Tanaopsidae, Błażewicz-Paszkowycz & Bamber, 2012

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2012, The Shallow-water Tanaidacea (Arthropoda: Malacostraca: Peracarida) of the Bass Strait, Victoria, Australia (other than the Tanaidae), Memoirs of Museum Victoria 69, pp. 1-235 : 210

Family Tanaopsidae fam. nov.

Diagnosis. Generally leptognathioid ( sensu lato) facies, pleon laterally convex and wider than pereon, antennule in female of four longer articles with or without minute distal article, in male with multisegmented flagellum; mandible pars incisiva distally rounded with adjacent serrated incisive margin, molar process either slender and pointed or absent; maxillule endite reflexed through about 90° and with five or six distal spines, one significantly more robust than the others; maxilliped endite flared. Cheliped with triangular, dorsally-inserted sclerite, fixed finger with two ventral setae, bifid terminal spine and bifid or trifid distal denticle on incisive margin. Pereopods 1 to 3 with setae, unguis longer than slender dactylus, both together about as long as or longer than propodus, dactylus with proximal seta; pereopods 4 to 6 with spines on merus, carpus (three in number) and propodus. Pleopods with plumose seta along entire outer margin of exopod, but restricted to distal half of outer margin of endopod; uropods biramous, rami with one or two segments.

Type genus: Tanaopsis Sars, 1896

Remarks. The present suprageneric classification of the Paratanaoidea is in a state of flux, owing to recent attempts at phylogenetic resolution involving cladistics, based on meristics and morphometrics ( Larsen & Wilson, 2002; Błażewicz-Paszkowycz & Poore, 2008; Bird & Larsen, 2009). The only of these studies to consider the genus Tanaopsis were Larsen & Wilson (2002) and Błażewicz-Paszkowycz & Poore (2008), but they were unable to resolve it to a family as defined by their generated clades.

The diagnostic features listed above taken together distinguish members of the genus Tanaopsis from all other paratanaoid genera of the leptognathioid sensu lato facies; that said, they constitute a diagnosis of the genus itself. Equally, exclusion of the unique features of the cheliped fixed finger does not allow inclusion of any other genera. Further detailed cladistic analyses may associate other genera, which would then require qualifying the familial diagnosis above, removing characters not consistent across all associated genera into the diagnosis of the genus Tanaopsis . Bird (2011) suggests possible affinities with Cristatotanais Kudinova-Pasternak, 1990 (including Spinitanaopsis Larsen, 2005 ).

It is further the case that Tanaopsis itself may not be monophyletic. There appear to be two groups of species, one with a pointed mandibular molar process and two-segmented uropod rami ( T. antarcticus Lang, 1967 ; T. cadieni Sieg & Dojiri, 1991 ; T. curtus Kudinova-Pasternak 1984 ; T. gallardoi ( Shiino, 1970) ; T. profunda Lang, 1967 ; T. canaipa Bamber, 2008 and one of the two species described below), the other without a molar process and with one-segmented uropod rami ( T. chotkarakde Bird & Bamber, 2000 ; T. kerguelenensis Shiino, 1979 [mandible unknown]; and one of the two species described below); the latter group also tend to have a more slender antennule. That said, T. laticaudata Sars, 1882 is described as being without a mandibular molar (Sars, 1896), but has two-segmented uropod rami. It is at present not possible to distinguish such groups as separate genera, as the type species of Tanaopsis sensu stricto, T. graciloides (Lilljeborg, 1864) needs proper redescription based on material from the northwest Atlantic (see Bamber et al., 2009).