Schizopera yeonghaensis, Karanovic, Tomislav & Cho, Joo-Lae, 2016

Karanovic, Tomislav & Cho, Joo-Lae, 2016, Four new Schizopera (Copepoda, Harpacticoida) from marine interstitial habitats in Korea, Zootaxa 4114 (1), pp. 1-32 : 10-15

publication ID	https://doi.org/ 10.11646/zootaxa.4114.1.1
publication LSID	lsid:zoobank.org:pub:B09ECE6E-3D79-47F0-B3B3-84823B28993D
DOI	https://doi.org/10.5281/zenodo.6062716
persistent identifier	https://treatment.plazi.org/id/1E50A92E-FF90-FFF4-C6B6-F0B0FD79B8B9
treatment provided by	Plazi
scientific name	Schizopera yeonghaensis
status	sp. nov.

Treatment

Schizopera yeonghaensis sp. nov.

( Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 , 16 View FIGURE 16 A)

Type locality. East Coast of Korea, Gyeongsangbuk-do province, Yeong Hae city, Daejin beach, mouth of Songcheon River, 36°33.959’N 129°25.518’E (same as for S. daejinensis sp. nov.).

Specimens examined. Holotype female ( NIBR IV 0000287247) and allotype male ( NIBR IV 0000287248), each dissected on one slide, and both collected from the type locality, 21 September 2011, leg. T. Karanovic.

Etymology. The species is named after the type locality, Yeong Hae city, with the addition of the Latin suffix for place “- ensis ”. The specific name consequently is an adjective for place.

Description. Female (holotype). Total body length, measured from tip of rostrum to posterior margin of caudal rami about 405 µm. Colour of preserved specimen, nauplius eye, body segmentation, integument thickness, surface and general shape of somites, and rostrum as in S. daejinensis . Habitus ( Figs. 4 View FIGURE 4 A, 16A) almost cylindrical, slender, without distinct demarcation between prosome and urosome; prosome/urosome ratio about 0.95 (in dorsal view); greatest width at posterior end of cephalothorax but difficult to establish; cephalothorax only about 1.2 times as wide as genital double-somite. Body length/width ratio about 4.2. All somites devoid of any spinules, except for anal somite and caudal rami. Hyaline fringe of all somites broad; those of all prosomites smooth, those of urosomites finely serrated. Surface of somites, rostrum, and caudal rami with total of 73 pairs of cuticular organs (15 pairs of cuticular pores and 59 pairs of sensilla) and one unpaired dorsal sensillum.

Cephalothorax ( Fig. 4 View FIGURE 4 A) smooth, about 1.2 times as long as wide in dorsal view; representing 23 % of total body length, tapering towards anterior end only in anterior half (in dorsal view). Hyaline fringe of cephalothoracic shield smooth, slightly wider than in S. daejinensis . Cephalothoracic shield with five pairs of pores (C-I, C-V, C- VI, C-VIII, and C-IX), 31 pairs of sensilla (C-2 to C-11 and C-13 to C-31), and one unpaired dorsal sensillum (C- 12); as in S. daejinensis sensilla C-19 and C-20 very close to each other, as well as sensilla C-22 and C-23; all sensilla homologous to those in S. daejinensis except for C-31 (in anterior part, between C-5 and C-7); four pores present in S. daejinensis missing (C-II, C-III, C-IV, and C-VII), while two novel ones present (C-VIII and C-IX; both in anterior part); relative position of some sensilla and pores slightly different than in S. daejinensis (for example pores C-V closer to sensilla C-8, and sensilla C-29 and C-30 closer to each other).

Pleuron of first free prosomite ( Fig. 4 View FIGURE 4 A) as in S. daejinensis , except for lack of sensilla pair FP1-5 and unpaired dorsal pore (FP 1-I).

Pleuron of second free prosomite ( Fig. 4 View FIGURE 4 A) as in S. daejinensis , with five pairs of sensilla (FP2-1 to FP2-5).

Pleuron of third free prosomite ( Fig. 4 View FIGURE 4 A) as in S. daejinensis , except for lack of sensilla pair FP3-3 and for sensilla FP3-1 and FP3-2 closer to each other.

First urosomite ( Fig. 4 View FIGURE 4 A) as in S. daejinensis , except for hyaline fringe serrated.

Second urosomite ( Fig. 4 View FIGURE 4 A, B) as in S. daejinensis completely fused with third urosomite into genital doublesomite, with three pairs of dorsal posterior sensilla (U2-1 to U2-3) and two pairs of ventro-lateral pores (U 2-II and U 2-III), but without lateral pore (U 2-I) or spinules. Genital complex ( Fig. 4 View FIGURE 4 B) similar to that in S. daejinensis ; epicopulatory bulb large about 1.3 times as long as wide; seminal receptacles reaching beyond anterior margin of epicopulatory bulb, about 0.75 times as long as epicopulatory bulb.

