PSEUDOPFENDERININAE Septfontaine, 1988

SCHLAGINTWEIT, FELIX & SEPTFONTAINE, MICHEL, 2023, Siphopfenderina Gen. Nov. (Type-Species Arenobulimina Geyikensis Solak, 2022), A Primitive Pfenderinid Foraminifera From The Cretaceous Of Neotethys, Acta Palaeontologica Romaniae 19 (1), pp. 53-60 : 54-55

Subfamily PSEUDOPFENDERININAE Septfontaine, 1988

Diagnosis: Test trochospirally coiled throughout. Siphonal canal situated axially, or massive axial columella made by interseptal pillars and calcitic infilled material between pillars in advanced forms. No subcameral tunnel. Vertical radial partitions may be present in the last chambers of advanced genera. Aperture single associated with siphonal structure, or multiple associated with pillars ( Septfontaine, 1988, p. 245).

Remarks: Septfontaine (1988) erected the subfamily Pseudopfenderininae including the two genera, Siphovalvulina Septfontaine, 1988 (with axial siphonal canal = hollow columella in Septfontaine, 2020, p. 149) and Pseudopfenderina Hottinger, 1967 (with axial solid columella). Concerning the terminology used, Hottinger (2006, p. 11) defined a columella “as a solid trochospiral structure formed by the basal walls of spiral chambers coalescing around the coiling axis, as in many gastropod shells”. Gale et al. (2018, p. 269) removed Siphovalvulina from the Pseudopfenderininae , instead including it in the new family Siphovalvulinidae defined (besides other features) as “triserial, may later become biserial … (and with)… “ paraporous wall ”. Leaving apart the problem of the distinction between pseudokeriothecal or paraporous walls, Siphopfenderina gen. nov. with a trochospire exhibiting numerous chambers per whorl cannot be includ- ed in the Siphovalvulinidae . It is herein included within the Pseudopfenderininae due to its primitive pfenderinid morphology and multiserial coiling (see also Septfontaine, 2020).

Siphopfenderina gen. nov.

Type species Arenobulimina geyikensis Solak, 2022 Holotype: The holotype specimen is the subaxial section illustrated by Solak (2022) in plate 1, figure A, thinsection labeled Gç47H and deposited in the collection of Paleontology at the General Geology Laboratory, Department of Geological Engineering (Mersin University, Turkey).

Etymology: The generic name is derived from the central siphon, combined with the name Pfenderina .

Diagnosis: Test free, elongate-conical, consisting of trochospirally coiled chambers arranged in a few sometimes irregularly whorls with a central siphon or hollow columella. The siphon may become larger in adult

Table 1

chambers forming a deep open umbilicus. Proloculus spherical, in apical position. Wall thick imperforate microgranular with pseudokeriotheca and covered by a tectum; septal walls solid.

Comparisons: Pseudopfenderina Hottinger, 1967 differs from Siphopfenderina above all by its solid columella and the lack of a pseudokeriothecal wall ( Fig. 1.1-1.5 ). Siphovalvulina Septfontaine, 1988 posses a central siphon like Siphopfenderina , but differs from the latter by a triserial test that may later become biserial (see Gale et al., 2018). It is worth mentioning that the central siphon or hollow columella (= pseudoumbilicus in Solak, 2022) is poorly visible in the illustrated specimens from Turkey. Many of them are subaxial, tangential or oblique sections, where the central siphon is not sectioned at all or only partly, randomly. Following the interpretation of Gale et al. (2018), the siphon is formed by addition of the interior wall of the successive chambers. Last but not least, Siphopfenderina gen. nov. may also be compared with the Maastrichtian Pseudochablaisia Schlagintweit, Septfontaine & Rashidi, 2019 ( Fig. 1.6-1.8 ). This lowtrochospirally coiled taxon shares with Siphopfenderina gen. nov. the presence of a central siphon and pseudokeriotheca. In Pseudochablaisia however, “a septal button (defined by Septfontaine, 1977) occurs in the basal center of the chambers at the floor of the simple slit-like aperture appearing as a dome-shaped knob” ( Schlagintweit et al., 2019, p. 111).

Other species: Besides Siphopfenderina geyikensis (Solak) comb. nov., the taxon described by Arnaud-Vanneau (1980) as Arenobulimina cochleata from the upper Barremian-lower Aptian of southern France is assigned to the genus Siphopfenderina . The central axial siphon (= columelle centrale in Arnaud-Vanneau, 1980, p. 449) is well discernible in the axial sections shown in pl. 81, figs. 11-13. Arenobulimina corniculum Arnaud-Vanneau, 1980 might also belong to Siphopfenderina showing a twisted axial siphon and, according to Solak (2022, p. 404), a pseudokeriothecal wall ( Arnaud-Vanneau, 1980, pl. 81, fig. 2). Also, for Arenobulimina corniculum, Arnaud-Vanneau (1980, p. 444) mentioned the presence of a “sorte de columelle” separating the chambers. Other specimens are clearly microgranular (pseudokeriotheca not visible) without agglutinated material compared to the deeper water “true” Arenobulimina . Thus, it gives evidence that the microgranular wall is (phylo)genetically separated from its isomorphic equivalent in deeper waters. It is worth noting that the general identification of the pseudokeriotheca depends on the quality of the thin section (e.g., thickness) and its state of preservation is often masked by diagenetic alteration ( Vicedo et al., 2014; Solak, 2021). It is worth mentioning that pfenderinids (including Siphopfenderina ) do not posses a so-called valvular tooth plate or dental plate (plaque dentaire in Arnaud-Vanneau, 1980, p. 444), instead there is a porous last chamber or sieve plate ( Redmond, 1964; Septfontaine, 1978). Species of Siphopfenderina might classically be differentiated by size and/or general morphology ( Solak, 2022, tab. 1). This in turn means that species are defined in some cases by subjective features (more ..., less ...), and partly also with overlapping biometric ranges.

Figures

Fig. 1 Comparison between Pseudopfenderina Hottinger (1-2), Siphopfenderina gen. nov. (3-5) (without scale), and Pseudochablaisia Schlagintweit, Septfontaine & Rashidi, 2019 (6-8). 1-2: from Hottinger (1967, pl. 19, figs. 9 and 16, Liassic of Morocco. 3: Aptian of Spain (see fig.1.9); 4: from Radoičić (1980, pl. 5, fig. 1, Upper Cretaceous,?Coniacian,?Santonian of Serbia). 5: Aptian of Iran (see fig. 1.7). 6-8: from Schlagintweit et al. (2029, fig. 7A, 7B, 6F = holotype, Upper Maastrichtian of Iran).