Tortanidae Sars, 1902

Lim, Byung-Jin & Min, Gi-Sik, 2014, Two species of Tortanus (Eutortanus) (Copepoda: Calanoida: Tortanidae) new to Korea, Journal of Species Research 3 (1), pp. 27-34 : 29-34

Family Tortanidae Sars, 1902

Genus Tortanus Giesbrecht, 1898 (in Giesbrecht and Schmeil, 1898)

Subgenus Eutortanus Smirnov, 1935

1 * Tortanus (Eutortanus) vermiculus Shen, 1955 ( Figs. 1-3)

Tortanus vermiculus Shen, 1955 , 80, figs. 5-6; Chen and Zhang, 1965, 117, figs. 5-8.

Material examined. Korea: Incheon: 2JJ, 5¥¥, Ganghwa-gun, Ganghwado Island , 1 Sep 2009, J.H. Jung; 4JJ, 5¥¥, same locality, 25 Oct 2010, B.J. Lim .

Description. Female: Body length 1.76 mm ( Fig. 1A). Cephalosome and first pedigerous somite completely separated; fourth and fifth pedigerous somites almost completely fused. Posterior corners of last pedigerous somite slightly asymmetrical, produced posterolaterally into a triangular process. Urosome 3-segmented, distal urosomite incompletely fused with caudal rami ( Fig. 1A); genital double-somite as wide as long; genital operculum located ventromedially, oval with posterior margin slightly convex ( Fig. 1B); anal somite incompletely fused with left caudal ramus and almost completely with right caudal ramus having uneven dorsolateral process on anterior right side. Caudal rami asymmetrical, right ramus slightly longer than left.

Antennule ( Fig. 1C) 18-segmented, ancestral segments II to IX, XI to XII, and XXVI to XXVIII completely fused. Armature as follows; I, 1; II-IX, 9+2ae; X, 1; XI- XII, 3+ae; XIII, 1; XIV, 2+ae; XV, 1; XVI, 2+ae; XVII, 2+ae; XVIII, 2+ae; XIX, 2+ae; XX, 2; XXI, 2+ae; XXII, 1; XXIII, 1; XXIV, 1+1; XXV, 1+1+ae; XXVI- XXVIII, 6+ae. Antenna ( Fig. 1D) coxa with a seta; basis and endopod fused; basis with 2 unequal setae; endopod 2-segmented, proximal segment with 1 outer seta and a row of spinules subterminally on inner margin, distal segment with 6 setae and a row of spinules subterminally. Mandible ( Fig. 1E, F) with gnathobase bearing 3 mono- Korean name: 1 *ffi대ÊAE푼ṀkfflNj(ŪÊ)

cuspid and 2 bicuspid teeth; endopod and exopod with 5 setae, respectively. Maxillule ( Fig. 1G) without basis, endopod and exopod; praecoxal arthrite bearing 12 setae and 1 minute seta; coxal endite with 3 stout, spinulose setae. Maxilla ( Fig. 1H) well developed; first and second praecoxal endites with 1 and 2 setae, respectively; first and second coxal endites with 1 and 3 setae, respectively; basal endite with 1 long and 2 short setae; endopod with 5 long and 2 rudimentary setae. Maxilliped ( Fig. 1I) with setal formula of praecoxal and coxal endites: 0, 2, 2, 1. Basis unarmed; endopod 1-segmented, with 4 setae.

Seta and spine formula of legs 1 to 4 ( Fig. 2 A-D) as follows:

Leg 5 ( Fig. 2E ) 3-segmented; both coxal segments fused completely with intercoxal sclerite to form a common base; basis with a seta at point two-thirds along outer margin; exopod 1-segmented, tapering distally; both exopods with row of hairs along inner margin; left exopod slightly longer than right.

Male: Body length 1.68 mm ( Fig. 3A, B ). Cephalosome and first pedigerous somite separated; fourth and fifth pedigerous somites completely fused. Last pedigerous somite slightly asymmetrical, produced into blunt process. Urosome 5-segmented, first urosomite asymmetrical; second urosomite longest. Caudal rami asymmetrical, right ramus slightly longer than left.

Right antennule ( Fig. 3C ) 16-segmented and geniculate; ancestral segments I to VIII, XXI to XXIII, and XXIV to XXVIII completely or incompletely fused. Armature as follows; I-VII, 10+2ae; VIII, 1; IX, 2; X, 1; XI, 2+ae; XII, 1; XIII, 1; XIV, 2+ae; XV, 1; XVI, 2+ ae; XVII, 2+ae; XVIII, 2+ae; XIX, 1+ae+process; XX, 1+ae+process; XXI-XXIII, 2+ae+2 processes; XXIV-XXVIII, 10+2ae.

Leg 5 ( Fig. 3D, E ) right and left coxal segments fused to form common base. Right leg chelate; basis produced

February 2014 LIM AND MIN - TWO NEW RECORDS OF TORTANIDAE FROM KOREA 31

A F E C B C B A G I H D-I D

inwards into triangular process bearing 1 seta; exopod angularly curved inwards, bearing pointed process and 6 short spines on inner margin. Basis of left leg with outer seta subterminally; exopod 2-segmented, first segment with 1 short spine subterminally, second segment with 1 distal and 2 subdistal spines.

Distribution. China (Fenghsien), Korea (Incheon).

Remarks. Shen (1955) first reported T. (E.) vermiculus from the coastal water of Fenghsien, Kiangsu Province. Later, Chen and Zhang (1965) redescribed this species from the Amoy. Until now, this species has been known as showing a restrictive distribution along the southern part of the East China Sea ( Ohtsuka et al., 1992; Ohtsuka and Reid, 1998; Itoh et al., 2001). The discovery of this species in Korean waters would expand the range of the hitherto known biogeography.

