Broeckinella Hensoni N. Sp., a New Larger Benthic Foraminifera from the Upper Maastrichtian of Iran and a Revision of the Genus Broeckinella Henson, 1948
Total Page：16
File Type：pdf, Size：1020Kb
https://doi.org/10.35463/j.apr.2020.01.06 ACTA PALAEONTOLOGICA ROMANIAE (2020) V. 16(2), P. 57-67 BROECKINELLA HENSONI N. SP., A NEW LARGER BENTHIC FORAMINIFERA FROM THE UPPER MAASTRICHTIAN OF IRAN AND A REVISION OF THE GENUS BROECKINELLA HENSON, 1948 Felix Schlagintweit1* & Koorosh Rashidi2 Received: 5 March 2020 / Accepted: 7 April 2020 / Published online: 14 April 2020 Abstract A new larger benthic foraminifera is described as Broeckinella hensoni from the upper Maastrichtian Tar- bur Formation of SW Iran (Zagros Zone). In comparison to the type species of the genus, Broeckinella arabica Hen- son, which also occurs in the Tarbur Formation, the new species has distinctly larger dimensions (e.g., size and thick- ness of test, chamber height). The first record of a microspheric specimen of B. arabica shows previously unrecorded annular chambers in the final test stage. Therefore, the generic diagnosis is herein emended. In the Tarbur Formation, both B. hensoni n. sp. and B. arabica occur in foraminiferal-algal wackestones. However, B. arabica occurs in a wid- er range of microfacies, including packstones and grainstones. It is assumed that Broeckinella originated in the Upper Cretaceous with Broeckinella neumannae Gendrot. The upper Albian Broeckinella aragonensis Peybernès is herein transferred to the porcellaneous genus Peneroplis Montfort. Keywords: Foraminiferida, taxonomy, biostratigraphy, Upper Cretaceous, Arabian Plate INTRODUCTION form or annular). Later, these Thanetian forms were as- cribed to a new genus by Sirel and Gündüz (1985): Vania The larger agglutinating benthic foraminifera genus with the type-species being Vania anatolica. Vania dif- Broeckinella was established by Henson (1948) on the fers from Broeckinella by its annular chambers in the basis of an equatorial section (external view of a weath- final part of its adult test. More recently, another allied ered surface, holotype specimen) from the Maastrichtian taxon was established by Sirel (2012) as Postbroeckinella Simsima Formation of Dukhan No. 1 well of Qatar asso- (type-species Postbroeckinella flabelliformis), also from ciated with Loftusia and Omphalocyclus. Nonetheless, the Thanetian of Turkey characterized by an initial biseri- there followed a long discussion about the type-strata al stage (?) and a flabelliform test. In fact, the Late Creta- belonging to the Paleocene and not the Maastrichtian ceous Broeckinella arabica and the two Thanetian taxa (e.g., Drobne and Hottinger, 1971). The common occur- Vania and Postbroeckinella can only be reliably distin- rence of Broeckinella in the Maastrichtian of the Tarbur guished in sections passing through the initial stage Formation of the Iranian Zagros (an equivalent to the and/or sections of adult specimens displaying either annu- Simsima Fm. of Qatar) acords with the original view of lar or flabelliform chambers (e.g., centered equatorial Henson (1948) (Schlagintweit and Rashidi, 2016). Hen- sections). Bearing in mind that in large-discoidal forms son placed Broeckinella (with subepidermal network, most sections are oblique ones, this makes a correct de- flabelliform to reniform chambers and, as now known, termination almost impossible when other accompanying agglutinated wall) and Broeckina Munier-Chalmas [with- taxa are missing, allowing an attribution either to the Late out subepidermal network, with shallow lateral partitions, Cretaceous or Thanetian. It is worth noting that forms annular chambers and porcellaneous wall structure, e.g., similar to Broeckinella are unknown from Danian- Caus et al., 2013] in the same family, the Meandropsini- Selandian strata. Last but not least, it should be men- dae. It must be speculated that this misinterpretation of tioned that for these taxa the morphological variability wall structure was due to the lack of thin-section speci- and differences between micro- and megalospheric spec- mens. According to the critical literature review of Cher- imens are poorly known. chi and Schroeder (1978), Broeckinella has an initial Concerning Broeckinella, there are three species (besides planispiral stage and a flabelliform test morphology (not the type-species B. arabica) that have been described: becoming annular in the adult part). This statement refers Broeckinella neumannae (Santonian of France, Gendrot, to the single specimen illustrated by Henson, that belongs 1968), Broeckinella magna (Valanginian of Switzerland, to the macrospheric generation as clearly demonstrated Septfontaine, 1978), and Broeckinella aragonensis (Late by Cherchi and Schroeder (1991). Information on the Albian of Spain, Peybernès, 1984). Broeckinella magna microspheric generation