Boreas, Cumberlidge & Sternberg, 2002

Cumberlidge, Neil & Sternberg, Richard V., 2002, The freshwater crabs of Madagascar (Crustacea, Decapoda, Potamoidea), Zoosystema 24 (1), pp. 41-79 : 75

Genus Boreas n. gen.

Potamon (Geothelphusa) – Nobili 1906: 1-4, fig. a. — Balss 1929: 356 [non Geothelphusa Stimpson, 1858].

Madagapotamon – Bott 1965: 347, 348 (part), fig. 9, pl. 5, figs 23-25 [non Madagapotamon Bott, 1965 s. str.].

TYPE SPECIES. — Boreas uglowi n. gen., n. sp.

ETYMOLOGY. — The genus name Boreas is taken from the Latin and Greek words for north, in reference to the distribution of this genus in the north of the island of Madagascar. Gender masculine.

DIAGNOSIS. — Carapace outline transversely oval (wider than long, cw/fw = 3.2, cl/fw = 2.3), moderately arched (ch/fw = 1.1); exorbital, epibranchial teeth both low, blunt, continuous with anterolateral margin; anterior carapace surface smooth, with faint granules in anterolateral corners, carinae in posterolateral regions; epigastric and postorbital crests both faint; frontal margin straight, front highly deflexed; mandibular palp two-segmented, terminal article with flat basal thickening at junction between segments; ischium of third maxilliped smooth (vertical sulcus either faint or absent); sternal sulcus s3/s4 reduced to two short side notches; walking legs (p2-p5) normal length, neither elongated nor shortened, ratio length merus p5 to cw 0.34-0.4.

REMARKS

The postfrontal crest, carapace outline shape, thoracic sternum, and mandible of Boreas n. gen. are similar to those of Skelosophusa . Boreas n. gen. can be distinguished from Skelosophusa , and indeed from all other genera of Madagascan freshwater crabs, by the following combination of characters: legs of normal length, a faint or completely absent vertical sulcus on the ischium of the third maxilliped, and a slim (rather than broad) terminal article of gonopod 1.