Third urosomite ( Fig. 4 View FIGURE 4 A, B) fused with second urosomite and very similar to that in S. daejinensis , except for ventral pair of sensilla (U3-3) with larger relative distance between them. Genital double-somite about as long as wide (ventral view).

Fourth urosomite ( Fig. 4 View FIGURE 4 A, B) narrower than genital double-somite and only about 0.7 times as long, with three pairs of posterior sensilla (U4-1 to U4-3), as in S. daejinensis , but with additional pair of minute anterior dorsolateral pores (U 4-I) and one pair of very closely spaced anterior ventral pores (U 4-II).

Shape of fifth urosomite ( Fig. 4 View FIGURE 4 A, B) as in S. daejinensis , about 1.2 times as long as fourth urosomite (ventral view), and ornamented with two pairs of pores (U 5-I and U 5-II) serially homologous to those on fourth urosomite.

Sixth urosomite ( Fig. 4 View FIGURE 4 A, B) as in S. daejinensis , except for lateral pores (U 6-I) situated much more anteriorly, minute anterior ventral spinules missing, and posterior spinules slightly more robust.

Caudal rami ( Fig. 4 View FIGURE 4 A, B, C) strongly sclerotized, about twice as long as wide in ventral view, almost cylindrical (somewhat tapering towards caudal end in posterior third and with convex inner margin), with space between them slightly less than one third of one ramus width; general ornamentation as in S. daejinensis , except for lack of pores CR-I and CR-II, ventral posterior spinules smaller; armed as in S. daejinensis with six elements, but their proportions somewhat different. Dorsal seta about as long as ramus; lateral proximal spine only 0.4 times as long as ramus; lateral distal seta inserted at about same level as lateral spine and slightly shorter than ramus; innermost apical seta only about 0.27 times as long as ramus; central apical seta with wing-like outgrowth near breaking plane, about three times as long as caudal ramus; outer apical seta only about 1.4 times as long as caudal ramus.

Antennula ( Fig. 5 View FIGURE 5 A) segmentation, ornamentation and armature formula as in S. daejinensis , but appendage much more slender and aesthetasc on fourth segment also more slender; second segment nearly twice as long as wide; length ratio of antennular segments, from proximal end and along caudal margin, 1: 2.3: 0.7: 0.9: 0.5: 0.6: 0.7: 1.4.

Antenna ( Fig. 5 View FIGURE 5 B) segmentation, armature and most ornamentation as in S. daejinensis ; coxa unornamented, 0.8 times as long as wide; allobasis almost three times as long as wide and 3.5 times as long as coxa, ornamented with single row of spinules on anterior surface; second exopodal segment about 3.7 times as long as wide and 1.1 times as long as first segment.

Labrum as in S. daejinensis (not illustrated).

Mandibula ( Fig. 5 View FIGURE 5 C) as in S. daejinensis , except for distalmost seta on basis very small, exopod minute, and endopod much more elongated (about 2.5 times as long as wide).

Maxillula and maxilla as in S. daejinensis (not illustrated).

Maxilliped ( Fig. 5 View FIGURE 5 D) segmentation, armature, and most ornamentation as in S. daejinensis ; coxobasis 1.8 times as long as wide, ornamented with posterior row of spinules on anterior surface; first endopodal segment about 2.7 times as long as wide and 1.6 times as long as coxobasis, cylindrical, slightly ovoid, ornamented as in S. daejinensis ; second endopodal segment 0.3 times as long as first and twice as long as wide; apical spine 2.3 times as long as second endopodal segment and 1.5 times as long as longest seta.

All swimming legs ( Fig. 5 View FIGURE 5 E, F, G) proportions, segmentation, most armature, and most ornamentation as in S. daejinensis .

First swimming leg ( Fig. 5 View FIGURE 5 E) as in S. daejinensis , except for coxa only about 1.8 times as wide as long and with row of smaller outer spinules; first endopodal segment nearly 0.9 times as long as entire exopod, 3.8 times as long as second endopodal segment, about 4.6 times as long as wide.

Second swimming leg ( Fig. 5 View FIGURE 5 F) and third swimming leg as in S. daejinensis , except for slightly more slender and with less robust outer spinules, and without inner seta on second exopodal segment.

Fourth swimming leg ( Fig. 5 View FIGURE 5 G) as in S. daejinensis , except for outer apical seta on third endopodal segment shorter than inner apical seta on that segment, and (as in second and third swimming legs) without inner seta on second exopodal segment.

Fifth leg ( Fig. 5 View FIGURE 5 H) shape, segmentation, armature, and most ornamentation as in S. daejinensis ; ovoid exopod with division line visible on both posterior and anterior surfaces; length ratio of endopodal armature elements, from inner side, 1: 1.2: 2.2: 1.4; exopod about as long as wide, length ratio of exopodal armature elements, from inner side, 1: 2.2: 2: 0.8: 0.7: 1.3.

