Suraqalatia Görmüş, Lawa & Al Nuaimy, 2017

Schlagintweit, Felix & Rashidi, Koorosh, 2018, Suraqalatia Brasieri Görmuş, Lawa & Nuaimy, 2017 (Larger Benthic Foraminifera; Suraqalatiidae N. Fam.) From The Late Maastrichtian Of The Tarbur Formation (Zagros Fold-Thrust-Belt) And Remarks On Dicyclina Munier-Chalmas, 1887, Acta Palaeontologica Romaniae 14 (1), pp. 21-29 : 22-26

Genus Suraqalatia Görmüş, Lawa & Al Nuaimy, 2017 Suraqalatia brasieri Görmüş, Lawa & Al Nuaimy, 2017 ( Figs. 3–5 )

2008 Pseudorbitolina cf. marthae Douvillé – Al-Kubaysi, figs. 2–12 (Maastrichtian Aqra Formation of Iraq).

2016 Pseudorbitolina marthae Douvillé – Al-Kubaysi and Abid, figs. 6-1 to 6-3 (Maastrichtian Aqra Formation of Iraq).

2016a Loftusia sp. – Schlagintweit et al., fig. 12b (Maastrichtian Tarbur Formation of Iran).

*2017 Suraqalatia brasieri n.gen., n. sp. – Görmüş et al., p. 2, figs. 3–5 (Maastrichtian Aqra Formation of Iraq).

Remarks. The specimens from the Tarbur Formation shown here only comprise tangential and oblique sections, whereas the original description of the Iraqi material was based on both thin-sections and isolated specimens. Therefore we refrain from a detailed description of the Iranian sections instead commenting the one given by Görmüş et al. (2017) thereby referring to their figures in the following. The specimens from the weathered rock surface (e.g. Figs. 3 /7a, 4/9 to 4/11) viewed from above and from the side ( Fig. 3 /6e) as well as the equatorial section shown in Fig. 4b of Görmüş et al. (2017) display its test morphology. Accordingly, Suraqalatia brasieri displays a low conical, mostly conico-concave test, sometimes irregularly bent, displaying annular (ring-shaped) chambers. Sometimes the tests also display a bending upwards of the final chambers. Note that such "reflexed convex forms" are recorded from some orbitolinids (e.g., Douglass, 1960, figs. 17, 21). The maximum test diameter of the Iraqian specimens was indicated as up to 7 cm and up to 60 chambers. The sections from Iran not affecting complete tests attain a size of up to 2.2 cm (~ half size of an incomplete specimen amounting for a total of ~ 4.4 cm). Whether or not the mentioned test irregularities reflect any kind of dimorphism is unknown but appears unlikely as no two typical morphologies, e.g., differing by their apical angles, occur. The initial part is poorly documented. No megalospheric embryo has been illustrated by Görmüş et al. (2017). The isolated specimens display a pustular apex ( Fig. 4 /10). The annular chambers making up the main test part are subdivided marginally by beams (primary and intercalary) and rafters forming a polygonal subepidermal network. The latter becomes coarser towards the chamber interior. Externally it is covered by a thin epiderm (about 15 µm in thickness) ( Fig. 5 this work).

In some sections of Görmüş et al. (2017, figs. 4/1a, 5/8) it appears that the main partitions are aligned in successive chambers. The interior part of the chambers does not show any structural elements (endoskeleton) (e.g., transverse section of Görmüş et al., 2017, fig. 3/4b, 3/12a, or Fig. 3b this work). Concerning the foramina, the information in the original description is not concrete, stating "apertures are numerous and lie in the epidermal parts at the edges of the test" (op. cit., p. 365). Some tiny foramina have been observed alternating with the beams ( Fig. 5 ). Summarizing, there is still a lack of knowledge concerning the initial part, and the foramina that are multiple but of unknown distributional pattern.

Microfacies. In the Tarbur Formation Suraqalatia brasieri was observed in wackestones/floatstones displaying variable amount of fine siliciclastic input. Besides rudist debris it is associated with other larger benthic foraminifera, common with Loftusia sp. , Omphalocyclus macroporus (Lamarck) , and Dicyclina schlumbergeri Munier-Chalmas , more rarely with Neobalkhania bignoti Cherchi, Radoičić & Schroeder , Persiella pseudolituus Schlagintweit & Rashidi and Dictyoconus bakhtiar . Schlagintweit, Rashidi & Babadipour. Besides some thalli of Salpingoporella pasmanica Radoičić , the paucity of calcareous algae is worth mentioning in the samples containing S. brasieri .

Occurrences and stratigraphy. Iraq: lower part of the Aqra Formation, Maastrichtian ( Görmüş et al., 2017). Iran: upper Maastrichtian Tarbur Formation (see Schlagintweit et al., 2016b). Görmüş et al. (2017, p. 365) noted the co-occurrence of Dicyclina and Loftusia with Suraqalatia . Due to the sole occurrence of the latter two taxa in the Maastrichtian of southeastern Turkey the authors state that the latter might extend in its distribution towards this area. If so this would imply the occurrence within the whole distributional area of Loftusia (see Fleury et al., 1990). As S. brasieri represents a taxon that can hardly be overlooked and that has not been illustrated elsewhere in the literature such an assumption remains just speculative and by no means proven. Last but not least, it should be mentioned that within the Tarbur Formation, S. brasieri has been observed in the two northern sections (Naghan and Mandegan sections) but not in the southern locality (?deeper environment) that we studied (Fasa section, see Schlagintweit et al., 2016b). Therefore it might be restricted to the middle and upper region of the Tarbur Formation within the Zagros Zone.

Figures

Fig. 3 Suraqalatia brasieri Görmüş, Lawa & Al Nuaimy, upper Maastrichtian Tarbur Formation of Mandegan (a, c) and Naghan sections (b, d, f); oblique, partly tangential sections. e development of annular chambers (in grey) in some orbitolinids (modified from Douglass, 1960, fig. 21) and two sections (X–X' and Y–Y') comparable to those illustrated in a–d, and f. Abbreviations: b = beam, ch = chamber, ib = intercalary beam, s = septum, sn = subepidermal network. Thin-sections: Rt 63 (a), 2NG 183 (b), Rt 36 (c), 2NG 146 (d), 2NG 169 (f).

Fig. 4 Suraqalatia brasieri Görmüş, Lawa & Al Nuaimy, upper Maastrichtian Tarbur Formation of Mandegan (a, e) and Naghan sections (b–d, f); oblique, partly tangential sections. Abbreviations: D = Dicyclina, L = Loftusia, N = Neobalkhania, O = Omphalocyclus. Scale bars = 1 mm. Thin-sections: Rt 63 (a), 2NG 183 (b), Rt 36 (c), 2NG 146 (d), 2NG 169 (f).

Fig. 5 Suraqalatia brasieri Görmüş, Lawa & Al Nuaimy, upper Maastrichtian Tarbur Formation of Mandegan section. Detailed view showing wall structure and exoskeleton (subepideremal network). Abbreviations: b = beam, ep = epiderm, f = foramen, s = septum. Thin-section Rt 63.