Dusky farmerfish

Stegastes nigricans was first described and named by Gerald Robert “Gerry” Allen and Alan R. Emery in 1985. The order Family Stegastes is derived from the Greek “stegastos,” which means on or covered. Nigricans is Greek for swarthy and black-skinned. Recent research has placed S.nigricans in the monophyly Pomacentrinae, which is closely related to the other subfamilies Amphiprioninae and Chominae. Amphiprioninae are clown fish, which are differentiated from other organisms in their family by their bright orange and white coloration across the body and over fins and relationship with anemone. There is high variation in morph patter of Amphiprioninae, especially around their face. Chrominae are closer on the phylogenetic tree to Pomacentridae than Amphiprioninae, but are able to be differentiated from Pomacentridae because Chrominae are very brightly colored with blues and purples while Pomacentridae are confined to mainly brown with some blues. These three families are all coral reef fishes, and there is usually a lot of variation and overlap from subfamily to subfamily. Damselfish have been documented in the fossil record for at least 50 million years. It has an average length of 9.0 cm, but can reach lengths of 14.0 cm. It has 12 dorsal spines, and 15 to 17 dorsal soft rays. It also has 2 anal spines and 12 to 14 anal soft rays. Adults are generally brown, with the dorsal parts of the head and nape being darker, grading to tan on the lower parts of the head and breast. The scales have darker brown margins. The lips are whitish, the suborbital is mostly blue, and the preopercle and opercle scales have blue centers. The median and pelvic fins are brown, the pectorals are dusky, and sometimes there's a well-defined dark brown or blackish spot at the base of the posteriormost dorsal rays, which distinguishes it from the S. lividus, where the spot is diffuse. When males are in courtship or guarding their eggs they have a broad white bar across the middle of the body and a pale blue stripe from the mouth to the upper part of the pectoral fin.