Paratanais Dana, 1852

BIRD, GRAHAM J., 2011, Paratanaoidean tanaidaceans (Crustacea: Peracarida) from littoral and shallow sublittoral habitats in New Zealand, with descriptions of three new genera and seven new species, Zootaxa 2891 (1), pp. 1-62 : 25

Paratanais Dana, 1852

Paratanais: Larsen (2001) : 358; Sieg (1983b): 478 –480; both for extensive bibliography and synonymy.

Diagnosis. see Larsen (2001).

Type species. Paratanais elongatus ( Dana, 1849) ; see also Bamber (1998).

Species included (Australasian only): Paratanais gaspodei Bamber, 2005 ; P. linearis Haswell ; Paratanais maleficus Larsen, 2001 ; P. malignus Larsen, 2001 ; P. oculatus (Vanhöffen, 1914) ?; P. paraoa n. sp.; P. perturbatius Larsen, 2001 ; P. tara n. sp.; P. vetinari Bamber, 2005 ; P. wanga Bamber, 2008 .

Incertae sedis within Paratanais : Paratanais tenuis Thomson, 1880 .

Remarks. It has scarcely been remarked that most of the species assigned to the genus do not conform to the pattern set by the type species P. elongatus with respect to pereonite proportions, pleonal setation, cheliped shape and pereopod setation. Large articulated plumose setae on the pleonal epimera do not feature in the diagnoses offered by Lang (1973: 223) or Larsen (2001: 358), were not figured on the type species ( Bamber 1998), and they are apparently absent on seven other species. Additionally, these setae may be present on all pleonites (e.g. P. maleficus , malignus , gaspodei and oculatus ) or only on pleonites 1–4 (e.g. P. martinsi Bamber & Costa, 2009 , P. wanga and the two new NZ species described here). A recent examination of the type of P. elongatus confirmed that it does have plumose epimeral setae on pleonites 1-4 (Bamber pers. comm.).

Sieg (1986a) stated that a revision of the genus was required and this has become more necessary with discovery of twelve more species since then—a casual view of the occurrence of particular characters in Paratanais might suggest a chaotic situation but, if the species truly form a monophyletic group, then a pattern of relationships should be discernible with more rigorous phylogenetic analyses. Ambiguities in character-scoring for phylogenetic analyses could be avoided by closer examination of the setation of pereopods and pleonites in the paratanaids, examples being the occurrence of three or four carpal spines on pereopods 4–6, as well as the distribution of plumose epimeral seta (if present). Sieg (1986a) also noticed two groups within the genus based on maxilliped palp setation and male antennule structure and this may prove to be valid. In addition to this complexity and the apparent anomalies, the genus also exhibits two traits that are conflicting with respect to species identification: the presence of differently-sized and shaped adult morphs (especially in females) within the same species and the sympatry of morphologically near-identical cryptic species, separable by molecular techniques (Larsen 2001).

Paratanais is a widespread genus extending from subantarctic to tropical regions, generally in littoral, sublittoral or shallow bathyal water situations and there is a rich Australasian fauna ( Bamber 2008). In contrast, in New Zealand there are only unconfirmed and unpublished records of P. oculatus (identifications by J. Sieg) but initial studies by me suggest that this taxon is not involved. Also, P. tenuis cannot be assigned to Paratanais as it has 4- segmented uropod endopods ( Thomson 1880: plate I fig 1b) and probably belongs to a genus within the Leptocheliidae . Lang (1973) regarded material, including males, from sub-tidal Cook Strait and Cape Palliser identified by Hurley (1957) as being synonymous with Leptochelia mirabilis Stebbing, 1905 . New material, ideally from the Otago Harbour type locality, is necessary to establish its real taxonomy.