Tonnacypris Diebel & Pietrzeniuk 1975

Genus Tonnacypris Diebel & Pietrzeniuk, 1975 Tonnacypris Diebel & Pietrzeniuk, 1975 (p. 87) Tonnacypris Diebel & Pietrzeniuk (Martens et al. 1992; p. 104) Tonnacypris Diebel & Pietrzeniuk (Griffiths et al. 1998; p. 516) Tonnacypris Diebel & Pietrzeniuk (Meish 2000; p. 301) Type species. Tonnacypris loessica Diebel & Pietrzeniuk, 1975 Diagnosis. Carapace 1.1–3.2 mm long; valves smooth, without denticles (porenwarzen); elliptical to subovate in dorsal view, LV overlapping RV; valves elongated in lateral view, about twice as long as high, calcified inner lamella narrow to broad, selvage (if present) marginal; LV with small peg on anteroventral side of calcified part of inner lamella, associated with reduced or completely absent inner list; inner list absent in RV; natatory setae on A 2 usually (except T. edlundi n. sp.) short; terminal segment of Mx palp trapezoical; seta d 1 on T 2 usually shorter than seta d 2, sometimes subequal. Species included. Recent: Tonnacypris lutaria Koch, 1838, T. glacialis Sars, 1890, T. estonica Järvekülg, 1960, T. tonnensis Diebel & Pietrzeniuk, 1975, T. convexa Diebel & Pietrzeniuk, 1975, T. edlundi n. sp., T. mazepovae n. sp. and T. sp. A–C (Schornikov 2007). Fossil: T. loessica Diebel & Pietrzeniuk, 1975 (Weichselian, Germany, opt.cit.), T. turcica Freels, 1980 (Upper Middle-Miocene to lower Upper-Miocene, Turkey, opt.cit.), T. angulata Yang, 1985 (Recent, Tibet, Huang et al. 1985) and T. (?) sp. (Sub-Recent, China, Mischke et al. 2003). Species excluded. T. sp. sensu Mazepova (2006) is here transferred to the genus Eucypris Vávra, 1891 (based on illustrated characters from both valves and hemipenis). Remarks. The original description of the fossil (Weichselian) type species did not contain information about soft parts. Martens (1992) and Griffiths et al. (1998) added some of these characters to the generic diagnosis (from Tonnacypris lutaria and T. glacialis respectively). Here, we give a complete description for all limbs of T. estonica (as no soft parts are available for the type species), and we describe differences of other species in comparison with this full description. A differencial diagnosis is provided for described species, this is not included for T. convexa and T. sp. A–C, as no information on the soft parts of these species is available. Tonnacypris angulata seems to have an aberrant valve shape. Type material from this fossil Chinese species should be re-examined to evaluate the generic assignment. Tonnacypris estonica (Järvekülg, 1960) (Figs. 1, 2 A, 3, 4, 5 D, 6, 21) Ilyodromus estonicus Järvekülg, 1960 (p. 32; figs. 1–5) Ilyodromus estonicus (Järvekülg) Danielopol & McKenzie 1977 (p. 309; figs. 9 C–F, 10 F, 11 E) Tonnacypris estonicus [sic] (Järvekülg) Griffiths et al., 1998 (p. 523) Material examined. Many parthenogenetic females were recovered, mainly from spring habitats (Table 1). From the examined material, representative SEM images are presented for OC.2998, 3004, 3006 and drawings of soft parts are included for OC. 2998–3000. Diagnosis. Carapace small (L: 1.05–1.33 mm) and elongate; in lateral view, anterior margin broadly rounded, posterodorsal margin sloping towards indistinct posterdorsal angle, posteroventral angle evenly rounded; peg at the anteroventral side of the inner lamella of LV variably expressed. A 2 with natatory setae reduced, longest just reaching or barely exceeding the proximal side of the terminal segment; claw G 2 on A 2 only slightly shorter than G 1 and G 3. Mx 1 with tooth bristles on third endite smooth; posterior seta of the CR transformed into slender, feathered claw. Redescription of female. Carapace in lateral view (Fig. 1 A) with highest point located at about 3 / 8 of length; LV higher than RV, overlapping latter anteriorly, posteriorly and ventrally; anterior margin broadly rounded, posterodorsal margin sloping towards indistinct posterdorsal angle, posteroventral angle evenly rounded; ventral margin slightly concave. Carapace in dorsal view (Fig. 1 B) elongated and slender, maximum width at midlength and lateral surfaces subparallel for about one-third of length; roundly pointed at anterior end, bluntly pointed at posterior end; antero- and posterodorsal lobe-like expansions of the LV distinctly overlapping the RV hinge dorsally; valves in inner view (Fig. 1 C–F) with broad calcified inner lamella at the anterior and posterior ends, narrower ventrally; inner list reduced in LV, peg on calcified inner lamella variably expressed; few marginal pores, with simple setae and simple, straight radial pore canals (Fig. 2 A); colour of Cp green with white zones near eyes, central muscle scars and ovaria. A 1 (Fig. 3 A) with seven segments; first segment with two setae on ventral and one seta and minute Wouters organ on dorsal side; second segment