Schedopontocypris raehyuki, Karanovic, 2020

Karanovic, Ivana, 2020, Two new Pontocyprididae (Ostracoda) species from Korea, Journal of Natural History (J. Nat. Hist.) 53 (45 - 46), pp. 2801-2815 : 2808-2812

Schedopontocypris raehyuki sp. nov. ( Figures 4 , 5 )

http://www.zoobank.org/ urn:lsid:zoobank.org:act:A18697AE-F331-4E10-B1E6-866752F83ADA

Holotype. Male, dissected on one slide, shell on SEM stub.

Allotype. Female, dissected on one slide, shell on micropaleontological slide ( NIBR IV0000815836 ).

Paratypes. Male dissected on one slide, shell on micropaleontological slide; one whole male on SEM slide; one whole female on SEM stub.

Type locality. South Korea, Geumgangsan , diving, 25 m, 29/06/2016, collector Raehyuk Jeong, 38°17 ʹ 47.4 ” N 128°33 ʹ 23.1 ” E .

Etymology. The species is named after Raehyuk Jeong (Hanyang University), who collected the material.

Description

Male. Length around 0.7 mm. Greatest height situated at mid-length, equalling 50% of the length ( Figure 4 (a,b)). Dorsal margin highly arched and sloping towards anterior and posterior margins. Posterior margin narrow, but not pointed. Anterior margin rounded. Ventral margin slightly concave around the mouth region. Muscle scar region consisting of five large, rounded scars, arranged in a typical pontocyprinid pattern. Line of concrescence narrow, but much more on the posterior end. Marginal pore canals short and not branching. Surface densely covered with sensilla ( Figure 4 (g)), some cylindrical originating from lip-like pores ( Figure 4 (e)), and others feathered ( Figure 4 (g)) or not ( Figure 4 (f)) but and originating from simple pores.

A1 ( Figure 5 (c)) eight-segmented, with a clear suture between the first and second segment. First segment with one anterior seta not reaching distal end of the second segment. Second segment with one long and one shorter posterior seta (shorter seat situated postero-distally); same segment with one seta reaching distal end of the following segment. Third and fourth segments with one antero-distal and one postero-distal seta each. Fifth and sixth segments with two long anterior setae and one short posterior seta. Seventh segment with a total of five setae, and terminal segment with two long setae and one seta transformed into a sensory organ (ya seta). Terminal segment very small, barely visible.

A2 ( Figure 5 (a)) five-segmented. Exopod reduced to a plate with one short seta. Swimming setae strongly reduced. Male sensory setae simple and situated postero-distally on the second endopodal segment. Penultimate segment with three claws (two long, one half as long), one long and one short seta. Only one claw observed on the terminal segment.

Md-palp four-segmented ( Figure 5 (m)). First segment with three setae. Suture between first and second segment not clearly visible, so there are a total of seven setae: three long and other short. Of the long setae, one is with a very broad base distally. Same segment(s) with two external seta. Penultimate segment with three external, two medial, and two internal setae (one long, which is also more claw-like, and one short); in addition one claw present on the same segment internally. End segment with four claws.

Mxl ( Figure 5 (e)) two-segmented. First segment with only three setae. Second segment with two claws and one tiny seta.

Prehensile palps ( Figure 5 (h,i)). Body robust and quadrate and fingers without rightangled hooks. Palps almost symmetrical. Pegs cylindrical and on both palps accompanied with one long and one short seta.

L6 ( Figure 5 (j)) six-segmented. Two first two segments (protopod) carrying four short setae. All setae on the endopodal segments short. All, except the terminal segment, carry only one seta. Terminal segment with two tiny setae and a long, distally gently curved claw.

L7 ( Figures 4 (i), 5(b)) five-segmented. Third segment with one thick seta originating not from the antero-distal end, but medio-distally. This seta reaching end of the penultimate segment. Penultimate segment with one short seta and with only one spine-like process antero-distally. Terminal segment very small and with chelate seta armed with distinct spines. Two additional setae present on the same segment: one as long as chelate seta, the other slightly longer.

CR ( Figure 5 (d)) with stout shaft. Anterior seta half as long as anterior claw. Anterior claw as long as posterior claw. More distal posterior seta thin and as long as posterior claw. Two more proximal setae thin, but one half as long as the other.

Hemipenis ( Figure 5 (f)) distally broad with rounded outer part, and with a long hook-like process on the opposite side ( Figure 4 (h)), and one hook-like projection close to the middle.

