Cyclopina busanensis, Karanovic, 2020

Karanovic, Tomislav, 2020, Four new Cyclopina (Copepoda, Cyclopinidae) from South Korea, ZooKeys 992, pp. 59-104 : 59

publication ID	https://dx.doi.org/10.3897/zookeys.992.54856
publication LSID	lsid:zoobank.org:pub:E604D905-F161-482D-9944-75496EEFF427
persistent identifier	https://treatment.plazi.org/id/F8FFA47A-D9C4-4826-A6F1-5F286041EE1A
taxon LSID	lsid:zoobank.org:act:F8FFA47A-D9C4-4826-A6F1-5F286041EE1A
treatment provided by	ZooKeys by Pensoft
scientific name	Cyclopina busanensis
status	sp. nov.

Treatment

Cyclopina busanensis View in CoL sp. nov. Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 17A View Figure 17

Type locality.

South Korea, South Coast, Busan, Sonjong Beach, intertidal sand, 35°10.741'N, 129°12.317'E.

Specimens examined.

Holotype ovigerous female dissected on one slide, collected from the type locality, 6 May 2016, leg. T. Karanovic. Paratypes: one male (allotype) and two females dissected on one slide each, seven females (one ovigerous) and five copepodids in alcohol, and five females on one SEM stub (together with specimens of other three species described here; row no. 2), all collected from the type locality, 6 May 2016, leg. T. Karanovic.

Etymology.

The species name refers to the type locality. It is an adjective for place, made with the Latin suffix - ensis.

Description.

Female (based on holotype and seven paratypes). Body length, excluding caudal setae, from 515 to 535 μm. Colour of preserved specimens light brown, nauplius eye not visible (Fig. 17A View Figure 17 ). Integument on all somites smooth (Figs 1 View Figure 1 - 3 View Figure 3 ), with light bacterial cover, spinules only on genital and anal somites and caudal rami, cuticular pores on all somites, and sensilla on all but penultimate somite; hyaline fringes of prosomites smooth, of urosomites serrated. Habitus (Figs 1A View Figure 1 , 3A View Figure 3 ) ca. 2.8 × as long as wide in dorsal view, with pronounced distinction between prosome and urosome; prosome ovoid, ca. 1.6 × as long as wide in dorsal view, nearly 1.3 × as long and 2.6 × as wide as urosome, its greatest width at posterior end of first pedigerous somite; urosome gently tapering towards posterior end, 3.3 × as long as wide, its greatest width at posterior end of fifth pedigerous somite (first urosomite). First pedigerous somite (Fig. 1A, F View Figure 1 ) not fused to cephalothorax, but its tergites partly covered with posterior extensions of cephalothoracic shield (Fig. 1A, E View Figure 1 ). Pedigerous somites without lateral expansions. Rostrum (Fig. 1C, B View Figure 1 ) well-developed, membranous, very broad. Cephalothorax (Figs 1A, C-E View Figure 1 , 3B, C View Figure 3 ) nearly conical,approximately as long as wide, and 1.3 × as long as free prosomites combined. Second to fourth free prosomites (Figs 1A, G, H View Figure 1 , 2A View Figure 2 , 3D View Figure 3 ) progressively shorter and narrower towards posterior end, and with fewer cuticular organs.

First urosomite (Figs 1A View Figure 1 , 2C View Figure 2 , 3A View Figure 3 ) shortest, laterally expanded in posterior part.

