Tanaidomorpha, Sieg, 1980

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 : 226

Tanaidomorpha incertae sedis

Species 33

Figure 152

Material examined. 6 mancae (manca 1) (J51791), Stn VC 30 C1, Victoria, Central Bass Strait , 38°35.53'S, 146°07.51'E, 40 m depth, 11 th May 1998, Smith-McIntyre grab, coll. N. Coleman.

Description. Body ( Fig. 152) glabrous, small, eight times as long as wide, length of all specimens 1.4 mm. Cephalothorax subrectangular, wider than long, with branchial chambers expanded as lateral rounded flanges over cheliped attachment; rostrum straight, smooth, with anterior margin of carapace protruding either side of rostrum as rounded lobes. Pereonite 1 trapezoidal, 0.8 times as long as cephalothorax, anteriorly 1.4 times as wide as pereonite length, posteriorly 0.8 times as wide as pereonite length; pereonites 2 and 3 rectangular, 0.75 times as wide as long, pereonite 2 almost as long as cephalothorax, pereonite 3 just shorter than pereonite 1; pereonites 4 and 5 hexagonal, pereonite 4 as wide as long and as long as pereonite 3, pereonite 5 about 1.5 times as wide as long and about half length of cephalothorax; pereonite 6 short, one-quarter as long as pereonite 5 and four times as wide as long. Pleon laterally convex, first four pleonites 5.2 times as wide as long, fifth pleonite as long as pereonite 6 and four times as wide as long. Pleotelson semicircular, twice as long as each anterior pleonite and twice as wide as long.

Antennule apparently of three articles. Posterior pereopods with prickly tubercles on carpus. Uropods biramous, each ramus of one segment.

Remarks. These specimens are all at the manca 1 stage, with a highly reduced pereonite 6, hardly longer than pleonite 1, and no pereopod 6. Their morphology shows no similarity to any known genus; in particular, the lobate structure of the cephalothorax is highly unusual, yet appears unlikely to be a juvenile character. The presence of prickly tubercles on the posterior pereopods suggests that this taxon may belong in the Typhlotanaidae (but see Bassoleptocheli a above). Without knowledge of the adult, it is at present not possible to assign this taxon to any category lower than Suborder, and it may well represent a distinct Family. “Species 33” is a Museum Victoria collection reference number.