Mayncina orbignyi ( Cuvillier & Szakall, 1949 )

SIMMONS, MICHAEL & BIDGOOD, MICHAEL, 2023, “ Larger ” Benthic Foraminifera Of The Cenomanian. A Review Of The Identity And The Stratigraphic And Palaeogeographic Distribution Of Non-Fusiform Planispiral (Or Near-Planispiral) Forms, Acta Palaeontologica Romaniae 19 (2), pp. 39-169 : 60-62

Mayncina orbignyi ( Cuvillier & Szakall, 1949)

Reference Illustration & Description

Arnaud-Vanneau & Prestat (in Schroeder & Neumann, 1985), Pl. 2, figs. 1-9, p. 16.

The genus Mayncina was introduced by Neumann (1965) with Daxia orbignyi (mistakenly referred to as “ Daxia d’orbignyi ” by Neumann) as the type species. Mayncina is similar to Biconcava and, in particular, Daxia . It is the most involute and broadly biconvex of the three genera and has tiny multiple (areal) apertures while the other two genera have single openings. Other potential confusion taxa include Stomatostoecha (Type species: Stomatostoecha plummerae ) described from the Albian of Texas. It has an aperture variously described as extensive slit-like ( Maync, 1972) or a vertical row of rounded openings ( Mikhalevich, 2004b) based on the figures of the holotype in Loeblich & Tappan (1988). Finally, Phenacophragma (Type species: Phenacophragma assurgens ) is similar but with an aperture as a slit at the top of the apertural face. All of these potential confusion taxa are difficult to separate in random thin-sections. See the Species Key Chart (Appendix) for diagnostic and other characteristics.

M. orbignyi is superficially very similar to Daxia cenomana (see that species discussion for key differences between the two, but note than in addition to the apertural difference, M. orbignyi is more inflated and distinctly biumbilicate). Loeblich & Tappan (1988) pointed out that specimens of D. cenomana illustrated by Neumann (1965) are in fact M. orbignyi (an error overlooked by Arnaud & Prestat in Schroder & Neumann, 1985).

M. orbignyi is the youngest species of Mayncina . Mayncina bulgarica Laug, Peybernès & Rey is a smaller form with a tendency to uncoil and become peneropliform (see comprehensive description by Maksoud, 2015), and has predominantly been referred to as occurring within the “Neocomian” (= approximately Berriasian – Hauterivian), with possible Albian records – for example, see Husinec et al. (2009) and Solak et al. (2021). Some Jurassic species have also been referred to Mayncina in the literature (e.g., Mayncina termieri Hottinger ) though should properly be referred to Lituolipora Gušić & Velić as discussed by Kabal & Tasli (2003) and Fugagnoli & Bassi (2015).

Mayncina hasaensis Basha is a poorly known species introduced from material from the late Cenomanian of Jordan ( Basha, 1978). From the limited illustrations it may have some affinity to Charentia cuvillieri .

Stratigraphic Distribution

(Late Albian?) middle Cenomanian.

M. orbignyi was first described from the middle Cenomanian of Charente, France ( Cuvillier & Szakall, 1949; Neumann, 1965). It was regarded by Arnaud-Vanneau and Prestat (in Schroeder & Neumann, 1985) as restricted to the middle Cenomanian, with tentative extension into the latest early Cenomanian and earliest late Cenomanian, but only limited evidence was provided in support. The only plausible well biostratigraphically calibrated records are those from the middle Cenomanian, with older records being unsubstantiated.

Decrouez (1978) recorded “ Mayncina d’orbignyi ” from the latest Albian – early Cenomanian (and possibly middle Cenomanian) of Greece, but without illustration, whilst Steuber et al. (1993) reported but did not illustrate a “cf.” form from the Cenomanian of Greece. Smith et al. (1990) and Orabi & Hamad (2018) also cite a middle Cenomanian age from Oman and Egypt respectively, but without adequate illustration. Both El Baz & Kassem (2020) and Shahin & El Baz (2021) record M. orbignyi from the supposed early – middle Cenomanian of the Gulf of Suez, but the illustrations are of disaggregated specimens and cannot have their identity confirmed. Likewise, an early-middle Cenomanian age is cited by Cherif et al. (1989) and by Orabi (1992), both from Sinai but without illustration. Shahin & Elbaz (2013) also cite a general Cenomanian age from Sinai, however their illustration is of an external (SEM) view and inadequate to determine the genus or species. Lastly concerning Egypt, El Baz and Khalil (2019) define a “ Daxia cenomana – Mayncina d'orbignyi Interval Zone” for the early Cenomanian of Sinai but provide no illustrations. A middle Cenomanian specimen from France illustrated by Bilotte (1985) cannot be confirmed as being this species.

De Castro (1991) mentions a “ Mayncina ” biozone for the Turonian carbonate platform in the central Apennines of Italy, but based on the limited information provided, it is difficult to assess this statement. However, it would appear not to refer to M. orbignyi or possibly Mayncina at all in the sense used herein but rather to Pseudocyclammina sphaeroidea Gendrot , which De Castro considered to belong in Mayncina .

Cenomanian records from Jordan ( Basha, 1978, 1979) are not confirmed by illustration, but an illustrated “cf.” form is recorded (as rare) from low in the (undifferentiated) Cenomanian or even “?Upper Albian” interval of Jordan by Weidich & Al-Harithi (1990). From the illustration of a single poorly preserved specimen its identity cannot be confirmed. Peybernès (1984) recorded, but did not illustrate, the species from the late Albian of the Pyrenees. Cherchi & Schroeder (1982) reported, but did not illustrate, a “cf.” form from the late Albian of Spain.

The illustrated records of M. orbignyi from the Barremian – Early Aptian of Sinai by Abu-Zied (2007) are most likely Choffatella decipiens Schlumberger.

Cenomanian Paleogeographic Distribution

Western/southern Neotethyan?

Arnaud-Vanneau & Prestat (in Schroeder & Neumann, 1985) only noted limited records from France and questionably Jordan. Additional reports cited above (whether identification is confirmed or not) indicate at best sporadic occurrences around the western and southern Neotethyan margins. An unusual record is that of Motamed al Shariati et al. (2016) who recorded but did not illustrate the species from the undifferentiated late Albian – early Cenomanian of the Lut Block in eastern central Iran. Specimens attributed to D. cenomana , but which may be M. orbignyi have been recorded from the middle to late Cenomanian of Mexico ( Omaña et al., 2012, 2019). Firm identification requires illustration of further material, not least axial sections. Records ascribed ‘cf.’ status or generic status only are not included in this geographic summary, nor are records from outside the Cenomanian.