with small Rome organ on ventral side and one seta on dorsal side; third segment with one seta on ventral and one seta on dorsal side; fourth and fifth segments with two setae on ventral and two on dorsal side; sixth segment with four long and one shorter seta; terminal segment with two long setae, one short, stout claw, and an even shorter aesthetasc Ya. A 2 (Fig. 3 B) with reduced exopod bearing two short and one longer seta; first segment of the endopod with aesthetasc Y on ventral side, on the apical side one large seta and six short natatory setae, the latter unequal in length, the first being the longest; second segment of the endopod with two setae at dorsal side, four t-setae and aesthetasc y 1 on ventral side, three z-setae, aethetasc y 2, and claws G 1, G 2 and G 3 on apical side, claw G 2 distinctly longer than terminal segment, about 0.70–0.95 the length of claw G 1; terminal segment with claws GM and Gm, seta g, and aesthetasc y 3 with a seta fused at the base of this aesthetasc; all terminal claws set with a row of small teeth. Masticatory process (Fig. 3 C) of Md with coxa elongated; Md-palp (Fig. 4 A) with four segments; first segment with respiratory plate on outer side and a group of four apical setae on inner side: one long seta, two “s”-setae with a double row of setulae, and one short smooth α-seta; second segment with group of three smooth setae on outer side, and a group of three smooth setae, one barbed seta, and one shorter, serrated β-seta on inner side; third segment with a group of four smooth setae on outer side, and five setae and one broader, long and serrated γ-seta on apical side; terminal segment apically with three claws and four setae. Mx 1 (Fig. 3 D) with three endites and a two-segmented palp; first segment of the palp with eight (5 + 3) setae; terminal segment spatulate, with three claws and three setae; first endite with serrate sideways-directed bristles; third endite with two smooth tooth bristles. T 1 (Fig. 4 B) protopodite with two a-setae, a single b- and d-seta, a relatively short c-seta on the basal part; masticatory process with 14 apical setae of different sizes and shapes; exopodite a respiratory plate with six plumose filaments; endopodite an unsegmented palp with three unequal apical setae. T 2 (Fig. 4 C) a six-segmented walking leg; length of seta d 1 (first segment) about 0.65–0.85 of length of seta d 2 (second segment); third and fourth segment each with one apical seta; fifth segment with two apical setae; sixth segment with two apical setae and a long claw, with cylindrical shaft and spinose blade. T 3 (Fig. 4 D, E) a four-segmented cleaning leg; first segment with long setae d 1, d 2 and dp; second segment with an apical seta e; third segment with medial seta f and distal rows of setulae associated with the pincer organ (modification of the terminal segment). CR (Fig. 4 F, G, Fig. 5 D) with proximal seta enforced, sparsely hirsute and distincly claw-like; two distal claws; slender, indistincly hirsute distal seta; posterior side of the ramus almost completely set with about eight indistinct groups of setulae, usually in single rows, the last two groups near the basis of the distal claws; attachment of the CR a simple, bifurcated branch. Measurements. Female: L = 1.05–1.33 mm (n = 15), H = 539–693 µm (n = 15), W = 438–499 µm (n = 2) Ecology. This is a crenophylic species, predominantly occurring in oligotrophic environments. Tonnacypris estonica seems to be indicative of good water quality in western Mongolian springs. High abundances have been recorded in shallow, slow-running spring water on silt or sandy substrate, with or without aquatic plants (Table 1). The species is also found in some streams and lakes, crawling on and in the sediment. Järvekülg (1960) reported adult females of this species all year round in coldwater springs (eurychronic). Temperature of the water in Mongolian localities: 3.5–16.8 °C, pH 6.9–9.1, conductivity 41–2670 µS/cm. Altitude: 905–2571 m in western Mongolia and around 80 m in northern Estonia. Males unknown. Distribution. Currently recorded only from Estonia and Mongolia, but is also mentioned in Polish (Sywula 1974) and Russian (Kurasov 1995) identification keys. The species is fairly common in springs along the Valley of the Great Lakes and in the northeastern part of the Mongolian Altai mountains (Table 1). Differential diagnosis. The species can be distinguished from: Tonnacypris tonnensis by its smaller size, inconspicuous posterodorsal angle, missing posterior peg on calcified lamella, longer G 2 claw on A 2, group of three setae next to β seta on Md palp, long γ seta on Md palp, eight setae on first segment of Mx palp and the claw-like proximal setae of CR. Tonnacypris edlundi n. sp. by its more elongated valves, single peg on the calcified inner lamella, short natatory