Schizopera gangneungensis, 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 : 15-20

Schizopera gangneungensis sp. nov.

( Figs. 7–9 , 12 A, 16C)

Type locality. East Coast of Korea, Gangwon-do province, Gangneung city, beach, mouth of Kyeongpo River, 37°47.824’N 128°55.085’E.

Specimens examined. Holotype female ( NIBR IV 0000287249) dissected on one slide, two paratype females together on one SEM stub ( NIBR IV 0000287250), all collected from the type locality, 29 March 2013, leg. T. Karanovic.

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

Description. Female (based on holotype and two paratypes). Total body length, measured from tip of rostrum to posterior margin of caudal rami ranging from 280 to 295 µm. Colour of preserved specimen, nauplius eye, body segmentation, integument thickness, surface and general shape of somites, and rostrum ( Fig. 9 B) as in S. daejinensis . Habitus ( Figs. 7 A, 8A, 16C) 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 1.1 times as wide as genital double-somite. Body length/width ratio about 4.7. All somites, except for cephalothorax, ornamented with at least one transverse row of minute spinules, in additon to sensilla and pores. Hyaline fringe of all somites broad; those of all prosomites smooth, those of urosomites finely serrated (see also Fig. 8 C). Surface of somites, rostrum, and caudal rami with total of 65 pairs of cuticular organs (14 pairs of cuticular pores and 51 pairs of sensilla) and one unpaired dorsal sensillum; all sensilla and pores, except for one pair of pores on third urosromite and one on caudal rami, homologous to those in S. daejinensis andr S. yeonghaensis .

Cephalothorax ( Figs. 7 B, 8B) smooth, about 1.3 times as long as wide in dorsal view (without rostrum); representing 28 % of total body length, tapering towards anterior end only in anterior quarter (in dorsal view). Hyaline fringe of cephalothoracic shield smooth, slightly wider than in S. daejinensis . Cephalothoracic shield with four pairs of pores (C-I, C-II, C-VI, and C-VIII), 28 pairs of sensilla (C-2 to C-11 and C-13 to C-29), and one unpaired dorsal sensillum (C-12); sensilla C-19 and C-20, as well as sensilla C-22 and C-23, very close to each other as in S. daejinensis and S. yeonghaensis ; four pores present in S. daejinensis missing (C-III, C-IV, C-V, and C-VII); one pore present in S. yeonghaensis also missing (C-IX); posterior lateral pair of sensilla present in S.

daejinensis and S. yeonghaensis missing (C-30); one anterior pair of sensilla present in S. yeonghaensis missing (C-31); relative position of sensilla and pores more similar to that of S. yeonghaensis than S. daejinensis .

Pleuron of first free prosomite ( Figs. 7 C, 8C) as in S. yeonghaensis , without sensilla pair FP1-5 and unpaired dorsal pore (FP 1-I), but with additional anterior dorsal row of minute spinules.

Pleuron of second free prosomite ( Figs. 7 C, 8C) as in S. daejinensis and S. yeonghaensis , with five pairs of sensilla (FP2-1 to FP2-5), but with additional anterior dorsal row of minute spinules.

Pleuron of third free prosomite ( Figs. 7 C, 8C) as in S. yeonghaensis , except for lack of sensilla pair FP3-4 and with additional three anterior dorsal rows of minute spinules.

First urosomite ( Figs. 7 D, 8C) as in S. yeonghaensis , except lateral pore U 1-I inserted more ventrally than lateral sensilla U1-2 and ornamented additionally with three anterior dorsal rows of minute spinules.

Second urosomite ( Figs. 7 D, 8D, 9A) as in S. yeonghaensis completely fused with third urosomite into genital double-somite, 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 with additional ventral pair of pores (U 2-IV) and three anterior dorsal row of minute spinules. Genital complex ( Fig. 9 A) similar to that of S. daejinensis and S. yeonghaensis ; epicopulatory bulb about 1.5 times as long as wide and much larger in proportion to somite; seminal receptacles reaching anterior margin of epicopulatory bulb, about 0.6 times as long as epicopulatory bulb.

