Amblyeleotris arcupinna, Arcfin Shrimpgoby

Description

Body Design

A small goby, pale grey with six brown bands laterally, the last on the base of the tail. Each of these is bordered with dark grey. The intervening pale areas are plain in the lower half and speckled in the upper half. There are fine bands of gold and blue in these intervening pale areas.

The face is plain with a vertical brown band below the eye and two horizontal rows of iridescent blue spots.

Fin Design

The fins are translucent except the ventral which is grey with a brown band, and the first dorsal which has a dark grey arc sub-terminally, from which is derived the species name. The pelvic fins have bands of several colours, predominantly opalescent white, blue and pink.

Diagnostic Features

The arc on the dorsal fin is the defining feature of the species. This is not always obvious and the best field character is the vertical line below the eye though a similar mark can be seen in other shrimpgobies.

Similar species

This goby is superficially similar to many of the species in its genus that are plain pale grey with a series of brown bands. The dorsal fin and facial markings are distinguishing features.

It is similar to A. rubrimarginata, the Redmargin Shrimpgoby but lacks the distinctive red margin to the dorsal fins.

It is similar to A stenotaeniata and A ogasawarensis in having a vertical line below the eye. In A stenotaeniata this has a distinct right angle in it. A ogasawarensis has four conspicuous red spots on the face and it lacks the dark speckles along the back.

Natural History 

Habitat 

Sandy slopes with scattered coral rubble and moderate to coarse sand at the base of a small coral wall in an area of strong currents.