Nezzazata Omara 1956

Genus Nezzazata Omara 1956 View in CoL

Nezzazata View in CoL is a small (generally <1 mm) trochospiral, planoconvex to unequally biconvex genus, typically with chambers containing a narrow internal plate extending back from one septum towards the previous septum ( Loeblich & Tappan, 1987). The wall is considered microgranular, and Schlagintweit & Yazdi-Moghadam (2022a) have demonstrated that in pristine material it is pseudokeriothecal. Whittaker et al. (1998) incorrectly considered the wall to be porcellaneous. The aperture extends from the umbilicus to the periphery, then bending sharply to parallel the peripheral margin, with an apertural tooth present. This toothplate extends backwards from its septum towards the previous septum but does not attach to it (see also comments under Trochospira avnimelechi View in CoL below).

Nezzazata View in CoL is a very common component of mid-Cretaceous Neotethyan microfossil assemblages, and there are numerous (c. 400) records of the genus in the literature. It is especially well known from middle and late Cenomanian strata. This was the period when nezzazatoids in general displayed their highest species diversity and morphological variation (Hamaoui in Schroeder & Neumann, 1985; Consorti et al., 2022).

The genus can also occur in suitable facies of the Early Cretaceous (for example in the Aptian Dariyan Formation of Iran where small morphotypes of Cenomanian taxa occur; Schlagintweit et al., 2024). The oldest published record of the genus is probably that of Hosseini et al. (2016) from Hauterivian strata in the Iranian Zagros (see also Gollestaneh, 1965) or that of Velić (1977) (see also Velić 2007) from the Hauterivian of Croatia. Other early records of the genus include, for example: Altiner & Decrouez (1982); Arnaud-Vanneau & Premoli Silva (1995); Arnaud-Vanneau & Sliter (1995); Neagu & Cîrnaru (2004); Husinec et al. (2009), Chiocchini et al. (2012), Ghanem & Kuss (2013), Hfaiedh et al. (2013); Solak & Taslı (2023), Navidtalab et al. (2024); and Alteneiji et al. (2024). The previously reported Early Cretaceous taxon Nezzazata simplex germanica Omara & Strauch is not regarded as a nezzazatid by a number of authors (e.g. Hamaoui in Schroeder & Neumann, 1985). A commentary on the early representatives of the genus, including the designation of new species can be found in Schlagintweit et al. (2024c).

Ranges of Nezzazata high into the Late Cretaceous are reported, but are often not substantiated by verified illustration (e.g. Ismail & Soliman, 1997). Nonetheless, there are sporadic records (e.g. Luperto Sinni & Richetti, 1978; Solak et al., 2019) that suggest the genus may be found in strata as young as Campanian and Maastrichtian. Nezzazata was introduced by Omara (1956) with just one species, Nezzazata simplex , from the Cenomanian of Egypt. Unaware of this publication, a few months later Smout (1956) introduced the synonymous genus Begia (type species Begia gyra ), with seven species described from what was thought to be the Turonian of southern Iraq, but is more probably Cenomanian. Since then, there has been some debate as to how many species of Nezzazata are valid (e.g., Reiss, 1957; Omara & Strauch, 1965; Hamaoui in Schroeder & Neumann, 1985; Whittaker et al., 1998; Omaña et al., 2019). There are currently 16 possible Nezzazata species in the WoRMS World Foraminifera database ( Hayward et al., 2024) of which 12 are considered as potentially valid, with most recorded from Cenomanian strata. In addition, a few others have also been named at some time in the literature, if only briefly. These taxa are shown in Table 2.

Many of the differences between the species introduced by Omara (1956), Smout (1956) and subsequent authors are minor in nature, thus we follow Hamaoui in Schroeder & Neumann (1985) and Consorti et al. (2022) and recognise in the Cenomanian Nezzazata simplex and Nezzazata ex gr. gyra , plus a further species, Nezzazata isabellae introduced by Arnaud-Vanneau & Sliter (1985) and known mostly, but not exclusively, from pre-Cenomanian strata. Arnaud-Vanneau & Sliter (1985) and Whittaker et al. (1998) recognise more species, but in the case of Whittaker et al. (1998), note that more taxonomic research is required.

Hamaoui in Schroeder & Neumann (1985) did not provide a definitive solution, stating that the lack of a statistical morphological/biometric study of the various species means it is not possible to determine if there is intraspecific variation, or distinct and separate taxa. According to Hamaoui in Schroeder & Neumann (1985), Nezzazata gr. gyra includes forms recognised as Begia gyra , B. conica and B. concava by Smout (1956). Nezzazata simplex includes forms recognised as B. calcarata , B. perforata and B. convexa . Nezzazata variabilis Basha and Nezzazata semirectilinea Basha are synonyms of Trochospira avnimelechi Hamaoui & Saint-Marc ( Schroeder & Neumann, 1985) . Trochospira is very similar; the two genera are sometimes used interchangeably (e.g., Berthou, 1973).

Three broadly defined (“pragmatic”) Nezzazata species are recognised herein as occurring in Cenomanian strata. A fourth distinctive taxon occurs in the late Albian. The characteristics of the four defined taxa are presented in Table 3 and they are discussed individually below.

It should be noted that random thin-sections will not always present views suitable for species identification and many records in the literature are thus questionable as to the species present (even the genus). There has also been an inconsistent use of species nomenclature in the many records of Nezzazata , with names used apparently interchangeably.

For a recent review and discussion of Nezzazata in terms of higher taxonomy see Schlagintweit & Yazdi-Moghadam (2022a). In essence, a pseudokeriothecal wall structure can be observed in Nezzazata in well-preserved specimens whereas typical forms appear homogenous and non-perforate.