Sixth leg ( Fig. 5 View FIGURE 5 I) as in S. daejinensis , except for inner seta about 1.8 times as long as outer seta. Male (allotype). Body length 345 µm. Segmentation as in female, except for genital somite and third urosomite not fused. Habitus ( Fig. 6 View FIGURE 6 A, B) slightly more slender than in female, but also cylindrical, and with similar proportions; body length/width ratio about 4.9 in dorsal view. Ornamentation of rostrum ( Fig. 6 View FIGURE 6 A, B), prosomites ( Fig. 6 View FIGURE 6 A, B), and first urosomite ( Fig. 6 View FIGURE 6 A, B, C), as well as colour and nauplius eye, as in female.

Genital somite ( Fig. 6 View FIGURE 6 A, B, C) more than twice as wide as long; ornamentation consists of three pairs of large dorsal sensilla (U2-1 to U2-3) and two pairs of ventro-lateral pores (U 2-II and U 2-III) as in female, but sensilla much further apart.

Third urosomite ( Fig. 6 View FIGURE 6 A, B, C) ornamented as in female, but not fused to second (genital) urosomite.

Fourth and fifth urosomites ( Figs. 6 View FIGURE 6 A, B, C) as in female, except for lack of ventral pair of pores (U 4-II and U 5-II).

Anal somite ( Figs. 6 View FIGURE 6 A, B, C) as in female.

Caudal rami ( Figs. 6 View FIGURE 6 A, B, C) slightly shorter in comparison with anal somite and less slender than in female but without any difference in armature or ornamentation, except for principal apical setae without any wing-like structure near breaking plane.

Antennula ( Fig. 6 View FIGURE 6 D) half as long as cephalothorax, strongly prehensile and 9-segmented (basically, female’s sixth segment subdivided in male), with geniculations between fourth and fifth and seventh and eighth segments; segments participating in geniculations strengthened with cuticular plates along anterior surface, with largest such plates on fifth segment; aesthetascs as in female, on fourth and last segments; first two and last two segments similar to female; setal formula: 1.9.8.8.1.0.1.4.6.

Antenna, labrum, mandibula, maxillula, maxilla, maxilliped, exopod and endopod of first swimming leg, exopod of second swimming leg, endopod of third swimming leg, and fourth swimming leg as in female.

First swimming leg ( Fig. 6 View FIGURE 6 E) with modified basis, inner margin very rigidly sclerotized, with spiniform smooth distal process and smaller process at its base. Inner spine on basis smaller than in female, without spinules at its base, inserted more proximally, and about as long as larger spiniform process.

Second swimming leg ( Fig. 6 View FIGURE 6 F) with transformed second and third endopodal segments. Second segment with part of inner margin protruded as rounded indistinct lobe, without ornamentation; inner seta shorter and more slender than in female. Third segment completely modified; inner seta unipinnate and longer than in female, inner apical seta missing, outer apical seta smooth and strong, much shorter that in female, outer apical spine transformed into smooth, lanceolate implement; outer distal corner produced into long, blunt spiniform process, about as long as lanceolate outer spine. As result of these transformations, third segment medially cleft.

Third swimming leg ( Fig. 6 View FIGURE 6 G) with very characteristic element on anterior surface of third exopodal segment, probably representing hugely enlarged tubular pore: swollen in basal part, with pore on tip, inserted at 2/5 and close to inner margin, reaching distal margin of third segment.

Fifth legs ( Fig. 6 View FIGURE 6 C, H) with medially fused baseoendopods. Endopodal lobe much smaller and shorter than in female, trapezoidal, reaching first third of exopod, armed with two very strong and bipinnate apical spines; inner spine about 1.9 times as long as outer one. Exopod ( Fig. 6 View FIGURE 6 H) slightly wider than long, armed with only five elements (one short lateral element missing); length ratio of exopodal armature elements, from inner side, 1: 4.8: 5.4: 1.2: 2.5.

Sixth legs ( Fig. 6 View FIGURE 6 C) expressed as pair of small, short cuticular plates, without armature or ornamentation; left one larger, better demarcated at base, and probably functioning as genital flap.

Variability. Only one female and one male of this species were collected and examined. Besides normal sexual dimorphism for this group of copepods (in urosomal segmentation, antennula, basis of first leg, endopod of second leg, exopod of third leg, fifth leg, and sixth leg) the male does not have ventral cuticular pores on urosomites (U 4- II and U 5-II). It is impossible at this stage to determine if this is also part of sexual dimorphism, or if the lack of ventral cuticular pores on these urosomites is part of sex-independent intraspecific variability. All other cuticular organs were identical in both sexes.