Acantharctus, Holthuis, 2002

Holthuis, Lipke B., 2002, The Indo-Pacific scyllarine lobsters (Crustacea, Decapoda, Scyllaridae), Zoosystema 24 (3), pp. 499-683 : 649-650

Genus Acantharctus n. gen.

TYPE SPECIES. — Scyllarus ornatus Holthuis, 1960 by present designation.

OTHER SPECIES. — So far only two species are known besides the type species: the West African Acantharctus posteli (Forest, 1963) and the eastern Pacific A. delfini ( Bouvier, 1909) n. comb.

ETYMOLOGY. — From akantha (Greek, latinized to acanthus), thorn, in reference to the sharp median thorn on the last segment of the thoracic sternum; and Arctus De Haan, 1849 , a junior synonym of Scyllarus Fabricius, 1775 .

DIAGNOSIS. — Carapace with rostral, pregastric, gastric and cardiac teeth; the pregastric tooth very small, smaller than any of the other teeth, sometimes hardly visible; the rostral tooth may be small, rather like a tubercle, or absent.

The abdomen has a distinct arborescent pattern of narrow grooves; the lobulated median figure is raised and forms a low median elevation, which on somites II to IV is of about equal height. The fourth antennal segment bears a single oblique carina, no additional carinae or rows of tubercles are present. The dactylus of P.2 is longer than that of the other legs. P.2 to P.5 are slender and do not have the propodus broadened. There is no pubescence on the lower margin of any of the segments. The anterior margin of the thoracic sternum is rather widely U-shapedly incised and may show an indistinct tubercle on either side of the medi- an incision. The last segment of the thoracic sternum shows in both sexes a strong median thorn.