Pseudocyclammina Yabe & Hanzawa 1926

Simmons, Michael, Bidgood, Michael, Consorti, Lorenzo & Schlagintweit, Felix, 2025, A Review Of The Identity And Biostratigraphy Of Cenomanian “ Larger ” Benthic Foraminifera: Part 2 - The Order Loftusiida (Excluding The Suborder Orbitolinina), Acta Palaeontologica Romaniae 21 (1), pp. 103-192 : 113-114

Genus Pseudocyclammina Yabe & Hanzawa 1926 (see Table 1 for diagnosis)

The inclusion of Pseudocyclammina in this subfamily/family does not follow Hayward et al. (2025) and the "WoRMS" database as discussed below.

Pseudocyclammina is a planispiral, agglutinated genus with coarse alveolar walls and septa that would appear to be relatively uncontroversial in terms of its higher classification but instead has become something rather more problematic. First proposed by Yabe & Hanzawa (1926) with the type species Cyclammina lituus Yokoyama, 1890 from the Late Jurassic – Early Cretaceous of Japan, it was said to differ from Cyclammina in having a cribrate rather than slit-like aperture and also having a tendency to uncoil.

No higher classification was proposed until Maync (1952) placed the genus in the Lituolidae family, Choffatellinae subfamily (and assigning d’Orbigny’s 1850 species – Lituola rugosa to Pseudocyclammina ). Loeblich & Tappan (1987) reassigned the Choffatellinae to the family Cyclamminidae Marie , superfamily Loftusiacea Brady.

However, almost contemporaneously, Septfontaine (1988) tentatively assigned Pseudocyclammina to a new family – the Hauraniidae ; new subfamily Amijiellinae , both within the superfamily Lituolacea . This was done primarily upon the basis of the “… progressive appearance of pillars in the ‘ Pseudocyclammina’ gr. parvula/muluchensis/ Anchispirocyclina lineage and in Alveosepta during the Upper Jurassic …” ( Septfontaine, 1988; p. 237; caption to figure 4). Loeblich & Tappan’s (1987; p. 102) genus description also included the phrase “… may have a few irregular pillars in a narrow zone …”. Septfontaine (1988) also noted in the same caption that Pseudocyclammina “ appears as polyphyletic ” (written as “… probably polyphyletic ” on p. 244). He went on to state that more research was needed, especially for Cretaceous taxa. Although illustrating several taxa in the Hauraniidae photographically, Pseudocyclammina was not one of them, and only a simple “cartoon- like” sketch was provided.

Despite Septfontaine’s evident uncertainty, several of his new families including the Hauraniidae were reassigned to a new suborder – the Orbitolinina – by Kaminski (2004) and maintained by him later ( Kaminski, 2014) and also to the present day in the WoRMS world foraminifera database ( Hayward et al., 2025). It was also a position followed, without discussion, by Simmons & Bidgood (2023). This new suborder was defined in full by Kaminski (2004; p. 251) as “ Test trochospiral or conical, later stage may have reduced number of chambers per whorl, or may become uniserial and rectilinear; chamber interior of advanced taxa subdivided by vertical or horizontal exoskeletal partitions or both, by radial or transverse partitions, or with interseptal pillars.” Kaminski’s re- assignment was presumably made on the basis that other genera in the Hauraniidae / Amijiellinae better fit the new subordinal criteria and Pseudocyclammina (although never firmly assigned to the family/subfamily by Septfontaine) was “swept up” with the others.

With the exception of “interseptal pillars” – which have not been conclusively proven in the genus (in an extensive treatment of exo- and endoskeletal structures, Hottinger, 1967, did not mention pillars in connection with any Pseudocyclammina species except P. muluchensis n. sp. which is now assigned to Streptocyclammina Hottinger ; see also Septfontaine, 1988, and see below) – none of the other subordinal characteristics of the Orbitolinina apply to what we know as Pseudocyclammina . It is difficult to envisage an obvious connection between the alveolar, planispiral Pseudocyclammina and, say, members of the family Orbitolinidae including “classic” internally- complex, uniserial cyclic/annular conical genera such as Orbitolina , for example (see Bidgood et al., 2024).

Moreover, we have seen no conclusive evidence for the presence of pillars in our studied Cenomanian material (e.g., Schlagintweit & Yazdi-Moghadam, 2023; see also Simmons & Bidgood, 2023) and, despite what may have been observed in Late Jurassic material and followed by us previously, we prefer to include (for the present paper) at least Cenomanian members of Pseudocyclammina within the Cyclamminidae herein, together with the morphologically similar genera Buccicrenata and Hemicyclammina (see also Albrich et al., 2015, p. 255).

Pseudocyclammina is a distinctive subspherical to somewhat axially compressed, planispiral (sometimes uncoiling) genus, with relatively thick, obviously alveolar, chamber walls and septa. In the mid-Cretaceous, Buccicrenata is the most likely confusion genus (see Buccicrenata ex. gr. subgoodlandensis herein), but can be distinguished by its single aperture, whilst that of Pseudocyclammina is cribrate. 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.

Pseudocyclammin a is a commonly encountered and arguably diverse genus in Jurassic – Early Cretaceous sediments of Neotethys (e.g. Hottinger, 1967; Banner, 1970; Whittaker et al., 1998) but is relatively uncommon in Cenomanian sediments with only two species known: Pseudocyclammina rugosa ( d’Orbigny, 1850) and Pseudocyclammina sarvakensis Schlagintweit & Yazdi-Moghadam, 2023 . Confusion taxa include the typically Late Jurassic – Early Cretaceous Pseudocyclammina lituus ( Yokoyama, 1890) and the Late Cretaceous Pseudocyclammina sphaeroidea Gendrot, 1968 and Pseudocyclammina massiliensis Maync, 1959 . P. sarvakensis is distinguished from all previously described Pseudocyclammina species by the relatively larger number of chambers (14-16) in the final whorl, and has not been observed to uncoil. P. rugosa is relatively large (0.8 – 4.3 mm in external diameter of the coiled portion according to Maync (1959 a) although illustrations in Maync (1952, 1959) 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) (a diameter: hickness 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 . A summary of the characteristics of the five Pseudocyclammina species mentioned above is shown in Table 2 and the two exclusively Cenomanian species are discussed below.

We have not considered in further detail the debate between describing the wall of Pseudocyclammina as “alveolar” (Schlagintweit & Yazdi- Moghadam, 2023; Simmons & Bidgood, 2023 and as used herein) or “labyrinthic” ( Gendrot, 1968; Maync, 1952, 1959) or a combination of both (Banner, 1966, 1970). Hottinger (2006) provided separate definitions (but not illustrations) for both kinds of structure/texture, but these are not unequivocal. Gušić (1975) also provided a discussion, distinguishing Everticyclammina from Pseudocyclammina claiming that the former genus is the only one to show an “alveolar exoskeleton” (p. 15) and the latter a “subepidermal meshwork type ” (p. 13). He went on to say (p. 15) that “ It is unclear whether Pseudocyclammina rugosa… possesses an alveolar rather than subepidermal meshwork exoskeleton… ” leading to more uncertainty in the terminology and raising the question of any significant difference between the terms. The terms used by the various authors above seem to be those of personal preference and further examination of type materials from many taxa would be required to provide clarification, which is beyond the scope of this work.