Genital double-somite (Figs 2C-E View Figure 2 , 3E, F View Figure 3 , 4A View Figure 4 ) ca. 1.2 × as long as wide in dorsal view, laterally expanded anterior part nearly 1.4 × as wide as posterior margin; anterior part (second urosomite) with one pair of narrowly spaced posterior dorsal sensilla (Fig. 3E View Figure 3 ), large dorsal medial pore in between them (Fig. 3E View Figure 3 ), one pair of widely spaced anterior dorsal sensilla, one pair of small widely spaced anterior dorsal pores, one pair of narrowly spaced ventral pores next to copulatory pore (Fig. 4A View Figure 4 ), and two pairs of large pores, two pairs of small pores, and longitudinal row of spinules next to genital apertures (Fig. 2D View Figure 2 ); posterior part (third urosomite) with also with one pair of narrowly spaced posterior sensilla and large dorsal medial pore in between them (Fig. 3F View Figure 3 ), one pair of lateral posterior sensilla (Fig. 2E View Figure 2 ), one pair of large lateral pores (Fig. 2E View Figure 2 ), one pair of widely spaced ventral pores (Fig. 4A View Figure 4 ), and two pairs of posterior ventral sensilla (Fig. 4A View Figure 4 ). Medial copulatory pore (Fig. 4A View Figure 4 ) hardly bigger than cuticular pores next to it, situated in first third. Copulatory duct (Fig. 4A View Figure 4 ) narrow, rigidly sclerotised, T-shaped. Seminal receptacles (Fig. 4A View Figure 4 ) weakly sclerotised, simple, ovoid, with space between them slightly wider than one receptacle, reaching posteriorly slightly beyond level of copulatory pore. Oviducts weakly sclerotised, short. Genital apertures situated laterally, covered by reduced sixth legs. Paired egg sacs ovoid, each containing 8-10 eggs, twice as long and ca. 1.2 × as wide as genital double-somite. Fourth urosomite (Figs 2F View Figure 2 , 3G View Figure 3 , 4A View Figure 4 ) ca. 0.6 × as long as genital double-somite, with sensilla and pores as in third urosomite, except ventral pores situated slightly more posteriorly and more narrowly spaced. Fifth urosomite (Figs 2F View Figure 2 , 3G View Figure 3 , 4A View Figure 4 ) 0.8 × as long as fourth urosomite, with medial dorsal pore and one pair of widely spaced ventral pores. Sixth (anal) urosomite (Figs 2G, H View Figure 2 , 3H View Figure 3 , 4A View Figure 4 ) nearly 0.8 × as long as fifth urosomite, with one pair of large dorsal sensilla, one pair of dorsal pores, two pairs of ventral pores, and three rows of slender spinules fringing anal sinus; anal operculum smooth, short, broad, slightly concave, situated in first third, represents 66% of somite’s width.

Caudal rami (Figs 2G View Figure 2 , 4A View Figure 4 ) cylindrical, ca. 3.7 × as long as wide and twice as long as anal somite, narrowly spaced on anal somite, diverging posteriorly; armed with one proximal lateral seta, one dorsal seta, and four terminal setae; ornamented with row of small spinules at base of proximal lateral seta, and posterior ventral row of spinules. All setae slender and pinnate, and all except dorsal seta uni-articulated at base; two central terminal setae much longer and stronger than others and both with breaking planes; dorsal seta inserted close to posterior margin, biarticulated at base; proximal lateral seta inserted atapproximately two fifths of ramus’ length; medial terminal seta 1.2 × as long as caudal ramus, 1.6 × as long as lateral terminal seta, 1.5 × as long as dorsal seta, and 2.5 × as long as proximal lateral seta.

Antennula (Figs 1A, B View Figure 1 , 5A View Figure 5 ) reaching two thirds of cephalothoracic shield with its distal tip, stout, smooth, cylindrical but tapering towards distal end, 10-segmented; no setae with breaking planes or biarticulated, one seta on fifth segment short and spiniform, largest seta on ultimate segment and seven setae on second and third segments bipinnate, all other setae smooth and slender; single slender aesthetasc on ultimate segment fused basally to slender seta; armature formula (ae = aesthetasc) 3.5.8.4.5.7.4.3.2.7+ae; sixth segment longest, ca. 2.8 × as long as wide, and more than 0.8 × as long as subsequent four segments combined; tenth segment 1.5 × as long as wide.

Antenna (Fig. 5B View Figure 5 ) slender, cylindrical, four-segmented, with highly mobile joint between second and third segment; first segment (probably allobasis) longest and widest, twice as long as wide, slightly curved, unornamented, armed with single strong medial-distal seta and twice as long exopodal seta; second segment (probably first endopodal) 0.8 × as long as basis, twice as long as wide, with spinules along medial convex margin, and with single medial seta inserted mid-length; second endopodal segment slightly narrower and only half as long as first endopodal, with spinules along lateral margin, and with four medial setae (shortest one inserted in proximal half, three near distal-medial corner; one distal seta spiniform, others slender); third endopodal segment 1.4 × as long as second endopodal and twice as long as wide, with spinules along lateral margin and seven apical setae (four strong and prehensile, three slender).