setae, the claw-like proximal setae of CR. Tonnacypris mazepovae n. sp. by its smaller size, more elongated valves, broader anterior calcified inner lamella, missing posterior peg on calcified inner lamella, longer G 2 claw on A 2, group of three setae next to β seta on Md palp, eight setae on first segment of Mx palp, smooth tooth bristles on third endite Mx, and clawlike proximal setae of CR. Tonnacypris glacialis by its smaller size, longer G 2 claw on A 2, group of three setae next to β seta on Md palp, eight setae on first segment of Mx palp, smooth tooth bristles on third endite Mx and the claw-like proximal setae of CR. Tonnacypris lutaria by its smaller size, longer G 2 claw on A 2, group of three setae next to β seta on Md palp, eight setae on first segment of Mx palp, smooth tooth bristles on third endite Mx and the claw-like proximal setae of CR. Remarks. Järvekülg (1960) reported on the discovery of this species from northern Estonia. The similarity between the claw-like proximal setae of this species with the spinous proximal setae typical of Ilyodromus Sars, 1894 (now transfered to Psychrodromus, Danielopol & McKenzie 1977) made him classify the new species as such. Danielopol & McKenzie (1977), who took into account more characters of soft parts, suggested that this species could represent a new genus close to Eucypris, but it was later (Griffiths et al. 1998) transferred to the genus Tonnacypris. The absence of fossil material and the limited modern distribution of the species made the latter authors suggest a relative recent evolutionary origin. Tonnacypris estonica has a large morphological variability in both valves (Fig. 6, see also Fig. 1 C–F) and soft parts (Fig. 6). The ‘typical’ form (the most common form in western Mongolia, with valve shape most similar to the original description) has relatively low valve height, relatively short G 2 claw on A 2, and relatively short d 2 seta on T 2. The ‘high’ form has on average the highest valve height, relatively long G 2 claws on A 2 and long d setae on T 2. There are also some ‘intermediate’ forms, which have also relatively high valves, but relatively shorter G 2 claws on A 2 and d setae on T 2 than the ‘high’ form. The forms mentioned here are just morphological groups of individuals, more to illustrate the variability between different specimens and different characters than as an attempt to group some kind of related lineages. The morphological forms co-occur in different sites and habitats in western Mongolia, but the ‘high’ form has only been recorded at the most elevated, alpine sites. There is also considerable variation in the peg on the left valve: sometimes this is well expressed and obvious, sometimes hardly noticeable. Tonnacypris tonnensis (Diebel & Pietrzeniuk, 1975) (Fig. 2 B, 5 A, 7, 8, 9, 21) Amplocypris tonnensis Diebel & Pietrzeniuk, 1975 (p. 93; pl. 2: fig. 1–6) Tonnacypris tonnensis (Diebel & Pietrzeniuk) Schornikov, 2007 (p. 123; pl. 3: fig. 1) Material examined. Parthenogenetic females were recovered from several Mongolian waterbodies (Table 1). SEM images are presented for OC.3002, 3007, 3008 and drawings of soft parts are included for OC. 3001. Diagnosis. Large (> 2 mm) species; in lateral view with dorsal margin parallel with ventral margin for about two-fifth of total length, posterodorsal angle rounded but distinct and posterodorsal margin steeply sloping towards narrow, evenly rounded posteroventral angle; calcified inner lamella anteriorly broad, ventrally with more or less pronounced pegs both anterior and posterior to the indentation of the ventral margin; inner list absent. A 2 with natatory setae reduced, barely reaching the distal part of the penultimate segment; claw G 2 on A 2 short; Md-palp with γ-seta stout. Mx 1 with smooth tooth bristles on the third endite; length of seta d 1 on T 2 about 0.6–0.7 length of d 2. Description of the female. Carapace in lateral view (Fig. 7 A, B, D) with greatest height approximately in the middle; LV higher than RV, also overlapping the latter anteriorly, posteriorly and ventrally; anterior margin broadly rounded, dorsal margin parallel with ventral margin for about two-fifth of total length, posterodorsal angle rounded but distinct and posterodorsal margin steeply sloping towards narrow, evenly rounded posteroventral angle, ventral valve margin slightly curved inwardly; carapace in dorsal view (Fig. 7 C) elongated subovate with maximum width just posteriorly from midlength, slightly pointed at both ends, more roundly pointed anteriorly; valves in inner view (Fig. 7 A, B, D) with calcified inner lamella very broad at the anterior end (about one-sixth from total length); about half as broad at the posterior end, at the ventral side narrower; LV with two pegs on the ventral side of the calcified inner lamella; lists absent; marginal pores