Oshoroclausia, Uyeno & Kakui, 2015

Uyeno, Daisuke & Kakui, Keiichi, 2015, The First Record of a Species of Clausiidae (Copepoda: Cyclopoida) from Japanese Waters, with the Proposal of a New Genus, Species Diversity 20, pp. 153-158 : 153-154

Genus Oshoroclausia n. g

Diagnosis of adult female. Body elongate, cylindrical, comprising cephalothorax and indistinctly segmented postcephalothoracic trunk. Cephalothorax with projecting rostral area bearing pair of sensory elements. Segmentation of second to fifth pedigers, genital complex, and 3-segmented abdomen indistinct. Genital complex with paired lateral lobes. Caudal rami divergent, fused to anal somite at base, bearing six caudal setae.

Antennule 3-segmented, proximal segment with two proximal lobes, all segments bearing simple setae. Antenna 2-segmented; basal segment unarmed; terminal segment peanut-shaped with median crease; proximal part covered with fine spinules; distal part bearing rounded protruding lobe covered with fine spinules, three small elements, and small, knob-like distal projection armed with two serrate spines and two simple setae. Labrum triangular, bearing pointed conical posterior projection and ornamented with paired patches of fine spinules. Mandible rod-like, with distal pointed spine. Paragnath rounded with horizontal concavity, covered with hairs. Maxillule with one medial and two distal setae. Maxilla 2-segmented; proximal segment (syncoxa) unarmed; distal segment (basis) bifurcate, bearing patches of fine spinules on each tip and single blunt element on posterior margin. Maxilliped unsegmented, subdivided into large, conical basal part with row of spinules on anterior margin and small, claw-like distal part.

Legs 1 to 4 biramous with 2-segmented rami; all setae naked. Intercoxal sclerites of legs 3 and 4 absent. Leg 5 2-segmented; proximal segment (protopod) fused to pedigerous somite; terminal segment (exopod) rod-like, bearing conical distal tip with apical seta and three minute setae on posterior margin. Leg 6 represented on each side by two simple setae located at base of lateral lobe of genital complex.

Adult male. Unknown.

Type species. Oshoroclausia shibazakii n. sp. by original designation.

Remarks. Oshoroclausia shares a biramous leg 4 with Likroclausia , Pontoclausia , and Rhodinicola (see Băcescu and Pór 1959; Ho and Kim 2003; Kim et al. 2013). Likroclausia clearly differs from Oshoroclausia in its cyclopiform body bearing a pair of antler-like lateral processes on the tergites of the second to fourth pedigerous somites (see Kim et al. 2013) (vs an elongate body without lateral processes on the tergites of the pedigerous somites). Pontoclausia can be distinguished from the new genus by the following combination of characters: its distinctly segmented cyclopiform body, 4-segmented antenna, 3-segmented rami on legs 1 to 4, and leg 5 with a free protopod (see Băcescu and Pór 1959) (vs elongate body lacking distinct segmentation between first pedigerous and anal somites, 2-segmented antenna, 2-segmented rami on legs 1 to 4, and protopod of leg 5 fused to fifth pedigerous somite). Rhodinicola is very similar to the new genus but can be distinguished by the following characters: elongate antenna 3- or 4-segmented with four terminal claws; swimming legs bearing inner coxal setae, and leg 5 bearing setae on anterior margin (see Levinsen 1878; Laubier 1970; Ho and Kim 2003; Björnberg and Radashevsky 2011; Kim et al. 2013) (vs antenna 2-segmented, its peanut-shaped terminal segment with two terminal claws, legs 1 to 4 lacking inner coxal setae, and leg 5 without setae on anterior margin).

Etymology. The name of the new genus, Oshoroclausia , is composed of “Oshoro” (the type locality) and “-clausia” (a common suffix in the Clausiidae ).