Bairdia (Bairdia)

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 : 52-53

Bairdia (Bairdia) sp. P1

(Pl. IV: Fig. 2 )

2013 Bairdia (Bairdia) sp. P1; Maillet: 161, pl. XXV, figs. 4–5.

Material. 4 specimens (4 C).

Description. Medium-sized elongated carapace, subhexagonal in lateral view, biconvex in dorsal view. Overlap of the larger LV over the RV along whole outline, more marked antero-dorsally. Bow-shaped projection in ventral view. Hmax at 1/3 posterior; Lmax at 1/3 dorsal; Wmax postero-dorsal. Dorsal margin straight in its middle part (on about 1/3 of Lmax), anteriorly and posteriorly oblique. Ventral margin straight to slightly concave in its middle part, becoming more convex at its extremities. Dorsal and ventral margins almost parallel. Anterior margin oblique and slightly convex, more arched in its ventral part and forming an angle of about 110° with the dorsal margin. Posterior margin slightly convex, more arched at its extremities and forming an angle of about 90° with the dorsal margin. Sharp anterior and posterior ends. Anterior end of the carapace higher than the posterior one. Carapace globally inflated, except flattening along anterior and posterior margins. Surface smooth. Curved oblique ridge on each valve of about 1/2 of Hmax located in the postero-dorsal part and extending from about mid-length of the dorsal margin towards the posterior end by longing the postero-dorsal margin. Ridge possibly bifurcated at its anterior extremity.

Discussion. A hexagonal carapace with a curved postero-dorsal ridge is a quite atypical character for bairdiids. Despite this, if these specimens are assigned to the Bairdia subgenus, the species remains unidentified. Occurrences. Middle Givetian (Candás Fm, mb C), Asturias (Peran-Perlora section).

Figures

FIGURE 2. Simplified stratigraphical column of the Candás Formation, standard conodont zonation and chronostratigraphy (according to García-Alcalde et al. 1979; García-López 1986 and García-López et al. 2002).