Tonnacypris lutaria ( Koch, 1838 )

Meeren, Thijs Van Der, Khand, Yondon & Martens, Koen, 2009, On Recent species of To n n a c y p r i s Diebel & Pietrzeniuk, 1975 (Crustacea, Ostracoda), with new species descriptions from Mongolia, Zootaxa 2015, pp. 1-41 : 30-33

Tonnacypris lutaria ( Koch, 1838)

( Figs. 19 , 20 , 21 )

Cypris lutaria Koch, 1838

Eucypris lutaria (Koch) Müller, 1912 (p. 171; fig. 51) Prionocypris lutaria (Koch) Sars, 1925 (p. 130; fig. 60.1) Eucypris lutaria (Koch) Bronshtein 1947 (p. 124; fig. 52) Tonnacypris lutaria (Koch) Diebel & Pietrzeniuk, 1975 (p. 88) Tonnacypris lutaria (Koch) Martens et al. 1992 (p. 104; fig. 6D–H)

Material examined. Two males and one female from the sexual Spanish material from T. lutaria . SEM images are presented for OC.3025, 3029 and drawings of soft parts are included for OC.3025, 3003. Two females of parthenogenetic Mongolian material from T. cf. lutaria . SEM images are included for OC.3005, 3010.

Diagnosis. Relatively large species (females> 2 mm, up to 3.2 mm); dorsal margin usually weakly arching; calcified part of the inner lamella anteriorly narrow, only slightly wider than posteriorly; peg on the anteroventral side of this lamella variably expressed; inner list absent; natatory setae on A2 short, third setae usually longest, with tip reaching the proximal side of the terminal segment; tooth bristles on third endite of Mx serrated; terminal segment of the right palp of male T1 rounded triangular, without indentation, inner curve of the basal part of this left palp with 90° angle.

Redescription of male. Valves in inner view ( Fig. 19 A, B) with greatest height situated just anteriorly of midlength, dorsal margin arching, posterodorsal angle indistinct; calcified part of the inner lamella anteriorly less than twice as wide as posteriorly, posteroventral almost as wide as posteriorly, narrowing towards the inconspicuous ventral indentation; anteroventral part of the calcified inner lamella of LV with a variably expressed peg.

Wouters organ not seen on A1. Rome organ small; terminal segment with two long setae and one short claw, and one small and slender Y-aesthetasc.

A2 ( Fig. 20 A) with z1 and z2 long, subequal claws, z3 a long seta, G1 a small claw (about two times the length of the terminal segment), G2 the longest claw and G3 a small seta (subequal to G1); terminal segment with long claw GM, shorter claw Gm, seta g and aesthetasc y3, with seta fused at the base of this aesthetasc; last two segments apically with protruding reinforcements surrounding the socket of the largest claws.

Mdpalp with smooth α-seta; a group of four smooth setae and one barbed seta associated with slightly serrated β-seta; and a longer, slightly more stout and serrated γ-seta.

Mx1 with seven (5+2) setae on the first segment of the palp; terminal segment of this palp spatulate; tooth bristles on third endite serrated; sideways directed bristles serrated.

T1 with two a-setae, and single b, d and c-seta; respiratory plate with six filaments; endopodite developed as asymmetrical, two-jointed clasping organ: penultimate segment of the right palp bearing two peg-like sensory organs, this segment of the left palp with three large such organs, terminal segment of the right clasping palp ( Fig. 20 E) triangular, the left clasping palp ( Fig. 20 D) with a 90° proximal angle at the inner side, and somewhat serrated along the frontal side; both terminal segments bearing another sensory organ distally.

T2 with seta d1 about half as long as seta d2; teeth on terminal claw quite large.

CR ( Fig. 20 F) with proximal seta proximally somewhat enforced; distal seta relatively short; ramus set with about six groups of setulae along the posterior margin.

Hemipenis ( Fig. 20 G) with outer lobe slender, not curving, distally slightly widening and terminally bluntly rounded, slightly shorter than the inner lobe; the latter broadly rounded and with a serration on the inner side of this lobe; labyrinth of the internal spermiduct with distinctly recurving loop ‘e’.

