Pseudocyclammina rugosa ( d’Orbigny, 1850 )

SIMMONS, MICHAEL & BIDGOOD, MICHAEL, 2023, “ Larger ” Benthic Foraminifera Of The Cenomanian. A Review Of The Identity And The Stratigraphic And Palaeogeographic Distribution Of Non-Fusiform Planispiral (Or Near-Planispiral) Forms, Acta Palaeontologica Romaniae 19 (2), pp. 39-169 : 82-84

Pseudocyclammina rugosa ( d’Orbigny, 1850)

Reference Illustration & Description

Maync (1952), Pl. 12, figs. 6-10, p. 50 and Maync (1959a), Pl. 1, figs. 10-15.

Pseudocyclammina is a well-established genus, occurring throughout the Jurassic and Cretaceous, and well known from its type species, P. lituus , which can be common in suitable Late Jurassic and Early Cretaceous facies from a number of locations across Tethys (e.g., Maync, 1959a; Banner, 1970; Kobayashi & Vuks, 2006). The test of Pseudocyclammina is typically a subspherical planispire, with relatively thick alveolar walls and septa. There is often an uncoiled stage. The aperture is cribrate (which distinguishes it from Buccicrenata ). Pseudocyclammina typically lacks the rapidly enlarging chambers and lobate equatorial profile of Buccicrenata . The alveoles are broad and less crowded than in Choffatella and similar genera.

The typical Cenomanian representative of the genus is P. rugosa , that despite illustration by Maync (1952, 1959a) remains poorly known. Lituola rugosa was introduced by d’Orbigny (1850) with a very short entry in a list of Cenomanian foraminifera, and there is no illustration. Maync (1952, 1959a) illustrated topotype specimens from the Cenomanian of Charente, France (see also BouDagher-Fadel et al., 2017) and discussed elements of the taxonomy (including his justification for placing the species in Pseudocyclammina ) and differences with similar taxa.

P. rugosa appears to be relatively large (0.8 – 4.3 mm in external diameter of the coiled whorl according to Maync (1959a) although illustrations in Maync (1952, 1959a) indicate maximum diameter, including uncoiled to be 4.78 – 6.0 mm) and this, together with a large chamber height, strongly curved thick septa, a rounded periphery, a relatively large axial thickness (0.7-2.3 mm) (diameter – thickness ratio 1 – 1.9, typically 1.4) and 5-7 chambers in the last whorl serve to distinguish it from other species of Pseudocyclammina and indeed Buccicrenata . Wall thickness in P. rugosa is 0.17 – 0.50 mm. 2-3 uncoiled final chambers can occur in both P. rugosa and B. ex. gr. subgoodlandensis . See the Species Key Chart (Appendix) for diagnostic and other characteristics.

Sampò (1969) illustrated a Pseudocyclammina from the Cenomanian of the Iranian Zagros as “ Cyclammina sp. (?)”. This relatively small form (external diameter 1.2 mm) with numerous chambers in the final whorl (in an approximately similar manner to the Late Cretaceous species Pseudocyclammina sphaeroidea Gendrot , see, for example, Schlagintweit, 1992) has been occasionally illustrated as P. rugosa in other publications on the Cenomanian Sarvak Formation of the Iranian Zagros (e.g., possibly Esfandyari et al., 2023). This form has new been described as a new species – Pseudocyclammina sarvakensis – by Schlagintweit & Yazdi-Moghadam (2023) (see below).

Stratigraphic Distribution

Albian – latest (?) Cenomanian.

Neumann et al. (1974) indicated that at its type locality, the species has a middle – late Cenomanian range. Rey et al. (1977) and Saint-Marc (1981) suggested that across Neotethys, this species ranges throughout the Albian and Cenomanian (see also Crosaz-Galletti, 1979), but in practice, despite many published occurrences, there are very few records of this species that have both plausible illustrations and precise biostratigraphic calibration. Its stratigraphic range may be confused by misidentification of, for example, Buccicrenata ex gr. subgoodlandensis .

