Where: Orenburg, Russian Federation (51.2° N, 58.2° E: paleocoordinates 44.0° N, 51.2° E)

• coordinate stated in text

• outcrop-level geographic resolution

When: Santonian (86.3 - 83.6 Ma)

• The second smaller outcrop exposes a small section consisting, from bottom to top, of four layers, and all vertebrate material came from layer 3. Several chondrichthyan taxa that are present in the Akkermanovka assemblage were found associated with foraminifera, radiolaria, and molluscs in Santonian strata in this region, i.e., Acrolamna acuminata, Cretoxyrhina mantelli, Eostriatolamia segedini, E. venusta, Hispidaspis cf. gigas, Pseudocorax laevis, Scapanorhynchus rhaphiodon, and Squalicorax kaupi. The presence of S. kaupi in our assemblage could indicate both a Santonian or an early Campanian age for the Akkermanovka assemblage. However, none of the other taxa that are characteristic for lower Campanian strata ("Squalicorax lindstromi Zone") in the Southern Urals are present in the Akkermanovka assemblage (see Amon et al., 1997). Nonetheless, certain taxa from Akkermanovka are also reported from Campanian deposits in Russia which are outside the Southern Urals; i.e., Eostriatolamia segedini, E. venusta, Pseudocorax laevis, and Squalicorax kaupi (Averianov and Popov, 1995; Ebersole et al., 2022). Acrolamna acuminata is regarded as a typical Santonian taxon in the Southern Urals and Russia in general (Zhelezko, 1987, 1990; Amon et al., 1997), however, similar morphotypes were also described from Campanian outcrops in the Southern Urals region: i.e., A. cf. acuminata, A. acuminata dilatata (Zhelezko, 1990; Amon et al., 1997). Cretoxyrhina mantelli and Ptychodus rugosus, on the other hand, are only known from lower and upper Santonian strata of the Southern Urals (Glickman and Zhelezko, 1979, 1990; Amon et al., 1997). However, scattered reports of post-Santonian occurrences of C. mantelli exist outside Russia in Europe (Siverson, 1992b; Sørensen et al., 2013) and North America (Siverson and Lindgren, 2005; Cook et al., 2017). Based on the taxa discussed above, a Santonian-?early Campanian age is suggested for the vertebrate assemblage in this study.

Environment/lithology: coastal; poorly lithified, glauconitic, pebbly, quartzose sandstone

Size class: macrofossils

Collection methods: Repository: Museum of the World Ocean (MMO) in Kaliningrad, Russian Federation

Primary reference: P. L. Jambura, S. V. Solonin, S. L. A. Cooper, E. V. Mychko, M. S. Arkhangelsky, J. Türtscher, M. Amadori, S. Stumpf, A. V. Vodorezov and J. Kriwet. 2024. Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia). Cretaceous Research 155(105779) [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 232890: authorized by Matthew Clapham, entered by Matthew Clapham on 05.01.2024, edited by Matthew Carrano

Creative Commons license: CC BY (attribution)