Schizopera daejinensis, 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 : 3-10

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.6062714
persistent identifier	https://treatment.plazi.org/id/1E50A92E-FF9B-FFF3-C6B6-F3BEFE0BBC65
treatment provided by	Plazi
scientific name	Schizopera daejinensis
status	sp. nov.

Treatment

Schizopera daejinensis sp. nov.

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 16 View FIGURE 16 B)

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.

Specimen examined. Holotype female ( NIBR IV 0000287246) dissected on one slide, collected from the type locality, 21 September 2011, leg. T. Karanovic.

Etymology. The species is named after the type locality, Daejin beach, 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 490 µm. Colour of preserved specimen yellowish. Nauplius eye not visible. Prosome comprising cephalothorax with completely fused first pedigerous somite and 3 free pedigerous somites; urosome comprising fifth pedigerous somite, genital double-somite (fused genital and first abdominal somites) and 3 free abdominal somites. Habitus ( Figs. 1 View FIGURE 1 A, B, 16B) spindle-shaped, not particularly slender, without distinct demarcation between prosome and urosome; prosome/urosome ratio about 1.15 (in dorsal view); greatest width at posterior end of cephalothorax; cephalothorax only about 1.3 times as wide as genital double-somite. Body length/width ratio about 3.6. Free pedigerous somites without pronounced lateral or dorsal expansions. Integument of all somites relatively well sclerotized, generally very smooth, without cuticular windows or pits. First two urosomites, anal somite, and caudal rami, with rows of minute spinules. Hyaline fringe of all somites broad; those of cephalothorax and pedigerous somites smooth, others finely serrated. Surface of somites, rostrum, and caudal rami with total of 75 pairs of cuticular organs (16 pairs of cuticular pores and 59 pairs of sensilla), one unpaired dorsal sensillum, and one unpaired dorsal pore.

Rostrum ( Fig. 1 View FIGURE 1 C) long and clearly demarcated at its base, anterior tip nearly reaching distal margin of second antennular segment, linguiform, about twice as long as wide, with smooth tip and single dorsal pair of sensilla (R- 1) at about 2/3 of its length.

Cephalothorax ( Fig. 1 View FIGURE 1 A, B) smooth, about as long as wide in dorsal view; representing 26 % of total body length, tapering towards anterior end in dorsal view. Hyaline fringe of cephalothoracic shield wide and smooth. Cephalothoracic shield ( Fig. 1 View FIGURE 1 A, B) with 7 pairs of pores (C-I to C-VII), 28 pairs of sensilla (C-2 to C-11 and C-13 to C-30), and one unpaired dorsal sensillum (C-12); sensilla C-19 and C-20 very close to each other, as well as sensilla C-22 and C-23; pores C-I to C-IV all in anterior ventral part, close to sensilla C-7; pores C-VI and C-VII about same size and more than twice as large as any other prosomal pore; sensilla C-2 at base of rostrum; sensilla C-22 to C-30 probably belonging to first pedigerous somite, incorporated into cephalothorax; lateral marginal zone includes sensilla C-5, C-7, C-11, C-21, and C-26 (see Fig. 1 View FIGURE 1 A); posterior marginal zone includes sensilla C-27 to C-30 (see Fig. 1 View FIGURE 1 A, B).

Pleuron of first free prosomite (second pedigerous somite) ( Fig. 1 View FIGURE 1 A, B) smooth, with one unpaired dorsal pore (FP 1-I) and seven pairs of long sensilla (FP1-1 to FP1-7); posterior marginal zone including sensilla FP1-1, FP1-2, and FP1-4 to FP1-7; sensilla pair FP1-3 situated slightly more anteriorly; sensilla FP1-1 and FP1-7 probably serially homologous to sensilla C-27 and C-30, respectively, on first pedigerous somite; other serial homologies difficult to determine; hyaline fringe wide and smooth.

