Typhlocypris choi, Karanovic, Ivana & Lee, Wonchoel, 2012

Karanovic, Ivana & Lee, Wonchoel, 2012, A review of candonid ostracods (Crustacea: Ostracoda: Podocopida) from East Asia, with descriptions of five new species from South Korea *, Zootaxa 3368, pp. 7-49 : 27-32

Typhlocypris choi sp. nov.

( Figures 12–14 )

Etymology. The species name is dedicated to Dr. Joo-Lae Cho (National Institute of Biological Resources, Korea), as a recognition of his outstanding contribution towards the knowledge of interstitial fauna of Korea.

Material examined. Holotype female (soft parts dissected on one slide, shell kept on micropaleontological slide NIBR 0000245055), from (type locality) South Korea, Gangwondo, Wonju, Jijeong, River interstitial, 37 0 23’30”N, 127 0 51’08”E; 24/06/2010, collector Joo-Lae Cho.

One female (in ethyl alcohol NIBRIV0000245056), from South Korea, Gangwondo, Pyeongchang, Jinbu, Namhan river (freshwater), interstitial, 37 0 36’56”N, 128 0 32’23”E; 12/06/2010, collector Joo-Lae Cho.

One juvenile female (in ethyl alcohol NIBRIV0000245057), from South Korea, Gangwondo, Pyeongchang, Jinbu, Odae river, interstitial, 37 0 36’43”N, 128 0 33’09”E; 24/04/2010, collector Joo-Lae Cho.

Description. Female. Carapace reniform in shape ( Figure 12 A, B) with the greatest H lying slightly behind middle L, equaling 50% of total L. Size: L= 0.7 mm. Dorsal margin almost evenly rounded and slightly more curved towards posterior and inclined towards anterior end. Anterior and posterior margins both broadly rounded, posterior being slightly narrower than anterior one. Ventral margin almost straight along entire L. Calcified inner lamella narrow on both ends, anteriorly equaling 12%, posteriorly less than 1% of total L. Fused zone also very narrow and marginal pore canals short, straight and denser anteriorly than posteriorly. Surface of shell covered with fine setulae, originating from small, but clear wart-like structures. No other surface ornamentation present. LV overlapping RV on all free margins.

A1 ( Figure 14 B). Appendage 7-segmented. First segment with two setae anteriorly and two posteriorly. One anterior seta situated more proximally, the other distally on segment. Posterior setae originate from same (or very close) spot. All setae pappose. Second segment with one anterior pappose seta, almost reaching distal end of fourth segment. Third segment with one anterior pappose seta not reaching distal margin of fifth segment. Fourth segment with one short posterior seta (not exceeding distal end of fifth segment), and two anterior, longer setae (exceeding distal end of terminal segment); all these setae pappose. Fifth segment with same chaetotaxy as fourth one. Penultimate segment with total of four setae; posteriormost seta “d” absent. Alpha seta not reaching distal end of terminal segment. Seventh segment with posterior, claw-like seta 1.5 times longer than terminal segment, one aesthetasc (ya) of the same length, and two longer pappose setae. L ratio of five distal segments equaling: 1: 1: 1.3: 1.3: 1.4. Rome and Wouters organs not present.

A2 ( Figure 13 B, E). Basal segment with total of three setae of subequal L, one situated dorsally and two ventrally on segment. Protopod with one, distally pappose seta exceeding distal margin of second endopodal segment. Exopod consisting of plate carrying one long (almost reaching distal end of first endopodal segment) and two short, pappose setae. Endopod 3-segmented. First endopodal segment with aesthetasc “Y” and antero-ventrally with two setae. Second segment with one medio-dorsal seta, only two “t” setae visible (exceeding distal end of terminal segment). Same segment medio-ventrally with short aesthetasc y1. Third endopodal segment with claws G1, G2 and G3; G2 being less than half as long as G1. Seta z1 transformed in short claw, slightly exceeding distal end of terminal segment, other two seta-like and of same L. Third segment distally with aesthetasc y2. Terminal segment with one long claw, GM and one short claw, Gm (twice as long as terminal segment). Terminal segment also armed with aesthetasc y3 (1.5 times as long as terminal segment) and one thin seta accompanying y3. Claws very gently serrated.

Md ( Figure 14 A). First segment of palp with one plumose seta (S1), one pappose, one short seta (S2), the short alpha seta, and one additional seta situated proximally on segment. Second segment dorsally with two setae, reaching distal end of following segment, ventrally with three setae originating from a small plate and one plumose seta; beta seta short and smooth. Penultimate segment dorsally with three almost equally long setae, gamma seta faintly pappose, and three additional setae of which one originating medially and two ventrally. Terminal segment with two strong, well-sclerotized claws (lateral one pappose distally, medial claw serrated) and two setae more ventrally. Exopod Md ( Figure 13 D) with seven rays.

