Tuesday, 14 August 2012

New species of Grenadier from Japan.

Grenadiers, or Rattails, are deepwater fish related to Cod and Hake. Most species are benthic, often forming large shoals patrolling food sources such as cold seeps or shipwrecks. Their biology is not well understood, but they are thought to be slow breeders, with populations placed at extreme risk by commercial fisheries. They have a distinctive body-plan, with elongate, roughly triangular bodies, with pointed, finless tails.

In a paper published in the journal Zootaxa on 6 August 2012, Naohide Nakayama and Hiromitsu Endo of the Laboratory of Marine Biology at the Faculty of Science at Kochi University describe a new species of Grenadier from Japan, based upon two specimens found in university collections during a review of Grenadiers in Japanese waters.

The new species is placed in the widespread genus Nezumia, which already contains over 50 species from around the world, and given the specific name shinoharai, in honor of Gento Shinohara of the National Museum of Nature and Science in Tokyo. Both specimens were gathered by bottom trawls, to the south of Japan, and were damaged in the process.

The first specimen was collected east of Boso Peninsula in April 1995, at a depth of between 627 and 673 m, and was recently transfered to the National Museum of Nature and Science in Tokyo, as part of a larger collection. It is a 244 mm fish preserved in ethanol alcohol, brownish in colour with black markings.

The first specimen of Nezumia shinoharai, preserved in alcohol. Scale bar is 20 mm. Nakayama & Endo (2012).

Map showing where the first specimen of Nezumia shinoharai was trawled up. Google Maps.

The second specimen was trawled up in Tosa Bay in May 1988 at a depth of 700 m, and is in the collection of Kochi University. This is a 198 mm fish, accompanied by a photograph taken when this specimen was fresh.

The second specimen of Nezumia shinoharai, photograph taken while the fish was still fresh, showing original colouration. Scale bar is 20 mm. Nakayama & Endo (2012). 

Map showing where the first specimen of Nezumia shinoharai was trawled up. Google Maps.


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