Eucytherura sp. 11

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. 11

Fig. 9: 7

Material.

1 RV, 2 LV in samples He19-18 and He19-24-25.

Occurrence.

Upper Aalenian, Bradfordensis Zone; SW Germany.

Description.

Very small, subrectangular to subtriangular. Anterior margin rounded with extremity slightly below mid-height; posterior margin pointed, apex above mid-height. Posterior cardinal angle rounded; anterior cardinal angle pronounced in both valves, slightly more rounded in left valve. Dorsal straight to slightly concave, ventral margin straight to slightly convex. Greatest height at anterior cardinal angle; greatest length above mid-height. Shell surface strongly reticulate, including the anterior and posterior margins. The coarse-meshed, very prominent reticulation is divided by three ribs, which in the median area delimit an approximately circular area. A middorsal - anteromedian rib, a second middorsal - posteromedian rib, and a ventral rib that is strongly curved up in the anterior midventral section towards the anteromedian region. Another rib starting at the anterior cardinal angle parallels the anterior edge of that circular area approximately halfway to the anterior margin. Eye-tubercle absent; internal details not observed.

Figures

Figure 9. (1) Cytherelloidea lordi Ainsworth, SMNS 70521 / 49, C, right view, L: 0.688 mm; sample He 19 - 19. (2) Bairdiacypris triangularis Ainsworth, SMNS 70521 / 50, C, right view, L: 0.309 mm; sample He 19 - 19. (3) Macrocypris aequabilis Oertli, SMNS 70521 / 51, C, left view, L: 0.349 mm; sample He 19 - 21. (4) Eucytherura cf. parairregularis Brand, SMNS 70521 / 52, C, right view, L: 0.281 mm; sample He 19 - 19; (5) Eucytherura cf. yunga Ballent and Whatley, SMNS 70521 / 53, RV, L: 0.304 mm; sample He 19 - 27. (6) Eucytherura sp. 5 Franz, SMNS 70521 / 54, RV, L: 0.295 mm; sample G 11 Fr; (7) Eucytherura sp. 11 Franz, SMNS 70521 / 55, RV, L: 0.327 mm; sample He 19 - 25. (8) Balowella catena (Franz et al.), SMNS 70521 / 56, RV, L: 0.308 mm; sample He 19 - 24. (9) Praeschuleridea ornata (Bate), SMNS 70521 / 57, RV, L: 0.578 mm; sample He 19 - 21; (10, 11)? Southcavea sp., (10) SMNS 70521 / 58, LV, L: 0.315 mm; (11) SMNS 70521 / 59, RV, L: 0.368 mm; sample He 19 - 24; (12) Pleurocythere kirtonensis Bate, SMNS 70521 / 60, RV, L: 0.597 mm; sample He 19 - 18. (13) Acrocythere aff. pumila Plumhoff, SMNS 70521 / 61, LV, L: 0.406 mm; sample He 19 - 27; (6) Opalinuston Formation, Lower Aalenian, Opalinum Zone, (1 - 5, 7 - 13) Achdorf Formation, Upper Aalenian (1 - 4, 9, 12) Bradfordensis Zone (Gigantea Subzone), (5, 7 - 8, 10 - 11, 13) Concavum Zone. Scale bars (if not indicated otherwise): 20 μm.