Crassispirellina, Gaillot, Vachard and Le Coze

Vachard, Daniel, Coze, François Le, Cózar, Pedro & Gaillot, Jérémie, 2019, Bozorgnites nom. nov. and Crassispirellina nom. nov.: New names for the preoccupied foraminiferal genera Bozorgniella and Crassispirella, Palaeontologia Electronica (4 A) 22 (1), pp. 1-7 : 3-5

Genus CRASSISPIRELLINA Gaillot, Vachard and Le Coze pro Crassispirella Gaillot and Vachard, 2007 emend.

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Etymology. Derivative of Crassispirella from Latin crassus (= fat), spira (= spire); i.e., thick-walled. The genus is feminine.

Type Species. Crassispirella hughesi Gaillot and Vachard, 2007 ( Figure 2 ). The holotype (plate 58, figure 10 in Gaillot and Vachard, 2007 = Figure 2.2 herein) is deposited in the collection of Total Company, Pau ( France).

Diagnosis. Test consisting of a proloculus followed by an undivided chamber. Planispiral coiling evolute. Some initial whorls are faintly glomospirally coiled. Aperture terminal simple. Thick porcellaneous wall bilayered with a darker tectum and an inner thicker greyish layer.

Other species. Hemigordius ? sp. A sensu Ueno (2001, plate 2, figures 19-20); H.? sp. B sensu Ueno (2001, plate 2, figure 23).

Occurrence. Late Changhsingian of Saudi Arabia; late Changhsingian of South China; Changhsingian of Turkey (Hazro); Lopingian of Persian Gulf (Gaillot and Vachard, 2007).

Remarks. Crassispirellina nomen novum is a planispiral evolute Neodiscidae that mimics several characters of cornuspirids, but fundamentally differs from the cornuspirids by its bilayered wall with a dark tectum and a thick and clear inner layer (very visible in the penulminate whorl of the holotype: Figure 2.2 ). Crassispirellina differs from other neodiscids by its planispiral coiling, and its test is discoid and biumbilicate. It encompasses several homeomorphous genera among the cornuspirids, which differ by their unilayered wall microstructure (e.g., Cornuspira, Postcladella , and Hoyenella ); but all of these genera are very small-sized.

On the other hand, Megacrassispirella Zhang in Zhang et al. (2016) has been described as being similar to Crassispirella . Crassispirellina differs from Megacrassispirella by its smaller size and smaller number of whorls. Nevertheless, some paratypes of Crassispirellina hughesi ( Figure 2.1, 2.6 ) are possibly transitional to Megacrassispirella . The similarity between both genera is confirmed herein, and it could also be possible that Megacrassispirella belongs to the family Neodiscidae and not to the Agathammininae, as originally stated. Alternatively, for classifications not based on the importance of the wall microstructure, an assignment of both genera to the Cornuspirinae might be acceptable.

Moreover, a poorly known genus, very large and described as bilayered, Kozhimia Igonin, 1998 , could be theoretically similar to Crassispirellina . However, this possible priority cannot be sustained for the following reasons. First, the two genera are of different ages: Kozhimia is Ufimian (early Middle Permian), whereas Crassispirellina is latest Permian in age. Second, the bilayered wall of Kozhimia is not precisely described nor visible on the unique illustration of Igonin (1998). Third, Kozhimia is only illustrated in equatorial section, and its perpendicular axial section remains hypothetically described in the text. Lastly, Kozhimia was never redescribed after its creation, which makes any further comparison purely hypothetical. In reality, Kozhimia seems to be more related to these large, late Early Permian and Middle Permian genera originally described as Hemigordius sensu Grozdilova, 1956 , sensu Rauzer-Chernousova in Akopian (1974), and sensu Kobayashi (2002, figures 9.19, 9.20); secondly as Neodiscus sensu Ueno (1992) ; thirdly as Neohemigordius sp. sensu Kobayashi (1993, plate 1, figure 3); and fourthly as Uralogordius Gaillot and Vachard (2007) synonym of “ Arenovidalina ” sensu Baryshnikov et al. (1982) not Ho (1959). Furthermore, the holotype of Kozhimia has similarities with the transverse section of Hemigordius discoideus Reitlinger, 1950 , illustrated by this author (plate 3, figure 14) from the Myachkovian (latest Moscovian) of Russia.

Compared with the evolutionary scheme of the Tournayellida sensu Hance et al. (2011), the relationships of Crassispirellina and Cornuspira are similar to those of Eoforschia and Eotournayella . Similarly, in foraminiferal history, a phylogenetic lineage, existing among the Loeblichioidea, which initially displayed a very deviated coiling (e.g., in Dainella or Pojarkovella ), leads finally to Loeblichia , which is a planispiral and evolute genus. As a consequence, Crassipirellina is maintained here in the Neodiscidae , even if the coilings of Neodiscus and Crassispirellina are very different.

No biological or paleobiological explanations have been given for such patterns of evolution: gigantism in the planispirally evolute lineages; adoption of a discoid planispirally coiled test in lineages initially nautiloid to subglobular and with strong deviations of the coiling axis. This is a very interesting issue in the evolution of the Foraminifera.

Figures

FIGURE 2. Crassispirellina hughesi (Gaillot and Vachard, 2007) modified from plate 55, figure 3; plate 56, figure 10; plate 59, figure 8; plate 66, figures 17-18; plate 69, figure 4 in Gaillot and Vachard (2007). 1, paratype relatively atypical (see comments in the text). 2, holotype. Axial section (see comments in the text). 3, paratype. Subequatorial section relatively well-preserved in the last whorls. 4-6, three paratypes in subaxial sections (see comments in the text for Figure 2.6). Scale bar equals 0.400 mm.