Ameiropsis gyeongjuensis, Bang, 2023

Bang, Hyun Woo, 2023, A new species of the genus Ameiropsis Sars G. O., 1907 (Copepoda; Harpactiocoida) from Korea, Journal of Species Research 12 (3), pp. 244-257 : 245-255

publication ID	https://doi.org/ 10.12651/JSR.2023.12.3.244
DOI	https://doi.org/10.5281/zenodo.13138552
persistent identifier	https://treatment.plazi.org/id/039B87AA-FFAB-EE15-9F96-0C3EFCF1F86B
treatment provided by	Felipe
scientific name	Ameiropsis gyeongjuensis
status	sp. nov.

Treatment

Ameiropsis gyeongjuensis View in CoL sp. nov. ( Figs. 1-9 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig )

Material examined. Holotype 1$( MABIK CR00253 740) dissected on 10 slides, and paratype 1♂ ( MABIK CR00253741 ) dissected on 5 slides. All from the type locality, Bong-gil Beach, Gyeongju, Korea (35°44′21.1″N, 129°29′03.0″E), collected by H.W. Bang and H. Moon on 8 January 2019. GoogleMaps

Etymology. The specific epithet, “ gyeongjuensis ” is based on the name of the location where the new species is found.

Description. Female. Total body ( Fig. 1A, B View Fig ) length from anterior margin of the rostrum to posterior margin of caudal rami 790 μm. Maximum width 195 μm measured at end of cephalothorax. Habitus semi-cylindrical, gradually tapering posteriorly, and prosome and urosome are not clearly distinguished.

Cephalothorax gradually tapering anteriorly, ornamented with sensilla as illustrated, and posterior margin with sensilla and plain hyaline frills. Rostrum ( Figs. 1A View Fig , 2A View Fig ) fused to cephalothorax, bell-shaped, blunt at tip, and with pair of sensilla near anterior margin. Pleural areas of cephalothorax not highly developed, so cephalic appendages are clearly exposed in lateral view ( Fig. 2A View Fig ). All pedigerous somites with plain hyaline frills.

Urosome ( Figs. 1A, B View Fig , 3A View Fig ) five-segmented, comprising P5-bearing somite, genital double-somite, and three free abdominal somites. Genital double-somite completely fused, subdivided by chitinous suture laterally, with paired laterodorsal rows of spinules, and with fine spinules on the posterior margin.

Genital apparatus ( Fig. 3A View Fig ) located near the anterior margin of the genital double-somite, with a small copulatory pore (arrowed in Fig. 3A View Fig ), and two large seminal receptacles. P6 represented by a single symmetric plate bearing one bipinnate outer and one inner bare seta.

Anal somite ( Figs. 1A View Fig , 3A View Fig ) cleft medially, with a transverse row of spinules on the ventral surface, and with coarse spinules on the posterior margin dorsally and ventrally; anal operculum flat with fine spinules.

Caudal rami ( Figs. 1A View Fig , 3A View Fig ) about as long as broad, each ramus with two dorsal and one lateroventral pore, and with seven setae: seta I and II bare; seta III bare, located near the distal corner; seta IV bipinnate and long; seta V unipinnate, longest; seta VI bare at an inner distal corner; seta VII articulated at base and bare.

Antennule ( Fig. 4A View Fig ), eight-segmented; segment-2 longest; segment-4 with one aesthetasc fused at base to a very long naked seta; segment-8 with an acrothek consisting of one apical aesthetasc fused basally to two apical setae; armature formula: 1-[1], 2-[9], 3-[8], 4-[4 + (1 + ae)], 5-[2], 6-[4], 7-[4], 8-[5 + (2 + ae)].

Antenna ( Fig. 2B View Fig ) composed of coxa, basis, two-segmented endopod, and two-segmented exopod. Coxa short and unarmed, with spinules on the anterior margin. Basis unarmed, with row of spinules and setules along abexopodal margin, basis and first endopodal segment partly fused. Exopod two-segmented; exp-1 large, with highly bulging outer margin, and with one biarticulated pinnate seta; exp-2 small, with one articulated pinnate and one broad, curved sabre-like seta apically. Endopod two-segmented; enp-1 about 2.5 times as long as wide, unarmed and unornamented; enp-2 with a transverse row of spinules close to an outer distal corner, with two pinnate spines and one small seta laterally, five geniculate and one unipinnate setae distally, and longest geniculate seta fused at the base with one smaller seta.

Labrum ( Figs. 2A View Fig , 3B View Fig ) large, protruding forward, and forms a beak-like structure.

Mandible ( Fig. 2C, D View Fig ). Coxal gnathobase well developed, with one unipinnate seta laterally and eight multicuspidate teeth. Basis with one unipinnate and one naked spine and one plumose seta, and with well-developed rami. Exopod with five plumose setae. Endopod with one inner plumose and five distal setae, of which three fused basally.

Maxillule ( Fig. 5A View Fig ). Praecoxal arthrite well-developed with two rows of spinules, with two setae on the anterior surface, one pinnate seta medially on the inner margin, and five elements around the distal margin. Coxal endite with one plumose and two bare setae. Basis with one spinulous and two bare setae apically. Endopod incorporated into the base, with one naked seta; exopod with two pinnate and one bare seta.

Maxilla ( Fig. 5B View Fig ). Syncoxa with two endites; proximal endite with two pinnate setae, distal endite broad with one strong unipinnate seta and one pectinate spine apically, and one naked seta subapically. Allobasis produced into a very strong spinulose claw, with one strong unipinnate spinulose spine. Endopod represented by minute segment, with three bare setae.

