Candonopsis (C.) transgrediens Brehm, 1923

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 : 35-40

publication ID	https://doi.org/ 10.5281/zenodo.281682
DOI	https://doi.org/10.5281/zenodo.6166606
persistent identifier	https://treatment.plazi.org/id/03D23B75-FF98-FFAA-FF5D-F8E6FB084E74
treatment provided by	Plazi
scientific name	Candonopsis (C.) transgrediens Brehm, 1923
status

Treatment

( Figures 17–19 View FIGURE 17 View FIGURE 18 View FIGURE 19 )

Synonymy. Candonopsis transgrediens Brehm, 1923 : p. 340, Figs. 3 View FIGURE 3 & 10–14 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 .

Material examined. One male and one female (soft parts dissected on slides, shell kept on micropaleontological slides NIBRIV245060, NIBRIV0000245061), 5 females and 5 males in ethyl alcohol (kept for future DNA studies), from South Korea, Daepyeong wetland, 35 0 20’24.1” N 128 0 20 ’06.06”E; 28/04/ 2011, collector HyunsuYoo.

One female (soft parts dissected on slides, shell not preserved NIBRIV0000245062) from South Korea, Daepyeong wetland, 35 0 20’24.1” N 128 0 20 ’06.06”E; 15/05/2010, collector Hyungi Jeong; temperature = 18.6 0C; pH = 7.57; salinity = 0.12‰.

Redescription. Male. Carapace reniform in lateral view ( Figure 17 View FIGURE 17 C, D) with the greatest H lying behind middle L, equaling 53% of total L. Size: L= 0.79 mm. Dorsal margin highly rounded in posterior part and gently inclined towards anterior. Anterior and posterior margins both broadly rounded, but posterior margin wider than anterior. Ventral margin slightly concave around mouth region. Calcified inner lamella narrow on both ends, anteriorly equaling 13% of total L, posteriorly equaling 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 18 View FIGURE 18 D). Appendage 7-segmented. First segment with two setae anteriorly and two posteriorly. One anterior seta situated more proximally, other distally on segment. Posterior setae originate from same (or very close) spot. All setae pappose. Second segment with one anterior pappose seta, reaching distal end of fourth segment. Third segment with one posterior seta slightly, reaching only half L of following segment. Fourth segment with two anterior, long setae (exceeding distal end of terminal segment). Fifth segment with two longer anterior setae (one half as long as other) and one short posterior seta, not reaching distal margin of following segment. Penultimate segment with total of four setae; posteriormost seta “d” seta present. Alpha seta absent. Seventh segment with posterior, claw-like seta which is 1.8 times as long as terminal segment, one aesthetasc (ya) of the same L as terminal segment, and two pappose setae, of which one is half as long as other. L ratio of five distal segments equaling: 1.4: 1: 1.3: 1.3: 1.3. Rome and Wouters organs not present.

A2 ( Figure 19 View FIGURE 19 D). Basal segment with one seta. Protopod with one, distally pappose seta exceeding distal margin of fourth endopodal segment, same segment with spines dorsally. Exopod consisting of plate carrying one long (almost reaching distal end of first endopodal segment) and two short, pappose setae. Endopod 4-segmented, penultimate segment divided with two male sexual bristles. First endopodal segment with one relatively long aesthetasc “Y” and antero-ventrally with two setae (one very long, other short). Second segment with two mediodorsal setae (one being “t4” seta); setae t3 and t2 transformed into sexual bristles (exceeding distal end of terminal segment) and one antero-ventral seta (t1). Same segment medio-ventrally with short aesthetasc y1, y2 also short. Third endopodal segment with claws G1, G2, z1 and z2, and setae G3 and z3. Claw G1 short (50% of first endopodal segment): G2 long (1.2 times longer than first endopodal segment); z1 much shorter than z2 and later as long as G2. G3 and z3 thin setae and half as long as G1 claw. Terminal segment with one long claw, Gm (approximately as long as first endopodal segment) and one short claw, GM (1.5 times shorter than Gm). Terminal segment also armed with aesthetasc y3 (as long as terminal segment) and one thin seta accompanying y3.

Md ( Figure 19 View FIGURE 19 A). First segment of palp with one plumose seta (S1), one pappose, short seta (S2), a 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 plumose setae originating from a small plate, one plumose shorter seta and beta seta. Penultimate segment dorsally with two almost equally long setae, gamma seta pappose, and four additional setae of which one originates medially and three ventrally. Terminal segment elongated with one strong, central claw and one seta on each side. Width: L ratio of terminal segment equaling 1: 6.

