Arctides Holthuis, 1960

Holthuis, Lipke B., 2006, Revision of the genus Arctides Holthuis, 1960 (Crustacea, Decapoda, Scyllaridae), Zoosystema 28 (2), pp. 417-433 : 418

Genus Arctides Holthuis, 1960

Arctides Holthuis, 1960: 154 . Gender: masculine.

TYPE SPECIES. — Scyllarus guineensis Spengler, 1799 , by original designation.

DIAGNOSIS. — Carapace rather high, not depressed, quadrangular in outline, slightly longer than wide. Upper surface rough, with tubercles. Cervical, postcervical and branchiocardiac grooves, not very deep. Marginal groove distinct; with shallow cervical, but no postcervical incision on lateral margin which bears several teeth. Orbits on anterior margin of carapace close to anterolateral angles; distance between orbit and anterolateral angle less than 1/10 of distance between orbits, latter widely open anteriorly; intercalated plate poorly developed. Antenna not forming part of orbit. Upper surface of carapace without distinct carinae, with several teeth present. Rostral, pregastric and gastric teeth in median line; two submedian cardiac teeth on cardiac elevation; two teeth on branchial region behind cervical groove; and distinct postorbital tooth. No posteromedian tooth. Entire surface of carapace covered with small squamiform tubercles surrounded by short bristle-like hairs, some tubercles larger, even becoming tooth-shaped.

First abdominal somite with deep uninterrupted transverse groove filled with hairs. Following somites with anterior half smooth and posterior part with complex sculpturation resembling that of Scyllarus arctus (Linnaeus, 1758) , but with grooves wider and sculpted figures more elevated.

Calcified part of telson with tooth on each posterolateral angle.

Distal part of antennular somite rather long, ending in two teeth placed close together at either side of median incision of segment.

Ultimate segment of antenna with many large and small teeth. Fourth segment with strong teeth on anterior and lateral margins.

Epistome, mouthparts and branchiae as in Scyllarides .

Pereiopods with first leg stronger than following ones. Dactyli naked, not flattened above. Fifth leg of female ending in chela.

Pleopods normal.

REMARKS

The genus contains three species, of which the oldest, Scyllarus guineensis Spengler, 1799 , is the type by original designation.

Formerly the species of the genus Arctides were assigned to Scyllarides , but they differ in so many points that it proved necessary to erect a separate genus for them. The three species may be distinguished with the help of the following key.