Cyclopina koreana, Karanovic, 2020

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

Cyclopina koreana sp. nov. Figures 7 , 8 , 9 , 10 , 11 , 17B

Type locality.

South Korea, East Coast, Gangneung, small beach, intertidal sand, 37°47.824'N, 128°55.085'E.

Specimens examined.

Holotype female dissected on one slide, collected from the type locality, 29 March 2013, leg. T. Karanovic.

Paratypes: two males and one female dissected on one slide each; three males, two females, and four copepodids in alcohol; one male and two females on one SEM stub (together with specimens of other three species described here; row no. 4); all collected from the type locality, 29 March 2013, leg. T. Karanovic.

Etymology.

The species name refers to South Korea. It is an adjective, agreeing in gender with the feminine genus name.

Description.

Female (based on holotype and three paratypes). Body length from 620 to 635 μm. Colour of preserved specimens yellowish, nauplius eye not visible (Fig. 17B ). Integument on all somites (Figs 7 , 8 ) smooth, with light bacterial cover, cuticular pores on all somites, spinules only on genital somite and caudal rami, and sensilla on all but penultimate somite; hyaline fringes of prosomites smooth, of urosomites serrated. Habitus (Fig. 7A ) ca. 2.6 × as long as wide in dorsal view, with pronounced distinction between prosome and urosome; prosome ovoid, ca. 1.5 × as long as wide in dorsal view, nearly 1.4 × as long and 2.6 × as wide as urosome, its greatest width at posterior end of first pedigerous somite; urosome nearly cylindrical, ca. 3 × as long as wide, its greatest width at posterior end of fifth pedigerous somite (first urosomite). First pedigerous somite (Fig. 7A ) not fused to cephalothorax, but its tergites partly covered with posterior extensions of cephalothoracic shield as in C. busanensis . Cephalothorax (Fig. 7A ) broader in anterior part than in C. busanensis , ca. 1.2 × as long as wide, and twice as long as free prosomites combined. Second to fourth free prosomites (Figs 7A-C , 8F ) progressively shorter and narrower towards posterior end, and with fewer cuticular organs; not many prosomal cuticular organs clearly homologous to those in previous species (compare Figs 2A , 8F ), except dorsal medial pores and several posterior sensilla (Fig. 7B, C ).

First urosomite (Figs 7D , 8G , 9A ) short, slightly laterally expanded in posterior part, with four dorsal sensilla and single dorsal medial pore.

Genital double-somite (Figs 7E, F , 8G , 9A ) ca. 0.9 × as long as wide in dorsal view, laterally expanded anterior part only ca. 1.1 × as wide as posterior margin; sensilla and pores as in C. busanensis . Copulatory pore, copulatory duct, seminal receptacles, oviducts, and genital apertures as in C. busanensis , except first part of copulatory duct slightly wider. Fourth urosomite (Figs 7E , 9A ) ca. 0.6 × as long as genital double-somite, with sensilla and pores as in C. busanensis . Fifth urosomite (Figs 7G , 8H , 9A ) 0.7 × as long as fourth urosomite, with medial dorsal pore and one pair of widely spaced ventral pores as in C. busanensis . Sixth urosomite (Figs 7G , 8H , 9A ) 1.2 × as long as fifth urosomite, with one pair of dorsal sensilla, two pairs of dorsal pores, and single pair of ventral pores; no spinules on fringes of anal sinus; anal operculum smooth, short, broad, slightly convex, situated in first third, represents 62% of somite’s width.

Caudal rami (Figs 7H , 8H , 9A ) cylindrical, ca. 3.5 × as long as wide and 1.5 × as long as anal somite, very widely spaced on anal somite, diverging posteriorly; armed as in C. busanensis ; ornamented with single sensilla near proximal lateral seta, row of small spinules at base of proximal lateral seta, and posterior ventral row of spinules. Proximal lateral seta inserted at ca. two fifths of ramus’ length; medial terminal seta nearly 0.9 × as long as caudal ramus, 1.6 × as long as lateral terminal seta, 0.8 × as long as dorsal seta, and 2.3 × as long as proximal lateral seta.

Antennula (Fig. 9B ) segmentation and most armature as in C. busanensis , but proximal half stouter and distal half slenderer; armature formula 3.6.8.4.5.6.4.2.2.7+ae; apical aesthetasc significantly shorter than in C. busanensis and fifth segment with two short setae; sixth segment longest, ca. 3 × as long as wide, and nearly 0.9 × as long as subsequent four segments combined; tenth segment nearly twice as long as wide.

Antenna (Fig. 10A ) as in C. busanensis , but another small exopodal seta present and second endopodal segment slightly longer.

Mandibula (Fig. 10B ) as in C. busanensis , except second endopodal segment with six setae, apical setae on fourth exopodal segment of markedly different lengths (outer one twice as long as inner one), and additional row of minute spinules at base of unicuspid teeth.

Maxillula (Fig. 10C ) segmentation and armature formula as in C. busanensis , but only one minute seta on praecoxal arthrite smooth, one seta on endopod markedly shorter than other endopodal setae, and both endopod and exopod slightly slenderer.