Mandibula (Fig. 5C, D View Figure 5 ) with large coxa, and smaller palp consisting of basis, two-segmented endopod, and four-segmented exopod; coxal gnathobase with relatively wide cutting edge consisting of four polycuspidate large teeth (ventralmost largest), three smaller unicuspid teeth (dorsalmost with serrated edges, others smooth), row of spinules at base of two central polycuspidate teeth, and two short setae; dorsalmost seta on cutting edge smooth, ca. 1.5 × as long as other, bipinnate seta; basis ovoid, 1.7 × as long as wide, with single medial seta; endopod 0.6 × as long as basis, with three setae on first and five setae on second segment; exopod slightly shorter than basis but much more slender, with armature formula 1.1.1.2; all setae on basis, endopod, and exopod slender and pinnate.

Maxillula (Fig. 5E, F View Figure 5 ) unornamented, composed of well-developed praecoxa and three-segmented palp; arthrite of praecoxa with six strong and pinnate apical spines, one isolated smooth spine on posterior surface, two spiniform plumose setae, and two smooth minute setae (or perhaps large spinules?) in between plumose setae and spines; proximalmost seta longest and strongest element, three × as long as other seta and ca. 1.1 × as long as longest and strongest (ventralmost) spine; coxa reduced to small endite partly fused to arthrite of praecoxa, bearing single slender seta, and another slender seta probably belonging to former epipodite; palp slightly smaller than praecoxa, composed of large rectangular basis, small ovoid endopod, and also ovoid but shorter and wider exopod; basis twice as long as wide, with short proximal and distal endites bearing three and two setae respectively; endopod slightly longer than greatest width of basis, ca. 1.5 × as long as wide, with two medial and four distal slender setae (one smooth, others unipinnate); exopod 0.8 × as long as endopod, as long as wide, with four distal slender and plumose setae.

Maxilla (Fig. 5G View Figure 5 ) stout, 1.6 × as long as wide, tapering towards distal end, ornamented with row of spinules along lateral margin and several spinules on endites, composed of syncoxa (fused praecoxa and coxa), basis, and three-segmented endopod; syncoxa largest, quadrate, with four setae on proximal endite and one seta on distal endite; basis ca. 0.6 × as long as syncoxa, also quadrate, with three setae on proximal endite and three setae on distal endite; first endopodal segment half as long as coxa, with basally fused, smooth and robust claw and two articulated setae, proximal seta strong and bipinnate, slightly longer than claw, distal seta smooth and minute; second and third endopodal segments combined slightly longer than first, second segment somewhat longer than third and armed with four strong setae, third segment armed with three strong and three slender setae.

Maxilliped (Fig. 5H, I View Figure 5 ) prehensile, slender, almost 3.5 × as long as wide, seven-segmented, composed of syncoxa, basis, and five-segmented endopod; syncoxa rhomboidal, approximately as long as wide, unornamented, with one element on proximal endite and three on distal endite; basis slightly smaller than syncoxa, quadrate, unornamented, with two setae on only endite; first endopodal segment nearly as long as syncoxa and basis combined, 1.6 × as long as wide, with row of long spinules along swollen medial margin, and with two spiniform setae near distal medial corner; distal part of endopod cylindrical, 0.7 × as long as basis, 2.4 × as long as wide, with armature formula 0.0.1.3, second endopodal segment partly fused to first endopodal and last segment half as long as any other; medial apical seta spiniform, 1.7 × as long as last four endopodal segments, twice as long as central apical seta, and 1.4 × as long as setae on first endopodal segment; other three endopodal setae slender.

