Asterocheres processus, Lee, 2024

Lee, Il-Hoi Kim and Taekjun, 2024, Copepods of the genus Asterocheres Boeck, 1859 (Siphonostomatoida: Asterocheridae) from Korean waters, Journal of Species Research 13 (2), pp. 185-254 : 202-205

publication ID	https://doi.org/ 10.12651/JSR.2024.13.2.185
persistent identifier	https://treatment.plazi.org/id/ED1887CB-FFEF-FFFF-FF41-B508B4B260D5
treatment provided by	Felipe
scientific name	Asterocheres processus
status	sp. nov.

Treatment

Asterocheres processus n. sp. ( Figs. 9 View Fig , 10 View Fig )

https://zoobank.org/urn:lsid:zoobank.org:act:9CC42A

9C-B9A6-4961-9AB6-7A23EA804047

Type material. Holotype (intact ♀; MABIK CR0025 4235), intact paratypes (4♀♀; MABIK CR00254236 ), and dissected paratype (♀) from mixed species of sponges, Munseom, Seogwipo, Jeju Island (33°13 ʹ 41.1 ʺ N, 126°34 ʹ 05.9 ʺ E), SCUBA diving, depth 28.1 m, coll. T. Lee , 06 April 2023 GoogleMaps . Holotype and intact paratypes have 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 alludes to the elongated distal process on the third endopodal segment of leg 1.

Female. Body ( Fig. 9A View Fig ) gradually narrowing posteriorly. Body length 767 μm in figured and described specimen. Prosome 516 μm long. Cephalothorax 335 × 440 μm, somewhat inflated. All prosomal somites with rounded lateral corners. Urosome ( Fig. 9B View Fig ) 4-segmented. Fifth pedigerous somite 109 μm wide. Genital double-somite wider than long (120 × 129 μm), widest at 47% region of double-somite; genital apertures positioned dorsolaterally slightly posterior to widest region; postgenital lateral margins bearing 12-15 spinules including slightly longer several posterior ones ( Fig. 10G View Fig ). Two free abdominal somites 50 × 62 and 30 × 53 μm, respectively; anal somite with row of spinules along posteroventral margin ( Fig. 9C View Fig ). Caudal ramus ( Fig. 9C View Fig ) 0.88 times longer than wide (21 × 24 μm), with 6 setae, short inner and longer outer margins, and unornamented distal margin.

Rostrum not developed. Antennule ( Fig. 9D View Fig ) 338 μm long, 20-segmented; 9th, 18th, and terminal segments armed with 7 setae, 2 setae + aesthetasc, and 11 setae, respectively, all other segments each with 2 setae; several setae on proximal segments feebly pinnate; first segment ornamented with several setules. Antenna ( Fig. 9E View Fig ) consisting of coxa, basis, small exopod, and 3-segment- ed endopod; coxa short, unarmed; basis 57 μm long, with longitudinal row of minute spinules; exopod twice longer than wide (10 × 5 μm), with 3 setae (2 unequal distal and 1 small proximal); first endopodal segment 49 μm long, unarmed but with row of spinules along outer margin; short second endopodal segment with 1 spiniform seta; third endopodal segment slightly longer than wide with 2 unequal setae distally; terminal claw straight, spiniform, 39 μm long.

