I observed this fish species from brackish water lagoon, surrounded by dynamic mangrove ecosystem located to South west coast line in Sri Lanka in 2010. no idea about micro habitat, but I think probably muddy bottom is preferred. size no longer than 5 cm. unfortunately I released specimen back to the habitat after taken those Photos. did not note down any taxonomical features. but as you can see no body colour (primary pinkish white) and it is blind (no eyes) , please see the attachments
please help , thanks
This is Caragobius urolepis (Bleeker 1852), an amblyopine goby (family Gobiidae). The species has been collected on soft mud bottoms near river mouths, including estuaries. It is distributed from India east to Fiji, and north to southern Japan.
The species is not really blind, but the eye is very small and rudimentary, covered by a membrane.
Reference:
Murdy, E. O. and K. Shibukawa 2003: A revision of the Indo-Pacific fish genus Caragobius (Gobiidae: Amblyopinae). Zootaxa, 301: 1-12.
This is Caragobius urolepis (Bleeker 1852), an amblyopine goby (family Gobiidae). The species has been collected on soft mud bottoms near river mouths, including estuaries. It is distributed from India east to Fiji, and north to southern Japan.
The species is not really blind, but the eye is very small and rudimentary, covered by a membrane.
Reference:
Murdy, E. O. and K. Shibukawa 2003: A revision of the Indo-Pacific fish genus Caragobius (Gobiidae: Amblyopinae). Zootaxa, 301: 1-12.
It is one of the worm or eel gobies - likely to be Trypauchen vagina, I think.
Trypauchen is definately has prominent ocular area and eyes visible, not covered.
Caragobius is most likely is the culprit on picture.
According to the description & the photographs, It is the burrowing gobie, Trypauchen vagina. Habitat- living under surface of mud. Its having very small eyes covered with skin. This feature me be a suitable adaptation for its habitat. It has recorded from Palk strait Sri Lanka.
It is probably not Trypauchen vagina.
Trypauchen vagina and Caragobius urolepis agree in their overall appearance and their pelvic-fin shape.
T. vagina is supposed to have 50-58 dorsal-fin rays, while I count ca. 40 here (which agrees with Caragobius urolepis that has 43 or fewer dorsal-fin rays, typically 39-40.
On the photograph, I also count ca. 35 anal-fin rays. Caragobius urolepis is supposed to have 31-36 anal-fin rays, while T. vagina has 43-50.
The predorsal length is here ca. 30% of SL (Caragobius urolepis: 27-41% of SL; Trypauchen vagina: less than 22 % of SL).
Trypauchen vagina is more elongate than the fish on these photographs, and has a smaller head.
Therefore, I conclude it is Caragobius urolepis.
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Reference for Trypauchen vagina:
Murdy, E. O. 2006: A revision of the gobiid fish genus Trypauchen (Gobiidae: Amblyopinae). Zootaxa No. 1343: 55-68.
Also useful:
Murdy, E. O. 2002: Karsten: a new genus of eel goby (Gobiidae: Amblyopinae) with a key to "Trypauchen" group genera. Copeia 2002 (no. 3): 787-791.
I concur with Ronald that it is a species of the genus Caragobius. The shape of the head, the eyes and the pectoral fins are rather distinct. In its revision Murdy recognised only two species, and the geographic distribution of C. urolepis corresponds to the location indicated.
However, since this group is scarcely known and characterised by extreme regressive evolution, I would be careful about discriminating it down to the species level. It may be an undescribed species.
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