Revision, Phylogeny and Biogeographic Comments on the Circumtropical Marine Percoid Fish Family Priacanthidae

The circumtropically distributed marine percoid family Priacanthidae, the bigeyes, is a relatively small (18 species in four genera) group of epibenthic predatory fishes occurring primarily in rocky or coral habitats at depths from 5 to 400 m or more. Two species are circumtropical in distribution, 13 occur in portions of the Indo-Pacific, one is confined to the eastern Pacific and two to the Atlantic. Complete familial, generic and species diagnoses and descriptions are given including osteology and scale morphology and complex nomenclatural problems are addressed. Five species in the genus Priacanthus are described as new and additional, taxonomically more cryptic, undescribed forms may exist pending acquisition of critical material. Hermaphroditism may occur in some individuals. Priacanthids possess several remarkable features including extremely modified scales, swim bladder modifications, extrinsic swim bladder muscles, unique eye morphology, and osteological conditions which were useful in hypothesizing relationships and corroborating the monophyly of the family. The genus Pristigenys (4 species) is hypothesized to be the sister group to all other priacanthids; Cookeolus (monotypic) is the sister group to Heteropriacanthus (monotypic) plus Priacanthus (12 species). Intrageneric relationships are hypothesized. No hypothesis of the phylogenetic position ofpriacanthids among percoids could be advanced. Correlation of the hypothesized familial phylogeny and the fossil record suggests that evolution of all genera predated the Miocene. Species level relationships indicate a closer relationship among species of the Hawaiian Islands and species to the southeast or east (Easter I., eastern Pacific, Atlantic) than either of these areas has to the west Pacific. Possible vicariant biogeographic scenarios are discussed along with problems of advancing biogeographic hypotheses for species groups having distributions interrupted by vast regions.