simple, with simple setae and simple, straight radial pore canals (Fig. 7 G, 2 B). Colour: whitish. A 1 (Fig. 8 A) with Wouters organ minute, Rome organ small; terminal segment with two long setae and one shorter claw, aesthetasc Ya subequal to the latter claw. A 2 (Fig. 8 B) with natatory setae short but unequal in length, the longest (usually second or third seta) just reaching the proximal edge of the terminal segment; claw G 2 distincly shorter than other terminal claws, usually about 1.2 times the length of the penultimate segment. Md-palp (Fig. 8 D) with smooth α-seta; serrated β-seta quite short and stout, associated with a group of four smooth setae and one barbed seta; serrated γ-seta stout. Mx 1 (Fig. 9 A) with seven (5 + 2) setae on the first segment of the palp; terminal segment of this palp slightly spatulate; tooth bristles on third endite smooth; sideways-directed bristles on first endite serrated; respiratory plate (Fig. 9 B) with 19 + 6 filaments. T 2 (Fig. 9 D) with length of seta d 1 about 0.65–0.70 the length of seta d 2. CR (Fig. 5 A, Fig. 9 G, H) with proximal seta slightly enforced, indistinctly hirsute; posterior side of the ramus almost completely set with about ten groups of setular fields. Measurements. L = 2.00– 2.15 mm (n = 5), H = 962 µm– 1.04 mm (n = 4), W = 880 µm (n = 1) Ecology. This species was found in two sites with a spring discharge zone and associated streams, one large lake (permanent), and one temporary pond, which was recently merged with the adjacent lake (Table 1). Water temperature of Mongolian localities: 3.5–12.5 °C, pH 7.8–9 and conductivity 282–479 µS/cm. Altitude: 1998–2426 m. Distribution. Living populations are currently only known from the northwestern part of the Mongolian Altaï mountains (Table 1), and from the Kirgizian Tien-Shan mountains (Schornikov 2007). Fossil Pleistocene material reported from Germany (Weichselian, Saalian, Elster; Diebel & Pietrzenik 1975; Griffiths 1995), France (Early Würm; Diebel & Pietrzenik 1975; Absolon 1976), Czech (Warthe; Absolon 1976) and the United Kingdom (Early Devesnian, Hoxnian; Green et al. 1983; Preece et al. 2006). Differential diagnosis. The species can be distinguished from: Tonnacypris estonica by its larger size, more conspicuous posterodorsal angle, steeply sloping posterior margin, anterior and posterior pegs on calcified inner lamella of LV, short G 2 claw on A 2, group of four setae next to β seta on Md palp, stout γ seta on Md palp, seven setae on the first segment of Mx palp and the slender proximal setae of CR. Tonnacypris edlundi n. sp. by its larger size, more elongated valves, more conspicuous posterodorsal angle, steeply sloping posterior margin, short claw G 2 on A 2, short natatory setae on A 2, group of four setae near β seta on Md palp, stout γ seta on Md palp and seven setae on the first segment of Mx palp. Tonnacypris mazepovae n. sp. by its more conspicuous posterodorsal angle, steeply sloping posterior margin, broader anterior calcified inner lamella, stout γ seta on Md palp and smooth tooth bristles on third endite Mx. Tonnacypris glacialis by its more conspicuous posterodorsal angle, steeply sloping posterior margin, anterior and posterior pegs on the calcified lamella of LV, conspiciuous posterodorsal angle, stout γ seta on Md palp and smooth tooth bristles on third endite Mx. Tonnacypris lutaria by its more conspicuous posterodorsal angle, steeply sloping posterior margin, anterior and posterior pegs on the calcified lamella of LV, conspicuous posterodorsal angle, stout γ seta on Md palp and smooth tooth bristles on third endite Mx. Remarks. This species was known as a fossil from Pleistocene sediments and was originally described in the genus Amplocypris Zalányi, 1944, because of the similarity with the elongated valves, pronounced posteroventral angle and occurence of a peg on the anteroventral calcified part of the inner lamella of the left valve in some species of this genus. When Recent specimens of Amplocypris tonnensis were discovered, the species was, based on similarities of soft parts, transferred to the genus Tonnacypris. We here present the first record from Mongolia, and the first description of the soft parts of this species.Published as part of 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, pp. 1-41 in Zootaxa 2015 on pages 4-16, DOI: 10.5281/zenodo.18593

Tonnacypris glacialis Sars 1890