Maxilliped ( Fig. 5C View Fig ). Syncoxa with inner rows of spinules, and one plumose seta. Basis about twice as long as wide, asetose, with rows of spinules on the inner margin, and with a row of spinules on the outer margin. Endopod represented by recurved claw, longer than basis, with two accessory setae near its base.

P1 ( Fig. 6A View Fig ). Intercoxal sclerite trapezoid, without ornamentation. Praecoxa small and triangular. Coxa ornamented with rows of spinules on the anterior surface. Basis with one strong pinnate seta on the outer corner, and one finely bipinnate spine on the inner distal margin; anterior surface with setules on the inner margin, and with spinules around the base of the inner and outer spine. Exopod three-segmented, all segments of about equal length; exp-1 with spinules along outer margin, and pinnate outer seta; exp-2 with spinules on outer margin, and with one outer spine and one plumose inner seta; exp-3 with two geniculate setae distally and three finely pinnate spines on outer margin. Endopod three-segmented; enp-1 elongate, extends well beyond the end of exopod, with setules along the inner margin and spinules along the distal margin, and with one plumose inner seta; end-2 smallest, with spinules on distal corner, and with one plumose seta on inner margin; enp-3 about twice as long as enp-2, with one plumose seta on inner distal margin, and two geniculate spines apically.

P2 ( Fig. 6B View Fig ). Intercoxal sclerite with a row of spinules on the anterior surface. Praecoxa small and triangular, with a row of spinules along the distal margin. Coxa rectangular, about 1.6 times as wide as long, with transverse rows of spinules on the anterior surface. Basis with one plumose seta on the outer distal corner, with a row of spinules on the inner distal margin, distal margin, and at the base of the outer spine, with a single pore on the anterior surface close to the outer seta. Exopod three-segmented; exp-1 with coarse spinules along outer margin and outer distal corner, with one inner plumose seta, and bipinnate outer spine; exp-2 with few outer spinules, with one plumose inner seta, and with one pinnate outer spine; exp-3 elongated, with two long plumose inner setae, one plumose seta and one bipinnate spine distally, and three serrate outer spines. Endopod three-segmented, all segments with outer spinules; enp-1 and enp-2 with plumose inner seta; enp-3 slightly elongated, with two inner pinnate setae, two long terminal setae, and one small spinulose outer spine.

P3 ( Fig. 7A View Fig ). Intercoxal sclerite, praecoxa, coxa, and basis as in P2. Rami three-segmented; exp-1 and exp-2 each with one inner plumose seta, and bipinnate outer spine, with coarse spinules along the outer margin; exp-3 elongated, with three plumose inner setae, one pinnate seta and one spine terminally, and three serrate outer spines. Endopod three-segmented; enp-1 and enp-2 with short plumose inner seta; enp-3 with three inner plumose setae, two long distal bipinnate setae, and one small serrate outer spine.

P4 ( Fig. 7B View Fig ). Intercoxal sclerite, praecoxa, and coxa as in P2. Basis semicircular, with a row of spinules on the outer distal margin, and with one unipinnate outer seta. Exp-1 and exp-2 with spinules on the outer margin, a plumose inner seta, and one bipinnate outer spine; exp-3 with three pinnate inner setae, a plumose seta and a pinnate spine terminally, and three outer spines.

Armature formulae as follows:

Exopod Endopod

P1 0.1.023 1.1.021

P2 1.1.223 1.1.221

P3 1.1.323 1.1.321

P4 1.1.323 1.1.221

P5 ( Fig. 3C View Fig ). Endopodal with separate exopod and baseoendopod. Exopod elongated, about 2.5 times as long as broad, with inner spinules and long outer setules, with one anterior tube pore, and with six setae; outermost seta long and bipinnate, second outer very longest and naked, second inner short and pinnate. Baseoendopod with outer setophore carrying one unipinnate seta, endopodal lobe triangular, with five pinnate setae.

Male. Total body ( Fig. 8A View Fig ) length from anterior margin of the rostrum to posterior margin of caudal rami 670 μm. Maximum width 153 μm measured at end of cephalothorax. General ornamentation and sensilla pattern same as in female except genital double somite; sexual dimorphisms in A1, P1 basis, P5, and P6.

Urosome ( Fig. 8B View Fig ) six-segmented, comprising P5-bearing somite genital somite, and four abdominal somites. Genital and first free abdominal somite with posterior continuous row of spinules ventrally.

Antennule ( Fig. 9A View Fig ) eight-segmented, haplocer, with geniculation between segments-7 and -8, and aesthetasc on segments-5 and -8; segment-2 longest, with nine bare and on pinnate setae; segment-4 very short with two setae. Armature formular: 1-[1], 2-[10], 3-[7], 4-[2], 5-[9 + (1 + ae)], 6-[3], 7-[1], 8-[6 + (2 + ae)]. Apical acrothek consisting of short aesthetasc and two long naked setae.

P1 ( Fig. 9B View Fig ) inner basal spine modified into a hookshaped element.

P5 ( Fig. 8C View Fig ) baseoendopods fused medially. Baseoendopod with outer setophore carrying a long unipinnate seta. Endopodal lobe not extending beyond the middle of exopod, with two pinnate setae. Exopod thinner than in female, about 3.5 times as long as wide, with five setae; second outer seta very short and bare.

P6 ( Fig. 8D View Fig ), asymmetrical, represented on both sides by a small plate, each plate with two pinnate and one naked seta.