Paratanaidae Lang 1949

PARATANAIDIDAE Lang, 1949

Three genera, Bathytanais Beddard, 1886; Paratanais Dana, 1852 and Pseudobathytanais Kudinova­Pasternak, 1991, representing about 23 nominal species, presently comprise the family Paratanaididae. Members of the family occur in depths ranging from <1 m to> 1000 m. Gutu and Sieg (1999) did not include Pseudobathytanais in the Paratanaididae, but a recent phylogenetic analysis strongly indicates that this genus should be placed in the Paratanaididae (Larsen & Wilson 2001). At present, 6 species of Bathytanais, 2 species of Pseudobathytanais and 15 species of Paratanais are known.

Diagnosis: Female. Medium body calcification. Carapace divided into 8 plates. Eyes present. Pereonite 1 not reduced. Pleon with 5 free pleonites, as wide as pereon, articulated setae lateral on pleonites. Antennule with 4­5 articles. Antenna article 3 with or without dorsal spiniform setae. Molar process broad. Labium with 2 lobes, medial processes absent. Maxilliped basis partly fused, endites not fused, broader than basis with 2 short flat setae. Cheliped attachment via sclerite. Marsupium (where known) with 4 pairs of oostegites. Pereopod coxa present on pereopods 1­3 but absent on pereopods 4­6, pereopods 4­6 dactylus and terminal setae fused to form a hook. Male and female pleopods well­developed (male Pseudobathytanais and Bathytanais unknown). Uropodal endopod with 2 articles although incomplete fusion may occur, exopod with 1­2 articles.

Male (where known). High sexual dimorphism. Body significantly shorter than female. Pereonites lesser developed than female. Pleonites more developed than female. Eyes large (> 25 % of carapace). Antennule with more than 7 articles, densely packed with aesthetascs. Cheliped not enlarged. Pleopod setae longer than on female.

Remarks: The genera Pseudobathytanais and Bathytanais are differentiated from other tanaidomorphs by the extremely long setulated setae of both antennule and antenna. Because of this highly apomorphic character, the genera are separated into the new subfamily Bathytanaidinae. Paratanais, the genotype of the family, is the only member of the monotypic subfamily Paratanaidinae Lang, 1949.

Bathytanais have been reported from both shallow water and (once) from abyssal depths, but the deep­sea record is treated with suspicion by a number of authors (Beddard 1886 a, 1886 b; Larsen & Wilson 1998) due to the presence of fully developed eyes. The new species from the Australian slope indicates that the genus may actually be present in the deep sea, despite the presence of eyes.