Kriushi locality, 2 km southeast from Kriushi village (Cretaceous of Russian Federation)

Where: Ul'yanovsk, Russian Federation (54.1° N, 48.6° E: paleocoordinates 47.0° N, 50.9° E)

• coordinate stated in text

When: Deshayesites volgensis ammonoid zone, Early/Lower Aptian (125.5 - 122.5 Ma)

• Only a small part of the lower Aptian is exposed in this locality and is contained within the Deshayesites volgensis Zone (Baraboshkin & Mikhailova, 2002)

Environment/lithology: marine; nodular, carbonaceous shale and shelly/skeletal, gray shale

• The specimen YKM 65931 was not found in situ but embedded in a large limestone nodule lying on the shoreline. Field observations by I. M. Stenshin & G. N. Uspensky suggest this nodule is similar to those of the ‘upper nodule bed’ and would thus belong to the lower A. matheronianum Zone. This age, based on the biostratigraphy of heteromorph ammonites, is, however, tentative; therefore, we date this specimen with no further precision than Deshayesites volgensis Zone, because the whole section is contained within this zone in the Kriushi area.

•A 3 meters-thick unit of homogeneous grey shale of the Ancyloceras matheronianum Zone overlies the dark shale of the V. schilovkensis Zone. The shale contains scattered shell detritus at the bottom, followed by a bed of large to very large (up to 3 meters in diameter) carbonate nodule [this is the horizon of the specimen]. The following monomorph ammonites are present in this part of the section: Deshayesites multicostatus Swinnerton, 1953, D. consubrinoides (Sinzow, 1898), D. sp., Paradeshayesites sengillyensis (Sasonova, 1958), P. similis (Bogdanova, 1991), and P. imitator (Glasunova, 1968), among others. The following heteromorph ammonites are present in this part of the section: Ancyloceras matheronianum d'Orbigny, 1842, Lithancylus aff. grandis (Sowerby, 1829), and L. glebi Michailova & Baraboshkin, 2001

Size class: macrofossils

Collection methods: surface (float),

• YKM, Ulyanovsk Regional Museum of Local Lore named after I. A. Goncharov], Ulyanovsk, Ulyanovsk Region, Russian Federation.

Primary reference: V. Fischer, M. S. Arkhangelsky, G. N. Upensky, I. M. Stenshin, and P. Godefroit. 2013. A new Lower Cretaceous ichthyosaur from Russia reveals skull shape conservatism within Ophthalmosaurinae. Geological Magazine [R. Benson/R. Benson]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 140146: authorized by Roger Benson, entered by Roger Benson on 03.03.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

 Ichthyosauria - Ophthalmosauridae
Leninia stellans n. gen. n. sp.
Leninia stellans n. gen. n. sp. Fischer et al. 2013 ichthyosaur
Holotype YKM 65931, an articulated but incomplete skull preserved in three-dimensions