Tonnacypris glacialis (Sars, 1890) (Fig. 18, 21, 22 D–F) Herpetocypris glacialis Sars, 1890 (p. 61; fig. 1) Eucypris glacialis (Sars) Vávra, 1891 Prionocypris glacialis (Sars) Brady & Norman, 1896 (figs. 50–68) Eucypris glacialis (Sars) Bronshstein, 1947 (p. 126; figs. 53, 54) Tonnacypris glacialis (Sars) Griffiths, 1995 (p. 523) Material examined. Three dissected females from Svaldbard. Valves were completely decalcified and hence destroyed during dissection. Drawings of soft parts are included for OC.3027, 3028. Additional description of female. For description and illustrations of valves, we refer to Griffiths et al. (1998). The material presented here was too decalcified to be able to give additional valve characters. A 2 (Fig. 18 A) with reduced natatory setae, third seta the longest and reaching the basis of the terminal segment; z 1 a short setae, z 2 and z 3 long setae, G 1 and G 3 long claws, G 2 a short claw (about 1.6 times the length of the terminal segment); terminal segment with a long claw GM, shorter claw Gm, seta g, and aesthetasc y 3, with seta fused at the base with this aesthetasc. Md palp with slender α-seta on the first segment, a strongly developed and serrated β-seta flanked by a group of four smooth seta on the second segment, and a long, serrated γ-seta on the penultimate segment (Fig. 18 C). Mx 1 with seven (5 + 2) setae on the first segment of the palp, tooth bristles on the third endite serrated. T 2 (Fig. 18 B) with seta d 1 reduced and seta d 2 of normal length. CR (Fig. 18 D) with proximal seta slightly hirsute, proximally slightly enforced; distal half of the posterior side of the ramus set with about six setular fields, these fields slightly wider than in the other species of the genus (2 or 3 parallel rows of setulae instead of 1 or 2). Measurements. Female: length = 1.56–1.68 mm (n = 3) Remarks. Griffiths et al. (1998) gave a whole range of measurements for Recent and Pleistocene populations. Most of these measurements of adult (sub-) Recent specimens fall in the range of 1.40–1.75 mm for the length and 710–900 µm for the height. They also suggested that the presence of this species indicates mean summer (June–August) temperatures of about 6 ° C. Bronshtein (1947) reports carapace lengths of up to 1.6 mm.Published as part of 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, pp. 1-41 in Zootaxa 2015 on pages 28-29, DOI: 10.5281/zenodo.18593

Tonnacypris lutaria Koch 1838

<i>Tonnacypris lutaria</i> (Koch, 1838) <p>(Figs. 19, 20, 21)</p> <p> <i>Cypris lutaria</i> Koch, 1838</p> <p> <i>Eucypris lutaria</i> (Koch) Müller, 1912 (p. 171; fig. 51) <i>Prionocypris lutaria</i> (Koch) Sars, 1925 (p. 130; fig. 60.1) <i>Eucypris lutaria</i> (Koch) Bronshtein 1947 (p. 124; fig. 52) <i>Tonnacypris lutaria</i> (Koch) Diebel & Pietrzeniuk, 1975 (p. 88) <i>Tonnacypris lutaria</i> (Koch) Martens <i>et al.</i> 1992 (p. 104; fig. 6D–H)</p> <p> <b>Material examined.</b> Two males and one female from the sexual Spanish material from <i>T. lutaria.</i> 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 <i>T.</i> cf. <i>lutaria</i>. SEM images are included for OC.3005, 3010.</p> <p> <b>Diagnosis.</b> 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.</p> <p> <b>Redescription of male.</b> 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.</p> <p>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.</p> <p>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.</p> <p>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.</p> <p>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.</p> <p>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.</p> <p>T2 with seta d1 about half as long as seta d2; teeth on terminal claw quite large.</p> <p>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.</p> <p>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’.</p> <p>Zenker’s organ muscular with numerous (about 46) internal spines (Fig. 20 C).</p> <p> <b>Additional description of female.</b> See Meisch (2000), and references therein. Fig. 13 C shows the detail of the apical chaetotaxy of the CR.</p> <p> <b>Measurements.</b> Male: L = 1.99 mm, H = 999 µm. Female: L = 2.35 mm, H = 1.18 mm</p> <p> <b>Differential diagnosis</b></p> <p>The species can be distinguished from:</p> <p> <i>Tonnacypris estonica</i> 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.</p> <p> <i>Tonnacypris tonnensis</i> 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.</p> <p> <i>Tonnacypris edlundi</i> <b>n. sp.</b> 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.</p> <p> <i>Tonnacypris mazepovae</i> <b>n. sp.</b> 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.</p> <p> <i>Tonnacypris glacialis</i> by its bigger size and rectangular angle on the inner curve of the terminal segment of the left clasping palp of the male.</p> <p> <b>Remarks</b></p> <p> 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 <i>T. cf. lutaria</i>. Martens <i>et al.</i> (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 <i>T.</i> cf. <i>lutaria</i>.</p>Published as part of <i>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, pp. 1-41 in Zootaxa 2015</i> on pages 30-33, DOI: <a href="http://zenodo.org/record/185936">10.5281/zenodo.185936</a&gt

Tonnacypris edlundi Meeren, Khand & Martens, 2009, n. sp.

