Namiotkocypria haysensis, Külköylüoğlu, 2018

Külköylüoğlu, Okan, 2018, A new genus and species in the ostracod family Candonidae (Crustacea: Ostracoda) from Texas, USA, Journal of Natural History 52 (19 - 20), pp. 1295-1310 : 1303-1305

Namiotkocypria haysensis sp. nov.

( Figures 2–6 )

Diagnosis

Similar to the genus.

Description of male. A medium-sized ostracod, with subrectangular to trapezoidal specimens (mean L = 0.69 mm, H = 0.37 mm, W = 0.34 mm; n = 5). Carapace surface smooth ( Figure 2a–h ) with normal pore canals ( Figure 3e,f ). LV overlaps RV at both ends. Greatest H near the centre of the valves. Marginal ends of carapace smooth, tubercles absent. Both valves flat to slightly concavedorsally with a pronounced slope posteriorly.

In dorsal view, carapace list slightly convex, posterior end being slightly more beak shaped than anterior. LV with lobe-like expansion covering RV in both sides. Internally, LV bears a tooth-like node antero-ventrally. This node is absent in RV. Inner lamella medium in size at both ends, posterior being slightly broader than anterior margin. Outer lamella wide (ca. 80% of valve). Four central muscle scars are clearly seen in the centre. Colour of valves opaque white.

A1 ( Figure 4a ): Seven-segmented. On the first segment, two well developed setae ventrally and one dorso-medial seta extending to end of third segment. All three setae slightly plumose at their base. Second segment wider than long, with a very short Romeorgan in ventral margin. One dorsal-apical seta smooth, about the size of second segment. Third segment with a short dorsal-apical smooth seta. Fourth segment with two unequally long smooth dorsal-apical setae and one ventral-apical seta reaching about to midpoint of terminal segment. Fifth segment with four setae: two sub-equally long smooth setae on dorsal-apical side about 6 times longer than terminal segment, and two unequally long setae on ventral-apical corner, shorter seta on ventro-apical margin about the size of ya seta slightly extending terminal segment, the long seta 6 times longer than the terminal segment. Penultimate (sixth) segment with four unequally long setae. One antero-distal seta slightly plumose, others smooth. Terminal segment with two unequally long setae plus ya seta about 2 times longer than the terminal segment, extending to about the length of the first third of the other setae.

A2 ( Figure 4b ): Five-segmented. Basal segment without setae. Exopodial plate with one long and two very short setae. First endopodal segment with aesthetasc Y placed medioposteriorly near middle of segment. On the same segment, one very long posteroproximal smooth seta extends to tips of terminal claws. There are 5 + 1 short natatory setae present (diagnostic character). First five equally long setae are about the size of the segment, sixth seta about one-third length of other setae. One well-developed, plumose seta almost reaching to the tips of terminal claws postero-distally. Penultimate segment divided into two (3 rd and 4 th) segments. t2 and t3 transformed into male bristles on the third segment; t3 curved but t2 almost straight, extending slightly beyond terminal segment. t1 and t4 setae not well seen. Three almost equally long setae present anterodorsally; one of them robust, smooth and claw-like, two others thiner. Two other setae present postero-distally; one medium-sized seta reaching behind terminal segment and y1 seta short, about ¼ length of medium-sized seta. Penultimate segment distally with G1 and G2 claws; G1 claw about half as long as G2. G3 claw seta-like and short. All three z -setae (z1–z3) well developed, z4 seta short, about as long as terminal segment; z1 almost claw-like about half as long as others. z2 and z3 setae reaching to the tips of claws. GM and Gm claws present on terminal segment, Gm very short (about the size of the terminal segment), GM about as long as G2 claw. Seta y2 not seen, seta y3 shorter than terminal segment. All claws smooth.

Md ( Figure 5a,b ): with a slender Md-coxa ending with 12 (five well-developed) coxal teeth and one slightly plumose, medium-sized seta dorsally. Md palp four-segmented; first segment with three almost equally long setae (S1–S2 setae plumose, another seta smooth), reaching about to tips of terminal claws, alpha seta very thin. Vibratory plate with seven almost equally long pappose setae. Second segment externally with two smooth setae about the size of penultimate segment, three plumose setae and one smooth seta present internally almost reaching tips of terminal claws, and one beta seta short, swollen. Penultimate segment with three smooth extero-lateral setae extending slightly past terminal segment and four (3 + 1 gamma) unevenly long and smooth setae intero-distally (external-most seta longest, extending slightly past terminal segment, while others are short, barely reaching midway point of terminal segment). Terminal segment with three strong claws, the middle one plumose and slightly longer than the other two. None of the claws is fused with terminal segment. Terminal segment 2 times longer than wide.

