The Indo-Pacific scyllarine lobsters (Crustacea, Decapoda, Scyllaridae) Author Holthuis, Lipke B. National Museum of Natural History, P. O. Box 9517, 2300 RA, Leiden (The Netherlands). text Zoosystema 2002 24 3 499 683 journal article 10.5281/zenodo.4689240 1638-9387 4689240 Genus Petrarctus n. gen. TYPE SPECIES. — Scyllarus rugosus H. Milne Edwards, 1837 by present designation. OTHER SPECIES. — Petrarctus brevicornis ( Holthuis, 1946 ) n. comb. ; P. demani ( Holthuis, 1946 ) n. comb. ; P. veliger n. sp. ETYMOLOGY. — From the Greek word petra , rock and the generic name Arctus De Haan, 1849 in reference to the very solid, knobby, stone-like body of the species of this genus. DIAGNOSIS. — Body very solid. Carapace with gastric and cardiac teeth.Rostrum without tooth but with a small dorsal tubercle; pregastric tooth absent or replaced by a weak transverse carina or a transverse row of tubercles.Abdomen with longitudinal median carina on somites II to V. Dorsal surface of somites II to V with a wide transverse median groove before and behind which there are tubercles or ridges, but there is no arborescent pattern of very narrow grooves. Fourth antennal segment with a single oblique dorsal carina, sometimes with an additional row of tubercles. Thoracic sternum anteriorly U-shaped with a narrow median incision, the latter sometimes very indistinct. No teeth or spines on the posterior margin of the sternum.