Oral siphon ( Fig. 9F View Fig ) narrow, 250 × 56 μm, extending to intercoxal plate of leg 1, widest at proximal 24% region. Mandible ( Fig. 9G View Fig ) consisting of slender stylet and 1-segmented palp; stylet 227 μm long, with 13 minute teeth at distal region ( Fig. 9H View Fig ), proximal one of them broader than others; palp segment 40 μm long, with 2 unequal setae distally, longer pinnate seta 167 μm long, smaller naked seta 64 μm long; palp segment plus longer seta 207 μm long, 0.91 times as long as stylet. Maxillule ( Fig. 9I View Fig ) bilobed; inner lobe (precoxal endite) about 73 μm long, tipped with 4 fragile setae and rows of setules; outer lobe (palp) small, 24 μm long, tipped with 3 naked setae. Maxilla ( Fig. 9J View Fig ) 2-segmented; distal segment (basis) as long as, but much slender than, proximal segment (syncoxa), with row of minute spinules along convex but margin of curved distal part. Maxilliped ( Fig. 9K View Fig ) consisting of coxa, basis, 4-segmented endopod, and terminal claw; coxa with 1 small seta at inner subdistal region; basis with 1 vestigial seta on inner margin and several minute spinules on outer margin; 4 endopodal segments with 2, 1, 1, and 1 setae, respectively; terminal endopodal segment 30 μm long; terminal claw relatively short, 55 μm long, 1.83 times longer than terminal segment.

Legs 1 ( Fig. 10A View Fig ), 2 ( Fig. 10C View Fig ), 3, and 4 ( Fig. 10E View Fig ) biramous, with 3-segmented rami. Leg 1 lacking inner seta on coxa.; third endopodal segment ( Fig. 10B View Fig ) 48 μm long (excluding outer distal process), characteristically bearing elongated, spiniform outer distal process of 27 μm long. Intercoxal plate and inner distal corner of legs 1-3 with several spinules. Outer margin of basis of legs 2-4 with spinules. Outer seta on basis of legs 1-4 well developed. Leg 3 similar to leg 2, except bearing 1 spine and 5 setae on third endopodal segment ( Fig. 10D View Fig ). Leg 4 lacking inner seta on coxa. Armature formula for legs 1-4 as follows:

Coxa Basis Exopod Endopod

Leg 1 0-0 1-1 I-1; I-1; III, 2, 2 0-1; 0-2; 1, 2, 3 Leg 2 0-1 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 2, 3 Leg 3 0-1 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 1 +I, 3 Leg 4 0-0 1-0 I-1; I-1; III, I, 4 0-1; 0-2; 1, 1 +I, 2

Leg 5 ( Fig. 10F View Fig ) consisting of 1 dorsolateral seta on fifth pedigerous somite and free exopod; exopodal segment 2.18 times longer than wide (37 × 17 μm), with sub-parallel lateral margins, 3 unequal setae distally, and row of fine spinules on outer margin; midterminal seta longest, 65 μm long; outer seta second longest. Leg 6 ( Fig. 10G View Fig ) represented by 1 small pinnate seta and 1 small spinule on genital operculum.

Male. Unknown.

Remarks. Asterocheres processus n. sp. may be differentiated from its congeners by two diagnostic features revealed in leg 1. Firstly, the coxa lacks an inner seta. Secondly, the third endopodal segment bears a prolonged outer distal process. The first feature is shared with five species in the genus: A. pilosus Kim, 2004 ; A. eugenioi Bandera & Conradi, 2014 ; A. sarsi Bandera & Conradi, 2009 ; A. trisetatus Kim, 2010 ; and A. banderae Kim & Lee, 2023 . The second feature is shared with four species ( A. crinoidicola Humes, 2000 ; A. mucronipes Stock, 1960 ; A. pilosus ; and A. unioviger Kim, 2010 ). Of the latter four species, A. mucronipes has been removed to the genus Stockmyzon Bandera & Huys, 2008 by these authors ( Bandera & Huys, 2008). Thus, A. processus n. sp. is comparable only with A. pilosus as only these two species have both the diagnostic features. Asterocheres pilosus is associated with the echinoid Eucidaris thouarsii (L. Agassiz & Desor, 1846) on the Pacific coast of Panama ( Kim, 2004a). In the latter species, the female antennule is 19-segmented, the mandibular palp is 2-segmented, the oral siphon extends to the insertions of the maxillipeds, the distal setae on the inner lobe of the maxillule are shorter than the distal seta of the outer lobe and one of the setae on the outer lobe is specialized with long setules, and the fourth leg has an inner coxal seta. These features of A. pilosus are not adjustable to A. processus n. sp.