Swimming legs (Figs 1A View Figure 1 , 6A-E View Figure 6 ) large, composed of short praecoxa, rectangular large coxa, triangular basis, three-segmented exopod, three-segmented endopod, and coxae of opposite appendages connected with squarish intercoxal sclerite; coxae of all legs with pore on anterior surface, row of spinules along lateral margin, and slender seta on medial-distal corner; intercoxal sclerites unornamented, with nearly straight distal margin; basis with slender lateral seta, anterior pore, row of long spinules along convex medial margin, row of minute spinules at base of lateral seta, and strong medial spine on first leg and short spiniform process instead on other legs; all exopodal segments with short spinules along lateral margin, and all endopodal segments with long and slender spinules along lateral margin; second endopodal segment of first to third leg with single anterior pore, third endopodal segment of first leg with two anterior pores, and third endopodal segments of second to fourth leg with single anterior pore; first and second exopodal segments with single lateral spine and single medial seta; first endopodal segments of all legs and second endopodal segment of first leg with single medial seta; second endopodal segments of second to fourth legs with two medial setae; third endopodal segments seta formula 6.6.6.5; third exopodal segment seta formula 4.5.5.5 and spine formula 4.4.4.3; third endopodal segment of fourth leg 1.7 × as long as wide and third exopodal segment of fourth leg ca. 1.5 × as long as wide; all setae slender and all spines lanceolate.

Fifth leg (Figs 2B View Figure 2 , 4A View Figure 4 ) small, two-segmented, with short intercoxal sclerite; first segment (presumably basis)approximately as long as wide, with single lateral seta, single anterior pore, several parallel rows of long spinules along convex medial margin, and distal row of minute spinules; second segment (presumably exopod) ca. 1.3 × as long as first but much narrower, 1.6 × as long as wide, with spinules along both medial and lateral slightly convex margins, apical central seta and two subapical spines; lateral spine 1.2 × as long as exopod and 1.6 × as long as medial spine.

Sixth leg (Fig. 2D View Figure 2 ) simple semi-circular flap, mostly fused to genital somite, approximately twice as wide as long, unornamented, with two dorsally directed setae; lateral seta much stronger and nearly twice as long as medial seta.

Male (based on allotype). Body length 503 μm. Urosome (Fig. 4B View Figure 4 ) slenderer than in female, and second and third urosomites fully articulated; ornamentation as in female, except ventral pores on third and fourth urosomites more widely spaced.

Caudal rami (Fig. 4B View Figure 4 ) slightly shorter than in female, but armature and ornamentation without significant differences.

Antennula (Fig. 5J View Figure 5 ) digeniculate, 15-segmented, with proximal geniculation between eighth and ninth and segments, and distal geniculation between thirteenth and fourteenth segments; armature formula: 2.5.4.2.6.1.1.2.2.1+ae.2.1.2.1.11+ae; thirteenth and fourteenth segments with strong cuticular ridges along anterior (geniculating) surface; ninth, eleventh, twelfth, and thirteenth segments with short spiniform seta each, all other setae slender and most also smooth.

Antenna, mandibula, maxillula, maxilla, maxilliped, and all four swimming legs as in female. Third endopodal segment of fourth leg (Fig. 6F View Figure 6 ) ca. 1.5 × as long as wide.

Fifth leg (Fig. 4B View Figure 4 ) segmentation, ornamentation, and armature of proximal segment as in female; armature of distal segment with two slender medial setae in addition to two spines and central apical seta as in female; lateral spine as long as distal segment and ca. 1.8 × as long as medial spine.

Sixth leg (Fig. 4B View Figure 4 ) also simple semi-circular flap, but better articulated than in female, with medial minute spine and two slender setae; lateral seta 1.7 × as long as central seta and more than 5 × as long as spine.

Variability.

Cuticular organs on the cephalothorax (Figs 1C-E View Figure 1 , 3B, C View Figure 3 ) often exhibited asymmetries in position and/or absence on one side and in different specimens, to the point that a complete survey was probably impossible. Cuticular organs on free prosomites showed fewer asymmetries in position (Fig. 3D View Figure 3 ) and rarely any absence, while those on urosomites showed no variability in position or number (Figs 2D View Figure 2 , 3E View Figure 3 ). There was no variability in the segmentation or armature formulae of appendages, and any variability in the proportion of segments or armature elements could not be confidently discounted as resulting from slight difference in position due to mounting of specimens and appendages.