Bairdiocypris vastus Polenova, 1952

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 : 48-49

Bairdiocypris vastus Polenova, 1952

(Pl. III: Fig. 16)

1952 Bairdiocypris vastus nov. sp.; Polenova: pl. 14, figs. 1–2.

1964 Bairdiocypris « géant »; Magne: pl. 17, figs. 33–34.

1979 Bairdiocypris vastus Polenova ; Olempska: 113, pl. 22, figs. 1–2. 1982 Bairdiocypris « géant » Magne; Milhau: 21, pl. 4, figs. 87–88.

1983b Bairdiocypris « géant » Magne; Milhau: 221.

1983 Bairdiocypris vastus Polenova ; Żbikowska: 66, pl. 19, fig. 7.

1988 Bairdiocypris vastus Polenova ; Milhau: 484, pl. 56, fig. 42.

aff. 1988 Bairdiocypris cf. livnensis Polenova, 1953; Milhau: 484, pl. 56, fig. 47. 2006 Bairdiocypris sp. A, aff. lamellaris Adamczak, 1976; Casier in Casier & Préat: pl. 4, fig. 3. 2009 Bairdiocypris vasta Polenova ; Maillet: 12, pl. 1, fig. 19.

2010 Bairdiocypris vastus Polenova ; Maillet: 40, pl. 1, fig. 22.

2011b Bairdiocypris rauffi Krömmelbein, 1952 ; Casier in Casier et al.: pl. 3, fig. 10. 2013 Bairdiocypris vastus Polenova ; Maillet: 150, pl. XXII, figs. 1–3. 2013 b Bairdiocypris vastus Polenova ; Maillet et al.: fig. 5A.

Material. 7 specimens (4 C, 2 V, 1 F).

Diagnosis. Polenova (1952, p. 135).

Description. Very large carapace (up to 2mm in length), with a rounded sub-trapezoidal outline in lateral view, biconvex and flattened in dorsal view. Overlap of the larger LV over the RV along whole outline, very pronounced dorsally. Marked bow-shaped projection. Hmax median; Lmax at 1/3 ventral; Wmax at 1/3 ventral. Dorsal margin of the smaller RV straight on 1/2 of Lmax in its median part, oblique anteriorly in its anterior part, oblique posteriorly in its posterior part. Dorsal margin of the larger LV regularly convex. Pronounced dorsal rim of the LV. Straight to very slightly concave ventral margin of the carapace. Well rounded anterior margin, more convex in its ventral part. Regularly convex posterior margin. Posterior end sharper at 1/3 ventral. Anterior part of the carapace higher than the posterior one. Carapace flattened at the anterior and posterior margins. Surface smooth.

Discussion. A characteristic thick-shelled Givetian species, classically found in peri-reefal agitated environments and easily identifiable by its huge size.

Occurrences. Lower to Middle Givetian (Hanonet, Trois-Fontaines, Terres d’Haurs, Mont d’Haurs and Névremont Fms, and Fromelennes Fm, Flohimont Mb), Ardenne (Flohimont, Cul d’Houille, Mont d’Haurs, Aisne and Aisemont sections), Middle Givetian (Candás Fm, mbs A and B), Asturias (Peran-Perlora section); Givetian, Russia, Boulonnais and Poland.