Conchoecia, Dana, 1849

Antonietto, Lucas Silveira, Carmo, Dermeval Aparecido do, Viviers, Marta Claudia, Neto, João Villar Queiroz & Hunt, Gene, 2016, Ostracoda (Arthropoda, Crustacea) from the Riachuelo Formation, Sergipe-Alagoas Basin, Brazil, Upper Aptian-Albian, European Journal of Taxonomy 244, pp. 1-57 : 8-10

Conchoecia ? sp. 1

Fig. 5 D–F

“ Conchoecia ” GA D 31 – Grosdidier 1979: 8, figs 60a–d.

Genus aff. “ Conchoecia ” sp. 150 – Rosenfeld & Raab 1983: 113, fig. 7.10. — Honigstein et al. 1985: figs 6.150, 7.150.

Conchoecia sp. 1 – Andreu-Boussut 1991: 437, figs 1.1–1.3. — Andreu 1992: 296, fig. 1.1. Conchoecia ? sp. Se6 aff. ‘ C ’ sp. GA D 31 – Viviers et al. 2000: 414, figs 10–11.

New material examined

BRAZIL: 1-US-1 well, Laranjeiras Municipality, Sergipe State (depths of 876, 891 and 900 m); Well ‘1', Laranjeiras Municipality, Sergipe State (depths of 510 to 540 m).

Measurements

Hypotype (LBP 10): carapace: length = 0.63 mm, height = 0.49 mm, width = 0.38 mm.

Hypotype (LBP 11): carapace: length = 0.53 mm, height = 0.43 mm.

Remarks

The presence of halocypridids in the Early Cretaceous of the Atlantic Ocean was first noticed by Pokorný (1964), when dealing with ostracods from the Coniacian of Czechoslovakia. Since then, several taxa have been tentatively classified in the genus Conchoecia by several authors (e.g., Colin & Andreu 1990), although the only morphological resemblance to this Recent genus has to do with the presence of a rostrum (some of the specimens; certainly not the current ones) and striate ornamentation. More detailed studies on the internal features of those specimens have never been performed, and are also not possible with the present material. Therefore, we opt to maintain the current taxonomic status, but doubtfully, in the hope of collecting better preserved specimens in the future.

Paleoecology and distribution

Conchoecia ? sp. 1 is a marine, shelf to neritic, possibly planktonic species occurring in the following localities and stages: Madiéla Formation, Gabon Basin, Gabon, lower–middle Albian ( Grosdidier 1979); Talme Yafe, Yavne Shales and Ḥaẕera Formations, Levantine Basin, Israel, Albian–lower Cenomanian ( Rosenfeld & Raab 1983); Agadir Basin, Morocco, upper Albian–lower Cenomanian ( Andreu-Boussut 1991); and Maruim Member, Riachuelo Formation, Sergipe-Alagoas Basin, Brazil, upper Aptian– Albian, Aracajuia benderi zone (MSA-0), Metacytheropteron sp. aff. M. sp. GA C 24 subzone (MSA- 0.5) ( Viviers et al. 2000).

Figures

Fig. 5. [facing page] Ostracods of the Riachuelo Formation, Sergipe-Alagoas Basin, Albian, Brazil. – A–C. Cytherella besrineensis (Bischoff, 1964) comb. nov. A. CP-669, right lateral view. B–C. CP-668. B. Left lateral view. C. Dorsal view. – D–F. Conchoecia? sp. 1. D, F. LBP 10. D. Right lateral view. F. Dorsal view. E. LBP 11, left lateral view. – G–I. Cytherelloidea btaterensis Bischoff, 1964. G. CP-671, right lateral view. H. CP-672, left lateral view. I. CP-673, dorsal view. – J. Cytherelloidea aff. globosa Kaye, 1964, CP-756, right lateral view. – K. Cytherella sp. 1, CP-670, lateral view. – L. Bairdoppilata pseudoseptentrionalis Mertens, 1956, CP-676, right lateral view. – M. Bairdoppilata sp. 1, CP-678, right lateral view. – N–P. Bairdoppilata comanchensis (Alexander, 1929) comb. nov., CP-674. N. Left lateral view. O. Right lateral view. P. Dorsal view. – Q–S. Bairdoppilata sp. 2, CP-757. Q. Right lateral view. R. Left lateral view. S. Dorsal view. Scale bars = 100 μm.