Third urosomite ( Figs. 7 D, 8D, 9A) fused with second urosomite, similar to that of S. daejinensis , but ornamented with single pair of sensilla (U3-1); without ventral pair of sensilla (U3-3) and lateral pair of sensilla (U3-2), dorsal surface with two anterior rows of minute spinules; genital double-somite about 0.8 times as long as wide.

Fourth urosomite ( Figs. 7 E, 8D, 9A) narrower than genital double-somite and only about 0.7 times as long, with single pair of posterior sensilla (U4-1); as in third urosomite without lateral (U4-2) and ventral (U4-3) sensilla; with additional anterior minute spinules on dorsal and ventral surfaces.

Fifth urosomite ( Figs. 7 E, 8D, E, 9A) as in S. daejinensis , slightly longer than fourth urosomite (ventral view), ornamented with anterior rows of minute spinules both on dorsal and ventral surface.

Sixth urosomite ( Figs. 7 E, 8E, 9A) as in S. daejinensis .

Caudal rami ( Figs. 7 F, 8E, 9A) strongly sclerotized, only about 1.4 times as long as wide in ventral view, almost cylindrical (somewhat tapering towards caudal end, but with nearly straight inner margin), with space between them slightly less than one half of one ramus width; general ornamentation as in S. daejinensis , except for one additional dorsal pair of pores (CR-IV), inner spinules short and distributed more centrally, and dorsal surface covered with several short rows of minute spinules; armed as in S. daejinensis with six elements, but their proportions somewhat different. Dorsal seta about 1.5 times as long as ramus; lateral proximal spine 0.7 times as long as ramus; lateral distal seta slightly longer than ramus; innermost apical seta about half as long as ramus; central apical seta about five times as long as caudal ramus; outer apical seta 3.3 times as long as caudal ramus.

Antennula ( Figs. 8 F, 9B, 12A) segmentation, length ratio of antennular segments, and armature formula as in S. daejinensis , except for second segment with eight instead of nine setae; first segment without spinules; second segment about 1.4 times as long as wide; one antennula in holotype abnormal, with reduced segmentation and armature in distal part ( Fig. 9 C).

Antenna ( Fig. 9 D) segmentation, armature and most ornamentation as in S. daejinensis ; coxa about as long as wide; allobasis almost 2.6 times as long as wide and 2.6 times as long as coxa; second exopodal segment about 2.9 times as long as wide and 0.9 times as long as first segment.

Labrum as in S. daejinensis (not illustrated).

Mandibula ( Fig. 9 E) as in S. daejinensis , except for distalmost seta on basis very small, exopod minute, with single apical seta, and endopod more elongated (about 2.3 times as long as wide).

Maxillula ( Fig. 9 F) as in S. daejinensis , except for coxa with only two elements, exopod distinct but minute, and endopod only twice as large as exopod; basis with only five elements but also with tubular pore. Maxilla as in S. daejinensis (not illustrated).

Maxilliped ( Fig. 9 G) segmentation, armature, and most ornamentation as in S. daejinensis but much more slender; coxobasis 1.4 times as long as wide, ornamented with row of spinules along inner margin; first endopodal segment about 3.5 times as long as wide and 2.1 times as long as coxobasis, cylindrical, slightly ovoid, ornamented with spinules only in proximal half; second endopodal segment 0.35 times as long as first and 3.5 times as long as wide; apical spine twice as long as second endopodal segment and 1.5 times as long as longest seta, with only two spinules.

All swimming legs ( Fig. 9 H, I, J, K) proportions, segmentation, most armature, and most ornamentation as in S. yeonghaensis , but most segments less slender.

First swimming leg ( Fig. 9 H) as in S. yeonghaensis , except for coxa without distal row of spinules; first endopodal segment 0.8 times as long as entire exopod, 3.8 times as long as second endopodal segment, about 3.6 times as long as wide.

Second swimming leg ( Fig. 9 I) as in S. yeonghaensis , except for shorter innermost apical and inner seta on third endopodal segment.

Third swimming leg ( Fig. 9 J) as in S. yeonghaensis , but with only two elements on third endopodal segment and without armature on first endopodal segment.

