Hydrophis schistosus Daudin, 1803 / Hydrophis zweifeli (Kharin, 1985). McDowell (1972) mentioned a specimen from Sepik River, East Sepik District, New Guinea (AMNH 104340) that was very similar to the ‘beaked sea snake’, H. schistosus, but showed some morphological characters which were not in accordance with H. schistosus. Later Kharin (1985) described a new species, Enhydrina zweifeli, based on McDowell´s (1972) data. The similarity with H. schistosus is striking. However, a recently published paper presented molecular evidence showing the two species represent distinct lineages and are not each other’s closest relatives, indicating convergent phenotypic evolution probably related to a specialist diet of large, spiny prey (Ukuwela, de Silva, Fry, Lee, & Sanders, 2012). Morphological analysis of 18 specimens from the Asian region and 12 specimens from Australia suggested the specimens in Australian waters all belong to H. zweifeli based on scale counts and colour pattern characters, thus excluding H. schistosus from Australian waters (Ukuwela, de Silva, et al., 2012). However, more molecular and morphological analyses of additional specimens are needed to determine the precise distributions of the two species (Ukuwela, de Silva, et al., 2012). Based on the above, we exclude H. schistosus from the list of sea snakes occurring in Australian waters in favour of H. zweifeli.

Published as part of Rasmussen, Arne Redsted, Sanders, Kate Laura, Guinea, Michael L. & Amey, Andrew P., 2014, Sea snakes in Australian waters (Serpentes: subfamilies Hydrophiinae and Laticaudinae) - a review with an updated identification key, pp. 351-371 in Zootaxa 3869 (4) on page 355, DOI: 10.11646/zootaxa.3869.4.1, http://zenodo.org/record/4947280