Pleuron of second free prosomite (third pedigerous somite) ( Fig. 1 View FIGURE 1 A, B) smooth, slightly narrower and shorter than pleuron of first free prosomite, without pores, with only five pairs of long sensilla (FP2-1 to FP2-5); posterior marginal zone includs sensilla FP2-1 and FP2-3 to FP2-5; sensilla pair FP2-2 longer than any other pair and situated slightly more anteriorly; dorsalmost pair of sensilla more widely spaced than on pleuron of first free prosomite but recognition of serially homologous pairs relatively easy (FP2-1 = FP1-1, FP2-2 = FP1-3, FP2-3 = FP1-4, FP2-4 = FP1-5, and FP2-5 = FP1-7); hyaline fringe wide and smooth.

Pleuron of third free prosomite (fourth pedigerous somite) ( Fig. 1 View FIGURE 1 A, B) also smooth but slightly narrower and significantly shorter (especially dorsally) than pleuron of second free prosomite, with six pairs of long sensilla (FP3-1 to FP3-6); all sensilla probably serially homologous to their counterparts with same Arabic numerals on pleuron of second free prosomite, except that FP3-5 has no counterpart and that FP3-6 = FP2-5; hyaline fringe smooth, narrow dorsally but wide laterally.

First urosomite (fifth pedigerous somite) ( Fig. 1 View FIGURE 1 A, B) slightly shorter than pleuron of third free prosomite but also smooth, with one pair of anterior lateral pores (U 1-I), one pair of ventro-lateral pores near base of fifth legs (U 1-II), and two pairs of dorsal sensilla (U1-1 and U1-2); sensilla pair U1-1 probably serially homologous to sensilla pair FP3-1, but serial homology of sensilla pair U1-2 not obvious (perhaps FP3-3); hyaline fringe very narrow and smooth.

Second urosomite ( Figs. 1 View FIGURE 1 A, B, 2A) completely fused with third urosomite into genital double-somite, with one dorsal and three ventro-lateral rows of minute spinules, with three pairs of dorsal posterior sensilla (U2-1 to U2-3) of uncertain serial homology, one pair of lateral pores (U 2-I) and two pairs of ventro-lateral pores (U 2-II and U 2-III); pores U 2-II and U 2-III close to each other. No remnant of hyaline fringe. Genital complex ( Fig. 2 View FIGURE 2 A) with single copulatory pore posterior to epicopulatory bulb (latter also serving as copulatory duct), two small seminal receptacles inside large, paired, genital apertures; apertures with two ventral gonopores, each covered by reduced sixth leg. Epicopulatory bulb large, ovoid with wider anterior part, strongly sclerotized, about 1.3 times as long as wide. Seminal receptacles very small, kidney-shaped, reaching anterior margin of epicopulatory bulb, about 0.65 times as long as epicopulatory bulb.

Third urosomite ( Figs. 1 View FIGURE 1 A, 2A) fused with second urosomite, smooth, with wide and finely serrated hyaline fringe and three pairs of posterior sensilla: one dorsal (U3-1), one lateral (U3-2), and one ventral (U3-3); establishing serially homologous sensilla of third and second urosomites not easy (possibly, U3-1 = U2-2). Genital double-somite about 0.8 times as long as wide (ventral view), with only small internal ridge dorso-laterally (but no external suture) indicating original segmentation.

Fourth urosomite ( Figs. 1 View FIGURE 1 A, B, 2A) narrower and shorter than genital double-somite, with single dorsal row of minute spinules, wide and finely serrated hyaline fringe, and three pairs of posterior sensilla (U4-1 to U4-3); all sensilla with homologous pairs on third urosomite (i.e., U4-1 = U3-1, U4-2 = U3-2, and U4-3 = U3-3).

Fifth urosomite (preanal) ( Figs. 1 View FIGURE 1 A, B, 2A) smooth, slightly narrower and longer than third urosomite, without sensilla or pores; hyaline fringe sharply serrated, ventrally as wide as that in third urosomite but dorsally extended into wide and long pseudoperculum, significantly overlapping sixth urosomite.