Maxilla (Fig. 10D ) as in C. busanensis , but with only three setae on proximal syncoxal endite, proximal basal endite less mobile and with one seta minute, endopodal claw smooth, and endopod four-segment.

Maxilliped (Fig. 10E ) segmentation and armature formula as in C. busanensis , but with longer syncoxa, shorter first endopodal segment, and two long setae on ultimate endopodal segment.

Swimming legs (Fig. 10A-E ) shape, segmentation, and ornamentation as in C. busanensis ; armature formula as in C. busanensis , except third exopodal segment of fourth leg with only four setae; all spines lanceolate; three setae on endopod of fourth leg also lanceolate, other setae slender; third endopodal segments seta formula 6.6.6.5; third exopodal segment seta formula 4.5.5.4 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. 1.6 × as long as wide.

Fifth leg (Fig. 8A, G ) shape, segmentation, armature formula, and ornamentation as in C. busanensis , but first segment slightly shorter (ca. 0.6 × as long as wide) and lateral spine on second segment also proportionately shorter (approximately as long as second segment and 1.3 × as long as medial spine).

Sixth leg (Fig. 8G ) as in C. busanensis .

Male (based on allotype and two other paratypes). Body length from 440 to 500 μm. Habitus (Fig. 8A ) similar to female, but slenderer. Urosome (Figs 8D, E , 9C ) also slenderer than in female, and second and third urosomites fully articulated as in C. busanensis ; ornamentation as in female.

Caudal rami (Fig. 9C ) slightly less widely spaced than in female, but armature and ornamentation without significant differences (perhaps dorsal seta somewhat shorter).

Antennula (Figs 8B , 11F ) shape, geniculation, segmentation, ornamentation, and almost all armature as in C. busanensis , but fifth segment with traces of additional segmentation, both aesthetascs longer, and tenth segment with additional short seta (armature formula therefore: 2.5.4.2.6.1.1.2.2.2+ae.2.1.2.1.11+ae).

Antenna, mandibula, maxillula, maxilla, maxilliped, and all four swimming legs (Fig. 8A, C ) as in female. Third endopodal segment of fourth leg (Fig. 11G ) ca. 1.6 × as long as wide, with proximal medial seta lanceolate along both sides; third exopodal segment (Fig. 11H ) with only four setae as in female, ca. 1.6 × as long as wide.

Fifth leg (Fig. 9C ) segmentation, ornamentation, and armature formula as in C. busanensis , i.e., with two medial setae on second segment; proximal segment as in female; lateral spine ca. 0.7 × as long as second segment and 1.1 × as long as medial spine.

Sixth leg (Fig. 9C ) as in C. busanensis , but broader and without minute medial spine; lateral seta 1.5 × as long as medial seta.

Variability.

Except for small differences in body size no other forms of variability were observed, but some specimens were damaged (e.g., with some setae broken off; see Fig. 7H ) so comparisons were somewhat limited.

Figures

Figure 2. Cyclopina busanensis sp. nov., paratype female 1, SEM photographs, all in dorsal view A tergite of fourth pedigerous somite B fifth leg C genital double-somite (= fused second and third urosomites) D sixth leg E detail of posterior part of genital double-somite F fourth and fifth urosomites G sixth urosomite (= anal somite) and caudal ramus H detail of sixth urosomite.

Figure 7. Cyclopina koreana sp. nov., paratype female 1, SEM photographs, all in dorsal view A habitus B second pedigerous somite C third pedigerous somite D first urosomite E genital double-somite and fourth urosomite F anterior medial pore on genital double-somite G fifth and sixth urosomites H caudal ramus.

Figure 8. Cyclopina koreana sp. nov., SEM photographs A-E paratype male 1, ventral view F-H paratype female 2, lateral view: A habitus B distal part of antennula C fourth swimming leg D fourth and fifth urosomites E sixth urosomite F tergite of fourth pedigerous somite G anterior part of urosomite, with fifth and sixth legs H fifth and sixth urosomites.

Figure 9. Cyclopina koreana sp. nov., line drawings A holotype female, urosome, ventral view B holotype female, antennula C allotype male, urosome, ventral view.

Figure 10. Cyclopina koreana sp. nov., line drawings, holotype female A antenna B mandibula C maxillula D maxilla E maxilliped.

Figure 11. Cyclopina koreana sp. nov., line drawings A-E holotype female F-H allotype male: A third endopodal segment of first swimming leg B third exopodal segment of first swimming leg C third exopodal segment of second swimming leg D third endopodal segment of second swimming leg E fourth swimming leg F antennula G third endopodal segment of fourth swimming leg H third exopodal segment of fourth swimming leg.

Figure 17. Light photographs of four new species (not to scale) A Cyclopina busanensis sp. nov., four females (two ovigerous) B Cyclopina koreana sp. nov., three females and four males C Cyclopina curtijeju sp. nov., two females D Cyclopina wido sp. nov., two females (one ovigerous) and one male.