Eurycletodes (Oligocletodes) vadumus, Bang, 2020

Bang, Hyun Woo, 2020, A new species of the genus Eurycletodes Sars G. O., 1909 (Copepoda: Harpacticoida: Argestidae) from South Sea of Korea, Journal of Species Research 9 (4), pp. 480-488 : 481-486

publication ID

https://doi.org/ 10.12651/JSR.2020.9.4.480

persistent identifier

https://treatment.plazi.org/id/03DCE149-F626-FB75-50B7-78C3BC1095CD

treatment provided by

Felipe

scientific name

Eurycletodes (Oligocletodes) vadumus
status

sp. nov.

Eurycletodes (Oligocletodes) vadumus View in CoL sp. nov.

( Figs. 2-5 View Fig View Fig )

Type locality. Hansando Island , 12 m water depth, South Sea of Korea. (34°46′33.2″N, 128°31′35.0″E) GoogleMaps .

Material examined. Holotype 1$ ( KDELIV 000000 3114) dissected on eight slides . Paratype 2$$( KDELIV0000003115 , KDELIV0000003116 ) dissected on eight slides. All from the type locality, collected by H.W. Bang and H. Moon in May 2019 .

Etymology. The species name is derived from the Latin ‘ vadum ’, meaning shallow water, referring to the depth of water of the type locality.

Description. Female. Body ( Fig. 2A, 2B View Fig ) cylindrical, no clear distinction between prosome and urosome. Total body length 619 μm (n = 3; range: 585-645 μm), measured from anterior margin of rostrum to posterior margin of caudal rami. Largest width measured at posterior margin of cephalic shield: 172 μm.

Rostrum ( Figs. 2A, 2B View Fig , 3A View Fig ) triangular, well-developed, fused to cephalothorax, with two sensilla. Cephalothorax ( Fig. 2A View Fig ) with reticulate pattern, pedigerous somites with posterior margin strongly serrated dorsally and laterally. Cephalothorax and free thoracic somites with sensilla arising from tubercles, sensillar pattern and tube pores on cephalothorax and body somites as figured.

Urosome ( Fig. 2A, 2B View Fig ) 5-segmented, comprising P5-bearing somite, genital double-somite and three free abdominal somites. All urosomites with coarsely denticulated posterior margin dorsally and laterally, covered with minute spinules dorsally, laterally and ventrally. Second and third urosomites partly fused forming genital-double somite. Genital field ( Fig. 5C View Fig ) positioned situated proximally on first half of genital double-somite, with a copulatory pore, and P6 reduced, represented by bifid processes (arrowed in Fig. 5C View Fig ). Anal somite ( Figs. 2A View Fig , 3H View Fig ) as long as board, almost square laterally and dorsally, with tube pores ventrally, anal operculum with several denticles and dorsal pair of sensillate tubercles.

Caudal rami ( Fig. 3I View Fig ) semi cylindrical, about 1.6 times as long as wide, with conspicuous tube pore ventrally (arrow in Figs. 2A View Fig , 3I View Fig ), each ramus with seven setae: setae I- II bare, short, of subequal lengths, seta III arising from small protrusion, seta IV bare, seta V longest, seta VI bare and short, arising at inner distal corner, seta VII tri-articulate at base.

Antennule ( Fig. 3B View Fig ). 6-segmented; segment 1 largest, with spinular rows, segment 3 with aesthetasc fused basally to seta and set on pedestal, segment 4 with modified element, last segment with six setae, two modified elements, one geniculate seta, and apical acrothek. Armature formula: 1-[0], 2-[3], 3-[3 + (1 + ae)], 4-[1], 5-[1], 6-[9 + acrothek]. Apical acrothek consisting of an aesthetasc fused basally to one bare and one geniculate seta.

Antenna ( Fig. 3C View Fig ). Allobasis, without abexopodal seta. Exopod reduced to an almost indiscernible bulb without armature (arrowed in Fig. 3C View Fig ). Allobasis and endopod with spinular row along inner margin, endopod with two bare inner spines, and four distal elements distally.

A A, B 50 B C C 50

Mandible ( Fig. 3D View Fig ) with gnathobase bearing three strong teeth around distal margin, without seta. Mandibular palp 1-segmented, with spinules subdistally, with three bare setae distally.

Maxillule ( Fig. 3F View Fig ). Praecoxal arthrite well-developed, with two bipinate, one unipinnate, and three bare spines distally, with bipinnate spine laterally, and with one bare

B

A surface seta. Coxa with one geniculate seta and one bare seta apically. Basis, endopod and exopod reduced.

Maxilla ( Fig. 3G View Fig ). Syncoxa with two endites and a row of long spinules along outer margin, proximal endite with two bare setae, distal endite with two slender setae and one strong spinulose element. Allobasis with spinules, drawn out into strong, slightly curved, distally bipinnate claw, with two bare setae. Endopod 1-segmented, small, with two naked setae.

Maxilliped ( Fig. 3E View Fig ). Subchelate. Syncoxa with one plumose seta on inner distal corner and with long setules or spinules. Basis with a row of spinules along palmar region, unarmed. Endopodal segment produced into strong and distally pinnate curved claw.

Swimming legs 1-4 with wide intercoxal sclerite and praecoxae, biramous, endopods 1-segmented, exopods 3-segmented. Coxae and bases with surface ornamentations of spinules as figured.

P1 ( Fig. 4A). Coxa slightly bigger than basis, with two spinular rows on anterior surface, and row of spinules along outer margin. Basis with strong bipinnate outer spine on outer margin and bipinnate spine on inner distal surface, with several spinules and setules as figured. Exopod 3-segmented, exp-1 longest, without inner seta; exp-2 with one stout, pinnate outer spine and one long, plumose inner seta; exp-3 with two pinnate distal setae and two well-developed pinnate outer spines. Endopod 1-segmented, with two distal setae and one pinnate outer spine.

P2-P4 ( Figs. 4B, 5A, 5B View Fig ) with small triangular praecoxa. Coxa large, with row of spinules on anterior surface. Basis with pinnate outer spine. Exp-1 twice as long as exp-2, with one pinnate outer spine, and one long plumose inner seta, except P4; exp-2 shortest, with one inner plumose long seta, and one bipinnate outer spine; third segment longest, with three bipinnate outer spines, two apical and two inner elements, P4 exp-3 proximal inner element bipinnate, short (arrowed in Fig. 5B View Fig ). Endopod 1-segmented, with spinules along inner to outer distal margins, with two pinnate distal setae.

Armature formula for swimming legs:

Exopod Endopod

P1 0.1.022 021

P2 1.1.223 020

P3 1.1.223 020

P4 0.1.223 020

P5 ( Fig. 4C) fused medially, and exopod and baseoendopod separate. Baseoendopod with a long outer setophore bearing one plumose basal seta, and with one pore near proximal area of setophore. Endopodal lobe with spinules at inner and outer margin, with two bipinnate setae and one pore on anterior surface. Exopod elongat- ed, 3.4 times as long as wide, with one pore on anterior surface near apical margin, with three outer and two terminal setae, and with one oblique cleavage ornamented on anterior surface near proximal area (arrowed in Fig. 4C).

Male. Unknown.

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