We describe a reasonably complete sauropod foot from the Early Cretaceous (Aptian–Albian) Ilek Formation at the Shestakovo locality in Western Siberia, Russia.It shows some primitive characters, such as slender metatarsals, a relatively long second pedal ungual, and three claws.In the likely presence of the laterodistal process on the first metatarsal the Shestakovo sauropod is similar with diplodocoids, but its more elongated and gracile first metatarsal resembles brachiosaurids (Brachiosaurus, Pleurocoelus, and Cedarosaurus), titanosaurids (Laplatasaurus), and Euhelopus. Pleurocoelus−like isolated teeth from the Shestakovo assemblage may support the brachiosaurid affinities of the Shestakovo sauropod, but a strongly procoelous mid−caudal vertebra from another locality in the same formation establishes the presence of a titanosaurid in the fauna.The foot described is referred here to as Titanosauriformes gen.et sp.indet.
Mammal remains from the Middle Jurassic (Bathonian) Berezovsk Quarry on the south of Krasnoyarsk Territory, West Siberia, Russia are referred to Docodonta indet. (two edentulous fragmentary dentaries) and Mammalia indet. (a single−rooted tooth). The dentaries exemplify a unique combination of plesiomorphic characters found among stem mammals only in Docodonta and Morganucodon: well developed Meckel’s groove, trough for postdentary bones with overhanging medial ridge and a diagonal ridge on the floor separating the “adductor fossa” and angular facet, and well developed and posteroventrally directed pseudangular process with facet for the reflected lamina of angular. Both specimens share with Docodonta the prearticular facet placed ventral to the angular facet and extending posteriorly to the mandibular foramen. This facet is not present in Morganucodon, where the prearticular lies medial to the angular. Medial position of the prearticular in Morganucodon is connected with the compound jaw articulation in this genus, in which a rudimentary articular−quadrate mandibular joint is present medially to the dentary−squamosal joint. In Docodonta indet. from Berezovsk Quarry, Haldanodon and Docodon the position of the prearticular ventral to the angular is connected with the position of the articular complex ventral to the dentary condyle. Such articular complex could not function as a mandibular joint and postdentary bones in Docodonta were used solely for sound transmission. One specimen from Berezovsk Quarry shares with Morganucodon a groove for replacement dental lamina, which was not reported previously for Docodonta. Mammal remains from Berezovsk Quarry are among the oldest occurrences for Docodonta, the first record of Jurassic mammals for Siberia, and only second such record for the whole of Russia.
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