Lichomolgella collata, Lee & Kim, 2025

Lee, Jimin & Kim, Il-Hoi, 2025, Three new species of Lichomolgella Sars G. O., 1918 (Copepoda, Cyclopoida, Sabelliphilidae) associated with Bryozoa in Korea, ZooKeys 1244, pp. 195-211 : 195-211

Lichomolgella collata sp. nov.

Figs 4 , 5

Type locality.

A tidal pool at northeastern tip of Yeongjong Island (37°29'27"N, 126°35'00"E), Incheon, Korea.

Type material.

• Holotype (♀, left maxilliped, left antenna, left leg 1 and left leg 2 are partially damaged; MABIK CR 00258576 ) from washings of colonies of the bryozoan Celleporina sp. , 11 September 2022, collected by I.-H. Kim . • Paratype (♀, dissected and figured) from the same host at type locality, 19 April 2022, collected by I.-H. Kim . Holotype has been deposited in the Marine Biodiversity Institute of Korea ( MABIK), Seocheon, Korea. Dissected paratype is kept in the collection of I.-H. Kim.

Etymology.

The specific name collat (Latin, meaning “ brought together ”) alludes to collection of the new species together with L. exigua sp. nov.

Description.

Female. Body (Fig. 4 A ) cyclopiform. Body length of dissected paratype 450 μm. Prosome rhomboidal, 317 × 195 μm. Cephalothorax 210 μm long, longer than wide, with faint dorsal suture line between cephalosome and first pedigerous somite. Lateral corners of all prosomal somites rounded. Urosome (Fig. 4 B ) 5 - segmented. Fifth pedigerous somite 36 μm wide. Genital double-somite 1.55 times longer than wide (82 × 53 μm), consisting of broader anterior 4 / 5 and narrower posterior 1 / 5; genital apertures positioned laterally at 70 % region of double-somite. Three abdominal somites 15 × 28, 15 × 28, and 20 × 28 μm, respectively. Anal somite (Fig. 4 C ) with row of fine spinules along posteroventral margin. Caudal ramus (Fig. 4 C ) 1.63 times longer than wide (22 × 13.5 μm), with 6 setae, ornamented with several fine spinules along ventrodistal margin; setae IV (Fig. 4 D ) and V broadened, tape-like, feebly pinnate; other setae naked; outer seta (seta II) positioned at 75 % region of outer margin of ramus.

Rostrum (Fig. 5 A ) strongly tapering, with blunt distal apex. Antennule (Fig. 4 E ) short, 119 μm long, 7 - segmented; armature formula 3, 13, 6, 3, 4 + aesthetasc, 2 + aesthetasc, and 7 + aesthetasc; all setae naked. Antenna (Fig. 4 F ) 4 - segmented; armature formula 1, 1, 2 + claw, and 3 + 4 claws; second segment (first endopodal segment) 2.45 times longer than wide (49 × 20 μm); fourth segment 1.67 times longer than wide (25 × 15 μm), inserted to outer side of distal margin of third segment; outermost one of 4 distal claws slender, setiform.

Labrum (Fig. 4 G ) with elongated, divergent posterior lobes; each lobe tapering, twice as long as wide, with transparent distal part. Mandible (Fig. 4 H ) with short inner margin, lacking inner notch; gnathobase with 1 large claw-like scale at outer proximal corner followed by denticulate outer margin, 2 rows of fine spinules along inner margin; distal part of gnathobase attenuated. Maxillule (Fig. 4 I ) with 3 naked setae at distal region. Maxilla (Fig. 4 J ) 2 - segmented; proximal segment (syncoxa) unarmed; distal segment (basis) with 4 teeth on distal margin, small, setule-like distal lash and 2 setae; inner seta (seta I) large, proximally expanded, with about 6 spinules along distal margin; anterior seta (seta II) slender, with 3 or 4 fine spinules on inner margin; seta III absent. Maxilliped (Fig. 5 B ) 3 - segmented; first segment longest, but unarmed; second segment with protruded inner margin, armed with 2 equal, serrated spines; third segment terminated in elongated, spiniform process, with 2 small setae proximally.

Leg 1 (Fig. 5 C ) with 3 - segmented exopod and 2 - segmented endopod; coxa lacking inner seta; first outer spine on third exopodal segment distinctly smaller than nearby spines. Legs 2 and 3 (Fig. 5 D, E ) with 3 - segmented rami. First spine on third exopodal segment of leg 2 small, as in leg 1. Leg 3 with third exopodal segment armed with 3 spines and 5 setae (formula II, I, 5). Leg 4 (Fig. 5 F ) with 3 - segmented exopod and 1 - segmented endopod; coxa lacking inner seta; endopodal segment twice longer than wide (18 × 9 μm), armed with 2 spines distally; lengths of these spines 16 (outer) and 26 μm (inner), Armature formula for legs 1–4 as follows:

Leg 5 (Fig. 4 B ) consisting of 1 dorsolateral seta on fifth pedigerous somite and exopod; exopodal segment (Fig. 5 G ) 17 × 8 μm, distally with 2 dentiform processes, and armed with 1 spine (15 μm long) and 1 naked seta (21 μm long). Leg 6 (Fig. 5 H ) represented by 2 large lobes, each bearing 1 naked seta distally.

Male. Unknown.

Remarks.

Lichomolgella collata sp. nov. can be characterized by four outstanding features: the endopod is two-segmented in leg 1 but three-segmented in legs 2 and 3; the inner coxal seta is absent in leg 1; the third segment (second endopodal segment) of the antenna is armed with one claw plus two setae (presumably resulting from the secondary loss of one seta); and the exopod of leg 5 bears one spine plus one seta (rather than two setae as in other species). Table 1 compares the new species with its congeners based on these and other distinguishing features.

Although L. collata sp. nov. was collected together with L. exigua sp. nov. from the same locality, they differ in multiple respects, including the presence of a row of fine spinules on the posteroventral margin of the anal somite in the former species. In addition to the above four distinguishing features of L. collata sp. nov., the latter species has a larger body, a more elongated antenna, and a mandible that is distally attenuated. Furthermore, the posterior lobes of the labrum are more elongated, the maxilliped has a different armature on the second and third segments, and the first outer spine on the third exopodal segment of legs 1 and 2 is markedly reduced in size.

Figures

Figure 4. Lichomolgella collata sp. nov., female. A. Habitus, dorsal; B. Urosome, dorsal; C. Anal somite and caudal rami, dorsal; D. Seta IV of caudal ramus; E. Antennule; F. Antenna; G. Labrum; H. Mandible; I. Maxillule; J. Maxilla. Scale bars: 0.05 mm (A); 0.02 mm (B, D – F); 0.01 mm (C, G – J).

Figure 5. Lichomolgella collata sp. nov., female. A. Rostrum; B. Maxilliped; C. Leg 1; D. Leg 2; E. Leg 3; F. Leg 4; G. Exopod of leg 5; H. Genital aperture. Scale bars: 0.01 mm (A, B, G, H); 0.02 mm (C – F).