Pinkspot Shrimpgoby
Cryptocentrus leptocephalus
Pinkspot Shrimpgoby
Cryptocentrus leptocephalus
Bleeker, 1876
Description
This is a medium-sized partner goby, around 8 cm in length, but will grow to a length of 12 centimetres. (Bray, 2018)
Body design
The body is pale green-brown above and grey-white ventrally with 6 to 7 brown bars along the body.
There are pink spots, blue spots and smaller white spots randomly arranged over the head which is dark brown above. These spots are continued over a series of dark dorsal saddles continuous with the lateral bars and running from behind the eyes to the caudal fin.
Fin design
The first dorsal fin is pale grey with a dozen dusky magenta circular or oval spots each outlined in blue. At the leading edge and the apex there is a blue outlined black ocellus 2to 3 times larger than the red spots. The margin is dark magenta underlined in blue. The second dorsal fin has the same pattern of spots and margin but the spots tend to coalesce into blue outlined magenta diagonals. The pectoral fin is transparent. The pelvic fin is opaque magenta with green highlights on the rays. The anal fin is green with maroon rays and blue outlined spots in the lower quarter. .
Diagnostic features
The multicoloured facial spots and the intricate design of the dorsal fins is obvious in the field.
Similar species
This species is frequently misidentifed as Cryptocentrus melanopus, the Singapore Shrimpgoby
It differs from Cryptocentrus melanopus in having smaller pinks spots and numerous pale dots on the head and upper back, and the third oblique body bar ending in part above the anal-fin origin. It occurs in the same area but lives in a different habitat, in 10 metres of water on white sand well away from mangroves and reef. Allen and Erdmann 2012, consider Cryptocentrus melanopus to be the same size as C. leptocephalus, but ours are consistently smaller. We could be looking at juveniles but we do not think so.
Nomenclature
Randall gives Cryptocentrus leptocephalus the common name Singapore Shrimpgoby.
Cryptocentrus geniornatus Herre, Smilogobius obliquus Herre, and S singapurensis Herre are regarded as synonyms (Randall).
Other Common Names: Pink Shrimpgoby, Pink Spot Shrimp Goby, Pink-speckled Shrimpgoby, Saddled Shrimp Goby, Singapore Shrimp-goby
Natural History
Habitat
In the low Isles we find this shrimpgoby in a very specific habitat. It lives in shallow coarse sandy areas with broken up shells and coral debris in very shallow water among and between mangrove trees. The water is so shallow that the burrows are left high and dry by more than a metre at low tide. This clearly poses problems from the point of view of keeping their heads below water. The burrows are probably correspondingly deep.
Within this habitat this is an abundant species with burrows evenly spaced about half a metre apart. They are also in silty sand near and under mangroves.
Behaviour
This species lives in very shallow water in areas where the sun reflectes ripples onto the sea floor. The pattern of this fish blends in beautifully with the sunlight ripples and helps it to camouflage.
Distribution
Published distribution:
South China sea and Tonga to northern Australia to Yaeyama Islands of SW Japan to Indonesia and New Caledonia. Throughout most of the East Indian region except the Andaman Sea.
Our records:
Indonesia; Batanta Island
Solomon Islands; Guadalcanal, Nggela Islands and Kolombangara.
Australia; Low isles
Associated Shrimp species
Associated Shrimps (five shrimp)
Banded Snapping Shrimp, Alpheus species 1
Chocolate Chip Snapping Shrimp, Alpheus species 2
Dark Marbled Snapping Shrimp, Alpheus macellarius
Green Snapping Shrimp, Alpheus species 4
Pale Marbled Snapping Shrimp, Alpheus djiboutensis