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Baissa (PIN collection 3064) (Cretaceous of Russian Federation)

Where: Buryatia, Russian Federation (53.3° N, 112.1° E: paleocoordinates 56.0° N, 108.5° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Zaza Formation, Aptian (125.5 - 112.6 Ma)

• C. longipoda, E. trisetalis and Lycoptera all occur in the Zaza Formation indicating that this formation could be correlated with the upper Yixian Formation and the lower Jiufotang Formation in western Liaoning, which have a duration of 122.5-120 Ma. So it is possible to assign the Zaza Formation to an Aptian age. Also correlated with Barremian-Aptian based on plants and pollen.

• group of beds-level stratigraphic resolution

Environment/lithology: lacustrine - large; lithified marl

• "The water body is reconstructed as an intermontane lake with the depth of 20 - 30 meters (LYAMINA 1980) situated within a granite massif. The presence of thick layers of the bituminous shales shows that the lake was meromictic, with the oxygen deficiency and high hydrogen sulphur level in the hypolimnion. However, the oxygenated epilimnion should be thick, with a lower boundary well beneath the limit of episodic wave action because no suffocation events are documented. The abundance of caddisflies, dobsonfly larvae and other groups intolerant to oxygen deficiency shows that in more shallow areas the water was clear and well-oxygenated even near the bottom. The lake ecosystem was highly productive as indicated by its complex trophic structure (Fig. 2) with several levels of predators up to the large sturgeon-like fish Stychopterus as well as by the extremely high abundance of planetonivorous phantom midges (SINICHENKOVA & ZHERIKHIN 1996)." ZHERIKHIN et al., 1999

Size class: macrofossils

Preservation: mold/impression

Reposited in the PIN

Primary reference: A. P. Rasnitsyn. 1975. Hymenoptera Apocrita of Mesozoic. Transactions of the Palaeontological Institute Academy of Sciences of the USSR 147:1-134 [M. Clapham/J. Karr] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 105969: authorized by Matthew Clapham, entered by Matthew Clapham on 28.02.2011, edited by Lindy Edwards and Jered Karr

Creative Commons license: CC BY (attribution)