Protoparamisophria, Ohtsuka & Nishida & Machida, 2005

Ohtsuka, Susumu, Nishida, Shuhei & Machida, Ryuji J., 2005, Systematics and zoogeography of the deep-sea hyperbenthic family Arietellidae (Copepoda: Calanoida) collected from the Sulu Sea, Journal of Natural History 39 (27), pp. 2483-2514 : 2491-2492

Genus Protoparamisophria n. gen.

Diagnosis

Female. Body compact. Prosome plump, about 2.6 times as long as urosome; prosomal ends almost symmetrical, with paired dorsolateral processes and lateral round lobes. Urosome with genital double-somite longer than wide; paired gonopores located anteriorly; paired copulatory pores located midway on ventral surface; seminal receptacles asymmetrical, tube-like; anal operculum lacking; caudal rami symmetrical, longer than wide.

Antennules asymmetrical, 22-segmented, left longer than right, and reaching beyond cephalosome; first (I–III) to eighth (X) segments with row of long setules along posterior margin; segments I–III and IV separate; segments II and IV of right antennule, and I, II, and IV of left antennule lacking aesthetasc. Antenna with two-segmented endopod; first endopodal segment bearing one inner seta, and second segment with three subterminal and six terminal setae; exopod indistinctly seven-segmented; terminal segment with one vestigial and two distinct setae. Mandibular gnathobase without patch of long setules; three teeth present, dorsalmost bicuspid; endopod represented by one rudimentary segment with two unequal setae terminally; seta on first to fifth exopodal segments not reduced. Maxillule with one process and five spines on praecoxal arthrite; coxal endite bearing single seta; coxal epipodite with eight setae; rudimentary basal seta present; endopod onesegmented, with three setae terminally. Maxilla with two setae and one vestigial element on first praecoxal endite; basal spine naked. Maxilliped with innermost seta on fourth and fifth exopodal segments not reduced; setae a and b (see Ohtsuka et al. 1994) on sixth segment not reduced.

Leg 1 with third exopodal segment bearing two outer spines. Leg 5 nearly symmetrical, with coxae and intercoxal sclerite partly fused; endopod represented by acutely pointed process bearing two plumose setae; exopod indistinctly three-segmented with suture subtly visible; first and second segments each with one outer spine; terminal segment bearing one spiniform seta and one subterminal and two terminal spines.

Male. Unknown.

Remarks

The new genus is generally similar to Paramisophria , but exhibits more plesiomorphic states both in the female genital system and in some appendages. In the new genus, paired copulatory pores open at mid-length on the ventral side of the genital double-somite, while in Paramisophria a single copulatory pore is located midway or on either the left or right side (cf. Ohtsuka and Mitsuzumi 1990; Ohtsuka et al. 1991, 1993, 1994; Heinrich 1996). The new genus displays paired, elongate seminal receptacles, each located between the corresponding copulatory pore and gonopore, with a short copulatory duct. In contrast, in some species of Paramisophria , the seminal receptacle is near the gonopore, with a relatively long, and in some cases, a highly curved copulatory duct (cf. Ohtsuka and Mitsuzumi 1990; Ohtsuka et al. 1993, 1994). These characteristics of the new genus seem to be relatively plesiomorphic with respect to the hypothetical calanoid ancestor as proposed by Huys and Boxshall (1991).

The exopod of the female fifth leg of the new genus displays the most primitive state in the family Arietellidae : indistinctly three-segmented; terminal segment with one outer, one subterminal and two terminal elements, all of which are separate at base from the segment. In some species of Paramisophria the exopod is indistinctly three-segmented, but the number of elements on the terminal segment is at most three elements and one process (in P. japonica Ohtsuka, Fosshagen and Go, 1991 ). In this case, the outer terminal spine of the new genus seems to be homologous to the terminal process of P. japonica . The new genus also has the following plesiomorphies, although some species of Paramisophria share some of them: (1) five spines and one process on the praecoxal arthrite of the maxillule; (2) the presence of a distinct seta on the coxal endite of the maxillule; (3) three setae on the maxillulary endopod; (4) two setae and one vestigial element on the first praecoxal endite of the maxilla; (5) separation of coxae and intercoxal sclerite in female leg 5; (6) two setae on the endopod of female leg 5.

Type species. Protoparamisophria biforaminis n. sp. (monotypic).

Etymology

The new generic name, Protoparamisophria , is derived from the Greek proto, meaning primitive, plus the closely related genus Paramisophria . Gender feminine.