The West African species of Bathygobius (Teleostei: Gobiidae) and their affinities



The circumtropical gobiid fish genus Bathygobius Bleeker, 1878 is discussed and defined in terms of external features, including the head lateral-line system, and osteology. Three West African species are recognized and redescribed: the amphiatlantic B. soporalor (Valenciennes, 1837) and two endemics, B. burtoni (O'Shaughnessy, 1875) and B. casamancus (Rochebrune, 1880). West African B. soporator differs significantly from western Atlantic material only in average values for predorsal scales and some body proportions, so that separation of eastern and western Atlantic populations as morphological species is not warranted. The affinities of the West African Bathygobius species are examined by means of phenetic (presence-only group-average clustering) and cladistic (Camin-Sokal, Dollo and Wagner) numerical processing of a binary database comprising 46 character states in 15 Operational Taxonomic Units (OTUs) formed by species of Bathygobius. Results do not indicate close common ancestry between the West African endemic species and B. soporator, which has probably colonized West Africa from the New World. The implications of various cladistic schemes for the relationships of certain other American species are also noted.