Taxonomic review of the “posteli-species group” of goatfishes (genus Parupeneus, Mullidae), with description of a new species from the northern Red Sea
The so-called “posteli-species group”, a new taxonomic group of the goatfish genus Parupeneus is reviewed. This group consists of five species distributed in different areas of the Indo-Pacific, of which four species are known to extend to or occur exclusively on the deeper shelf or uppermost slope of 120-250 m: P. chrysonemus from Hawaiian Islands and Johnston Island, P. louise from French Polynesia (Central Pacific), P. moffiti from Guam (West Pacific) and P. posteli from Réunion, now also recorded from the southern Mascarene Plateau, Mauritius, South-Western Indian Ocean. One new species, P. sinai n. sp., from the northern Red Sea is here described based on a single preserved specimen collected during a French research mission about 90 years ago, of which no locality and depth information exist and the fresh colour when alive or after death is unknown. All five posteli-group species are very similar in morphometric and meristic characters, having a relatively shallow caudal peduncle, particularly long barbels, a high gill-raker number which – in combination with lack of dark body and fin pigmentation – distinguish them from all other congeners. Based on detailed examination of 62 morphometric and meristic characters, taxonomic accounts for each species and interspecific comparisons are provided, considering also size-related variation in body form in two species of which specimens of a wide size range were available for studies. Parupeneus sinai n. sp. clearly differs from the other four posteli-group species by a shorter head and snout, a lower ninth dorsal-fin ray, and in a combination of several other characters including body depth, barbel length and number of gill rakers. Comparisons among the remaining four species revealed that morphometric and meristic characters have a higher diagnostic significance than fresh colour patterns, which vary considerably among individuals. Morphological similarities of the posteli-species group with a taxonomic group of mostly deep-water species of the goatfish genus Upeneus, the importance to account for body-form allometry in comparative morphological studies of goatfishes, and the need to further enhance taxonomic research on goatfishes in yet insufficiently explored areas are discussed.