Mxl ( Figure 14 C). Palp 2-segmented, first segment with four setae: three originating antero-distally, and one medio-distally. All these setae pappose. Terminal segment with two claw-like setae and four setae, one situated between claws, and three situated more posteriorly.

L5 ( Figure 13 A). With two rays in exopod, one each “a”, “b”, and “d” seta. Protopod with three short setae distally.

L6 ( Figure 13 C). Basal segment with one seta (d1). Endopod 4-segmented. Setae “e”, “f”, and “g”) all relatively short and pappose. Terminal segment with distal claw and two lateral, short setae (h1 and h3). Distal claw 1.3 times longer than combined L of three distal segments.

L7 ( Figure 14 F). Basal segment with “d1”, “d2” and “dp” setae. Endopod 3-segmented, and only “g” seta present distally. Terminal segment armed with two long and one short seta. L ratios between three “h” setae equaling: 1: 2.2: 2.7.

UR ( Figure 12 C). Relatively short and stout ramus, symmetrical rami. Posterior seta long and exceeding postero-distal margin of the ramus. Anterior seta much shorter and only ¼ L of anterior claw. Both claws strongly serrated. L ratio between anterior margin, anterior claw, posterior claw and posterior seta equaling: 2.3: 1.9: 1.6: 1.

Genital field ( Figure 12 D) rounded and without any projections.

Male. Unknown.

Remarks and affinities. The genus Typhlocypris Vejdovský, 1882 is at the moment subdivided into two subgenera: Typhlocypris s.str. and Pseudocandona Kaufmann, 1900 . The nominal subgenus is divided in eremita –, caribbeana –, rostrata –, and prespica – group ( Karanovic 2005b). The new Korean species belongs to the caribbeana – group of species. This group is defined by a relatively long “h1” seta on the L 7 in comparison to the terminal segment, by a 4-segmented L7 and by the presence of three setae internally on the second segment of the Md-palp. It comprises approximately 20 species (see Karanovic 2006). Typhlocypris choi sp. nov. has a relatively low carapace, with an evenly rounded dorsal margin and by this characters it is closely related to several species. Typhlocypris arcuata ( Klie, 1932) , described from east Java ( Klie 1932), is a bit higher in lateral view and the UR is much shorter than in the new species. Typhlocypris annae ( Méhes, 1913) , described from Columbia ( Méhes 1913) and also found in Florida ( Furtos 1936), has a much shorter seta “h3” on the terminal segment of L7. Typhlocypris geratsi ( Broodbakker, 1983) from Venezuela ( Broodbakker 1983) and T. parvula ( Sars, 1926) from Canada ( Sars 1926) both have a shorter “h3” seta and also a shorter UR, as well as dorsal margin of the carapace not so evenly rounded. The Korean species is most closely related to Pseudocandona abei Smith & Janz, 2008 , known from the southern basin of Lake Biwa ( Smith & Janz 2008). This species is retained by the authors in the genus Pseudocandona , which is in fact a junior synonym of Typhlocypris (see discussion in Karanovic 2005b). The carapace shape of the Japanese and Korean species is almost the same as are many details of the morphology. They differ in the following details: P. a b e i has a much shorter most distal seta situated anteriorly on the first segment of the A1; posterior setae on the third, fourth and fifth segments in T. choi are longer than in P. abei ; and posterior seta on the UR is much longer in P. abei than in the new species. Unfortunately, both species are known only after females and their similarity may indicate a very close relationship. However, we think that these differences are sufficient enough when dealing with allopatric subterranean taxa with restricted distributions. Further studies and possible finding of males will clarify this issue, and hopefully bring new characters.

Figures

FIGURE 12. Typhlocypris choi sp. nov., holotype (female): A, RV, inside view; B, LV, outside view; C, UR; D, genital field. Scales = 0.1 mm.

FIGURE 13. Typhlocypris choi sp. nov., holotype (female): A, L 5; B, basis and protopod of A 2; C, L 6; D, vibratory plate on Md; E, A 2. Scales = 0.1 mm.

FIGURE 14. Typhlocypris choi sp. nov., holotype (female): A, Md; B, A 1, arrow pointing the absence of seta “ d ”; C, Mxl palp; D, rake-like organ; E, UR attachment; F, L 7. Scales = 0.1 mm.