Dimorphipodia, Lee & Huys, 2019

Lee, Jimin & Huys, Rony, 2019, New Ancorabolidae (Copepoda: Harpacticoida) from Korea: two new genera, revisionary notes and updated identification keys, Zoological Journal of the Linnean Society 187, pp. 331-377 : 334-336

GENUS DIMORPHIPODIA GEN. NOV.

u r n: l s i d: z o o b a n k. o r g: a c t: 3 2 2 B 9 7 1 F - B 3 5 7 - 4AA4-A6E1-CB4CE2496329

Diagnosis: Ancorabolinae . Body cylindrical, tapering slightly posteriorly, without clear demarcation between prosome and urosome. Urosomites without paired processes or tubercles. Cephalothorax with large, conical frontolateral horns; posterior margin without paired laterodorsal processes; lateroventral margin forming setulose lobate outgrowth. Somites bearing P2–P4, each with paired dorsal processes which are distinctly smaller in ♂; none of the thoracic processes dendroid; pleural areas with setular tufts. Genital somite (anterior half of genital double-somite in ♀) with lateral bulbous projections.Ventral posterior margins of urosomites with very fine setular extensions. Body somites and caudal rami with conspicuous tube-pores dorsally and laterally. Anal operculum with fine setules. Caudal rami elongate and cylindrical, with seven setae; seta III pinnate. Sexual dimorphism in body size, antennule, P2–P4 exopods, P3 endopod, P5, P6, genital segmentation and degree of development of dorsal body processes .

Rostrum small, discernible in dorsal aspect; fused to cephalic shield; with paired plumose sensilla, membranous projections and long distinctive midventral tube-pore subapically. Antennule four-segmented in ♀, six-segmented and with one segment distal to geniculation in ♂; aesthetasc arising from segments 3 and 4 in ♀, segments 5 and 6 in ♂; segment 1 elongate and with long spinules along anterior margin. Antenna with allobasis showing partial suture halfway along outer margin, abexopodal margin with two setae of equal length; exopod entirely absent; free endopodal segment with three lateral and six distal elements. Mandible with robust coxa; palp one-segmented, uniramous with five setae (three endopodal, one basal and one exopodal). Maxillule with two elements on coxal endite; basis with four elements; exopod and endopod completely incorporated into basis, represented by two and three setae, respectively. Maxillary syncoxa with two well-developed endites, each with three elements; allobasis drawn out into claw with three accessory elements around its base; endopod minute, with two setae. Maxilliped subchelate, slender and elongate; syncoxa with one reduced seta; endopod drawn out into long, narrow, curved claw with one accessory seta.

P1–P4: Intercoxal sclerites wide and narrow; praecoxae well developed; coxae small, trapezoid; bases extremely transversely elongate. P1 endopod absent, original position indicated by slightly membranous area with small nodule; exopod two-segmented, exp-2 with four geniculate setae and one outer bipinnate seta. P2–P 4 ♀ with three-segmented exopods; endopods absent (P2) or two-segmented (P3–P4); without inner setae on exp-1 and endopodal segments; exp-3 with only two outer spines. P2–P4 exp- 2 ♂ inner seta much longer than in ♀. Exp- 3 ♂ with one (P2, P4) or two (P3) inner setae; apical elements longer than in ♀. P3 endopod ♂ three-segmented; enp-2 elongate, anterior surface produced distally into recurved apophysis; enp-3 with two apical setae. Armature formula as follows:

P5 uniramous in both sexes; basal setophore reduced to short cylindrical outgrowth; endopodal lobe vestigial, represented by two minute setae and one ( ♀) or two ( ♂) conspicuous tube-pores; exopod elongate, with one inner, one apical and three outer elements (middle outer spine shortest and displaced to posterior surface), fused with baseoendopod in ♀, distinct in ♂. Female genital field located anteriorly, with moderately large copulatory pore; gonopores covered by common genital operculum derived from medially fused P6 with one naked seta on either side. Male P6 asymmetrical; without armature; functional member represented by small membranous flap.

Type and only species: Dimorphipodia changi

Etymology: The generic name is derived from the Greek δις ( dis, twice), μορφή ( morphe, form) and πους ( pous, foot) and refers to the sexual dimorphism expressed on the exopods of each of the swimming legs (P2–P4). Gender: feminine.