Cyclocypris dalyana, Külköylüoğlu & Hutchins & Yavuzatmaca & Schwartz, 2021

Külköylüoğlu, Okan, Hutchins, Benjamin T., Yavuzatmaca, Mehmet & Schwartz, Benjamin F., 2021, Hyporheic ostracods (Crustacea, Ostracoda) from Texas (USA) with six new species, Zootaxa 5046 (1), pp. 1-63 : 37-46

Cyclocypris dalyana n. sp.

( Figs 23–27 )

Type locality. San Marcos River at Scull Road, Guadalupe Basin, Guadalupe County, Texas, USA (Lat: 29,849432, Long: -97,856785), Elevation ~ 154 m ASL.

Etymology. This species is named in honor of Dr. Marie Maynard Daly (1921-2003). In 1947 she became the first African American woman in the USA to earn a Ph.D. in chemistry. During a long career of teaching and re- search, she worked hard to increase representation of women and minorities in science. We hope that naming this species in her honor might inspire those who may otherwise be discouraged from doing so to study and appreciate the natural sciences. Gender feminine.

Material examined. Holotype. One male dissected in lactophenol solution with soft body parts slide mounted and sealed with translucent nail polish (no: OK-TX-SM-160901 H3-1); valve kept in micropalaeontological slide (no: OK-TX-SM-160901 H3-2). Collected from type locality on 16 September 2016 by Benjamin T. Hutchins and Aaron Swink.

Allotype. One female from the type locality (no: OK-TX-SM-160901 H3-3). Collected by Benjamin T. Hutchins and Aaron Swink.

Dissected paratypes. One male (no: OK-TX-SM-160901 H3-4) and one female (no: OK-TX-SM-160901 H3- 5) dissected in lactophenol solution with soft body parts slide mounted and sealed with translucent nail polish. Collected from type locality by Benjamin T. Hutchins and Aaron Swink. One male (no: OK-TX-SM-Bosgue-H1) and one juvenile dissected in lactophenol solution with soft body parts, collected from upstream end of riffles at Bosque River, Brazos Basin , Texas .

Non-dissected paratypes. Five males and five females, and one valve kept in 70% ethanol. Collected from type locality by Benjamin T. Hutchins and Aaron Swink.

Repository. The holotype and paratypes are stored at the Limnology Laboratory of the Biology Department, Bolu Abant İzzet Baysal University, Bolu, Turkey .

Description: Measurements (in µm). Male (n=6): LV: 457–500 (mean = 482), RV: L=455–498 (mean = 478); H: 272–290 (mean =282); W=294. Female (n=6): LV: 456–500 (mean = 478), RV: L=455–490 (mean = 472); H: 272–288 (mean =280); W=292.

Carapace ( Figs. 23–24 ) small and rounded. LV overlapping RV. Carapace surface smooth and with shallow pits in dorsal-ventral area of carapace center. Males slightly larger than females or similar in size ( Figs. 23A–D ). Anterior and posterior margins of both valves without tubercles. Dorsal margin slightly ovoid, sloping posteriorly. Greatest height near center. Pore openings simple, with seta. Carapace ovoid, with greatest width near midlength in dorsal view ( Fig. 23E ). Ventral margin straight ( Fig. 23F ). Calcified inner lamella wider anteriorly than posteriorly in internal view ( Figs. 24A–D ). Inner list with anterior margin wider in RV than LV, with diamond-shaped ornamentations in wide area. Four central muscle scars present slightly below center ( Fig. 24E ). Color opaque to light brown.

A1 ( Fig. 25A ): Seven-segmented. First segment with two long smooth ventral setae extending to end of terminal segment and medium size smooth dorsal seta. Second segment almost square, without seta. Rome and Wouters organs absent. Third segment with one long dorso-apical smooth seta. Fourth and fifth segments each with two long dorso-apical and one ventro-apical setae. Penultimate segment with two short dorso-apical setae and one ventro-apical seta. Terminal segment with two very long setae and aesthetasc ya longer than last four segments.

A2 ( Fig. 25B ): Five-segmented. Exopodial plate with two very short setae and one long smooth seta about as long as next segment. Second segment with one long smooth posterior seta and plumose aesthetasc Y about ¾ length of segment. Natatory setae on third segment reduced, not reaching penultimate segment. One dorso-apical and ventro-apical setae present on third segment, both smooth. Penultimate segment subdivided, y1 and y2 aesthetasc not apparent, t-setae and z setae (z1–3) reduced or absent. G1 claw short spine-like, about 1/3 as long as G2 and G3 claws. Terminal segment with aesthetasc y3 shorter than Gm claw. All three claws longer than length of last four segments combined.