Mxl ( Figure 5c ): with three endites and Mxl palp; first and second endites each with six short setae, third endite with two plumose bristles and three short setae. Base of first endite with one short, slightly robust seta about half as long as the endite. First segment of the palp with four setae anteriorly and one shorter smoth seta postero-distally. Second (terminal) segment square in shape, with three smooth claws and one short seta. Vibratory plate with 14 plumose long setae (not drawn).

Rake-like organ ( Figure 6c ): with about 10 + 2 very small teeth.

T1 ( Figure 5d,e ): asymmetric left and right palps with well-developed pointing finger. Right prehensile palp robust, wider than left palp, finger curved and horn-shaped, ending with a short claw-like process, lower part of trunk ending with a sharp pointing process. Left palp with hook-shaped, curved finger. Vibratory plate with five well developed plumose setae about as long as palp. Two short, unequal a and one equally long b and d setae present, c seta not seen. Masticatory process with 12 plumose setae.

T2 ( Figure 5g ): Five-segmented without d1 basal seta. e seta absent or rudimentary (see Discussion below). f seta short, extending about one-third the length of the third segment. Penultimate segment antero-apically with one very small g seta (see Discussion below). Terminal segment with one short h3 and one long smooth claw h2 about as long as last four segments.

T3 ( Figure 6a ): Four-segmented. First segment with three (d1, d2 and dp) setae, dp seta slightly plumose and longer than both d1 and d2 setae, extending to the next segment. Seta e absent, seta g absent or rudimentary (see Discussion below), and f seta short and smooth. Terminal segment subrectangular, about 2 times longer than wide with three setae (length: h3> h1> h2). h3 seta slightly plumose, long exceeding the length of all four segments. L ratios of h1–3 setae are 2.0:1.2:10.

UR ( Figure 6b ): Normally developed with two serrated claws and two smooth (anterior and posterior) setae present, posterior seta slightly shorter than anterior seta, about 1/3 the length of posterior claw. UR attachment simple with one ventral branch.

Hemipenis ( Figure 6e ): Lobe a longer than lobe b. Both lobes almost distally rounded. Spermatozoa with typical coiled.

Zenker organ ( Figure 6d ): with 5 + 2 whorls of spines, ending with 12 corrugated opening.

Etymology. The species is named by adding the suffix -ensis to the type locality (Hays county).

Accompanying species. Two new species of Candoninae ( Külköylüoğlu et al. 2017a, 2017b) were also collected from the same locality.

Description of female. Female similar in shape and size (mean L = 0.68 mm, H = 0.36 mm, W = 0.32 mm; n = 6) to male. A2 ( Figure 4c ) four-segmented. Third segment undivided. Six swimming setae on the first endopodial A2 segment, slightly shorter than on male. Two equally long antero-medial setae smooth, reaching the end of the segment. t1 seta present postero-medially, barely extending to tips of terminal segment. y1 seta short, about ¼ the length of t1 seta. y2 seta not seen. Seta z1 similar to male but z2 and z3 setae are normally developed and shorter, about half the length of male setae. G claws of A2 weakly serrated and with lengths GM ≈ G1> G3> G2 ≈ Gm. First thoracopod (T1) normally developed, with five well-developed plumose setae on the vibratory plate and with two short unequally long a seta. Seta b shorter than seta d. Palp of T1 ending with three very short h-setae (h2> h1 ≈ h3) ( Figure 5f ). Masticatory process of T1 ending with about 12–13 setae. Genital field without appendages as is the typical shape of the family ( Figure 6f ) All other parts are similar to those of the holotype male.

Figures

Figure 2. Namiotkocypria haysensis sp. nov. (a) LV external and (b) LV internal view. (c) RV external, (d) RV internal view (note broken part); (e) RV external view of posterior and (f) anterior ends. (g–h) Internal view of posterior ends of LV and RV. a, c, e, f: male; b, d, g, h: female. Scale bars: a–f = 100 µm; g–h = 50 µm; arrows indicate anterior end.

Figure 3. Namiotkocypria haysensis sp. nov. (a) Dorsal view of carapace. (b) Anterior and (c) posterior ends from dorsal view. (d) Central muscle scars from internal view. (e) External and (f) internal view of pore openings with and without sensory seta, respectively. a–c, e, male; d, f, female. Scale bars: a– c = 100 µm; d = 50 µm; e = 1 µm; f = 5 µm. Arrow indicates anterior end.

Figure 4. Namiotkocypria haysensis sp. nov. (a) A1; (b) A2; (c) A2. a–b, male; c, female. Scale bar: 10 µm.

Figure 5. Namiotkocypria haysensis sp. nov. (a) Md; (b) Md coxa; (c) Mxl; (d) right clasping organ (T1); (e) left clasping organ (T1); (f) T1; (g) T2. a–e, g, male: f, female. Scale bar: 10 µm.

Figure 6. Namiotkocypria haysensis sp. nov. (a) T3; (B) UR; (c) rake-like organ; (d) Zenker; (e) Hemipenis. a-e, male: (f), female genital organ. Scale bar: 10 µm.