A world-wide review of species of the deep-water crangonid genus Parapontophilus Christoffersen, 1988 (Crustacea, Decapoda, Caridea), with descriptions of ten new species

A review of species of the genus Parapontophilus Christoffersen, 1988 (Decapoda, Caridea, Crangonidae) from the world oceans is presented. This study is based on the large collection obtained during French expeditions in the eastern Atlantic, western Indian, and tropical western and southern Pacific oceans, and on additional material from various museums and institutions in the world. Eighteen species, including ten new species, are divided in two informal species groups, P. gracilis (Smith, 1882) group and P. modumanuensis (Rathbun, 1906) group. The first group contains 11 species: P. gracilis (type species of the genus), P. abyssi (Smith, 1884), P. junceus (Bate, 1888), P. profundus (Bate, 1888), P. occidentalis (Faxon, 1893), P. talismani (Crosnier & Forest, 1973), P. cornutus n. sp., P. cyrton n. sp., P. difficilis n. sp., P. geminus n. sp. and P. longirostris n. sp. The second group contains seven species: P. modumanuensis (Rathbun, 1906), P. demani (Chace, 1984), P. caledonicus n. sp., P. juxta n. sp., P. psyllus n. sp., P. sibogae n. sp. and P. stenorhinus n. sp. Six taxa originally described as full species by their authors and occasionally treated as subspecies, viz. P. gracilis, P. abyssi, P. junceus, P. profundus, P. occidentalis, and P. talismani, are here maintained as full species because of the existence of morphological differences and of the partial overlap of geographical or bathymetrical ranges. All species are diagnosed or rediagnosed, and illustrated. Synonymies of Pontophilus challengeri Ortmann, 1893 with Parapontophilus abyssi and of Pontophilus occidentalis var. indica de Man, 1918 with Parapontophilus junceus were confirmed. A key to aid in the identification of all Parapontophilus species is given, although it should be used with caution because of intraspecific variations exhibited by many of the species. Bathymetrical and geographical distributions of species are also summarized. All but P. sibogae n. sp. are exclusively found at more than 200 m depth, and particularly three species, P. abyssi, P. occidentalis, and P. talismani, occur at abyssal depths exceeding 3000 m. Parapontophilus sibogae inhabits shallow water, recorded at depth of 11 m in the type locality. Two species, P. gracilis and P. talismani, appear restricted to the Atlantic Ocean, although widely distributed there. Three species, P. abyssi, P. longirostris n. sp., and P. juxta n. sp. occur in the Indian Ocean; P. abyssi is also widely distributed in the Atlantic and P. longirostris extends to the central Pacific. Parapontophilus occidentalis appears restricted to the eastern Pacific. Other species are distributed in the range of the western Pacific to French Polynesia.