<i>Tonnacypris edlundi</i> n. sp. <p>(Figs. 2 C, 5B, 10, 11, 12, 13, 21)</p> <p> <b>Type locality.</b> Grassy outflow stream from Bakhlagiin spring (49°10’46”N, 90°17’03”E). No water chemistry data is available for the type locality itself, but a nearby site (49°11’30”N, 90°14’14”E) at the source of the spring also contained this species: pH 7.9; conductivity 1222 µS/cm (corrected to 25°C); TDS 876 mg /L; T 6.3°C, DO 11.5 mg /L.</p> <p> <b>Type material.</b> Holotype: male (OC.2988), soft parts dissected in glycerin in a sealed slide, valves stored dry in a micropalaeontological slide. Dimensions: L = 1.25 mm, H = 677 µm.</p> <p>Allotype: female (OC.2989), dissected and stored in the same way as holotype. Dimensions: L = 1.32 mm, H = 687 µm.</p> <p>Paratypes: OC. 2990–2997 (most specimens dissected and used for SEM, some whole animals preserved in 70% EtOH).</p> <p> <b>Material examined.</b> Specimens were retrieved from several sites in western Mongolia (Table 1). SEM images are presented for OC. 2990, 2994, 2995 and drawings of soft parts are included for OC.2990, 2992.</p> <p> <b>Derivation of the name.</b> This species is named after Mark Edlund (Science Museum of Minnesota, Minneapolis), in recognition of his scientific contributions to the taxonomy and ecology of Mongolian diatoms.</p> <p> <b>Diagnosis.</b> Moderately large species (females up to 1.5 mm); anterior and posterior margins broadly rounded; inner lamella of the LV with one anteroventral and one posteroventral peg, anteroventral peg associated with a reduced inner list. A2 with long natatory setae, tips usually slightly exceeding the terminal claws. Mx1 with tooth bristles of the third masticatory endite smooth; terminal segment of the right clasping palp of the male stout and distinctly triangular.</p> <p> <b>Description of male.</b> Valves in lateral view with greatest height just anteriorly of midlength; LV overlapping RV ventrally; anterior margin broadly rounded, posterodorsal margin sloping, inconspicuous posterodorsal angle proceeding to widely curved and evenly rounded posterior margin; valves in dorsal view elongated subovate with greatest width at midlength; LV overlaps RV at both ends, which are slightly pointed; valves in inner view (Fig. 10 A, B) with ventral margin only slightly concave; dorsal margin sloping almost straight between highest point and posterodorsal angle; calcareous part of the inner lamella anteriorly broad, more than twice as broad as posteriorly, ventrally narrow; in LV posterdorsal angle slightly less pronounced and two pegs on the ventral side of the calified inner lamella, the anterior peg associated with reduced inner list; few marginal pores with simple, straight setae and simple, straight radial pore canals; false pore canals branching (Fig. 2 C); colour: whitish.</p> <p>A1 with Wouters organ small, protruding and lobe-like; Rome organ small; terminal segment with two long setae, one short claw, and one small, slender Y-aesthetasc.</p> <p>A2 (Fig. 11 A) with natatory setae just reaching or reaching slightly beyond distal end of terminal claws; apical chaetotaxy: z1 and z2 longest claws, z3 a long seta, G1 a small claw, G2 a long claw (slightly shorter than z1 and z2), G3 a small seta; terminal segment with long claw GM, shorter claw Gm, seta g, aesthetasc y3 with a seta fused at the base of this aesthetasc; last two segments apically with protruding reinforcements surrounding the socket of the largest claws.</p> <p>Md palp with short, smooth α-seta; a group of three smooth setae and one barbed seta associated with serrated β-seta, which is slightly longer than the α-seta; and equally long, slightly stouter, serrated γ-seta.</p> <p>Mx1 with eight (5+3) setae on the first segment of the palp; terminal segment of this palp spatulate; tooth bristles of third endite smooth; sideways-directed bristles serrated.