Eucytherura sp. 10

Wannenmacher, Norbert, Dietze, Volker, Franz, Matthias & Schweigert, Guenter, 2021, New records of ostracods and ammonites from the Aalenian (mainly Concavum Zone) of the Zollernalb (Swabian Alb, SW Germany), Zitteliana 95, pp. 1-55 : 9

Eucytherura sp. 10

Fig. 10: 17, 18

Material.

1 RV, 1 LV in samples He19-24-25.

Occurrence.

Upper Aalenian, Bradfordensis Zone (Gigantea Subzone) to Concavum Zone; SW Germany.

Description.

Very small, subovoidal. Anterior margin asymmetrically rounded with extremity below mid-height; posterior margin rounded, apex above mid-height. Anterior and posterior cardinal angles rounded; both slightly more pronounced in right valve. Dorsal margin slightly concave in ther right valve, slightly convex in the left one. Greatest height at anterior cardinal angle; greatest length above mid-height. Shell surface reticulate, with wide rectangular to polygonal meshes. Eye-tubercle absent.

Right valve: A long, well-defined frontal rib runs from the anterior cardinal angle to the anteroventral margin. The lateral surface is characterized by three fine ribs, the first of which starts in the median region, runs a short distance towards the anterior cardinal angle, then bends perpendicularly towards the anterior margin and after a second 45° bend towards the anteroventral margin. The median rib starts mid-posteriorly above mid-height and ends anteromedianly below mid-height. A long, upwardly curved ventral rib runs from the posteroventral margin to the anteroventral region. One (or two) ribs parallel the ventral rib on the ventral side of the valve.

Left valve: The frontal rib is slightly curved (preservation?) and only weakly developed. The (dorso)median - mid-anterior rib meets the ventral rib at an 60° angle. The median rib starts mid-posteriorly above mid-height and ends anteromedianly at mid-height. Two ribs parallel the ventral rib on the ventral side of the valve. Further, especially internal details were not observed, partly for preservation reasons.

Figures

Figure 10. (1) Polycope cf. riegrafi Brand, SMNS 70521 / 62, C, right view, L: 0.345 mm; sample He 19 - 27. (2)? Liasina cylindrica Ainsworth, SMNS 70521 / 63, RV, L: 0.412 mm; sample Lin 18 - 1. (3) Cardobairdia toarcensis Ainsworth, SMNS 70521 / 64, LV, L: 545 mm; sample He 19 - 26. (4) Macrocypris? liassica Bate and Coleman, SMNS 70521 / 65, C, right view, L: 0.750 mm; sample He 19 - 27; (5) Patellacythere paravulsa cf. tenuis Brand, SMNS 70521 / 66, LV, L: 0.522 mm; sample He 19 - 27. (6) Patellacythere ungulina (Triebel and Bartenstein), SMNS 70521 / 67, LV, L: 0.405; sample Mue 19 - 1; (7) " Monoceratina " aff. posterocarinata Brand, SMNS 70521 / 68, C, right view, L: 0.324 mm; sample He 19 - 21. (8) Tanycythere posteroelongata Cabral et al., SMNS 70521 / 69, C, right view, L: 0.676 mm; He 19 - 27. (9) Cytheropterina alacostata Franz et al., SMNS 70521 / 70, LV, L: 0.368 mm; sample He 19 - 27; (10 - 13) Cytheropterina crassicostata sp. nov., (10) holotype, SMNS 70521 / 71, RV, L: 0.516 mm; sample He 19 - 27; (11) paratype, SMNS 70521 / 72, LV, L: 0.556 mm; sample He 19 - 26, (12) paratype, SMNS 70521 / 73, RV, ventral view, L: 0.557 mm; sample He 19 - 27; (13) paratype, SMNS 70521 / 74, LV, inner view, L: 0.555 mm; sample Ro 19 - 4; (14) Procytherura sp. 5, SMNS 70521 / 75, RV, L: 0.363 mm; He 19 - 24; (15) Eucytherura aff. yunga Ballent and Whatley, SMNS 70521 / 76, LV, L: 0.312 mm; sample He 19 - 27. (16) Eucytherura sp. B Boomer and Ballent, SMNS 70521 / 77, RV, L: 0.277 mm; sample He 19 - 25. (17, 18) Eucytherura sp. 10, (17) SMNS 70521 / 78, LV, L: 0.392; sample He 19 - 25, (18) SMNS 70521 / 79, RV, L: 0.278 mm; sample He 19 - 24. Achdorf Formation, Upper Aalenian, Concavum Zone. Scale bars (if not indicated otherwise): 20 μm.