Zenker’s organ muscular with numerous (about 46) internal spines ( Fig. 20 C).

Additional description of female. See Meisch (2000), and references therein. Fig. 13 C shows the detail of the apical chaetotaxy of the CR.

Measurements. Male: L = 1.99 mm, H = 999 µm. Female: L = 2.35 mm, H = 1.18 mm

Differential diagnosis

The species can be distinguished from:

Tonnacypris estonica by its short claw G2 on A2, group of four setae next to β seta on Md palp, serrated tooth bristles on the third endite of Mx, seven setae on the first segment of Mx palp and slender proximal setae on CR.

Tonnacypris tonnensis by its more rounded posterior margin, single anterior peg on calcified lamella LV, long γ seta on Md palp and serrated tooth bristles on the third endite of Mx palp.

Tonnacypris edlundi n. sp. by its single anterior peg on calcified lamella LV, short claw G2 on A2, short natatory setae on A2, group of four setae next to β seta on Md palp, serrated tooth bristles on the third endite of Mx, seven setae on the first segment of Mx palp, straight outer lobe of the hemipenis and rounded triangular shape of terminal segment right clasping palp of the male.

Tonnacypris mazepovae n. sp. by its single peg on the calcified lamella of LV and lack of distinct indentation at the basis of the terminal segment of the right clasping palp of the male.

Tonnacypris glacialis by its bigger size and rectangular angle on the inner curve of the terminal segment of the left clasping palp of the male.

Remarks

Variability for this species is relatively well known from western Europe. Meisch (2000) reported a length range of 2.1–2.7 mm for females in western and central Europe, and up to 3.2 mm in northern Africa. Akatova (1950) reported a male with length of 1.68 mm and heigth of 840 µm. Because of differences in the hemipenis morphology between Akatova’s material and this new Spanish material (see discussion), we presently refer to the former as T. cf. lutaria . Martens et al. (1992: fig. 6D–H) provided SEM pictures for female specimens from Israel. Compared with the Spanish material here decribed, quite substantial differences are present in valve characters. In specimens from Israel, the anterior margin of the valves is more roundly curved, the posterodorsal margin is slightly higher, the posteroventral angle is also more widely curving and the ventral margin is more concave. Our Mongolian parthenogenetic material compares more favorably with this material from Israel, but has some differences as well. The valves are less elongated, the posterodorsal angle is more pronounced and the ventral margin is again less concave. Because of these differences, and because we did not find males to confirm identification, we tentatively refer to our new, parthenogenetic, Mongolian material as T. cf. lutaria .

Figures

FIGURE 13. Tonnacypris edlundi n. sp. Ψ A) Md (plate) B) Mx 1, with indication of number of setae on the first segment of the palp, endites incompletely drawn; C) T 1, with indication of setae a, b, c, d; D) T 2, with indication of setae d 1 and d 2; E) T 3; F) T 3, detail of apical structures (Pincer’s organ); G) CR; H) attachment of CR. Scale: A, D, E, G, H = 200 µm; B = 100 µm; C = 141 µm; F = 40 µm. (OC. 2992)

FIGURE 19. Tonnacypris lutaria ♂ (A, B) and Ψ (C, D) and Tonnacypris cf. lutaria Ψ (E, F) A) RV, iv (OC. 3025); B) LV, iv (OC. 3025); C) RV, iv (OC. 3029); D) LV, iv (OC. 3029); E) RV, iv (OC. 3005); F) LV, iv (OC. 3005). Scale: 500 µm.

FIGURE 20. Tonnacypris lutaria ♂ A) A 2, with indication of aesthetascs Y, y 1, y 2, y 3 and claws z 1, z 2, G 1, G 2, GM, Gm and setae z 3, G 3, g; B) T 2, with indication of setae d 1 and d 2; C) Zenker’s organ; D) T 1, left clasping palp; E) T 1, right clasping palp; F) CR and attachment; G) Hemipenis, with indication of internal structures. Scale: A, C – F = 200 µm; B = 260 µm; G = 400 µm. (OC. 3025)

FIGURE 21. Length-height plot for Tonnacypris species in this study.