Eucytherura foveolata sp. nov.

Fig. 6: 12-14

Eucytherura sp. 4. - 2018 Franz et al., p. 72, plate 3: 22

Etymology.

From fovea (lat.) = pit; referring to the characteristic pits on the lateral surface.

Holotype.

One carapace, figured in Fig. 6: 12, SMNS 70521/12.

Paratypes.

Two carapaces, figured in Fig. 6: 13, 14, SMNS 70521/13-14.

Type locality.

Drillcore KB 1/93 Geisingen (SW Germany).

Type horizon.

Opalinuston Formation, Zillhausen Subformation, sample G08Fr, Lower Aalenian.

Material.

19 C, 2 RV, 2 LV from samples He 19-3-12 and from the Geisingen clay pit.

Diagnosis.

A small-sized species of the genus Eucytherura with the following characteristics: pitted lateral surface with a fine median rib.

Description.

Very small, subrectangular. Left valve slightly larger than right with dorsal overlap. Anterior margin rounded with extremity slightly below mid-height; posterior margin pointed in right and bluntly rounded in left valve, apex above mid-height. Posterior cardinal angle rounded; anterior cardinal angle pronounced in both valves. Dorsal margin straight in left, slightly convex in right valve; ventral margin straight or slightly concave. Greatest height at anterior cardinal angle; greatest length above mid-height. Ornament consists of a fine median, horizontal or subdiagonal rib, accompanied on both sides by shallow, about 15 μm wide, round or subangular pits with a rough surface. A third row of such pits running antero-medianly - postero-ventrally; further pits in variable numbers and positions scattered on the lateral surface. Particularly striking are 4 rhomboidally grouped pits (Fig. 6: 12) in the mid-dorsal area. Eye-tubercle only weakly developed. Internal details not observed.

Comparisons.

All other previously known species of Eucytherura have a well-developed ornamentation with sharp or broad ribs and/or reticulate surfaces.

Occurrence.

Lower Aalenian, Opalinum Zone; SW Germany.