Fourth swimming leg ( Fig. 9 K) as in S. yeonghaensis , but with only two elements on third endopodal segment and no armature on first and second endopodal segment. Outer apical seta on third endopodal segment shorter than inner apical seta, and (as in second and third swimming legs) without inner seta on second exopodal segment.

Fifth leg ( Fig. 9 L) general shape, segmentation, most armature, and most ornamentation as in S. daejinensis ; exopod much less ovoid and more pentagonal in shape, but also with division line visible only on posterior surface; endopodal lobe only reaching first third of exopod, without spinules, but with cuticular pore on anterior surface; length ratio of endopodal armature elements, from inner side, 1: 1.5: 1.7: 1.7; exopod about as long as wide, armed with only five elements (one small lateral seta missing), length ratio, from inner side, 1: 2: 2.3: 0.3: 0.7.

Sixth leg ( Fig. 9 M) as in S. daejinensis , but no innermost spine visible, both setae smooth, and inner seta about 1.5 times as long as outer seta.

Male. Unknown.

Variability. One antennula in the holotype female was abnormal ( Fig. 9 C), with a reduced armature and segmentation in the distal part, but the opposite appendage in the same specimen ( Fig. 9 B), and in all paratypes ( Fig. 8 F) was normal. One paratype female was missing the sensilla pair C-13 on the cephalothorax, which was present in other specimens ( Fig. 8 B). All other cuticular organs were identical in all specimens, including the lack of lateral and ventral posterior sensilla on urosomites.

Figures

FIGURE 7. Schizopera gangneungensis sp. nov., paratype female 1, SEM photographs: A, habitus, lateral; B, cephalothorax, lateral; C, free prosomites, lateral; D, anterior part of urosome, lateral; E, posterior part of urosome, lateral; F, caudal rami, lateral. Sensilla and pores on somites and caudal rami homologous to those in S. daejinensis sp. nov. and S. yeonghaensis sp. nov. assigned the same Arabic and Roman numerals. Black arrowheads pointing some of the most prominent specific features; white arrowhead poiting intraspecific variability.

FIGURE 8. Schizopera gangneungensis sp. nov., paratype female 2, SEM photographs: A, habitus, dorsal; B, cephalothorax, dorsal; C, free prosomites, dorsal; D, anterior part of urosome, dorsal; E, posterior part of urosome and caudal rami, dorsal; F, antennula, dorsal. Sensilla and pores on somites and caudal rami homologous to those in S. daejinensis sp. nov. and S. yeonghaensis sp. nov. assigned the same Arabic and Roman numerals; novel ones numbered consecutively from anterior to posterior end and from dorsal to ventral side. Black arrowhead pointing one of the prominent specific features; white arrowhead poiting intraspecific variability.

FIGURE 9. Schizopera gangneungensis sp. nov., holotype female, line drawings: A, urosome, ventral; B, rostrum and antennula, ventral; C, anterior part of abnormal antennula, ventral; D, antenna, posterior; E, mandibular palp, anterior; F, maxillular palp, anterior; G, maxilliped, posterior; H, first swimming leg, anterior; I, second swimming leg, anterior; J, basis and endopod of third swimming leg, anterior; K, endopod of fourth swimming leg, anterior; L, fifth leg, anterior; M, sixth leg, anterior. Pores on somites and caudal rami homologous to those in S. daejinensis sp. nov. and S. yeonghaensis sp. nov. assigned the same Roman numerals; novel ones numbered consecutively from anterior to posterior end and from dorsal to ventral side. Arrowheads pointing some of the most prominent specific features. Scale bars 50 µm.

FIGURE 12. Schizopera gangneungensis sp. nov. (A), paratype female 1; and Schizopera sindoensis sp. nov. (B – D) paratype male 1; SEM photographs: A, anterior part of cephalothorax, lateral; B, antennula, lateral; C, bases of first swimming legs, lateral; D, exopod of fifth leg, lateral. Sensilla and pores on cephalothorax homologous to those in S. daejinensis sp. nov. assigned the same Arabic and Roman numerals.