Ejaculatory tube ( Figure 5 (g)) cylindrical.

Female shell ( Figure 4 (c)) similar to male. A2 ( Figure 5 (k)) with one additional very short seta on the penultimate segment anteriorly. L6 ( Figure 5 (l)) with 3-segmented endopod. Penultimate segment with one seta, terminal segment with two short setae and a claw. Basis with a tuft of six setae and with two additional setae. Two posterior setae situated proximally the CR ( Figure 5 (n)) subequally long. All other appendages are similar to male.

Key to genera with living representatives of Pontocyprididae (excluding Australoecia McKenzie, 1967 )

1. A1 robust, with heavily chitinized segments, and short, claw-like setae.. ...................... 2

– A1 slender with thin, often long setae.. ......................................................................................... 5

2. Accessory seta on the terminal segment of L6 as long as terminal claw (often as strong as terminal claw)... ...................................................................................................................................... 3

– accessory seta on the terminal segment of L6 much shorter than terminal claw (almost never strong)... ............................................................................................................................................. 4

3. Zone of concrescence ventrally enlarged.. ............... Robustoargilloecia Hartmann, 1986

– Zone of concrescence not ventrally enlarged.. .................. ................. Argilloecia Sars, 1866 4. A1 8-segmented, swimming setae long, pectinate seta on L7 without teeth (not pectinate).. ......................................................................................................... Abyssocypris Bold, 1974

– A1 7-segmented, swimming setae short/absent, pectinate seta on L7 clearly pectinate... ............................................................................................................................. Iliffeoecia Maddocks, 1991

5. Terminal segment of A2 with large hook... Pontocypria Mueller, 1894

– Terminal segment of A2 without a hook... ................................................................................... 6

6. Six adductor muscle scars present on the shell, CR very large, equalling at least onethird of the whole animal, all posterior setae on CR transformed into claws.. ....................... ..................................................................................................................... Peripontocypris Wouters, 1997

– Five adductor muscle scars present on the shell, CR robust, but not as large, posterior setae sometimes strong, but not claw-like... ................................................................................... 7

7. Shell ventrally flattened, elongated, with beak-like anteroventral region of the carapace in lateral view.. ................................................................................... Comontocypris, Wouters, 1987

– Shell not ventrally flattened, and only posterior end of the carapace can be elongated, no beak-like anteroventral region of the carapace in lateral view.. ....................................... 9

9. A1 eight-segmented (with six-segmented endopodite).. .................................................... 10

– A1 clearly seven-segmented (with five-segmented endopodite).. ........................................... ........................................................................................................................... Kareloecia Maddocks, 1991

10. Swimming setae on A2 well developed (at least reaching middle of the terminal claws) in both sexes... ........................................................................................................................................... 11

– Swimming setae on A2 vestigial (not reaching middle of the second endopodite segment of A2) in both sexes, or only in females.. ... Schedopontocypris Maddocks, 1969

11. Fingers (hooks) on the male prehensile palps right angled.. ................................................. .................................................................................................................... Ekpontocypris Maddocks, 1969

– Fingers (hooks) on the male prehensile palps rounded or elongated...12

12. Posterior end of the carapace sharply pointed, prehensile palps strongly asymmetrical.. ........................................................................................................................... Pontocypris Sars, 1866

– Posterior end of the carapace not sharply pointed and prehensile palps faintly asymmetrical.. ............................................................................................................................................. 13

13. Posterior claw on CR shorter than anterior... Propontocypris ; Sylvester-Bradley, 1947

– Claws on CR subequally long.. ...................... ..................... Thomontocypris Maddocks, 1991

Figures

Figure 4. SEM of Schedopontocypris raehyuki sp. nov. (a, b, d–i) male; (c) female; (a) LV, external view; (b) LV, internal view; (c) whole animal, external view from the right side; (d) anterior margin of the LV, external view; (e–g) details of the carapace surface pores and sensilla; (h) hemipenis; (i) terminal segments of L7.

Figure 5. Line drawings Schedopontocypris raehyuki sp. nov. (a–j) male; (k–n) female; (a) A2; (b) three terminal segments of L7; (c) A1; (d) CR; (e) Mxl palp and endites; (f) hemipenis; (g) ejaculatory tube; (h) left prehensile palp; (i) right prehensile palp; (j) L6; (k) three distal segments of A2; (l) L5; M, Md palp, (n) CR. Scales 0.1 mm.