Loftusiida Kaminski & Mikhalevich, 2004

Schlagintweit, Felix & Rashidi, Koorosh, 2017, Persiella Pseudolituus N. Gen., N. Sp., And Flabelloperforata Tarburensis N. Gen., N. Sp., Two New Larger Benthic Foraminifera From The Upper Maastrichtian Of Iran, Acta Palaeontologica Romaniae 13 (2), pp. 3-19 : 5-7

Order Loftusiida Kaminski & Mikhalevich, 2004

?Suborder Biokovinina Kaminski, 2004

Remarks: The suborder Biokovinina was defined by Kaminski (2004, p. 250) as follows: “Test free or attached, may be coiled in the early stage, later uncoiled or branched. Wall finely agglutinated, traversed by pores, or with a coarsely perforate or canaliculate inner layer and an outer imperforate layer”. Flabelloperforata n. gen. displays the wall structure of the Biokovinoidea . The unbranched forms assigned to this suborder are classically planispirally coiled forms that may uncoil in the adult stage. In Flabelloperforata n. gen. the initially coiling chambers are flaring becoming flabelliform, unknown so far from the Biokovinina and lower rank categories accounting for only a tentative assignment to this group.

?Superfamily Biokovinoidea Gušić, 1977

?Family Biokovinidae Gušić, 1977

Genus Flabelloperforata n. gen.

Type species: Flabelloperforata tarburensis n. sp.

Origin of the name: The name refers to the flabelliform test morphology and the tiny pores within the wall.

Horizon and locality: Late Maastrichtian limestones of the Tarbur Formation of the Mandegan and Naghan sections ( Fig. 2 ).

Diagnosis: Test free, flattened (to undulating), flabelliform, with rounded periphery. Initial part with spirally coiled chambers continuously increasing in size as added, then rapidly increasing in breadth, becoming flabelliform (but never cyclic). Chambers without any structures (no exo- and endoskeleton). The chamber sutures are distinctly depressed. Wall and septa equal in thickness. Solid septa are pierced by numerous (multiple) foramina, arranged in several parallel rows. Wall thin, dark-microgranular-like with close-set simple unbranching parapores (pseudo-keriotheca-like); thin epiderm present, may be decorticated.

Remarks and comparisons: First of all, we have to state that no section of the Iranian specimens demonstrates a cyclic (annular) chamber arrangement. The genus Flabellocyclolina (type-species F. laevigata ), established by Gendrot (1964) from the Coniacian-Santonian of southern France shares some similarities (test morphology, no internal structures) with Flabelloperforata n. gen. The foraminal type of the former is multiple with only one row of openings. Instead, the specimens from the upper Maastrichtian of Iran display foramina arranged in several parallel rows. Another difference is the wall structure, simple, microgranular, heterogeneous, without pores in Flabellocyclolina and pseudo-keriotheca-like in Flabelloperforata n. gen. More precisely, Gendrot (1964, p. 530, translated) stated: “Under normal light as well as under crossed Nichols, the wall shows a dark, heterogeneous aspect, but without any discernible grain”. With respect to Flabelloperforata n. gen., Flabellocyclolina can be considered a more primitive form, and its potential ancestor.

A possible section of Flabelloperforata tarburensis was illustrated by Afghah (2009, pl. 1, Fig. 4 ) from the Tarbur Formation as Vania anatolica Sirel erroneously concluding an early Paleogene age (see discussion in Schlagintweit et al., 2016a). Vania is different from Flabelloperforata n. gen. above all by its well developed subepidermal network of beams and rafters (exoskeleton) and its finely agglutinating imperforate wall. Other sections of Vania anatolica by Afghah (2016, Fig. 5h ) belong to the cyclic Neobalkhania bignoti Cherchi, Radoičić & Schroeder ( Fig. 5 ). Like Vania , Neobalkhania possesses an exoskeleton (see Cherchi et al., 1991) and an agglutinating imperforate wall, different from Flabelloperforata . It is worth mentioning that in the Tarbur Formation, both Flabelloperforata tarburensis and N. bignoti can co-occur. Summarizing, the test morphology combined with the lacking of any internal chamber structures (exo- /endoskeleton) and the pseudo-keriotheca-like wall structures differentiate Flabelloperforata n. gen. from all other genera.

Figures

Fig. 2 Location of the Naghan and Mandegan sections, the type localities of Flabelloperforata tarburensis n. sp., and Persiella pseudolituus n. gen., n. sp. (taken from google maps)

Fig. 4 Vertical distribution of Persiella pseudolituus n. gen., n. sp. and some other larger benthic foraminifera in the Tarbur Formation of the Mandegan section.

Fig. 5 Neobalkhania bignoti Cherchi, Radoičić & Schroeder from the upper Maastrichtian of the Tarbur Formation of the Mandegan (a), and Naghan sections (all others). a Subaxial section of a large specimen (diameter ~7 mm). b Axial section of a megalospheric specimen. c Four specimens in (sub)axial sections, and Dicyclina sp. (D). d Tangential section showing subepidermal network with coarse primary partitions (right below) and finer secondary partitions (left below). e Oblique axial section of a megalospheric specimen. f Fragmentary equatorial section, P = Persiacyclammina maastrichtiana Schlagintweit & Rashidi. g Oblique section of a megalospheric specimen showing large embryo with opening to the second annular chamber. Scale bars: a–b, d, f–g = 0.3 mm; C, E = 0.6 mm. Thin-sections: Rt 113 (a), 2NG 109 (b), 2NG 128 (c), 2NG 201-1 (d), 2NG 120 (e), 2NG 81 (f–g).