Bairdoppilata pseudoseptentrionalis Mertens, 1956

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 : 14-15

Bairdoppilata pseudoseptentrionalis Mertens, 1956

Fig. 5L

Bairdoppilata pseudoseptentrionalis Mertens, 1956: 182 , figs 8.7–8.10, 13.89–13.90. Bairdoppilata pseudoseptentrionalis – Howe & Laurencich 1958: 82, unnumbered figs. — Weaver 1982: 24, figs 4.1–4.3. —?Jarvis et al. 1988: 34, fig. 15j.

Cytherina subdeltoidea Münster, 1830 –? Roemer 1841: 105, fig. 16.22. —? Reuss 1845: 54, fig. 5.38.

Cythere (Bairdia) subdeltoidea – Jones 1849 pars: 23, fig. 5.15a–c, e–f.

Bairdia subdeltoidea –? Jones & Hinde 1890: 5, figs 2.31–2.34.

Bairdia pseudoseptentrionalis – Oertli 1963: pl. 72, pl. 73, fig. l, pl. 76. —? Kaye 1965: 223, figs 2.1, 2.3–2.6. —? Gründel 1966: 15, fig. 1.18. —? Keen & Siddiqui 1971: 63, fig. 1.2. — Hart 1973: 281, fig. 4. —? Babinot et al. 1985a: 172, fig. 5l. 1.

Bairdia sp. – Majoran 1989: 9, figs 2.5–2.7.

Bairdoppilata sp. 1 – Piovesan et al. 2013: 244, fig. 3.8a–b.

non Cythere (Bairdia) subdeltoidea – Jones 1849 pars: 23, fig. 5.15d.

non Bairdia pseudoseptentrionalis – El-Nady et al. 2008: 544, fig. 2.6.

non Bairdia gr. pseudoseptentrionalis – Babinot et al. 1985b: 224, figs 55.15–55.16.

New material examined

BRAZIL: P384 outcrop, Riachuelo Municipality, Sergipe State (MP-1509 to MP-1513), approximate coordinates 10°43' S, 37°12' W; Porto dos Barcos 3 outcrop, Riachuelo Municipality, Sergipe State (samples MP-1460, MP-1468 and MP-1469), approximate coordinates 10°43' S, 37°10' W; São José 1 outcrop, Riachuelo Municipality, Sergipe State (samples MP-1574, MP-1680 and MP-1697), approximate coordinates 10°44' S, 37°13' W.

Type locality and stratum

194 well, Dalum oil field, Germany; Lower Chalk Group, upper Albian.

Measurements

Homeotype (CP-676): carapace: length = 0.91 mm, height = 0.58 mm, width = 0.44 mm.

Homeotype (CP-677): left valve: length = 0.91 mm, height = 0.55 mm.

Remarks

The diagnosis follows Mertens (1956). Historically, Bairdoppilata pseudoseptentrionalis Mertens, 1956 has been mistaken for B. subdeltoidea ( Münster, 1830) , as the former species has never been adequately illustrated since its description by Münster (1830). Several sub-species were added to Bairdoppilata subdeltoidea during the 19 th century, which increases the difficulties in establishing its current taxonomic status. The most recent review of the species is in Deroo (1956), who renamed it as Bairdoppilata roemeri , with a lower Cretaceous–Tertiary stratigraphic range. Assuming the species is still valid, it has to be separated from Bairdoppilata pseudoseptentrionalis , at least in terms of age; the former is considered later Cretaceous–Tertiary ( Münster 1830), while the latter is from the late Albian– Cenomanian ( Mertens 1956). The specimens in Kaye (1965), Gründel (1966) and Jarvis et al. (1988) present a straighter posterior portion of the dorsal margin in the left valve, when compared to the more rounded one in B. pseudoseptentrionalis . In Keen & Siddiqui (1971) and Babinot et al. (1985b), the specimens presents a generally wider overlapping and less rounded overall shape.

Paleoecology and distribution

Bairdoppilata pseudoseptentrionalis is a shelf to neritic marine species occurring in the following localities and stages: Anglo-Paris Basin, France, middle Albian ( Oertli 1963); Lower Chalk Group, Germany, Albian–Cenomanian ( Mertens 1956); Gault, Greensand and Holywell Nodular Chalk (including Plenus Marl Member) Formations, Anglo-Paris Basin, England, Albian–Cenomanian ( Jones 1849; Hart 1973; Weaver 1982); Bordj Ghdir Basin, Algeria, lower Cenomanian ( Majoran 1989); Florianópolis and Guarujá Formation, Santos Basin, upper Aptian–middle Albian ( Piovesan et al. 2013); and in the present work, Angico and Taquari Members, Riachuelo Formation, Sergipe-Alagoas Basin, uppermost Aptian–middle Albian, Aracajuia benderi zone (MSA-0), Sergipella viviersae (MSA-0.2) and Praebythoceratina amsittenensis (MSA-0.3) subzones, Brazil.

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.