Mxl ( Figure 17 View FIGURE 17 E). Palp 2-segmentd, first segment dilated and 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.

Prehensile palps ( Figure 17 View FIGURE 17 G, H). Palps strongly asymmetrical, right one with more curved dorsal margin, and curved finger, while left one with more straight dorsal margin and straight finger. Subterminal structures more developed on right palp.

L6 ( Figure 18 View FIGURE 18 C). Basal segment with one seta (d1). Endopod 4-segmented (on one leg penultimate segment distally subdivided, creating a 5-segmented endopod). 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 as long as combined L of three distal segments.

L7 ( Figure 18 View FIGURE 18 E). Basal segment with “d1”, “d2” and “dp” setae. Endopod 4-segmented, with all setae present. Terminal segment armed with two long and one short seta. L ratios between three “h” setae equaling: 1: 1.7: 2.4. UR ( Figure 18 View FIGURE 18 A). Symmetrical, missing posterior seta and with strong denticles along posterior margin. Both claws strongly serrated. Posterior claw shorter than anterior one and with prominent teeth medially, while these teeth on anterior claw less pronounced. L ratio between anterior margin, anterior claw and posterior claw equaling: 2.8: 1.3: 1. Attachment ( Figure 17 View FIGURE 17 B) with one dorsal and one ventral branch.

Hemipenis ( Figure 17 View FIGURE 17 F). Lobe “a” triangular but with rounded tip. Other lobes low. Inner duct coiled.

Zenker organ with seven rows of spines.

Female. Slightly smaller than males ( Figure 16 View FIGURE 16 A, B), L= 0.71 mm, otherwise very similar to male, except that dorsal margin posteriorly less wide.

A2 ( Figure 19 View FIGURE 19 B). Endopod 3-segmented. Three “t” setae on penultimate segment present, and second endopodal segment postero-medially with two setae. Seta “z1” transformed into claws, slightly longer than terminal segment. Claws G1–G3 equally long. Terminal segment with long claw GM and short Gm. All claws gently serrated.

L5. Three setae present in exopod.

UR ( Figure 19 View FIGURE 19 C) Similar to male, symmetrical. L ratios between anterior margin, anterior, and posterior claws equaling: 2.2: 1.4: 1. Medial teeth on anterior claw more developed than in males.

Genital field ( Figure 19 View FIGURE 19 C). Rounded and without projections.

All other appendages same as in male.

Remarks and affinities. This species was originally described from a marsh in Canton, China. Brehm (1923) provided only a couple of drawings and a brief description. Based on this, it was difficult to give it a proper generic position, and consequently it was omitted from the key to the genus provided by Karanovic & Marmonier (2002) and Karanovic (2012). This species is also mentioned by Lee et al. (2000) as C. cf. transgrediens collected from around Ulsan, Korea. The authors, however, provide no other details of their record. The species collected for this study is here identified as Candonopsis transgrediens based on a very peculiar ornament on the posterior margin of the UR, i.e. a row of relatively thick teeth. This feature is indeed illustrated by Brehm (1923), but its relevance and correctness was unclear, because all other drawings provided in the same paper are of a low quality. With our Korean material, we can now establish this specific ornament of the UR as a unique feature of C. transgrediens , distinguishing it from all other representatives of the genus. Candonopsis transgrediens belongs to the nominal subgenus because it has a basal seta on the L6 (see Karanovic 2004). It is very closely related to the group of species where the posterior claw on the UR carries a distinctive spine, a grouping that was proposed by Klie (1932). Namely, this author divided the genus into three species groups: 1. both claws carry one prominent spine; 2. both claws without a spine; 3. only the posterior claw has a prominent spine. In Klie's time groups even had separate geographic distribution, i.e. species from the first and the last groups were known only from Africa and Australia, while species from the second group were restricted to Europe and the Americas. Along with the discovery of more species and genera within the tribe Candonopsini ( Karanovic & Marmonier 2002; Karanovic 2004, 2007, 2008), Klie's biogeographic delimitation of species groups could no longer be sustained.

The redescription of Candonopsis transgrediens provides an opportunity to place this species into the key to the Candonopsis (Candonopsis) species of the world. This key is modified after Karanovic (2012).