Tricornina (Tricornina)

Maillet, Sebastien, Milhau, Bruno, Vreulx, Michel & Posada, Luis-Carlos Sánchez De, 2016, Givetian ostracods of the Candás Formation (Asturias, North-western Spain): taxonomy, stratigraphy, palaeoecology, relationship to global events and palaeogeographical implications, Zootaxa 4068 (1), pp. 1-78 : 21

Tricornina (Tricornina) sp. A

(Pl. I: Fig. 13)

? 1962 Tricornina ovata nov. sp.; Blumenstengel: 8, pl. IV, figs. 75–76.? 1963 Tricornina ovata Blumenstengel ; Le Fèvre: pl. 2, figs. 18–20.? 1985 Tricornina ? sp. A; Casier: 837.

? 2004 Tricornina sp. ex. gr. T. sp. A sensu Becker, 1975; Becker in Becker et al.: 73, pl. 2, figs. 5–6.? 2004 Tricornina (Bohemina) sp. B; Dojen et al.: fig. 6 (4–5).

2013 Tricornina (Tricornina) sp. A; Maillet: 61, pl. VI, figs. 11–12. 2013 a. Tricornina (Bohemina) sp. A; Maillet et al.: pl. 1, fig. 35.

Material. 1 specimen (1 C).

Description. Medium-sized elongated carapace, rounded sub-triangular outline in lateral view, biconvex in dorsal view. Very slight ventral overlap of the larger LV over the RV. Hmax at 1/4 anterior; Lmax along the dorsal margin; Wmax mid-ventral. Straight hinge line and dorsal margin. Anterior cardinal angle of about 115°. Ventral and dorsal margins clearly converging posteriorly. Carapace slender posteriorly with a posterior end forming an angle of about 35°. Regularly convex anterior margin. Carapace flattened along the anterior margin. Slight nodes at extremities of the anterior margin, slightly projecting over the ventral and dorsal margins. From the Hmax ventral point towards posterior, oblique and slightly convex ventral margin. Long ventral spine at mid-length and pointing backwards on both valves (= lateral wings). Surface smooth.

Discussion. Small Tricornina with rather tenuous lateral spines, however, the collected specimen is incomplete. Its morphology is close to Tricornina ovata Blumenstengel, 1962 , to Tricornina ? sp. A in Casier (1985) and to Tricornina sp. ex. gr. T. sp. A sensu Becker, 1975 in Becker et al. (2004).

Occurrence. Lower Givetian (Chefar el Ahmar Fm), Saoura (Km 30 section), Middle Givetian (Candás Fm, mb A), Asturias (Peran-Perlora section).