Paragathotanais robustus Bird & Holdich, 1988

Bird, Graham J, 2010, Tanaidacea (Crustacea, Peracarida) of the North-east Atlantic: the Agathotanaidae of the AFEN, BIOFAR and BIOICE projects, with a description of a new species of Paragathotanais Lang, Zootaxa 2730, pp. 1-22 : 5-6

Paragathotanais robustus Bird & Holdich, 1988

Fig. 2 E

Bird & Holdich (1988): 1605–1608, figs 2b, h, i, 6–7. Guerrero-Kommritz (2003): 3.

Larsen (2006): 108, 120.

Identification reference. Bird & Holdich (1988).

Distribution records from the AFEN, BIOFAR & BIOICE surveys. Recorded from 22 BIOICE stations, from the Denmark Strait, Iceland Basin, and Irminger Basin, at depths 256–1533 m. Not recorded in the AFEN and BIOFAR material. The highest count was 123 specimens from BIOICE sample 2475, Iceland Basin, at 842 m.

Distribution elsewhere. From North Feni Ridge to the South Biscay Slope, at depths 1279–2246 m ( Bird & Holdich 1988).

Remarks. Care is needed to distinguish this species from P. nanus when they co-occur in samples (see above) but the broader pleon and more pointed pleotelson are diagnostic characters ( Fig. 2 E). As with the previous two agathotanaid species, the recorded upper bathymetric limit of P. robustus is now much shallower, raised from 1279 m (see above) to 256 m. A similar range of benthic temperatures of 2–4o C is also evident.

Figures

FIGURE 2. Comparative habitus of Paragathotanais nanus and P. robustus of similar sizes: A, P. nanus, non-ovigerous female; B, P. nanus, angular form, possibly “ incipient male ”; C, P. robustus. pereopod- 1 propodus, dactylus and unguis: D, P. nanus; E, P. nanus angular form. Scale bar: 0.5 mm for A – C, 0.25 mm for D – E.