New Species of Cave Loach Discovered in Vietnam

Live specimen of Draconectes narinosus. Photo by Boris Sket.

A new genus and species of cave loach (family Nemacheilidae) was recently described by Dr. Maurice Kottelat from a cave on Van Gio Island in Halong Bay, Vietnam in the September issue of Revue Suisse de Zoologie (Kottelat 2012). Specimens were originally collected by Drs. Boris Sket and Peter Trontlej during a cave biological inventory of several caves within Halong Bay for Fauna and Flora International in 2003. Only five individuals of this species were observed and just two collected representing the type series.

The new genus is distinguished from other genera in the family Nemacheilidae by the presence of lateral line pores on the head and body situated at the tips of small papillae and a row of papillae that presumably also have lateral line pores along each side of the dorsal fin. The genus name Draconectes is derived from the Greek words 'drakon' for dragon and 'nectes' for swimmer in reference to the type-locality on Van Gio Island in Halong Bay. Halong means 'descending dragon' in Vietnamese. The specific epithet narinosus is Latin for 'who has large nostrils.'

With the description of D. narinosus, three species of cavefishes have been formally described from Vietnam and at least 14 species from the Indochina Peninsula with several others awaiting description.

Halong Bay is located in northeastern Vietnam in an area of rich carbonate deposits, which includes 1,600+ karst islands and islets. Cave and karst development in the region has been occurring for the past 20 million years, although the Halong Bay itself is believed to have formed from the erosion of limestone forming the Halong Depression primarily in the Miocene (26 - 10 Mya) and subsequent flooding by the sea and erosion more recently in the Pleistocene and Holocene (2 Mya to present). Halong Bay is a UNESCO World Heritage Site. Given the geological history of the area, other populations of D. narinosus or other undescribed but closely related species might be found on other islands of Halong Bay and on the mainland in Vietnam.

The abstract of the original species description can be found at http://www.ville-ge.ch/mhng/pdf/rsz119_3.pdf.

Citations:

Kottelat, M. 2012. Draconectes narinosus, a new genus and species of cave fish from an island of Halong Ray, Vietnam (Teleostei: Nemacheilidae). Revue suisse de Zoologie / Swiss Journal of Zoology 119 (3): 341-349.