Thenus Leach, 1815

Burton, T. E. & Davie, P. J. F., 2007, A revision of the shovel-nosed lobsters of the genus Thenus (Crustacea: Decapoda: Scyllaridae), with descriptions of three new species, Zootaxa 1429 (1), pp. 1-38 : 12

Thenus Leach, 1815

Thenus Leach, 1815: 335 , 338. Gender Masculine. Name placed on the Official List of Generic Names in Zoology by the International Commission on Zoological Nomenclature in Opinion 519 (published in 1958). Type species by monotypy: Thenus indicus Leach, 1815 .

Sagaritis Billberg, 1820: 134 . Type species by monotypy Scyllarus orientalis Lund, 1793 .

Scyllibacus Desjardins, 1831: 46 . Type species by monotypy Scyllibacus orientalis Desjardins, 1831 . If Scyllibacus orientalis Desjardins is a new combination of Scyllarus orientalis Lund, 1793 , Scyllibacus falls as a junior subjective synonym of Thenus Leach, 1815 ; if it is considered to be a new species, Scyllibacus is a nomen nudum ( Holthuis, 1991).

Diagnosis. Body dorso-ventrally depressed; carapace broader than long; anterolateral borders of carapace broadly expanded upwards, with a single broad, acute tooth behind the orbit; outer orbital angle spinous, forming maximum carapace width; eyes within deep orbits protected by several robust teeth; carapace and abdomen sculptured with fine granules and tubercles amongst patchy tomentum; carapace and first five abdominal segments with elevated median dorsal ridge, which on carapace, has three forward and upwardly directed teeth; a rostral process of two short sharp spines separated by broad v-shaped sinus; antennae with second and fourth segments broadly flattened and expanded, with long curving teeth on anterolateral margins; antennules rising from beneath rostral process and extending just beyond anterior margins of antennae; abdominal segments each with lateral margins expanded downwards concealing pleopods; telson longer than broad, calcified and stiff proximally, thin and soft distally; uropods well developed and expanded beyond posterior margin of telson. Ventrally four pairs of pleopods arising from abdominal segments 2–5 and decreasing in size posteriorly; exopods larger than endopods. Pereiopods relatively long and slender; dactyli sharp, corneous tips long and acute on anterior pair, becoming shorter and blunter posteriorly; dactyli of posterior three pairs each with two dorsal rows of coarse setae. Maxillipeds relatively large, well developed; branchiostegites smooth, relatively featureless.