Sixth urosomite (anal) ( Figs. 1 View FIGURE 1 A, B, 2A) slightly narrower and only about 0.6 times as long as fifth urosomite (ventral view), slightly cleft medially in posterior part, with one pair of large dorsal sensilla (U6-1), one pair of large lateral pores (U 6-I), and posterior row of spinules at base of each caudal ramus; anal operculum very short, narrow, and convex, completely covered by pseudoperculum, with posterior row of numerous hair-like minute spinules, representing 46 % of somite's width; anal sinus widely opened, without any chitinous projections, with weakly sclerotized walls and two diagonal rows of long, hair-like spinules.

Caudal rami ( Figs. 1 View FIGURE 1 A, 2A) strongly sclerotized, about 1.4 times as long as greatest width in ventral view, almost cylindrical (somewhat tapering towards caudal end in posterior third and with slightly convex inner margin), with space between them slightly less than one quarter of one ramus width; ornamented with posterior row of large spinules (four large ventral spinules and five dorsal), several small spinules at base of lateral setae, numerous long and slender spinules along posterior half of inner margin, and three pairs of pores: one pair of posterior dorsal pores (CR-I), and two pairs of posterior ventral pores (CR-II and CR-III); armed with six elements (two lateral, one dorsal, and three apical). Dorsal seta slender and apically pinnate, about as long as ramus, inserted at about 2/3 of ramus length in shallow recess, triarticulate at base (i.e., inserted on two pseudojoints). Lateral proximal spine stout, bipinnate, inserted at 2/3 of ramus length, and 0.7 times as long as ramus. Lateral distal seta slender, smooth, inserted slightly ventro-laterally at 3/4 of ramus length, and about as long as ramus. Innermost apical seta smooth, slender, and small, about 0.35 times as long as ramus. Central (principal) apical seta with breaking plane, very strong, distally pinnate, about five times as long as caudal ramus. Outer apical seta more slender than central apical seta, pinnate along outer margin in distal half, about three times as long as caudal ramus.

Antennula ( Fig. 2 View FIGURE 2 B) 8-segmented, approximately half as long as cephalothorax, with slender aesthetasc on eighth segment fused basally to two apical setae, robust aesthetasc on fourth segment reaching far beyond tip of appendage and fused basally to slightly longer seta; setal formula 1.9.5.3.2.3.4.7. Two lateral setae on seventh segment and four on eighth segment biarticulate (i.e., inserted on short pseudojoint). All setae slender and smooth. One diagonal row of spinules on dorsal surface of first segment as only ornamentation. Length ratio of antennular segments, from proximal end and along caudal margin, 1: 1.6: 0.6: 0.6: 0.4: 0.3: 0.6: 1.5. Second segment about 1.3 times as long as wide.

Antenna ( Fig. 2 View FIGURE 2 C) comprising coxa, allobasis (fused basis and first endopodal segment), one-segmented endopod, and much smaller two-segmented exopod. Coxa short, 0.9 times as long as wide, without armature, with two slender spinules on outer margin. Allobasis most robust segment, almost twice as long as wide and also twice as long as coxa, ornamented with four small spinules along inner margin, and two diagonal anterior rows of small spinules in proximal half. Endopod 3.5 times as long as wide and about 1.2 times as long as allobasis, more slender proximally, with two surface frills distally; lateral armature consisting of two strong, unipinnate spines flanking small, slender seta; apical armature consisting of seven elements: one smooth, slender, short seta, one smooth short spine, and four geniculate setae, longest fused basally to another smooth, slender, and much shorter seta; longest geniculate seta also most robust, and bipinnate; other geniculate setae smooth. Ornamentation of second endopodal segment consisting of longitudinal row of large spinules along inner margin and posterior row of small spinules between lateral and apical armature elements. Both exopodal segments of about same width, slender in comparison to other antennal segments; second segment about 3.7 times as long as wide and 1.25 times as long as first segment; first segment armed with 1 unipinnate subapical seta, unornamented; second segment ornamented with transverse apical row of slender spinules, armed apically with one smooth, slender seta and one strong, bipinnate spine of about same length as former, both about 1.3 times as long as segment.