</p> <p>T1 protopodite with at the basal part two a-setae, single b, c and d-seta, masticatory process with 14 setae; exopodite a respiratory plate with six plumose filaments; endopodite developed asymmetrical as twosegmented palp with clasping function: penultimate segment of the right palp stout, rectangular and bearing two peg-like, subequal sensory organs (Fig. 11 B), penultimate segment of the left clasping palp elongated, rectangular and bearing two smaller, unequal sensory organs (Fig. 11 C); terminal segment of the right clasping palp (Fig. 11 B) stout and distinctly triangular, of left clasping palp (Fig. 11 C) sickle-shaped and tapering towards distal end, both terminal segments have distally a sensory organ.</p> <p>T2 with length of seta d1 about 0.75–1.0 length of seta d2; teeth on terminal claw quite large.</p> <p>CR (Fig. 11 F) with proximal seta slightly hirsute, proximal slightly enforced; distal setae relatively long; posterior part of the ramus almost completely set with>10 fields of setulae.</p> <p>Hemipenis (Fig. 11 D) with outer lobe curved, distally tapering and bluntly pointed, reaching only slightly beyond the inner lobe; the latter broadly rounded; Zenker’s organ muscular with numerous internal spines (Fig. 11 E).</p> <p> A <b>dditional description of female.</b> Valves in lateral view (Fig. 10 C,D) as in the male, but larger in all dimensions; ventral indentation slightly less pronounced and posterodorsal angle slightly wider than in the male; carapace in dorsal view (Fig. 10 E) subovate and slightly pointed at anterior side, more evenly rounded at posterior side; pore canals straight and simple (Fig. 10 F), false pore canals branching (Fig. 2 C); colour: whitish.</p> <p>A1 (Fig. 12 A) as in male.</p> <p>A2 (Fig. 12 B) with natatory setae long, the longest usually reaching slightly beyond the proximal edge of the terminal segment; G1 and G3 long terminal claws, G2-claw slightly shorter, about four-fifth of the length of G1; z1-seta slightly shorter than G2, z2 and z3 setae subequal in length with G2.</p> <p>Mdpalp (Fig. 12 C) as in male.</p> <p>Mx1 (Fig. 13 B) as in male.</p> <p>T1 (Fig. 13 C) protopodite, masticatory process and exopodite as in male; endopodite an unsegmented palp with three unequal apical setae.</p> <p>T2 (female with slightly less developed teeth on terminal claw Fig. 13 D), T3 (Fig. 13 E, F) and CR (Fig. 13 G, H and Fig. 5 B) basically as described for the male.</p> <p> <b>Measurements.</b> Female: L = 1.30–1.52 mm (n = 5), H = 687–840 µm (n = 5), W = 670–678 µm (n = 2) Male: L = 1.20–1.31 mm (n = 4), H = 632–733 µm (n = 4)</p> <p> <b>Ecology.</b> This species was found in a spring and the associated stream outflow, in two streamlets also close to the spring discharge, and also in two wetlands associated with nearby streams (Table 1). With the natatory setae being unusually long for this genus, this species should be quite mobile, especially in flowing waters. Temperature of the water of the various habitats in which the species was found: 6.0–15.5°C, pH 7.5–7.9 and conductivity 500–1270 µS/cm. Altitude: 1057–1946 m. In the type locality, where also a lot of juveniles were found, sex ratio was close to 1:1 (14 ɗ and 12 Ψ recovered). The present populations of this species could thus have an obligatory sexual reproduction.</p> <p> <b>Differential diagnosis.</b></p> <p>The species is distinguished from:</p> <p> <i>Tonnacypris estonica</i> by its slightly higher valves, anterior and posterior pegs on the inner lamella of LV, long natatory setae on A2 and slender proximal setae of CR.</p> <p> <i>Tonnacypris tonnensis</i> by its smaller size, rounded posterior margin, long claw G2 on A2, long natatory setae on A2, group of three setae next to β seta on Md palp, long γ seta on Md palp and eight setae on the first segment of Mx palp.</p> <p> <i>Tonnacypris mazepovae</i> <b>n. sp.</b> by its smaller size, broader anterior calcified lamella, long claw G2 on A2, long natatory setae on A2, group of three setae next to β seta on Md palp, smooth tooth bristles on the third endite of Mx, eight setae on the first segment of Mx palp and stout, distinctly triangular terminal segment of the right clasping palp of the male, which lacks an indentation near the basis.