Xestoleberis hujeongensis, Yoo & Tanaka & Tsukagoshi & Lee & Karanovic, 2019

Yoo, Hyunsu, Tanaka, Hayato, Tsukagoshi, Akira, Lee, Wonchoel & Karanovic, Ivana, 2019, Cytheroid ostracods (Crustacea) from South Korea, with description of a new species, Zoosystema 41 (22), pp. 419-441 : 429-435

Xestoleberis hujeongensis n. sp.

( Figs 9-12 )

urn:lsid:zoobank.org:act:16FC529D-CF2B-43D4-8E90-3636CC8EED48

TYPE MATERIAL. — Holotype. ♂, South Korea, intertidal-zone algae at Hujeong Beach, Hujeong 2-gil, Jukbyeon-myeon , Uljin-gun , Gyeongsangbuk-do. 37°04’12.3”N, 129°25’01.0”E, 0.1 m depth, dissected on one slide, NIBRIV0000753780, and valves mounted on the micropaleontological slide, NIBRIV0000753780.

Allotype. ♀, same locality as holotype, dissected on one slide, NIBRIV0000834106, valves on the micropaleontological slides NIBRIV0000834106.

Paratypes. 3 ♂ and 3 ♀, same locality as holotype, dissected on two slide each, NIBRIV0000834107 , NIBRIV0000834333 , NI- BRIV0000834334 , NIBRIV0000834107 , NIBRIV0000834335 , NIBRIV0000834336 , valves on the micropaleontological slides, NIBRIV0000834333 , NIBRIV0000834334 , NIBRIV0000834107 , NIBRIV0000834335 , NIBRIV0000834336 . — 6 specimens kept in 2 ml vial in 99% ethanol, NIBRIV0000834109 . — 4 specimens kept in 2 ml vial in 99% ethanol, MNHN .

TYPE LOCALITY. — Intertidal-zone algae at Hujeong Beach, Hujeong 2-gil, Jukbyeon-myeon , Uljin-gun , Gyeongsangbuk-do, 37°04’12.3”N, 129°25’01.0”E, 0.1 m depth .

ETYMOLOGY. — The species is named after the beach from where it was collected.

DESCRIPTION OF MALE

Carapace ( Figs 9A, B, E, F ; 10A, B )

L max = 512 Μm, L min = 480 Μm, L average = 492 Μm, H max = 309 Μm; H average = 289 Μm, H min = 268 Μm, N = 4 specimens. Elongate to subovate in lateral view, dorsal margin arched, with the greatest H behind middle, equaling 57% c. 61% of L, ventral margin slightly sinusoid. Posterior margin rounded, anterior margin almost semi-circle. Carapace smooth, except for anterior end which carries one patch of wart like ornament ( Fig. 9A ). Carapace with setae arising from pore canals along anterior and ventral margins. Pore canals visible along anterior and ventral margins ( Fig. 10A, B ), relatively long and not branching. Outer lamella with a crack postero-ventrally ( Fig. 9F ). Muscular scar imprints consisting of a row of four vertical scars and one frontal scar present ( Fig. 11I ). Hinge antimerodont ( Fig. 9B ).

Antennule ( Fig. 10E )

Six-segmented. First segment with setulae on postero-proximal margin. Second segment with setulae antero-medially and antero-distally, one bare seta postero-distally not reaching end of third segment. Third segment with one plumose seta antero-distally not reaching end of fourth segment. Fourth segment with two bare setae antero-distally, twice longer than fifth segment, and one bare seta on distal margin not reaching end of fifth segment. Fifth segment with three bare setae on distal margin, twice longer than fifth segment. Terminal segment with two setae on distal margin, twice longer than same segment. Length ratios between six segments: 4.8: 4.1: 1.7: 1.9: 2.1: 1.

Antenna ( Fig. 10C )

Four-segmented. Exopod transformed into two-segmented spinneret seta. First endopodal segment with setulae posteromedially. Second segment with setulae present on anterior margin and with one plumose seta posterior-distally reaching half of the third segment. Third segment with two bare setae antero-medially not reaching end of the same segment, two plumose setae postero-medially not reaching end of the same segment, and one strong plumose seta postero-distally; setulae present on antero-proximal margin and postero-distal margin. Fourth segment with two claw-like setae on distal margin, setulae present on distal margin. Length ratios between four segments: 13.3: 3: 10.6: 1

Mandibule ( Fig. 10F , F’, H)

Coxa with five teeth on distal margin, one bare seta posterodistally, and two bare setae antero-distally. Palp 4-segmented. First segment bearing exopodite composed of two long setae, with one plumose seta antero-medially reaching end of the second segment, and one plumose seta on central margin reaching end of terminal segment. Second segment with two plumose setae medio-distally exceeding distal margin of the third segment; one long plumose seta antero-distally, and one bare seta postero-distally. Third segment with two sub-equally long plumose setae antero-distally, accompanied by one half of long bare seta; same segment with one claw-like seta mediodistally.Terminal segment with three claw-like setae, all serrated.