Md-palp ( Fig. 25C ): Md-palp four-segmented, well-developed Md-coxa with 6–7 teeth and one dorsal and one ventral smooth seta. First segment with one plumose S1 seta, S2 seta absent, one smooth thin seta slightly shorter than S1, alpha seta short and slender. Vibratory plate with six plumose short setae. Second segment with a group of four plumose unequally long setae, beta seta cone-shaped and stout and slightly hirsute, two smooth, unequally long dorsal setae. Penultimate segment with three unequally long smooth dorsal setae (middle one claw-like), with gamma seta smooth and spine-like (slightly longer than terminal segment), with three apical setae, and with two ventro-apical setae (one longer than terminal segment, one very short and smooth). Terminal segment rectangular, two times longer than wide, with three claw-like (tips plumose) and one smooth setae.

Mx1 ( Fig. 26A ) with three endites and two-segmented Mx1-palp. First and second endites each with five short setae. Third endite with one claw-like bristle and four short setae. Vibratory plate with 18–19 long setae (not shown). First palp with three unequally long outer apical setae and one short almost sub-apical seta. Terminal palp squarish (height shorter than width), with four equally long claw-like smooth setae.

T1 ( Figs. 26B, C ): Transformed into prehensile palps. Setae a, b and d present. Two very short and one stout and long a-setae present (diagnostic character), c seta not apparent. Vibratory plate with five unequally plumose setae. Right palp slightly wider distally than left palp, ending with terminal hook-like process and with one short apical spine.

T2 ( Fig. 26D ): Five-segmented. d1 seta medium in size, setae d2 and dp absent. Setae e, f and g present with lengths: e> f> g. Terminal segment subrectangular, with two equally long short h1 and h3 setae, h2 seta long clawlike.

T3 ( Fig. 26E ): Four-segmented. First segment with three basal segments (d1, d2, dp). Setae e, f and g present with lengths: e ≈ f> g. Terminal segment long, rectangular in shape, with reflexed h3 seta and two shorter (h1 and h2) setae.

Rake-like organ ( Fig. 26F ): ventrally branched, with thin teeth.

Uropod ( Fig. 26G ): with relatively robust ramus, claws well-developed and serrated. Anterior seta (Sa) slightly shorter than claws. Posterior seta very short. Caudal attachment with two ventral branches.

Zenker’s organ ( Fig. 27A ): seven rows (5 + 2) of spines.

Hemipenis ( Fig. 27B ): Outer lobe quadrate/truncate distally. Inner lobe wide and rounded.

Female description: Carapace similar to male. A2 four-segmented, with short seta-like G2 claw about 1/3 of G1 and G3 claws ( Fig. 27C ). T1 with three unequally long and smooth apical setae with lengths: h2>h1≈h2 ( Fig. 27D ). Genital organ simple, rounded (not drawn). All other soft body parts similar to male.

Accompanying ostracod species. See Appendix 2.

Differential diagnosis. LV overlapping RV. Carapace surface with few shallow pits from dorsal to ventral margins. First segment of A1 with two very long, ventral setae extending to end of terminal segment. Wouters and Rome organs absent in A1. A2 with very short natatory setae, y1 and y2 aesthetasc absent, t-setae and z setae (z1–3) reduced or absent. T1 with three a setae (one plumose and spine-like), male clasping organs asymmetrical. T2 with one d1 seta, d2 and dp setae absent. T3 with smooth e, f and g setae. First segment of Md with one plumose S1 seta, S2 seta absent. Second segment with four plumose setae. Mx1 with one bristle. Hemipenis with well-developed outer and inner lobes. Zenker’s organ with five medial and two apical rows of spines.

