Thursday, August 2, 2018

[Ichthyology • 2018] Rhinogobius immaculatus • A New Species of Freshwater Goby (Teleostei: Gobiidae) from the Qiantang River, China


Rhinogobius immaculatus
Li, Li & Chen, 2018


Abstract
A new freshwater goby, Rhinogobius immaculatus sp. nov., is described here from the Qiantang River in China. It is distinguished from all congeners by the following combination of characters: second dorsal-fin rays I, 7–9; anal-fin rays I, 6–8; pectoral-fin rays 14–15; longitudinal scales 29–31; transverse scales 7–9; predorsal scales 2–5; vertebrae 27 (rarely 28); preopercular canal absent or with two pores; a red oblique stripe below eye in males; branchiostegal membrane mostly reddish-orange, with 3–6 irregular discrete or connected red blotches on posterior branchiostegal membrane and lower operculum in males; caudal-fin base with a median black spot; and no black blotch on anterior part of first dorsal fin in males.

Keywords: Gobiidae, Rhinogobius, New species, Qiantang River, China

 Figure 5: Coloration of head and first dorsal fin of male  Rhinogobius immaculatus sp. nov. Specimen collected from Xiuning County, Anhui Province, China. Specimen not preserved.


Figure 4 Male (A) and female (B) Rhinogobius immaculatus sp. nov. 
Specimens collected from Xiuning County, Anhui Province, China. Specimens not preserved.  

Rhinogobius immaculatus sp. nov.

Diagnosis: Most similar to Rhinogobius wuyanlingensis in number of vertebrae (27) and preopercular canal pores (2 or 0 vs. 2), but differing by fewer pectoral-fin rays (14–15 vs. 17–18), fewer anal-fin rays (I, 6–7 vs. I, 8), fewer transverse scales (7–9, modally 8 vs. 9–10), absence of a black blotch on anterior part of first dorsal fin in males (vs. present), and branchiostegal membrane mostly reddish-orange, with irregular blotches posteriorly in males (vs. with red stripes).
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Distribution and ecology: Known only from streams of the Qiantang River basin in Zhejiang and Anhui Provinces, China (Figure 6). Most often found in shallow (10–50 cm deep) low-gradient streams, with sand and gravel mixed substrate.
Adult Rhinogobius immaculatus sp. nov. are small in size. The smallest female with mature oocytes was 22.4 mm SL. The largest specimen collected in the field was 26.3 mm SL. The largest captive specimen kept in an aquarium for 29 months was 32.8 mm SL.

Etymology: The specific name, immaculatus, is derived from Latin in (without) and maculatus (spotted), an adjective, alluding to the absence of a black blotch on the anterior part of the dorsal fin in adult males.


Fan Li, Shan Li and Jia-Kuan Chen. 2018. Rhinogobius immaculatus, A New Species of Freshwater Goby (Teleostei: Gobiidae) from the Qiantang River, China. Zoological Research. 39(6); 396-405. DOI: 10.24272/j.issn.2095-8137.2018.065


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