Labrum ( Fig. 1 View FIGURE 1 D) large, trapezoidal, rigidly sclerotized, with straight cutting edge, ornamented with numerous slender apical and subapical spinules, as well as several rows of spinules of various lengths and orientations along posterior surface.

Mandibula ( Fig. 1 View FIGURE 1 E) with cutting edge of coxa wide, armed with one tricuspidate tooth in ventral part, three bicuspidate teeth in central part, four simple (unicuspidate) teeth (or large spinules?) in dorsal part, and two smooth dorsalmost setae; coxa unornamented. Basis smaller and shorter than coxa, about 2.6 times as long as wide, armed with three unipinnate slender setae along inner margin; ornamented with single large spinule at base of ventralmost seta. Endopod one-segmented, as long as wide, armed with two lateral and five apical smooth setae. Exopod very small but distinct segment, armed with two slender apical setae (one smooth, one bipinnate).

Maxillula ( Fig. 1 View FIGURE 1 F, G) with large praecoxa, arthrite highly mobile, armed apically with nine strong spines, one of which smooth, other unipinnate; armed laterally with two smooth, slender setae and ornamented with four spinules at base of arthrite. Coxa small, armed with four inner elements, three of which smooth and slender setae, while one very strong, spiniform, and unipinnate. Inner margin of basis with one strong, curved, unipinnate spine, five smooth, slender setae, one tubular pore, and several small spinules. Endopod one-segmented, small, about twice as long as wide, armed with three apical smooth setae, innermost seta longest. Exopod fused to basis, armed with two slender and unipinnate apical setae.

Maxilla ( Fig. 2 View FIGURE 2 D) composed of syncoxa, basis and two-segmented endopod. Syncoxa ornamented with two outer rows of spinules on outer margin, large, ovoid, with three endites, each armed with two subequal pinnate setae; distal endite ornamented with posterior row of spinules, other two endites unornamented; proximal seta on distal endite strongest. Basis much smaller than syncoxa, elongate, armed with two apical claw-like spines (both unipinnate along convex margin) and one smooth and slender apical seta; longest basal spine about as long as basis and 1.35 times as long as smaller basal spine; basal seta slightly longer than longer basal spine. Endopod very small, short and wide, first segment about as long as wide and twice as long as second segment, armed with five slender and smooth setae, two on first segment and three on second segment.

Maxilliped ( Fig. 2 View FIGURE 2 E) prehensile, three-segmented, composed of coxobasis and two-segmented endopod. Coxobasis 1.3 times as long as wide, cylindrical, unornamented, armed with three strong, unipinnate setae on inner (median) margin, longest one nearly as long as coxobasis. First endopodal segment about 2.4 times as long as wide and 1.5 times as long as coxobasis, slightly ovoid, ornamented with one longitudinal row of large spinules on anterior surface and one row of smaller spinules along inner margin; armed with two short, slender setae, one centrally on inner margin and other subapically on posterior surface. Second endopodal segment smallest, only 0.35 times as long as first and three times as long as wide, armed apically with one claw-like unipinnate spine and three smooth, slender setae; spine more than twice as long as second endopodal segment and 1.7 times as long as longest seta.

All swimming legs ( Figs. 3 View FIGURE 3 A, B, C, D, E, 16B) slender, short in comparison to body length and width, composed of small unarmed triangular praecoxa, large unarmed quadrate coxa, smaller armed basis, threesegmented exopod, and three-segmented endopod. Coxae in all pairs of legs connected by unornamented intercoxal sclerite. All exopodal and endopodal segments of about same length, except for much longer first endopodal segment of first leg.

