Givetian ostracods of the Candás Formation (Asturias, North-western Spain): taxonomy, stratigraphy, palaeoecology, relationship to global events and palaeogeographical implications
Author
Maillet, Sebastien
Author
Milhau, Bruno
Author
Vreulx, Michel
Author
Posada, Luis-Carlos Sánchez De
text
Zootaxa
2016
4068
1
1
78
journal article
10.11646/zootaxa.4068.1.1
b9c1e3a3-e591-4b34-9f30-d6d88a230673
1175-5326
270644
80E89736-33F2-4FF5-9B01-8B7239407875
Bairdia (Bairdia)
sp. P4
(Pl. IV:
Fig. 5
)
2013
Bairdia
(
Bairdia
)
sp. P4; Maillet: 161, pl. XXV, fig. 8.
Material.
1 specimen
(1 C).
Description.
Large elongated carapace, subtrapezoidal to subhexagonal in lateral view, biconvex in dorsal view. Overlap of the larger LV over the RV very pronounced dorsally, otherwise slight at free margins of the carapace. Bow-shaped projection in ventral view. Hmax median; Lmax at 2/5 ventral; Wmax slightly ventral. Dorsal margin regularly convex in its middle part, becoming more convex towards anterior and posterior and then concave near anterior and posterior extremities of the carapace. Ventral margin convex, becoming more arched at its extremities. Dorsal and ventral margins converging both posteriorly and anteriorly. Anterior margin slightly concave in its dorsal part to the anterior end point about at mid-height, and, from this point, regularly convex in its ventral part. Anterior end forming an angle of about 110°. Posterior margin slightly concave in its dorsal part to the posterior end point (posterior Lmax point), and from this point, convex in its ventral part. Posterior end very sharp and forming an angle of about 85°. Anterior end of the carapace higher than the posterior one. Anterior part of the carapace higher than the posterior one. Surface smooth.
Discussion.
This single specimen is close to
Bairdia
(
Bairdia
)
sp. P3, but shows a sharper posterior part than this species. It may also remind
B. siliklensis
Rozhdestvenskaja, 1962
, but the overlap of the valves is more pronounced dorsally in the present species.
Occurrences.
Middle Givetian (Candás Fm, mb A), Asturias (Peran-Perlora section).