Pseudorbitolina schroederi Luger, 2018

Schlagintweit, Felix, 2020, Maastrichtian Larger Benthic Foraminifera From The Arabian Plate Sensu Lato: New Data From Somalia, Turkey, And Iran, Acta Palaeontologica Romaniae 16 (2), pp. 69-83 : 78-80

Pseudorbitolina schroederi Luger, 2018

Fig. 7

1948 Pseudorbitolina marthae Douvillé – Henson, p. 102, pl. 6, fig. 17, pl. 11, fig. 6?, text-fig. 16 (Maastrichtian Simsima Formation of Qatar, see Sugden and Standring, 1975).

1974b Pseudorbitolina marthae Douvillé – Meriç, pl. 1, figs. 1-4, pl. 2, figs. 1-3 (upper Maastrichtian of SE Turkey).

1979 Pseudorbitolina marthae Douvillé – Radoičić, pl. 8, figs. 1–3 (Maastrichtian of Iraq).

2016b Pseudorbitolina cf. marthae Douvillé – Schlagintweit et al., p. 41, Figs. 3e–f , 11 (Maastrichtian of Iran).

2016 Antalyna korayi Farinacci & Köylüoğlu – Deghani et al., pl. 2, fig. 13 (Maastrichtian Tarbur Fm. of Iran).

non 2016 Pseudorbitolina marthae Douvillé – Al-Kubaysi and Abid, figs. 6–1 to 6–3 (= Suraqalatia brasieri Görmüş, Lawa & Al Nuaimy ).

2018 Pseudorbitolina schroederi n. sp. – Luger, p. 72, pl. 7, figs. 6–9 (upper Maastrichtian Auradu Formation of Somalia).

Remarks: With its convexo-concave test of annularconcentric chambers more or less throughout the complete ontogeny, Pseudorbitolina represents a rather unusual representative among the orbitolinids. In the drawing of Douvillé (1912, fig. 3), the monospecific genus Pseudorbitolina shows a subspherical proloculus in apical position displaying a septulated supraembryonic zone at its top (like in Palorbitolina , see Schroeder, 1963, fig. 1). The thin-section specimens illustrated by Neumann (1978, pl. 1, fig. 7, pl. 2, fig. 6) in transverse sections instead show an embryo in apical position consisting of a spherical proloculus and a hemispherical septulated deuteroconch arranged laterally to the former. In conclusion, there are still informations lacking on the exact structure of the embryo in Pseudorbitolina (incl. interpretation of elements). In the revision of the species provided by Neumann (1978), the author concludes that it represents a good marker for the Campanian. Schlagintweit et al. (2016b, p. 41) already remarked that obviously there is a stratigraphic discrepancy between the occurrences in Western Europe and the Middle East area (incl. also the record from Somalia; see synonymy). Both, Meriç (1974) and Schlagintweit et al. (2016b) also remarked the greater test dimensions of the Middle East specimens.

Luger (2018, p. 72) described Pseudorbitolina schroederi as possessing the same internal structure like the type-species P. marthae . The test size (diameter) of the Campanian P. marthae is 2-3 mm ( Douvillé, 1910; Neumann, 1978). For the Maastrichtian P. schroederi Luger (2018) indicated a maximum diameter of 6.08 mm. The separation of two Pseudorbitolina species based on size, different stratigraphy, and apparently different palaeobiogeographic distribution is accepted here. Note that in the Maastrichtian deposits of SE Turkey, P. marthae is restricted to the southeastern part belonging to the Arabian platform ( Meriç, 1974a; Özer et al., 2009).

Figures

Fig. 7 Pseudorbitolina schroederi Luger from the Maastrichtian of Somalia (Auradu Formation, a-b), and Iran (Tarbur Formation, c-d). a, b from Luger (2018, pl.7, figs. 7-8; holotype in 7), c-d from Naghan section (d from Schlagintweit et al. (2016b, fig. 11c as Pseudorbitolina marthae).

Fig. 3 Larger benthic foraminifera from the Maastrichtian of Iran (Tarbur Fm.: a, d, f-h, j-k, m-n, p-t), Somalia (Auradu Formation: b-c, e, l, o), and Turkey (Garzan Fm.: i). a-b Accordiella? tarburensis Schlagintweit & Rashidi (a from Schlagintweit and Rashidi, 2016, fig. 6a, holotype, Mandegan section; b from Luger, 2018, pl. 13, fig. 6 as Dukhania? cherchii, holotype). c, g Dictyoconus bakhtiari Schlagintweit, Rashidi & Babadipour (c from Schlagintweit et al., 2016b, fig. 10b, Naghan section; g from Luger (2018, pl. 6, fig. 4 as Dictyoconus sp. 1). d, e-f, h Gyroconulina columellifera Schroeder & Darmoian (e from Luger, 2018, pl. 7, fig. 3; d from Schlagintweit et al., 2016a, fig. 4k, Mandegan section; f, h Naghan section). i–n Gen. et sp. indet. (i from Çoruh et al., 1997, pl. 76, fig. 5 as Dictyoconella complanata; l from Luger, 2018, pl. F-2, fig. 9 as Antalyna korayi; j-k, m-n Naghan section). o–t Antalyna korayi Farinacci & Köylüoğlu (o from Luger, 2018, pl. F-2, fig. 10; p-t Naghan section).