Anisomenaeus, Bruce, 2010

Bruce, A. J., 2010, A revision of the systematic position of Periclimenaeus spinimanus Bruce, 1969 (Crustacea: Decapoda: Pontoniinae) and the designation of Anisomenaeus gen. nov. *, Zootaxa 2372 (1), pp. 338-340 : 338-339

Anisomenaeus gen. nov.

Diagnosis. Small shrimp of subcylindrical body form. Rostrum well developed, compressed, dorsally and ventrally dentate. Carapace smooth, glabrous, inferior orbital angle obsolete, orbit generally feebly developed, with small supraorbital tubercle, epigastric and hepatic spines absent, antennal spine present, anterolateral lateral angle of branchiostegite rounded. Abdomen smooth, glabrous, first tergite with dorsal anterior median lobe, pleura with posterior margins rounded. Telson with two pairs of dorsal spines, three pairs of posterior spines. Eye normal, with globular cornea. Antennule normal. Antenna with basicerite unarmed, scaphocerite well developed. Epistome unarmed. Mandible without palp, molar process robust, incisor reduced to acute process; maxillula with bilobed palp, upper lacinia spinose, lower lacinia setose; maxilla with simple palp, basal endite bilobed, scaphognathite normal; maxillipeds without special features, exopodal flagella slender with four long plumose terminal setae and several shorter adjacent setae. First maxilliped with bilobed epipod, second maxilliped with small subrectangular epipod without podobranch, third maxilliped with ischium fused to basis, coxa with small rounded lateral plate, without medial process, small arthrobranch present. First pereiopods slender, chela with fingers short, stout, scaphoid, dactylus with simple bidentate tip, fixed finger simply acute distally, cutting edges entire, basi-coxal articulation with protuberant process. Second pereiopods well developed, chelae unequal, dissimilar, major chela with palm densely spinose, dactylus spinose, without molar process, cutting edge entire, tip acute; fixed finger without proximal fossa, longitudinally grooved, medial margin entire, lateral margin feebly crenulate, merus and ischium ventrally spinose; minor chela with palm spinose, dactylus spinose, compressed, tip bidentate, fingers closing with shearing action, fixed finger similar, cutting edge entire. Ambulatory pereiopods normal, dactyli short, biunguiculate, without basal process, propodus spinulate. Uropod with protopodite unarmed, with distolateral tooth with spine medially.

Type species. Periclimenaeus spinimanus Bruce, 1969 , by present designation and monotypy.

Etymology. From an - not, and iso -, the same (Greek), and part of the name Periclimenaeus first used by Borradaile (1915), that is, different from Periclimenaeus . Gender masculine.

Systematic position. Closely resembling Periclimenaeus Borradaile , in which it was originally placed, but immediately distinguishable by the absence of a dactylar molar process and a fixed finger fossa on the major second pereiopod chela, characters that are diagnostic of the genus Periclimenaeus . Anisomenaeus gen. nov. also differs from Periclimenaeus in the very dense spinulation of the second pereiopod chelae. The fingers of the minor second pereiopod also close with a shearing action, a character not occurring in Periclimenaeus although typical of the genera Typton Costa and Epipontonia Bruce. The genus contains only a single species.