Tuesday, March 21, 2017

[Ichthyology • 2017] Rhinogobius mizunoi • A New Species of Freshwater Goby (Teleostei: Gobiidae) from Japan


Rhinogobius mizunoi 
Suzuki, Shibukawa & Aizawa, 2017



Abstract
 A new freshwater goby, Rhinogobius mizunoi, is described based on six specimens from a freshwater stream in Shizuoka Prefecture, Japan. The species is distinguished from all congeneric species by the following combination of characters: I, 8 second dorsal-fin rays; 18–20 pectoral-fin rays; 13–18 predorsal scales; 33–35 longitudinal scales; 8 or 9 transverse scales; 10+16=26 vertebrae 26; first dorsal fin elongate in male, its distal tip reaching to base of fourth branched ray of second dorsal fin in males when adpressed; when alive or freshly-collected, cheek with several pale sky spots; caudal fin without distinct rows of dark dots; a pair of vertically-arranged dark brown blotches at caudal-fin base in young and females.

Key words: amphidoromous, fish taxonomy, Rhinogobius sp. CO, valid species



Rhinogobius mizunoi sp. nov.
 (Japanese name: Ruri-yoshinobori)

Diagnosis. Rhinogobius mizunoi is distinguished from all congeners by having the following unique combination of characters: 13–18 predorsal scales; 33–35 longitudinal scale series; 8 or 9 transverse scale series; 10+16=26 vertebrae; first dorsal fin elongate in male, its distal tip reaching to base of fourth branched ray of second dorsal fin when adpressed; when alive or freshly-collected, cheek with several pale sky spots; caudal fin lacking distinct rows of dark dots; a pair of dark brown blotches at caudal-fin base in young and females.

Distribution. Known from middle reaches or mountain torrents of freshwater streams in Japan (western Hokkaido southward to southern Kyushu) and Cheju Island, Korea (Akihito et al., 2013); sometimes landlocked in freshwater reservoirs (e.g., Mizuno, 1989). 

Etymology. The new species is named after Dr. Nobuhiko Mizuno, the former professor of Ehime University, Japan, in honor of his great contribution to our knowledge of the ecology of freshwater fishes in Japan, particularly gobies of Rhinogobius.


Toshiyuki Suzuki, Koichi Shibukawa and Masahiro Aizawa. 2017. Rhinogobius mizunoi, A New Species of Freshwater Goby (Teleostei: Gobiidae) from Japan. Bulletin of the Kanagawa prefectural Museum (Nat. Sci.). 46; 79-95.

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