Hase, Corgosinho, Paulo H. C., Kihara, Terue C., Schizas, Nikolaos V., Ostmann, Alexandra, Arbizu, Pedro Martinez & Ivanenko, Viatcheslav N., 2018

Corgosinho, Paulo H. C., Kihara, Terue C., Schizas, Nikolaos V., Ostmann, Alexandra, Arbizu, Pedro Martinez & Ivanenko, Viatcheslav N., 2018, Traditional and confocal descriptions of a new genus and two new species of deep water Cerviniinae Sars, 1903 from the Southern Atlantic and the Norwegian Sea: with a discussion on the use of digital media in taxonomy (Copepoda, Harpacticoida, Aegisthidae), ZooKeys 766, pp. 1-38 : 1

Hase gen. n.

Diagnosis.

Female body sturdy with clear distinction between prosome and narrower urosome. Prosome 5-segmented, with cephalosome and four free pedigerous somites. Cephalosome with minute spinules covering surface and anastomosing reticulation towards rostrum and along margins; posterior margin slightly serrate. Pedigerous somites with reticulation along ventroposterior margins; lateral margins of third and fourth pedigerous somites smooth or expanded posteriorly forming hook-like projections laterally; posterior margins serrate. Urosome 5-segmented, comprising P5 bearing somite, genital double-somite, two free abdominal somites, and telson. Genital double-somite and two free abdominal somites with hook-like projections ventrolaterally. Genital double-somite original segmentation indicated by transverse, serrate surface ridge with reticulation and sensilla dorsal and laterally, completely fused ventrally; genital field with copulatory pore located in median depression; gonopores covered by operculum derived from sixth legs and by anteriorly directed flap arising from somite wall; P6 fused genital opercular plate armed with two setae. Telson with well-developed anal operculum; large anal opening with folded and reticulated cuticle; surface ornamentation consisting of pair of sensilla dorsally, minute spinules and pair of pores ventrally; ventral posterior margin with minute setules. Furca symmetrical; approximately 3.4 × as long as maximum width; distinctly convergent. Each ramus with seven setae: setae I-III not inserted close to each other; seta I proximal, laterally inserted, spiniform and bipinnate; seta II median, dorsally inserted, spiniform, and bipinnate; seta III subdistal, laterally inserted, spiniform and bipinnate; setae IV and V distally inserted, bipinnate and fused basally; seta VI distally inserted, minute and naked; seta VII dorsally inserted, close to seta III, tri-articulate at base and pinnate.

Rostrum fused to cephalic shield; tip rounded, with tuft of spinules along distal margin or slightly bifid and smooth; with pair of sensilla near apex. A1 7-segmented, proximal segments 1-3 cylindrical or subcylindrical; distal segments flattened. Segment I the longest; segment III with aesthetasc fused basally to single seta and set on distinct pedestal; segment VII with aesthetasc fused basally to one seta. Armature formula: I-[1], II-[8-9 elements], III-[10-12 + (1 + Ae)], IV-[3], V-[2], VI-[2], VII-[6-7 + (one naked + Ae)]. A2 3-segmented, comprising cylindrical coxa and allobasis, and 1-segmented flattened enp. Coxa small. Basis and enp-1 fused, forming elongate allobasis and with abexopodal seta. Enp medial armature four elements, apical armature 3-4 spines, one seta, and three fused elements. Exp 4-segmented; armature formula: I-[2], II-[1], III-[1], IV-[2-3].

Md. Coxa with well-developed musculature, gnathobase curved inwards, bearing several multicuspid teeth and single seta on inner distal margin. Palp well developed, comprising basis, enp and exp. Basis with four setae. Enp 1-segmented with three lateral setae and 6-7 apical setae. Exp 4-segmented; armature formula: I-[2], II-[1], III-[1], IV-[2]. Mx1. Praecoxa with row of spinules; arthrite well developed and with 13-14 elements. Coxa endite cylindrical, bearing 5-6 setae distally; epipodite absent. Basis and enp fused; basis with eleven setae; enp incorporated into basis, represented by 2-3 naked setae. Exp 1-segmented, with 2-3 setae. Mx2 comprising syncoxa fused to allobasis, and 4-segmented enp. Syncoxa/allobasis with four endites; proximal coxal endite with five pinnate setae; distal coxal endite almost completely incorporated into syncoxa, with three setae; proximal basal endite with three setae; distal basal endite with two setae and one spine. Enp-1 endite forming strong claw; accessory armature consisting of two setae, one or two spines and zero or one tube pore; armature of fused enp-2 represented by three or four elements. Free enp 3-segmented; armature formula: I-[claw; 3-4 spines/setae; 0-1 tube pore], II-[3-4], III-[2], IV-[2-3], V-[3-4]. Mxp with elongated syncoxa, strong basis and 2-segmented enp; syncoxal endites represented proximal to distal by two elements, 3-4 elements, and 2-3 elements; basal endite represented by two elements. Enp with armature formula: I-[2], II-[four elements].

Pereopods biramous; exp and enp flattened, bent inwards, especially on P1 and P2. Praecoxa without ornamentation. Coxa without ornamentation (P1) or ornamented (P2-P4). Basis with (P1 and P2) or without (P3 and P4) one seta on outer proximal corner, with one seta on inner distal corner of P1. Exp 3-segmented. Enp 3-segmented (P1), 2-segmented (P2 and P3) and 1-segmented (P4). P5 1-segmented, pointing outwards, fused to supporting somite. Exp with three elements. P1-P4 spine and setal formulae as follows:

Etymology.

The generic name, Hase , from German, means “hare”, and refers to the very superficial resemblance of the new species to a hare or rabbit. Gender masculine.

Type species.

Hase lagomorphicus sp. n., by present designation.