Maxillule ( Fig. 10G )

Palp present, 2-segmented. First segment with two setae, second segment with two claws, one fused with segment. First and second endites with three to four teeth-like setae respectively. Vibratory plate with 16 setae.

Leg 5 ( Fig. 11E )

Four-segmented. First segment with one plumose seta postero-proximally not reaching end of the same segment, two plumose setae antero-distally reaching half of the second segment, and two plumose setae antero-medially: one plumose seta reaching end of the first segment, another not reaching end of the same segment. Second segment with setulae along anterior margin and one plumose seta antero-distally reaching 1/3 of the terminal segment. Third segment with setulae on distal margin. Terminal segment with setulae along anterior and distal margins, one claw on distal margin. Length ratios between four segments: 3.4: 2.1: 1: 1.2.

Leg 6 ( Fig. 11F )

Four-segmented.First segment with one plumose seta posteroproximally not reaching end of first segment; two plumose setae antero-medially not reaching end of the same segment; one plumose seta antero-distally reaching half of the second segment. Second segment with one plumose seta antero-distally not reaching end of the third segment, setulae present along anterior margin. Third segment with setulae along anterior margin. Terminal segment with one claw on distal margin and setulae present on distal margin. Length ratios between four segments: 2.9: 2.2: 1: 1.5.

Leg 7 ( Fig. 11G )

Four-segmented. First segment with one plumose seta postero-proximally not reaching end of the first segment; one plumose seta antero-medially reaching end of the same seg- ment and one plumose seta antero-distally reaching 2/3 of the second segment. Second segment with one plumose seta antero-distally reaching end of the third segment and setulae present along anterior margin. Third segment with setulae present on distal margin. Terminal segment with one claw on distal margin and setulae present along anterior margin and distal margin. Length ratios between four segments: 2.6: 2.5: 1: 1.6.

Hemipenis ( Fig. 12A, B)

Conspicuous cuticle present along the rim. Hemipenis with strongly asymmetrical lobes. Lobes foot-like, but more robust on right than on left Hp. Ejaculatory duct terminated on distal lobe. Three bare setae present near the upper central margin and one small seta called caudal process on between left and right ( Fig. 12B).

DESCRIPTION OF FEMALE

Carapace ( Figs 9C, D, G, H ; 11A, B )

Slightly larger than male, L approximately 546 Μm H approximately 336 Μm, number of specimens = 5, notable pore canals and setae present anteriorly and postero-distally ( Fig. 11A, B ). Carapace ornamentation same as in male, but without wart like feature on anterior margin ( Fig. 9C ). Outer lamella with crack on postero-ventral margin ( Fig. 9G ) Muscular scar imprints consisting of a row of four vertical scars and one frontal scar ( Fig. 11J ). Hinge antimerodont ( Fig. 9H ).

Antennule ( Fig. 11D )

Same as in male, with exception that all setae are thicker than in male.

Antenna, Mandibule

Same as in male.

Maxillule ( Fig. 11C )

Palp present. 2-segmented. First segment with three bare setae antero-distally. Second segment with two plumose setae distal margin. Masticatory process with three endites. First to third endites with four bare setae on distal margin. Vibratory plate same as in male.

Legs 5, 6, 7

Same as in male.

Genital field ( Fig. 11H )

Bean-shaped ovary. Genital lobes with total of five plumose setae situated on distal margin.

Figures

FIG. 9. — Xestoleberis hujeongensis n. sp., male NIBRIV0000753780: A, LV external view; B, RV internal view; E, posterior part of RV; F, postero-ventral part of RV; female NIBRIV0000834106; C, LV external view; D, RV internal view; G, postero-ventral part of RV; H, hingement structure (antimerodont). Arrows: point of divided outer lamella. Abbreviations: see Material and methods. Scale bars: A-D, 200 μm; E, G, 100 μm; F, H, 50 μm.

FIG. 10. — Xestoleberis hujeongensis n. sp.,male NIBRIV0000753780:A, left Valve internal view; B, RV internal view; C, A2; D, BO;E, A1; F, first to third segments of Md palp; F’, terminal segment of Md palp; G, Mxl; H, coxa of Md. Abbreviations: see Material and methods. Scale bars: 100 μm.

FIG. 11. — Xestoleberis hujeongensis n. sp.: A-D, H, J, female NIBRIV0000834106: LV internal view (A), RV internal view (B), endites of Mxl (C), A1 (D); GF (H); muscular scar (LV) (J); E-G, I, male NIBRIV0000753780: L5 (E); L6 (F); L7 (G); muscular scar (LV) (I). Abbreviations: see Material and methods. Scale bars: A-H 100 μm, I, J 50 μm.