First swimming leg ( Fig. 3 View FIGURE 3 A) with small, short, and wide intercoxal sclerite, concave at distal end and without spiniform protrusions. Praecoxa ornamented with posterior row of minute spinules on anterior surface. Coxa more than twice as wide as long, ornamented with four rows of spinules on anterior surface; spinules in outer proximal row small and widely spaced, other three rows with 10 to 11 long and slender spinules. Basis with one inner and one outer strong, pinnate spine, inner one stronger and about 1.2 times as long as outer; ornamentation consisting of several minute spinules at base of outer spine, row of long spinules at base of inner spine, one row of large spinules along distal margin between endopod and exopod, and one cuticular pore at base of outer spine, all on anterior surface. Exopod armed with single outer-distal spine on first and second segments, and with two outer spines and two apical geniculate setae on third segment; all exopodal segments ornamented with strong spinules along outer margin and subdistally, and along inner margin of second segment; first exopodal segment with additional arched row of strong spinules on anterior surface proximally; inner geniculate seta on third segment about as long as entire exopod and about 1.45 times as long as outer geniculate seta. Endopod geniculate, with first segment nearly 0.8 times as long as entire exopod, 2.8 times as long as second endopodal segment, about 3.6 times as long as wide; third endopodal segment about 1.3 times as long as second endopodal segment; endopodal armature consisting of one strong and long inner seta on first segment (inserted at about 4/5), and three setae on third segment (innermost slender and smooth, middle longest and geniculate, outermost spiniform seta (or spine?) half as long as middle one); endopodal ornamentation consisting of strong spinules along outer margin on all segments, and along inner margins of first two segments.

Second swimming leg ( Fig. 3 View FIGURE 3 B) with smaller praecoxa than in first leg, also ornamented with posterior row of spinules on anterior surface. Coxa ornamented with three short horizontal rows of large spinules on anterior surface. Intercoxal sclerite with paired, pointed, distal protrusions. Basis armed only with outer bipinnate spine, ornamented with single large spinule at base of outer spine, with minute spinules along distal margin at base of endopod, and single cuticular pore at base of outer spine. Distal inner corners of first and second exopodal and endopodal segments with serrated hyaline frills. All exopodal and endopodal segments ornamented with strong spinules on outer margins; first and second endopodal and second and third exopodal segments also with weaker spinules along inner margins. Exopod armed with outer-distal spine on first and second segments, inner seta on second segment, two outer spines and two apical setae on third segment; all spines and setae strong and bipinnate; outer apical seta on third segment appearing transitional in form between spine and seta, with outer margin furnished with short spinules and inner margin with long, slender spinules. Endopod about as long as exopod, armed with single inner seta on second segment, and four elements on third segment: outer-distal short spine, two apical long setae, and one inner strong seta (inserted at 2/3).

Third swimming leg ( Fig. 3 View FIGURE 3 C) very similar to second, except for basis armed with outer slender seta instead of spine and first endopodal segment with one inner seta.

Fourth swimming leg ( Fig. 3 View FIGURE 3 D, E) similar to third leg, except for intercoxal sclerite with less sharp distal protrusions, endopod slightly smaller, and third endopodal segment without inner seta.

Fifth leg ( Fig. 3 View FIGURE 3 F) biramous, composed of large, broad baseoendopod and small, ovoid exopod, with division line visible on posterior surface only. Baseoendopod with outer basal smooth seta arising from relatively short setophore. Endopodal lobe almost triangular, extending to 3/4 of exopod, armed with four spiniform elements (two inner ones probably spines, two outer ones probably spiniform setae); length ratio of endopodal armature elements, from inner side, 1: 1.8: 2.5: 2.3. Exopod about 1.1 times as long as maximum width, armed with six elements: two innermost apical ones strong and bipinnate, outer apical one smooth and slender, distal and central outer ones short, unipinnate, and spiniform, and proximal outer one long, strong and also unipinnate; length ratio of exopodal armature elements, from inner side, 1: 1.7: 0.9: 0.45: 0.3: 1.

Sixth leg ( Fig. 3 View FIGURE 3 G) very small cuticular plate covering gonopore, armed with two slender setae and innermost minute spine; inner seta smooth, about twice as long as outer bipinnate seta; minute spine fused to cuticular plate. Male. Unknown.