Family Elapidae H. Boie in F. Boie, 1827 (13 species) Elapidae H. Boie in F. Boie, 1827: 510 (type genus Elaps Schneider, 1801). A note on sea snakes in Singapore. Sea snakes is a colloquial term used for 73 species of marine snakes (Heatwole 1999). Collectively, sea snakes are composed of species within the following nine genera: Aipysurus (9 species), Emydocephalus (3 species), Ephalophis (1 species), Hydrelaps (1 species), Hydrophis (50 species), Laticauda (8 species), and Parahydrophis (1 species). Phylogenetically, sea snakes do not form a monophyletic group, with Laticauda radiating much earlier in Elapidae than the other six genera, which do constitute a monophyletic clade (Sanders et al. 2013; Figueroa et al. 2016). Delineating Singapore’s sea snake assemblage is confounding mainly because Sworder (1923) listed 24 species as occurring in Singapore. At that time, only nine species were reported from Singapore. The rest, Sworder (1923) presumed may occur in Singapore for various reasons. Later, Lim & Lim (1992) listed 21 species of sea snakes for Singapore, but did not comment on why these species were listed. Between 1981 and 1982, Voris, Jeffries, and Yang examined sea snakes caught by fishermen operating out of several locations in Singapore, mainly Horsburgh Lighthouse, Kangkar Fish Market, prawn ponds in Jurong, and kelongs in Tuas and Lim Chu Kang. Although Horsburgh Lighthouse (located on Pedra Branca) is part of Singapore’s territorial jurisdiction, it lies 54 km from mainland Singapore and its boundary is not contiguous with that of mainland Singapore (Fig. 1). Following Kwik & Lim (2020), we have excluded records from Pedra Branca/ Horsburgh Lighthouse. The Kangkar Fish Market refers to a fishery port in Serangoon where fish and other marine animals caught for food were brought and sorted (Sinoda et al. 1978). Discards (“trash fish”) were often the source of biological specimens (Sinoda et al. 1978; Kwik & Lim 2020). Many of the trawlers that operated out of this centre would fish around Horsburgh Lighthouse (Pedra Branca) and sometimes beyond Singapore’s territorial waters. For this reason, records from Kangkar Fish Market material are also excluded unless exact Singapore locality data is present. In total, Voris, Jeffries and Yang collected specimens of five species of sea snakes (Aipysurus eydouxii, Hydrophis hardwickii, Hydrophis schistosus, Hydrophis spiralis, and Hydrophis stokesii), Acrochordus granulatus, and two homalopsids (Cerberus schneiderii and Gerarda prevostiana) from Singapore’s waters. The following eight sea snake species were also collected, Hydrophis cyanocinctus, Hydrophis fasciatus, Hydrophis inornatus, Hydrophis klossi, Hydrophis ornatus, Hydrophis peronii, Hydrophis stokesii, and Hydrophis viperinus, but did not have a specific locality reported so we do not consider these as valid Singapore records. As most of the specimens are labelled Voris and Jeffries, we refer to their research by that name. Most of their specimens were deposited at FMNH and the Raffles Museum. Herein, we recognise nine native sea snake species, Aipysurus eydouxii, Hydrophis hardwickii, Hydrophis platurus, Hydrophis schistosus, Hydrophis spiralis, Hydrophis stokesii, and Laticauda colubrina. We exclude the remaining 22 reported sea snake species from Singapore’s herpetofauna checklist, with the status of Hydrophis cyanocinctus and Hydrophis viperinus being uncertain as there is some evidence suggesting they may have been recorded in Singapore. Of the 32 species of sea snakes covered in de Haas’ (1950) checklist of snakes of the Malay Archipelago, he only included Aipysurus eydouxii, Hydrophis schistosus, Hydrophis spiralis, Hydrophis stokesii, and Laticauda colubrina for Singapore.

Published as part of Figueroa, Alex, Low, Martyn E. Y. & Lim, Kelvin K. P., 2023, Singapore's herpetofauna: updated and annotated checklist, history, conservation, and distribution, pp. 1-378 in Zootaxa 5287 (1) on pages 187-188, DOI: 10.11646/zootaxa.5287.1.1, http://zenodo.org/record/7960319