ABSTRACT
Th e inclusion of Tigrigobius in Elacatinus, as suggested by Hoese and Reader (2001a), is currently debated. In this chapter Elacatinus and Tigrigobius are treated as separate genera. Tigrigobius was fi rst proposed as a subgenus of Gobiosoma by Fowler (1931). When Ginsburg (1933) revised the species of Gobiosoma and Garmannia, he placed Tigrigobius as a subgenus of Garmannia, and Elacatinus as a subgenus of Gobiosoma. When Böhlke and Robins (1968) revised the Atlantic species of Gobiosoma they placed both Tigrigobius and Elacatinus as subgenera of Gobiosoma. Th ey remained there until Hoese and Reader (2001a) made Tigrigobius a subgenus of Elacatinus, noting that Elacatinus differs from Gobiosoma in having 28 vertebrae (versus 27) and in several osteological characters of the skull. Recent molecular work by Rüber et al. (2003) indicates that Tigrigobius is not monophyletic. Two clades are recovered for species of Tigrigobius: one clade contains T. macrodon (type of Tigrigobius), T. saucrus, and T. dilepis; the other clade T. gemmatum, T. pallens, T. multifasciatus, T. limbaughi and the genera Risor, Ginsburgellus, and Evermannichthys. Futher studies are required to resolve the status of Tigrigobius. Th e Elacatinus clade of Rüber et al. (2003) includes two subclades, one containing fi shes that dwell on sponges, the other that inhabit corals. Th e coral species all exhibit cleaning behavior. Elacatinus comprises 21 species, all but one found in the western Atlantic. Th e single eastern Pacifi c species, E. puncticulatus, is basal to the rest of the Elacatinus clade (Rüber et al., 2003) and exhibits a combination of characters found in both Elacatinus and Tigrigobius. Th e species all possess a bright stripe along the upper side of the body, from the eyes caudally, and are commonly known as the “neon” gobies (Colin, 1975). Th ey lack scales, except for basicaudal scales on some species. Most species also possess a connection between the snout and upper lip, known as the rostral frenum. Th e species and their diff ering color morphs have very restricted, nonoverlapping, geographic distributions (Colin, 2010; Randall and Lobel, 2009). See Colin (2010) for a detailed list of color morphs and distributions. Most of the species are Caribbean, with others in the Gulf of Mexico and the offshore islands of Brazil. The following species are currently recognized: E. atronasus, E. chancei, E. colini, E. evelynae, E. fi garo, E. genie, E. horsti, E. illecebrosus, E. jarocho, E. lobelia, E. lori, E. louisae, E. oceanops, E. phthirophagus, E. pridisi, E. prochilos, E. puncticulatus, E. randalli, E. serranilla, E. tenox, and E. xanthiprora (Fig 1D, Table 2.1.2).
