A new species of Argyromys (Rodentia, Mammalia) from the oligocene of the valley of lakes (Mongolia): its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan

We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene

First evidence of a neonate dentition in pareiasaurs from the Upper Permian of Russia

Finds of juvenile parareptiles are rare in the fossil record. We describe partial upper dentition with large vacuities between bones belonging to a neonate pareiasaur (preserved skull fragment is 22.4 mm long). The specimen was collected within 5 m from a skeleton of an adult specimen of Deltavjatia vjatkensis (Hartmann-Weinberg, 1937) (Pareiasauridae) from red calcareous mudstones in the upper part of the Vanyushonkov Member of Ursulov Formation (Upper Permian, Upper Tatarian substage, Vishkil'skiy regional stage) of Kotel'nich locality, Vyatka River region, Russia. Referral to Deltavjatia vjatkensis is based on the presence of heterodont dentition: spatulate maxillary, triconodont vomerine and conical, palatine and pterygoid teeth located on well-developed palate ridges. This is the first positively identified record of the neonate pareiasaur dentition

The formability of sheet blanks in the product under conditions of intense heat

When forming products from thermoplastic polymers and compositions on their basis, including sheet blanks, are passing heat and mechanical processes, which require special study: heating and cool-ing, viscous-plastic flow, sealing and shrinkage, the deformation of viscous stretching, consolidation. For sheet workpieces made of recycled polypropylene it was determined the kinetics of cooling in two modes: convective heat transfer in air and contact heat exchange in the chilled form. The work-pieces sheets for the study were obtained at the extrusion head of the manifold type. When molding product the experiment took place in conditions that are very close to real. Temperature measurement was carried out on the surface and in the center of the workpiece. To obtain the temperature profile across the thickness of the blank numerical analysis on the basis of the solution of the heat equation for one-dimensional flow was carried out. It is shown that the results of analytical calculation and experiment correlate well. The derived dependences used to determine the magnitude of the visco-fluid layer by thickness of the workpiece, which ensures the formab ility of the material in the fina l product, as well as to identify the optimal temperature and time parameters, while ensuring the adhesion bonds between the two heat-ed molds in the process of forming a composite product