has been lacking. These authors displays a coarsely agglutinated alveolar wall structure conclude that there is no verified other record of B. ara- (e.g. holotype specimen in Septfontaine, 1978, pl. 1, fig. bica besides that of its type-locality. The forms described 1) but not a delicate subepidermal network as reported as B. arabica by Drobne and Hottinger (1971) from the from B. arabica. Cherchi and Schroeder (1982a) note the Thanetian of Slovenia were doubted as belonging to Hen- resemblance of "B." magna to both Pseudochoffatella son's taxon. In this respect, Cherchi and Schroeder (1975) Deloffre and Balkhania Momontova and raise doubts noted the lack of information about the initial part and about the exact geometric pattern of the foramina (? missing evidence for the chamber morphology (flabelli- aligned in a row or cribrose). Broeckinella aragonensis ________________________________ 1 Lerchenauerstr. 167, 80935 München, Germany, *Corresponding author: [email protected] 57 2 Department of Geology, Yazd University, 89195-741 Yazd, Iran, [email protected] Felix Schlagintweit & Koorosh Rashidi Fig. 1 Peneroplis aragonensis (Peybernès) nov. comb. a Equatorial section. b Broken axial section (both from Peybernès, 1984, pl. 1, fig. 1 and 7, Late Albian of Spanish Pyrenees). c Detail from d showing fine surface ornamentation (striae). d Slightly oblique equatorial section. e Subaxial section showing fine striae of surface ornamentation (c-e from the Late Albian Barce- naciones Formation, Cantabria, N-Spain, leg M. Najarro). displays a homogeneous dark wall lacking a subepider- algae (James and Wynd, 1965). Towards the southwest, mal network (text-fig. 1a-b). Among the three new taxa the Tarbur Formation interfingers with the Gurpi For- described by Peybernès (1984) from the upper Albian of mation that usually underlies the former. In the strati- Spain, Fischerina? carinata displays the same porcella- graphic chart of Iran provided in 1995 by the Geological neous wall structure as "B." aragonensis, with a thin but Society of Iran, the Tarbur Formation is assigned to the distinct bright outer layer. Cherchi and Schroeder (1982b, Campanian-Maastrichtian interval. In recent times several pl. 2, figs. 1–7) illustrated the same form from the upper new genera of larger benthic foraminifera were described Albian of Asturia, northwestern Spain as "Soritidae inc. from the upper Maastrichtian of the Tarbur Formation sed." Supplemented by our own material from the upper (e.g., Schlagintweit and Rashidi, 2016, 2018; Consorti Albian of Cantabria (Najarro, 2015, for details) (Fig. 1c– and Rashidi, 2018; Consorti et al., 2019). Herein Broeck- e), Broeckinella aragonensis is considered as a repre- inella hensoni n. sp. and Broeckinella arabica Henson are sentative of Peneroplis De Montfort in accordance with described from two localities: the Naghan and Mandegan the assumed porcellaneous wall texture, its peneroplid sections (Fig. 2). test morphology, multiple foramina, and test surface or- namentation (striae) (e.g., Peybernès 1984, pl. 3, fig. 17; STUDIED SECTIONS see also text-Figure 1a–b). Peneroplis aragonensis can be compared with the late Albian-middle Cenomanian P. Naghan section parvus De Castro, 1965 and the early late Cenomanian P. cairoensis Chiocchini, 2008. With a maximum test diam- The studied section in the folded Zagros belt is located eter of 4.5 mm (Peybernès, 1984), P. aragonensis is approximately 50 km south west of the town of Naghan, much larger then P. parvus (De Castro, 1965: up to 0.82 near the village Gandomkar and is herein named the Na- mm) and also P. cairoensis (up to 1.2 mm). In addition, ghan section. The section occurs on the road from the the chambers of the latter are less arched than in P. ara- towns of Naghan and Izeh. At this locality, the Tarbur gonensis. It is worth mentioning that another porcellane- Formation is underlain by the Gurpi Formation and over- ous soritid was described by Deloffre and Hamaoui lain by the Paleocene Sachun Formation. Lithologically, (1969) as Pseudobroeckinella soumoulouensis from the the Gurpi Formation consists of dark, grey calacareous Santonian of France. shale with planktonic foraminifera. The Sachun For- In summary, with Pre-late Cretaceous of the genus doubt- mation consists of gypsum, red shales, anhydrite and ful, Broeckinella is herein considered as a foraminiferal some layers of carbonates. The thickness of the Tarbur genus originating in the Late Cretaceous Global Matura- Formation in the Naghan section is about ~ 274 m. It is tion Cycle of Hottinger (1999), with three species: B. composed of medium to thick-bedded grey limestone, neumannae Gendrot, B. arabica Henson, and B. hensoni shales and marls and can be subdivided into 5 units (from n. sp. the later species as described herein the present base to top) paper from the Tarbur Formation