Rajkanella hottingerinaformis Schlagintweit & Rigaud, 2015

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 : 129

Rajkanella hottingerinaformis Schlagintweit & Rigaud, 2015

Reference Illustration & Description

Schlagintweit & Rigaud (2015), Figs. 3 & 4 , p. 195-198.

Schlagintweit & Rigaud (2015) described this form from the middle-upper Cenomanian of Kosovo and remarked upon its similarity with the Paleocene genus Hottingerina Drobne, 1975 , from which it differs mainly by retaining a rounded aperture throughout growth, by possessing striate ornamentation and by not uncoiling. See the Species Key Chart (Appendix) for diagnostic and other characteristics.

Although the presence of numerous, interiorly-peripheral, short, beams convey a superficial similarity, it differs from contemporary genera such as Pseudorhapydionina and Pseudorhipidionina by having a coiled, lenticular test, a less complex aperture and lacks the tendency to uncoil. Fissumella , an early Albian genus introduced by Cruz-Abad et al. (2017) is morphologically close to Rajkanella , but in the latter genus the aperture is rounded whereas in Fissumella it is an elongate fissure.

Schlagintweit & Rigaud (2015) did not come to any conclusions regarding dimorphism in Rajkanella , but which was noted in Hottingerina species ( Drobne, 1975).

Stratigraphic Distribution

Middle – late Cenomanian.

Although compared with Paleocene forms, Schlagintweit & Rigaud (2015) recorded this species alongside middle-late Cenomanian taxa such as Pseudorhapydionina dubia , Vidalina radoicicae , Pastrikella balkanica (Cherchi, Radoičić & Schroeder) , Pseudonummoloculina regularis , Chrysalidina cf. gradata and Nezzazata cf. simplex from their material in Kosovo. Consorti & Schlagintweit (2021a) using additional Kosovan-Albanian material and the co-occurrence of other age-diagnostic taxa, confirm a late Cenomanian age.

It was also found in the middle and upper parts of the Sarvak Formation (=middle-late Cenomanian), Iranian Zagros, by Yazdi-Moghadam & Schlagintweit (2020, 2021) and Schlagintweit & Yazdi-Moghadam (2020, 2021, 2022a).

Cenomanian Paleogeographic Distribution

(Central – Eastern) Neotethys.

Not widely recorded except from those references mentioned above (i.e., confirmed by illustration in Kosovo-Albania and the Iranian Zagros).

Figures

Fig. 3 Cenomanian paleogeography with regions indicating the location of most planispiral LBF in this study. There are a few additional records from, for example, Peru, Afghanistan and Tibet. (Base paleogeographic map courtesy of Halliburton).

Fig. 4 Distribution map of type descriptions/specimens in this study.