Regarding its distribution within the Cenomanian, Bilotte (1973, 1985) illustrated plausible specimens from the Pyrenees and indicated that the species ranges throughout the Albian and Cenomanian in that region. Simmons et al. (2020b) illustrated a probable specimen of P. rugosa from the middle Cenomanian of south-east Turkey. However, a single axial specimen precludes confident identification.

The Cenomanian record of Kalantari (1976) is of B. ex. gr. subgoodlandensis , likewise the Albian record from the Zagros of Sampò (1969). Illustrated records from the late Cenomanian of Mexico ( Aguilera-Franco, 2003; Omaña et al., 2013) are most likely of Ammobaculites sp. (see also unillustrated record by Aguilera-Franco et al., 2001). Some illustrated records from the Cenomanian of Portugal ( Berthou, 1973; Boavida, 2013; Andrade, 2018), appear to be more compatible with B. ex. gr. subgoodlandensi s or cannot be confirmed as P. rugosa . Illustrated records from the Late Cenomanian of Morocco ( Ettachfini, 1993, 2006; Ettachfini & Andreu, 2004) appear to be of Ammobaculites / Lituola sp. , B. ex. gr. subgoodlandensis , or are indeterminate.

A form named as Pseudocyclammina cf. rugosa from the Cenomanian of Tunisia ( Bismuth et al., 1967) is small and its identity unclear (see also Bismuth et al., 1981 for an unillustrated record). Likewise, the records of relatively small “ P. rugosa ” from the Cenomanian of Armenia ( Danelian et al., 2014).

Illustrated records from the Aptian or older (e.g., Kalantari, 1976; Afghah & Haghighi, 2014 from the Iranian Zagros) are not this species (that of Afghah & Haghighi, 2014 = Ammobaculites sp. or Lituola sp. ), and unillustrated records from Aptian and older strata (e.g., Habibnia et al., 2010; Mansouri-Daneshvar et al., 2015; Afghah et al., 2016) should be treated with caution.

An unillustrated report from the Coniacian – Maastrichtian of Spain ( Gräfe, 2005) should most likely be regarded as erroneous.

Cenomanian Paleogeographic Distribution

Western Mediterranean –?Arabian Plate within Neotethys.

As can be understood from the limited number of confirmed records mentioned above, the paleogeographic distribution of this species is hard to determine. It has been described without illustration from the Albian – top Cenomanian of Lebanon ( Saint-Marc, 1970, 1974a, 1980, 1981); the early Cenomanian of the Dinarides ( Velić, 2007); the middle and late Cenomanian of Tunisia ( Abdallah et al., 1995; Touir et al., 2017); the middle – late Cenomanian of southern Iraq ( Al-Dulaimy et al., 2022); the Sarvak Formation of the Iranian Zagros ( Omidvar et al., 2014a, b; Assadi et al., 2016; Navidtalab et al., 2020; Ashgari et al., 2022); Provence ( Babinot et al., 1988); early Albian – top Cenomanian of Portugal ( Rey et al., 1977; Berthou & Schroeder, 1978; Berthou & Lauverjat, 1979; Crosaz-Galletti, 1979; Rey, 1979); Aquitaine ( Deloffre & Hamaoui, 1979); Syria ( Mouty et al., 2003); and Kuwait (El-Naggar & Al-Rifaiy, 1973). An illustration from the Cenomanian of Greece is unclear (Decrouez, 1978). A specimen illustrated as “ Buccicrenata? rugosa ” from the early Cenomanian of the Oman Mountains ( Simmons & Hart, 1987) is not clearly this species (it may be Buccicrenata ex. grp. subgoodlandensis ), whilst unillustrated P. rugosa has been mentioned from the late Cenomanian of the Oman Mountains ( Rabu, 1993).