It is difficult to compare original specimen, because of poor description.

Tortanus (Eutortanus) vermiculus is readily distinguished from other congeners by: anal somite and right caudal ramus of female with uneven dorsolateral process, and right exopod of leg 5 in male with long process along proximal inner margin.

The amplified DNA was 631 bp in length. The partial CO1 sequence of T. (E.) vermiculus was determined for the first time and registered at GenBank (Accession no: JN605791).

1 * Tortanus (Eutortanus) komachi Itoh, Ohtsuka and Sato, 2001 ( Figs. 4-6)

Tortanus (Eutortanus) komachi Itoh, Ohtsuka and Sato, 2001: 59 , figs. 1-5.

Material examined. Korea: Gangwon-do: 5JJ, Goseong-gun, Goseong port, 17 Apr 2011, BJ Lim; 208JJ, 17¥¥, Gangneung-si, Gyeonso-dong, Gangneung port, 13 May 2011, SS Hong; 7JJ, Cheongho-dong, Sokchosi, Cheongchoho, 12 Mar 2012, JH Song.

Description. Female: Body length 2.4 mm ( Fig. 4A). Cephalosome and first pedigerous somite completely separated; fourth and fifth pedigerous somites incompletely fused. Posterior corners of last pedigerous somite asym- Korean name: 1 *OiṞÑAE푼ṀkfflNj(ŪÊ)

metrical, produced posterolaterally into triangular process.

Urosome 3-segmented ( Fig. 4A, B), genital double somite about 2 times as long as second one; third segment completely fused with caudal rami. Caudal rami asymmetrical; both ramus almost same in length.

Antennule ( Fig. 4C), antenna ( Fig. 4D), mandible ( Fig. 4E, F), maxillule ( Fig. 4G), and maxilliped ( Fig. 4I) similar to those of T. (E.) vermiculus . Maxilla ( Fig. 4H) well developed; first and second praecoxal endites with 1 and 2 setae, respectively; first and second coxal endites with 2 and 3 setae, respectively; basal endite with 1 long and 2 short setae; endopod with 5 long and 2 rudimentary setae. Armature formula of legs 1 to 4 as in T. (E.) vermiculus ( Fig. 5 A-D).

Leg 5 ( Fig. 5E ) 3-segmented; basis with seta on outer margin; exopod 1-segmented, left exopod slightly longer than right; endopod absent.

Male: Body length 2.3 mm ( Fig. 6E ). Prosome about 1.8 times as long as urosome. Cephalosome and first pedigerous somite completely separated; fourth and fifth pedigerous somites incompletely fused. Posterior corners of last pedigerous somite asymmetrical, produced posterolaterally into blunt process ( Fig. 6 A-D).

Urosome 5-segmented, second to fourth segments subequal in length; distal segment incompletely fused with caudal rami. Caudal rami asymmetrical, right ramus slightly longer than left.

Right antennule ( Fig. 6F ) 15-segmented and geniculate; ancestral segments I to VIII, XXI to XXIII, and XXIV to XXVIII completely or incompletely fused. Armature as follows; I-VIII, 11+2ae; IX, 2; X, 1; XI, 2+ae; XII, 1; XIII, 1; XIV, 2+ae; XV, 1; XVI, 2+ae; XVII, 2+ae; XVIII, 2+ae; XIX, 1+ae+process; XX, 1+ae+process; XXI-XXIII, 2+ae+2 processes; XXIV-XXVIII, 10+2ae.

Right leg 5 ( Fig. 6G ) 2-segmented; basis produced inwards into a long isosceles triangular process with 2 setae on posterior surface; exopod with 2 long and 4 short spines along inner margin. Left leg 2-segmented; first segment with a seta on outer margin; second and third segments incompletely fused and with 1 medial spine on outer margin, 3 spines on inner margin and 1 terminal short spine.

Distribution. Korea (East Sea), Japan (south coast of Akita).

Remarks. The Korean specimens coincide well with the

Japanese specimen of the original description with the following two minor differences: (1) the fifth pedigerous somite of male produced posteriorly into blunt process in the Japanese specimen, but the present specimens display a slightly sharp process; (2) right caudal ramus is slightly longer than left one in the original specimen, but the caudal rami of the present Korean specimen are almost same in length.

The amplified DNA was 614 bp in length. The partial CO1 sequence of T. (E.) komachi was determined for the first time and registered at GenBank (Accession no: JN605792).

Figures

Fig. 2. Tortanus (Eutortanus) vermiculus, female. A. leg 1, anterior view. B. leg 2, anterior view. C. leg 3, anterior view. D. leg 4, anterior view. E. leg 5, anterior view. Scale bar: A-E=0.1 mm.

Fig. 3. Tortanus (Eutortanus) vermiculus, male. A. habitus, lateral view. B. habitus, dorsal view. C. right antennule. D. leg 5, posterior view. E. right leg 5, anterior view. Scale bars: A, B=0.25mm, C-E=0.1 mm.

Fig. 5. Tortanus (Eutortanus) komachi, female. A. leg 1, posterior view. B. leg 2, posterior view. C. leg 3, posterior view. D. leg 4, posterior view. E. leg 5, anterior view. Scale bar: A-E=0.1 mm.

Fig. 6. Tortanus (Eutortanus) komachi, male. A-D. variability of prosomal end, dorsal view. E. habitus, dorsal view. F. right antennule. G. leg 5, anterior view. Scale bars: A-D=0.25 mm, E=0.5 mm, F-G=0.1 mm.