Remarks. Külköylüoğlu (2008) described the 13 th Cyclocypris species , C. vinyardi Külköylüoğlu , from a spring in Nevada, USA. Twenty-one nominal species of the genus Cyclocypris have previously been described worldwide ( Meisch et al. 2019) although Karanovic (2011) underscored several taxonomic problems in the subfamily Cyclocypridinae . Four species ( C. anacola Smith et al. , C. brevisetosa (Bronstein) , C. mediosetosa Meisch , C. diebeli Absolon ) have short natatory setae that do not extend beyond the terminal claws of A2 ( Smith et al. 2015). In C. mediosetosa and C. diebeli , natatory setae reach the tips of the terminal segment (longer than the penultimate segment), whereas in C. anacola and C. brevisetosa , these setae do not extend to the end of the penultimate segment. In C. anacola , the setae do not even reach the penultimate segment. The length of natatory setae in C. dalyana n. sp. is similar to C. anacola . However, there are several major differences between the two species: (1) While RV>LV in C. anacola, LV >RV in C. dalyana n. sp.; (2) a tiny Rome organ on A1 is present in the former species but not in the later; (3) G2 and Gm claws on A2 are shorter in C. dalyana n. sp. than in C. anacola ; (4) there are three a-setae on T 1 in C. dalyana n. sp. (one of them is spine-like) but two thin a-setae in C. anacola (three a-setae are present in C. ovum (Jurine) , but they are longer and plumose in the new species); (5) Md S1 and S2 setae are present in C. anacola but the S2 seta is absent in the new species; (6) Md gamma seta is strongly developed in C. dalyana n. sp., but this seta is thinner and shorter in C. anacola ; (7) there are four claw-like setae on the terminal segment of Md-palp in C. dalyana n. sp., but three in C. anacola ; (8) the outer lobe (lobe a) is narrow and the inner lobe (lobe b) is triangular in C. anacola while the outer lobe is truncate and the inner lobe is rounded in C. dalyana n. sp.

Species with LV>RV were provisionally assigned to the subgenus Laevicypris by Krstić (1995) while species with the opposite character state (RV>LV) were assigned to Cyclocypris . However, some authors (e.g., Matzke- Karasz 1995; Matzke-Karasz et al. 2004; Meisch et al. 2019) argue that these valve character states arose more than once during the diversification of the genus and are therefore not appropriate for assignment to phylogenetically meaningful subgenera. This implies that more characters are needed to define higher taxonomic (e.g., subgenus, genus, etc.) levels, but there are no rules about the appropriate number of characters used to define species or genera. Krstić (1995) proposed the Laevicypris subgenus for two species: C. diebeli and C. laevis (O. F. Müller) . However, there are seven other species ( C. klughi Meisch et al. , C. nahcotta Dobbin , C. scrobiculata Klie , C. sharpei Furtos , C. washingtoniensis Dobbin , C. wyomingensis Ferguson , and C. dalyana n. sp.) also with LV>RV, suggesting that the character is more common than thought by Krstić. Detailed taxonomic studies are needed to better elucidate systematic relationships within the genus.

Ecology: Species of the genus Cyclocypris have a wide geographical distribution ( Meisch et al. 2019) and are reported from a variety of aquatic habitats such as springs, creeks, lakes and relatively deep waters. We found C. dalyana n. sp. in the hyporheic zone at the edge of a stream where water temperature was 26.1°C, dissolved oxygen was 6.26 mg /L, pH was 8.22, and specific conductance was 549 µS/cm. The species lacks swimming setae on A2, so is not able to swim. Smith et al. (2015) reported C. anacola from seeps and crevices at natural and artificial cave entrances in Jeju Island ( South Korea). The authors did not provide additional ecological information about the type locality but indicated that the reduction of natatory setae did not suggest restriction to subterranean habitats since the species has eyes and dark coloration of the carapace. The species may use the cooler cave or groundwater habitats as a refuge. Similarly, C. dalyana n. sp. was found within the hyporheic zone where groundwater exchange occurs, but it was part of a community of both stygobionts and epigean species.

Figures

FIGURE 23. Cyclocypris dalyana n. sp. (A, B, E, F) Male, (C, D) Female, (A) RV and (B) LV external view, (C) RV and (D) LV external view, (E) dorsal view, (F) ventral view. Scale bar: 100 µm.

FIGURE 24. Cyclocypris dalyana n. sp. (A, B) Male, (C, D, E) Female, (A) LV and (B) RV internal view, (C) LV and (D) RV internal view, (E) normal pore openings with setae, (F) muscle scars. Scale bar: 100 µm for A–D, 50 µm for E and F.

FIGURE 25. Cyclocypris dalyana n. sp. Male. (A) A1, (B) A2, (C) Md. Scale bar: 55 µm.

FIGURE 26. Cyclocypris dalyana n. sp. Male. (A) Mx1, (B) Right clasping organ, (C) Left clasping organ, (D) T2 (note to curved H2), (E) T3, (F) Rake-like organ, (G) Ur. Scale bar: 55 µm.

FIGURE 27. Cyclocypris dalyana n. sp. Male. (A) Zenker’s organ, (B) Hemipenis (chitinous parts shaded). Female (C–D): (C) A2, (D) T1. Scale bar: 55 µm.