Cribellopsis arnaudae Chiocchini 1989
Creators: name: Schlagintweit, Felix
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Chromista
Foraminifera
Globothalamea
Loftusiida
Orbitolinidae
Cribellopsis
Cribellopsis arnaudae

description: Cribellopsis arnaudae Chiocchini, 1989
The Somali species Cribellopsis prestati possess striking similarities (e.g., rather voluminous embryo at the apex or slightly eccentric, bilocular with deuteroconch, equivalent exoskeleton, central zone with poor tendency to form an anastomosing reticulum, first and second order vertical partitions) with a taxon described by Chiocchini (1989) as Cribellopsis arnaudae from the upper Albian of southern Italy (see Chiocchini et al., 2012, fig. 9) (Fig. 1c, f–g, m, p, q, s). For both P. prestati and C. arnaudae, the original descriptions indicate (among others) as distinguishing criteria the comparably large-sized (sub)apical bilocular embryo and the ratio test height/diameter commonly around 1 (Peybernès and Delmas, 1981, p. 82; Chiocchini 1989, p. 46). Although Peybernés and Delmas (1981, p. 82) had only poorly preserved transverse sections at hand, they noted the presence of three intercalary beams ("trois cloisons secondaires"). The only differences seem to be a higher apical angle (see comments below for C. aff. arnaudae of Cruz-Abad 2018) and smaller dimensions in C. prestati, as indicated in the original descriptions (see comments below) (see Table 1). The differences can partly be explained by the exclusion of large-sized (presumably B-forms) of C. prestati on the one hand, combined with exclusion of juvenile specimens of C. arnaudae on the other hand. Prestat (1977, pl. 12, fig. 10) illustrated from the same level a large-sized low-conical orbitolinid of visibly identical internal structure as Iraqia sp. This specimen, here interpreted as a microspheric specimen, was not included in the species concept of P. prestati by Peybernès and Delmas (1981), and is here re-illustrated in Fig. 1r. Chiocchini (1989, pl. 2, figs. 2, 6, 15), on the other side, illustrated specimens of C. arnaudae with test diameter <0.4 mm, but the lowest value for the corresponding range was indicated as 0.685 mm. With maximum test height of 0.55 mm (Saint-Marc, 1974), the Lebanese specimens obviously belong to small-sized juvenile forms. Another example is the number of chambers in adult specimens indicated as "12 to 18" by Chiocchini (1989). The two large specimens shown in Chiocchini (1989, pl. 2, figs. 1 and 8), display about 25 chambers (almost the double maximum size as indicated). Summarizing, this means principally, that biometric data and respectively comparison tables included in original descriptions must be carefully checked, in cases be remeasured, and interpreted by subsequent workers (e.g., exclusion/inclusion/mixing of juvenile, adult specimens, A- and B-forms).
description: Published as part of Schlagintweit, Felix, 2020, Cribellopsis Moulladei (Saint-Marc, 1974) Nov. Comb. (Foraminiferida, Orbitolinidae): An Albian Marker Taxon Of The Southern Neotethysian Margin, pp. 37-41 in Acta Palaeontologica Romaniae 16 (1) on page 39, DOI: 10.35463/j.apr.2020.01.04, http://zenodo.org/record/10520716