Eucytherura eberti, Wannenmacher & Dietze & Franz & Schweigert, 2021

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 : 7

Eucytherura eberti sp. nov.

Fig. 6: 9-11

Eucytherura aff. scottia (Whatley, 1970). - 2018 Franz et al., p. 72, plate 3: 17.

Eucytherura aff. scottia (Whatley). - 2019 Dietze et al., fig. 11.

Etymology.

In honour of the German palaeontologist Martin Ebert, who initiated the investigation of the Geisingen clay pit with his extensive preliminary work.

Holotype.

carapace, figured on Fig. 6 : 9, SMNS 70521/9.

Paratypes.

two carapaces, figured on Fig. 6 : 10, 11, SMNS 70521/10-11.

Type locality.

Heiligenbach valley near Hechingen-Beuren (SW Germany).

Type horizon.

Achdorf Formation, claystone below the Inopernabank, bed no. 39 in Fig. 4 ; Bradfordensis Zone.

Material.

10 C, 28 RV, 34 LV from the Heiligenbach, Thanheim and Roschbach sections and the Geisingen clay pit.

Diagnosis.

A new species of Eucytherura with broad, smooth posterodorsal, frontal and ventral ribs. Intercostate areas weakly reticulate.

Description.

Very small, subrectangular. Left valve slightly larger than right with anterodorsal and posterodorsal overlap. Anterior margin weakly rounded with extremity below mid-height; posterior margin pointed in right and bluntly rounded in left valve, apex above mid-height. Posterior cardinal angle pronounced in both valves; anterior cardinal angle more rounded in right than in left valve. Dorsal margin slightly convex to straight; ventral margin medianly slightly convex. Greatest height at anterior cardinal angle; greatest width antero-ventrally; greatest length above mid-height. Ornament consists of a series of broad longitudinal ribs and swellings, and with weakly reticulate intervening areas. A broad, posteriorly weakly alate rib extends from a postero-ventral position across the ventro-lateral surface of the valve, terminating antero-ventrally. A similar broad rib extends mid-posteriorly to mid-dorsally. The eye tubercule is well developed and is connected to a narrower frontal rib, which parallels the anterodorsal margin. A less prominent second rib or elongate swelling parallels the latter mid-anteriorly. Intercostate areas are weakly reticulate, with a characteristic row of small elongate pits above the muscle-scar field. 3-4 small marginal denticles occur anteriorly. Normal pores few and wide-spaced. Internal details not observed.

Comparisons.

Euytherura eberti closely resembles Eucytherura scottia Whatley, 1970 from the Callovian and Oxfordian of Scotland. It differs mainly in the length of the dorsal rib, the absence of the anterior tubercles, being replaced by two parallel ribs and the pits above the musclescar-field.

Distribution.

Lower Aalenian to Upper Aalenian, Opalinum to Bradfordensis zones (Gigantea Subzone); SW Germany.

Figures

Figure 4. Section Heiligenbach, upper part, above the Rostrote Kalkbank, combined with the Muehlbaechle, Roschbach and Hausterberg sections. WS = Wedelsandstein Formation; Murchis. = Murchisonae; Di. = Discites Zone; Op. Sz. = Opalinum Subzone; " Co. Sz. = " Comptum " Subzone; Bradf. Sz. = Bradfordensis Subzone.

Figure 6. (1) Cardobairdia tesakovae Franz et al., SMNS 70521 / 1, LV, L: 0.426 mm; sample He 19 - 6; (2) Patellacythere cf. vulsa, SMNS 70521 / 2, LV, L: 0.51 mm; sample He 19 - 9; (3) Procytherura celtica Ainsworth, SMNS 70521 / 3, RV, L: 0.301 mm; sample He 19 - 12. (4, 5) Procytherura euglyphea Ainsworth, (4) SMNS 70521 / 4, RV, L: 0.320 mm; sample He 19 - 1; (5) SMNS 70521 / 5, LV, L: 0.327 mm; sample He 19 - 12. (6, 7) Procytherura multicostata Ainsworth, (6) SMNS 70521 / 6, LV, L: 0.336 mm; sample He 19 - 9; (7) SMNS 70521 / 7, RV, L: 0.319 mm; sample He 19 - 16. (8) Procytherura sp. 2 Franz et al., SMNS 70521 / 8, RV, L: 0.325 mm; He 19 - 8. (9 - 11) Eucytherura eberti sp. nov., (9) holotype, SMNS 70521 / 9, C, left view, L: 0.306 mm; sample He 19 - 18; (10) Paratype, SMNS 70521 / 10, C, right view, L: 0.292 mm; sample He 19 - 21; (11) paratype, SMNS 70521 / 11, C, dorsal view, L: 0.318 mm; sample He 19 - 26. (12 - 14) Eucytherura foveolata sp. nov., (12) holotype, SMNS 70521 / 12, C, left view, L: 0.327 mm; sample G 08 Fr; (13) paratype, SMNS 70521 / 13, C, right view, L: 0.318 mm; sample G 12 Fr; (14) paratype, SMNS 70521 / 14, C, right view (detail), image width: 0.07 mm; sample G 12 Fr; (15) Eucytherura liassica Bate and Coleman, SMNS 70521 / 15, LV, L: 0.304 mm; sample He 19 - 17. (16) Eucytherura michelseni (Finger), SMNS 70521 / 16, LV, L: 0.324 mm; sample He 19 - 18. (1 - 6, 8, 12 - 14) Opalinuston Formation, Lower Aalenian, Opalinum Zone; (7, 9 - 11, 15 - 16) Achdorf Formation, Upper Aalenian, (7) Murchisonae Zone, (15) Bradfordensis Zone (Bradfordensis Subzone), (9, 10, 16) Bradfordensis Zone (Gigantea Subzone), (11) Concavum Zone. Scale bars (if not indicated otherwise): 20 μm.