Gigarcanum delcourti (370 mm SVL) is part of the New Caledonian diplodactylid radiation. With a gecko fauna of at least 71 species of diplodactylid geckos and six species of gekkonid geckos, New Caledonia ranks as perhaps the world’s richest and most highly endemic gecko hotspot.