Paraugaptiloides Ohtsuka, Boxshall and Roe, 1994

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 : 2497-2498

Genus Paraugaptiloides Ohtsuka, Boxshall and Roe, 1994

Diagnosis

Emended part only; see Ohtsuka et al. 1994. Male left geniculate antennule fringed with long setules posteriorly on compound segments I–IV only or segments I–IV to V; segment I with one or two setae. Second endopodal segment of antenna with two or three inner setae. Mandibular endopod one-segmented with two terminal setae of unequal length, or absent. Leg 4 with or without vestigial element on inner distal corner of coxa. Male fifth legs with basis and coxa of right leg separate or incompletely fused; right endopod unisegmented, rudimentary or well-developed; second exopodal segment of right leg expanded inwards or extremely elongated, third segment triangular, tapering distally, or lamellar; left endopod two-segmented, with second segment originating from inner base of first segment; second exopodal segment of left leg expanded inwards or outwards, third segment with two or three heavily chitinized, long processes.

Remarks

The monotypic genus Paraugaptiloides was established to accommodate Paraugaptilus magnus Bradford, 1974 by Ohtsuka et al. (1994). This species was first collected off New Zealand (1697 m) ( Bradford 1974), and subsequently from the south-western Indian Ocean (1060–1070 m) ( Heinrich 1993). The genus is considered to be deep-sea hyperbenthic ( Bradford 1974; Heinrich 1993; present study). The second congener described below was discovered in the Sulu Sea, which confirms the validity of the genus. Although known only by the male, it is readily distinguishable from other arietellid genera by a combination of the following characters: (1) presence of a large cuticular process on the left antennulary compound segment XXIV–XXV; (2) lack of a seta on the first endopodal segment of the antenna; (3) two or three inner setae on the second endopodal segment of the antenna; (4) outer seta on the fifth exopodal segment of the mandible, relatively long; (5) maxillule with one basal and two endopodal setae; (6) basal spine of the maxilla furnished with a spinular row; (7) innermost setae on the fourth and fifth endopodal segments of the maxilliped not vestigial; (8) outermost seta on the sixth endopodal segment of the maxilliped vestigial; (9) left and right endopods of the fifth leg two- and one-segmented, respectively. However, the new species described below has different armature on the antenna, mandible and leg 4 from those of P. magnus , and necessitates an emendation of the generic diagnosis.

Although the fifth legs of the males appear to differ greatly in these two species, some homologous structures can be clearly traced on the basis of their number and position; namely the second endopodal segment of the left leg originates from the inner proximal part of the first segment; the third exopodal segment of the left leg bears four elements; the outer terminal corner of the second exopodal segment of the right leg bears a patch of fine setules and a triangular or round process with a minute spinule terminally. These differences in the fifth legs seem to be important at the specific level.

The genus seems to be associated with the sea-bottom ( Bradford 1974; Heinrich 1993; present study), although it was previously regarded as pelagic ( Ohtsuka et al. 1994).