Geographic Variation in Skull Morphology of the Japanese Crocodile Newt, Echinotriton andersoni (Amphibia: Urodela: Salamandridae), Inferred from Geometric Morphometrics

The Anderson's crocodile newt, Echinotriton andersoni, is an endangered species distributed in the islands of Central Ryukyus, Japan. This well known to show high intraspecific genetic variation among islands, but its morphological has not been explored. We examined skull this including enigmatic specimens collected from Taiwan by using geometric morphometrics, and found sexual differences geographic mainly between Okinawa group (Okinawajima Island) Amami Group (Amamioshima Tokunoshima Islands). further close resemblance Taiwanese female Amamioshima Island.