</p> <p> <i>Tonnacypris glacialis</i> by its smaller size, anterior and posterior pegs on the calcified lamella of LV, long claw G2 on A2, long natatory setae on A2, group of three setae next to β seta on Md palp, smooth tooth bristles on the third endite of Mx, eight setae on the first segment of Mx palp and stout, distinctly triangular terminal segment of the right clasping palp of the male.</p> <p> <i>Tonnacypris lutaria</i> by its smaller size, anterior and posterior pegs on the calcified lamella of LV, long claw G2 on A2, long natatory setae on A2, group of three setae next to β seta on Md palp, smooth tooth bristles on the third endite of Mx, eight setae on the first segment of Mx palp and stout, distinctly triangular terminal segment of the right claping palp of the male.</p>Published as part of <i>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, pp. 1-41 in Zootaxa 2015</i> on pages 16-22, DOI: <a href="http://zenodo.org/record/185936">10.5281/zenodo.185936</a&gt

FIGURE 17. Tonnacypris mazepovae n in 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

FIGURE 17. Tonnacypris mazepovae n. sp. Ψ A) Mx 1, with indication of number of setae on the first segment of the palp, endites incompletely drawn; B) T 2, with indication of setae d 1 and d 2; C) T 3; D) T 3, detail of apical structures (Pincer's organ); E) T 1, with indication of setae a, b, c, d; F) CR; G) attachment. Scale: A = 100 µm; B, C, E, F = 200 µm; D = 39 µm. (OC. 3020,3021

On recent species of Tonnacypris Diebel & Pietrzeniuk, 1975 (Crustacea, Ostracoda), with new species descriptions from Mongolia

The ostracod species Tonnacypris estonica (Järvekülg, 1960), T. tonnensis (Diebel & Pietrzeniuk, 1975), T. edlundi n. sp. and T. mazepovae n. sp. are here reported from Mongolia. Redescriptions of females of T. glacialis (Sars, 1890) and males of T. lutaria (Koch, 1838) are included. The revised generic diagnosis maintains the main character of the anteroventral peg on the calcified part of the inner lamella of the left valve, but this character has a significant level of morphological variability between species of this genus. This is also true for several characters of soft parts, which results in a broader concept for the genus. Different ecological strategies and reproductive modes are present. New records also change the evolutionary and zoogeographical scenario of the genus

Oligocene stratigraphy across the Eocene and Miocene boundaries in the Valley of Lakes (Mongolia)

Cenozoic sediments of the Taatsiin Gol and TaatsiinTsagaan Nuur area are rich in fossils that provide unique evidence of mammal evolution in Mongolia. The strata are intercalated with basalt flows. 40Ar/39Ar data of the basalts frame the time of sediment deposition and mammal evolution and enable a composite age chronology for the studied area. We investigated 20 geological sections and 6 fossil localities of Oligocene and early Miocene deposits from this region. Seventy fossil beds yielded more than 19,000 mammal fossils. This huge collection encompasses 175 mammal species: 50% Rodentia, 13% Eulipotyphla and Didelphomorphia, and 12% Lagomorpha. The remaining 25% of species are distributed among herbivorous and carnivorous large mammals. The representation of lower vertebrates and gastropods is comparatively poor. Several hundred SEM images illustrate the diversity of Marsupialia, Eulipotyphla, and Rodentia dentition and give insight into small mammal evolution in Mongolia during the Oligocene and early Miocene. This dataset, the radiometric ages of basalt I (∼31.5 Ma) and basalt II (∼27 Ma), and the magnetostratigraphic data provide ages of mammal assemblages and time ranges of the Mongolian biozones: letter zone A ranges from ∼33 to ∼31.5 Ma, letter zone B from ∼31.5 to ∼28 Ma, letter zone C from ∼28 to 25.6 Ma, letter zone C1 from 25.6 to 24 Ma, letter zone C1-D from 24 to ∼23 Ma, and letter zone D from ∼23 to ∼21 Ma.Open access funding provided by Austrian Science Fund (FWF). This research was supported by four projects of the Austrian Science Fund (FWF): P-10505-GEO, P-15724-N06, P-23061-N19 to G.D.-H. and a Lise Meitner grant M-1357-B17 to O.M. Travel expenses of G.D.-H. to China and Mogolia were partly covered by the Austrian Academy of Sciences.Peer Reviewe