Kelleria vaga, Kim, 2000

Kim, Il-Hoi, 2000, Poecilostomatoid Copepods from an Intertidal Mud Flat in the Yellow Sea, Journal of Natural History 34 (3), pp. 367-432 : 402-406

Kelleria vaga n. sp.

( Figures 20 ±22)

Material examined. Three mm, one, l one copepodid V m collected from stagnant water on the intertidal mud ¯at at Jakyak-do Island, o Inchon, on 1 September 1996. Holotype (m) and two paratypes (one m and one copepodid V m) will be deposited in the US National Museum of Natural History , Smithsonian Institution. Allotype and one paratype (both dissected) are kept in the collection of the author .

Female. Body (®gure 20A) narrow, 1.01 mm long. Greatest width 331 mm. Prosome spindle-shaped and consisting of cephalosome and four metasomites. Urosome (®gure 20B) ®ve-segmented. Fifth pedigerous somite 102 mm wide. Genital double-somite 125Ö 160 mm, with distinctly expanded anterior two-thirds and narrower posterior part. Three abdominal somites 39 Ö63, 27 Ö58, 48 Ö 54 mm, respectively, without ornamentation. Caudal ramus elongate, 100Ö 22 mm (4.55:1), with parallel margins. Lateral seta located slightly posterior to mid-point of caudal ramus. Outer lateral and inner dorsal setae naked. Other setae plumose. Outer posterior corner of caudal ramus with a small duct and terminal pore.

Rostrum narrow and long, with round posterior tip (®gure 20C). Antennule (®gure 20D) 249 mm long, seven-segmented, with armature formula 4, 13, 6, 3, 4 +1 aesthetasc, 2 +1 aesthetasc, and 7 +1 aesthetasc. Plumose setae are one on ®fth and sixth segment, and four on terminal segment. Antenna (®gure 20E) slender, foursegmented, with armature formula 1, 1, 3 +1 claw, and 5 +2 claws. Claws on third and terminal segments slender and setiform. Second and terminal segments with minute spinules on outer margin, each segment about 2.4 and 3.3 times longer than wide, respectively.

Labrum (®gure 20F) deeply incised, with round posterior corners; posterior margin of each lobe unornamented. Mandible (®gure 20G) with tapering, moderately long lash; proximal notch shallow; inner margin oblique to lash, with rather large spinules; outer margin denticulate and proximally with a row of several small spinules. Maxillule (®gure 20H) with three terminal spinulated setae, one lateral seta, and serrate membrane on distal half of outer margin. Maxilla (®gure 21A) two-segmented; ®rst segment unarmed; second segment with one slender seta and one large, terminally bifurcate, spinulated seta; distal portion of second segment curved perpendicularly to proximal portion, tapering and sharply pointed, with nine or ten large spines of unequal sizes. Maxilliped (®gure 21B) three-segmented. First segment unarmed and longest. Second segment with two large setae of similar size; proximal seta with long and thick setules both sides of proximal third, and small setules on distal margin of remaining two-thirds. Third segment small, with one long (86 mm), naked seta, one small plumose seta, and two more smaller, naked setae.

Leg 1 (®gure 21C), leg 2 (®gure 21D) and leg 3 with three-segmented rami. Leg 4 (®gure 21F) with three-segmented exopod and one-segmented endopod; inner seta on coxa minute; exopod with three or two spines on outer margin (formula III, I, 5 or II, I, 5); endopod with or without spinule-like small process on outer margin; median one of two terminal spines larger than the inner. Armature formula of legs 1±4 as follows:

Leg 5 (®gure 21G) composed of one seta near corner of ®fth pedigerous somite and free segment; free segment 50Ö 15 mm (3.3:1), margins nearly parallel, with small angular proximal protuberance on inner margin, one terminal spiniform process, and terminally one spine (31 mm) and one naked seta (45 mm). Leg 6 represented by one seta in genital area and distantly isolated, one spinule and one setule; the latter two located on dorsal surface of genital double-somite (®gure 20B).

Male. Body more slender than that of female, 877 mm long. Urosome (®gure 22A) six-segmented. First urosomal somite 75 mm wide. Genital somite 131Ö 130 mm, as long as wide, with round lateral margins. Four abdominal somites 35 Ö56, 31 Ö48, 23 Ö44, and 35Ö 46 mm, respectively. Caudal ramus 75Ö 21 mm (3.57:1).

Rostrum and antenna as in female. Antennule with three more aesthetascs than in female: two on second and one on fourth segment (indicated by dark dots in ®gure 20D). All aesthetascs extending over end of antennule.

Mouth parts as in female, except for maxilliped. Maxilliped (®gure 22B) consisting of three segments and terminal claw. First segment unarmed. Second segment with two setae at proximal third of inner margin and spinules on entire inner margin. Third segment unarmed. Claw long, 152 mm, evenly curved, proximally with two moderately long setae.

Leg 1 (®gure 22C) with two spines and four setae ( II, 4) on terminal endopodal segment. Legs 2±4 as in female. Free segment of leg 5 23 Ö 10 mm (2.30:1), without proximal protuberance; terminal spine 21 mm, and seta 34 mm. Leg 6 represented by two setae and one spinule on genital ¯ap (®gure 22A) .

Etymology. The speci®c name vaga is derived from the Latin vagus (= wandering). It alludes to its unknown host relationship.

Remarks. No further species have been added to this genus since Humes and Stock’s (1973) revision of the lichomolgoid copepods. According to Humes and Stock’s key to the species of Kelleria , K. vaga n. sp. keys out to K. camortensis Sewell, 1949 in couplet 7. The latter species, recorded from the Indian Ocean by Sewell (1949), has caudal rami which are 2.75 longer than wide, and two subequal terminal setae on the free segment of leg 5. These features are not applicable to the Korean species, because the caudal rami of the latter are 4.76 times longer than wide, and the free segment of leg 5 has one spine and one seta.

Kelleria vaga seems to be related to K. pectinata (A. Scott, 1909) which was redescribed by Humes and Ho (1969). Both have the well developed anterior expansion of the genital double-somite, and a similar maxilla and terminal armature of the maxilliped. However, the new species has more slender caudal rami, a shorter free segment of the female leg 5, and di erent type of armature on the male leg 5.

Figures

FIG. 20. Kelleria vaga n. sp., female: (A) habitus, dorsal; (B) urosome, dorsal; (C) rostral area, ventral; (D) antennule; (E) antenna; (F) labrum; (G) mandible; (H) maxillule. Scales: A = 0.1 mm; B±E= 0.05 mm; F±H= 0.02 mm.