Cribellopsis arnaudae Chiocchini (Cruz-Abad 2018

Cribellopsis aff. arnaudae Chiocchini (Cruz-Abad, 2018)

Last but not least, Cribellopsis aff. arnaudae Chiocchini has recently been reported from the upper Albian of southern Italy by Cruz (2018) differing from C. arnaudae by a more acute apical angle and a higher number of chambers in the last 0.5 mm test length. In any case, the higher apical angle fits within the range observed in "P". prestati. The differences are here interpreted as environmentally driven rather than being of taxonomic importance (= separate species). It is worth mentioning, that in juvenile specimens the apical angle is mostly higher whereas in adult stages there is a tendency for test widening (Schroeder, 1962, p. 174). In conclusion, also the forms described as Cribellopsis aff. arnaudae Chiocchini by Cruz-Abad (2018) are considered as subjective synonyms of Cribellopsis moulladei as interpreted herein.

Stratigraphy: Peybernès and Delmas (1981) described Paracoskinolina prestati from the upper? Albian Mustahil Formation of Somalia based on material from Prestat (1977) (see synonymy). It is worth mentioning that the top of the Mustahil Formation is considered an earlymiddle Albian age by Russo et al. (1991). There are contrasting views about the stratigraphic distribution of Cribellopsis arnaudae from Italy. In the original description C. arnaudae was considered a good marker species for lower Albian inner platform carbonate facies (Chiocchini, 1989, p. 40). Later, in a new stratigraphic compilation, C. arnaudae was assigned a short interval within the lowermost upper Albian (Chiocchini et al., 2012, fig. 9). In a recent contribution by Schmitt et al. (2019, in press), C. arnaudae was reported from the lower Albian based on Strontium isotope stratigraphy (and biostratigraphic data). Taking into account these contrasting views, it appears pragmatic, for the moment being, to consider C. moulladei an Albian marker taxon.

Palaeobiogeography: C. moulladei (Saint-Marc) and the proposed junior synonyms Paracoskinolina prestati and Cribellopsis arnaudae have so far not been reported from the northern Neotethysian margin. Lebanon, southern Italy and Somalia were belonging to the southern Neotethysian margin (e.g., Dercourt et al., 1993). With respect to the Northern Neotethysian margin, there were more endemic taxa of Lower Cretaceous Orbitolinidae (Cherchi et al. 1981; Arnaud-Vanneau 2006) (Table 2). C. neoelongata (Cherchi & Schroeder, 1978), C. elongata (Dieni et al., 1963), C. thieuloyi Arnaud-Vanneau, 1980 and C. schroederi Arnaud-Vanneau, 1980 are all only known from areas formerly belonging to the northern Neotethysian margin in the upper Hauterivian-lower Aptian period (Clavel in Granier et al., 2013).