Dyspontius alatus, Kim, 2016

Kim, Il-Hoi, 2016, Siphonostomatoid copepods (Crustacea) mainly associated with marine invertebrates from Korean waters, Journal of Species Research 5 (3), pp. 393-442 : 400-403

publication ID	https://doi.org/ 10.12651/JSR.2016.5.3.393
persistent identifier	https://treatment.plazi.org/id/96353C58-E763-FFA9-FF59-FB95FE15FC03
treatment provided by	Felipe
scientific name	Dyspontius alatus
status	sp. nov.

Treatment

Dyspontius alatus View in CoL n. sp. ( Figs. 5 View Fig , 6 View Fig )

Material examined. One$(holotype) from a sponge, in the depth of 50 m, off Munseom in Seogwipo (approximately 33°12′40″N, 126°34′30″E), Jeju Island, 12 October 2013, collected by S.H. Kim. Holotype ($, dissected and mounted on a glass slide, NIBRIV0000680700 ) has been deposited in NIBR, Incheon, Korea. GoogleMaps

Female. Body ( Fig. 5A View Fig ) moderately broad and 838 μm long. Cephalothorax 461 × 482 μm, slightly wider than long, with weakly produced anterior apex ( Fig. 5F View Fig ) and pointed posterolateral corners. Dorsal tergites of somites ornamented with simple or 26branched (5branched one being most common) setules ( Fig. 5C, D View Fig ). Second and third pedigerous somites much narrower than cephalothorax, 72 × 338 and 61 × 294 μm, respectively, with their epimeral regions ( Fig. 5C View Fig ) markedly extending posterolaterally. Fourth pedigerous somite distinctly reduced, similar to fifth pedigerous somite in size and 136 μm wide. Urosome ( Fig. 5B View Fig ) 5segmented. Fifth pedigerous somite 123 μm wide, tapering laterally, with pointed lateral apices. Genital doublesomite 100 × 191 μm, consisting of expanded anterior and narrower posterior parts; anterior part characteristically with winglike, broad epimera extended over posterior margin of somite; margins of epimera rounded. Three abdominal somites 31 × 72, 27 × 66, and 42 × 65 μm, respectively. Caudal ramus ( Fig. 5E View Fig ) 35 × 27 μm, 1.30 times as long as wide, armed with 6 setae and ornamented with setules on inner margin; inner dorsal seta (seta VII) naked, other 5 setae plumose.

Rostrum ( Fig. 5F View Fig ) longer than wide, strongly sclerotiz ed, with rounded posterior margin. Antennule ( Fig. 5G View Fig ) 252μm long and 9-segmented; first segment 54 μm long; second segment, longest, 61 μm long; armature formula 1, 9, 1, 6, 2, 2, 2, 2, and 11 + aesthetasc; aesthetasc on terminal segment slightly more than 1/3 times as long as antennular length. Antenna ( Fig. 5H View Fig ) with short, unarmed coxa; basis 35 × 17 μm, with fine setules at proximal region and on outer margin; exopod small, tipped with 2 unequal setae; first endopodal segment 31 × 14 μm, unarmed, but ornamented with setules on outer margin; second endopodal segment 29 × 13 μm, armed with 1 lateral and 2 distal setae, 1 elongate distal spine (67 μm long), and ornamented with rows of setules.

Oral siphon ( Fig. 5I View Fig ) relatively broad, 327 μm long, extending beyond base of maxilliped but not reaching leg 1; distal apex setulose. Mandbile represented by stylet bearing several teeth and spinules distally ( Fig. 5J View Fig ). Maxillule ( Fig. 6A View Fig ) bilobed; inner lobe 62 μm long, with 2 small naked apical setae of equal length (15 μm long); outer lobe 46 μm long, with 2 large, spinulose setae (larger one 59 μm long) and 1 small naked seta. Maxilla ( Fig. 6B View Fig ) 2segmented; syncoxa unarmed; basis slender, with 1 small seta and row of minute spinules in distal region; terminal claw clearly defined from basis, with rows of spinules. Maxilliped ( Fig. 6C View Fig ) 6segmented; armature formula 1, 1, 2, 0, 1, and 1 + claw; syncoxa (first segment) with nippleshaped projection at inner distal corner; basis also with nippleshaped projection at proximal third and with numerous minute spinules along distal third of inner surface; inner seta on basis small and located at distal third of segment; terminal claw more than twice as long as terminal endopodal segment, with fine spinules along inner margin.

Legs 13 biramous, with 3segmented rami ( Fig. 6D, E View Fig ). Leg 4 ( Fig. 6F View Fig ) with 3segmented exopod; endopod absent. Leg 1 ( Fig. 6D View Fig ) lacking inner element on basis; first exopodal segment with thick setules on outer margin; second exopodal segment characteristically lacking outer spine. Leg 2 ( Fig. 6E View Fig ) with dentiform process on posterior margin of basis between rami. Legs 3 and 4 lacking inner seta on coxa. Armature formula for legs 1 4 as follows:

Coxa Basis Exopod Endopod

Leg 1: 01 10 I1; 01; II, 2, 3 01; 02; 1, 2, 3 Leg 2: 01 10 I1; I1; III, I, 5 01; 02; 1, 1 + I, 3 Leg 3: 00 10 I1; I1; III, I, 5 01; 02; 1, 1 + I, 3 Leg 4: 00 10 I1; I1; III, I, 5 (Absent)

Leg 5 ( Fig. 6G View Fig ) represented by 2 papillae tipped with 1 plumose and 2 small, naked setae, respectively, on ventral surface of fifth pedigerous somite. Leg 6 ( Fig. 6G View Fig ) represented by 3 unequal setae, including minute one, on genital operculum.

Male. Unknown.

Etymology. The specific name alatus is a Latin meaning “winged”, alluding to the possession of the winglike epimera of the genital doublesomite.

Remarks. By having 2 spines plus 4 setae on the third exopodal segment of leg 1 and a welldeveloped exopod in uniramous leg 4, the new species is included in the genus Dyspontius Thorell, 1860 . The new species reveals three outstanding morphological features that are not observable in six congeners, as follows: (1) the genital doublesomite has welldeveloped, winglike epimera; (2) the basis of leg 1 lacks an inner distal seta; and (3) the second exopodal segment of leg 1 lacks an outer spine. The presence of the winglike epimera of the genital doublesomite is a characteristic feature of the genus Pteropontius Giesbrecht, 1895 , but the new species is not related to Pteropontius , because in this genus the segmentation and setation of leg 1 are reduced, with at most 2segmented exopod.