Venyukovia

Little can be said of the overall anatomy of Venyukovia beyond its mandibles and teeth. The partial jaw as preserved measures 52 mm long and is 18 mm high, including the crowns of the teeth. Ivakhnenko (1996) compared Venyukovia favourably to Otsheria, identifying a similar "shearing" dental apparatus between them compared to the more specialised jaws of Ulemica. Like Otsheria, the 'cheek' teeth are bulbous and roughly as wide as they are long. Notably, Venyukovia appears to lack a lower dentary shelf, a bony structure on the lower jaws of the venyukovioids Ulemica and Suminia and the dicynodonts. This shelf was an attachment point for the powerful lateral adductor jaw muscle that allowed these anomodonts to chew, pulling the mandible backwards, and the absence of the lateral dentary shelf in Venyukovia suggests it may have also lacked this muscle, restricting its jaws to simple up-and-down motions. ==Discovery and naming==

The only known fossil of Venyukovia was discovered in 1908 by Russian geologist Pavel Nikolaevich Venyukov, for whom it would later be formally named after in 1922. The specimen, now catalogued as PIN (Paleontological Institute) 48/1 was found by Venyukov isolated in a spoil heap of the Kargaly Mines of Orenburg. However, they had since shut down by the time Venyukovia was discovered, and the precise mining locality from where it was collected is unknown. Venyukov brought his finds to Russian palaeontologist Vladimir P. Amalitskii (a.k.a. Amalitzky), and in a posthumous publication of his notes in 1922 were formally named and briefly described as Venyukovia prima. Amalitskii had not recognised Venyukovia as a non-mammalian synapsid, and instead had thought it was a triconodont mammal (similar to the first therapsid fossils from Russian copper mines, which were also initially mistaken for true mammals in 1838). Venyukovia was later correctly shown to be a therapsid by Efremov in 1938, although he interpreted it as a dinocephalian. The true anomodont affinities of Venyukovia were not recognised until 1942 by the English palaeontologist D. M. S. Watson, who would later coin the infraorder Venyukovioidea for it and similar forms from Russia that had been discovered since then with American palaeontologist Alfred Romer in 1956. Historically, numerous more complete skulls and jaws were referred to Venyukovia from Isheevo, Tatarstan and named as a second species (V. invisa) by Efremov in 1940. In 1983, Chudinov synonymised V. invisa with V. prima, however, in 1996 V. invisa and all its material were moved to their own genus entirely by Russian palaeontologist Mikhaïl Ivakhnenko, Ulemica. In the same paper, Ivakhnenko commented on similarities between the type specimen of Venyukovia and Otsheria, highlighting that the jaw and dental anatomy of Venyukovia matches what would be expected from Otsheria, a venyukovioid known only by its skull, and has even regarded them as potential synonyms. At the same time, Ivakhnenko also regarded the referred specimen PIN 48/2 as being more similar to Ulemica than Venyukovia. Thus, Venyukovia is now represented solely by the lecotype mandible. ==Classification==

Venyukovia is a member of the infraorder Venyukovioidea, a clade of basal anomodonts related to dicynodonts. Anomodonts were a highly successful group of therapsids, largely represented by dicynodonts but also by a handful of basal genera. Venyukovia was one of the first such basal anomodonts to be discovered, although it was mistaken to be an early mammal at first by Amalitskii due to its mammal-like dentition. ==Palaeoenvironment==

Although found across various individual mines and mixed in spoil heaps, the fossil flora and fauna of the Kargaly Mines can be recognised as a fossil assemblage. Namely, they have been correlated to the better known Ocher Assemblage Zone to the East. The Kargaly Mines have produced a diverse array of tetrapod, fish, invertebrate (including bivalves, conchostracans, and insects) and plant fossils, although due to their often fragmentary nature specific identifications are uncertain. Other tetrapods include, Chalcosaurus (a lanthanosuchoid parareptile), early tetrapods such as the seymouriamorph Discosauriscus netschajevi and an unidentified gephyrostegid, while temnospondyls are known by the archegosauroid Platyoposaurus. Numerous fossils from a wide variety of plants have also been discovered in the copper sandstones of the Kargaly Mines. These include spore-bearing plants like lycopods, horsetails such as Paracalamites, a Phyllotheca-like species, and trunks of the tree-like Calamites, as well as indeterminate ferns. Seed ferns are represented mostly by peltaspermaceans, including pinnate Permocallipteris and monopinnate Compsopteris leaf fronds, whereas the angaropeltacean Phylladoderma is rarer. Ginkgophytes are represented by the leaves Psygmophyllum, Kerpia, and Baiera, while conifers are known by Tylodendron shoots, Steirophyllum, and Cordaicarpus seeds. From the sedimentology of the deposits, the locality has been interpreted as being located near the foothills of the Paleo-Urals, with abundant vegetation growing around high-energy streams with heavy run-off from the western slopes of mountains. The forests were dominated by conifers and ginkgophytes, with an undergrowth of ferns and seed ferns and horsetails along the riverbanks. ==References==