Where: Russian Federation (63.4° N, 161.2° E: paleocoordinates 54.0° N, 16.4° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Magiveem Formation, Gzhelian to Gzhelian (303.7 - 295.5 Ma)

• Middle Magiveem Formation, Jakutoproductus expositus-Palaeoneilo parenica zone. Upper Upper Carboniferous–lower part of the Lower Permian, lower half of the Orochian Horizon. Hindeodus and Streptognathodus were recovered in the studied location from within the middle part of the Magiveem Fm of the Parenian Regional Stage (Horizon). The ammonoid Eoshumardites aff. lenensis (Popow) was found near the base of the formation (Kutygin et al., 2008). The genus is an index of the Kasimovian in Siberia (Ruzhenzev, 1975; Kutygin et al., 2008), although its upper range may extend into at least the middle Gzhelian (Bogoslovskaya, 1997). The age of the succession above the studied bioherm came from another location downstream from the confluence with the Munugudzhak River, approximately 80 km north west from the studied locality. The early Sakmarian ammonoids Uraloceras margaritae Kutygin and Ganelin and Kolymoglaphyrites lazarevi Kutygin and Ganelin were identified in the middle part of Munugudzhak Horizon (Kutygin and Ganelin, 2011), which correlates approximately with the upper part of the Magiveem Formation at the studied location (Biakov, 2010). Accordingly, the age of the entire Magiveem Fm is considered here as Kasimovian–Sakmarian, although the lower Artinskian age for the uppermost part of the formation cannot be excluded. Because of the stratigraphic position of the conodont-bearing horizon within the middle Magiveem Fm (middle part of the 120 m-thick member 3 in Fig. 2) and the biostratigraphy of bivalves and brachiopods, we consider the age of the horizon as Gzhelian-lower Asselian. In terms of local biostratigraphy, it corresponds to Prothyris elongatus bivalve Zone or Verchojania mirandus brachiopod Zone (Ganelin and Biakov, 2006; Biakov, 2010).

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified siliciclastic sediments

Size class: macrofossils

Preservation: mold/impression

Collection methods: Repository: SVKNII

Primary reference: A. S. Biakov. 2019. Bivalves of northeast Asia at the Carboniferous-Permian transition. Paleontological Journal 53:241-251 [M. Clapham/M. Clapham/M. Clapham]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 202204: authorized by Matthew Clapham, entered by Matthew Clapham on 29.06.2019

Creative Commons license: CC BY (attribution)