Bairdiacypris sp. 3, Bradfield, 1935

Forel, Marie-Béatrice & Grădinaru, Eugen, 2020, Rhaetian (Late Triassic) ostracods (Crustacea, Ostracoda) from the offshore prolongation of the North Dobrogean Orogen into the Romanian Black Sea shelf, European Journal of Taxonomy 727, pp. 1-83 : 23-24

Bairdiacypris sp. 3

Fig. 6S

Material examined

ROMANIA • 1 RV; Black Sea , Romanian Continental Shelf , borehole 817LV, sample CM31B; Rhaetian, Upper Triassic; MNHN.F. F63212 • 1 complete carapace; same collection data as for preceding; Rhaetian, Upper Triassic; MNHN.F. F63344 .

Dimensions

L = 1060 µm; H = 481 µm; H/L = 0.45.

Occurrence

Romanian Continental Shelf, Black Sea, Rhaetian, Upper Triassic (this paper).

Remarks

Bairdiacypris sp. 3 is close to Fabalicypris n. sp. in Kristan-Tollmann et al. 1980 from the Rhaetian of Iran ( Kristan-Tollmann et al. 1980), but the present species has a tripartite dorsal margin at RV

with longer DB and lacks the Fabalicypris offset of the ventral overlap. Bairdiacypris sp. 3 is also close to Bairdiacypris ? sp. 2 in Lord & Lambourne 1991 from the Pliensbachian, Early Jurassic, of Turkey ( Lord & Lambourne 1991), from which it differs in being larger with a less elongate posterior end. Bairdiacypris sp. 3 shares a strong similarity with Bairdiacypris sp. B in Bolz 1971 from the Rhaetian interval of the Northern Calcareous Alps ( Bolz 1971b), which is only shown as inner views. However, Bairdiacypris sp. 3 has a shorter DB and a larger PB with maximum of convexity located higher. Bairdiacypris sp. 3 is also larger than Bairdiacypris sp. B in Bolz 1971 (L = 690–950 µm; H = 320–500 µm; H/L = 0.44–0.55), with a similar H/L ratio; this characteristic could relate to ontogeny. It is nevertheless worth noting that the H/L ratio of Bairdiacypris sp. B in Bolz 1971 mainly ranges from 0.44 to 0.48 ( Bolz 1971b: 231). The dimensions provided for the specimen illustrated in Bolz (1971b: pl 8, fig. 104) are L = 900 µm and H = 500 µm, leading to an H/L ratio of 0.55.

Figures

Fig. 6 (opposite page). SEM micrographs of ostracods from borehole 817 Lebăda Vest, drill core CM31, western portion of Black Sea shelf, Rhaetian, Late Triassic. All specimens are housed in the collections of the Muséum national d’histoire naturelle, Paris, France (MNHN). A. Bairdia sp. 8, same specimen as in Fig. 5U, dorsal view. B–C. Bairdia sp. 9. B. Right lateral view of a carapace, sample CM31C (MNHN.F.F63198). C. Same specimen, dorsal view. D–E. Bairdiacypris multidentata Bolz, 1971. D. Right lateral view of a carapace, sample CM31A (MNHN.F.F63199). E. Right lateral view of a carapace, sample CM31B (MNHN.F.F63200). F–O. Bairdiacypris argonautaii Forel sp. nov. F. Paratype 2, right lateral view of a carapace, sample CM31A (MNHN.F.F63201).G. Paratype 1, external view of a right valve, sample CM31B (MNHN.F.F63202). H. Right lateral view of a carapace, sample CM31A (MNHN.F.F63203). I. Right lateral view of a carapace, sample CM31A (MNHN.F.F63204). J. Right lateral view of a carapace, sample CM31B (MNHN.F.F63205). K. Same specimen, dorsal view. L. Right lateral view of a carapace, sample CM31A (MNHN.F.F63206). M. Right lateral view of a carapace, sample CM31A (MNHN.F.F63207). N. Same specimen, dorsal view. O. Right lateral view of a carapace, sample CM31A (MNHN.F.F63208). P. Bairdiacypris sp. in Forel et al. 2018, external view of a right valve, sample CM31A (MNHN.F.F63209). Q. Bairdiacypris sp. 1, external view of a right valve, sample CM31A (MNHN.F.F63210).R. Bairdiacypris sp. 2, external view of a right valve, sample CM31C (MNHN.F.F63211). S. Bairdiacypris sp. 3, external view of a right valve, sample CM31B (MNHN.F.F63212). T–U. Bairdiacypris? sp. 4. T. Right lateral view of a carapace, sample CM31B (MNHN.F.F63213). U. Right lateral view of a carapace, sample CM31A (MNHN.F.F63214). Scale bars: 100 µm.