Vol 53, No 4 (2019)

Descriptions of four new radiolarian species from the material collected from the Cenozoic deposits of the submarine Vityaz Ridge (the island slope of the Kuril–Kamchatka Trench) are provided in the article. The descriptions of the new species Amphistylus gladiusiacus sp. nov. and Thecosphaerella tochilinae sp. nov. from the Upper Eocene–Lower Oligocene deposits are based on the criteria established for the class of spherical porous Sphaerellaria: the number of skeletal shells, the shape of the cortical shell, and the development of the system of spines and axopodial complex. The new species Stylotrochus bipedius sp. nov. and S. tripedius sp. nov. from the Lower Pleistocene are considered among stauraxon radiolarians of the class Stauraxonaria due to the discoid geometric shape of their skeleton. The history of changes in the systematic position of the family Spongodiscidae is reviewed, and a proposal is made to restore the name of the order Discoidea Haeckel, 1862.

A new genus Perakella gen. nov. including two species: P. shakhtauensis sp. nov. from the Upper Asselian of Middle Cisuralia and P. batteni sp. nov. from the Middle Permian of Malaysia, is described. A unique find of this genus in the reef limestones of Shakhtau is further evidence of the presence of elements of Tethyan taxa in the Early Permian communities of the Uralian corridor.

This paper briefly discusses changes in phylogenetic reconstructions and in opinions on the system of the family Medlicottiidae Karpinsky. The most recent version of the classification, proposed in the revised Treatise … (Furnish et al., 2009) is critically reviewed. Based on revision of old and examination of new data, the classification accepted by the present author is substantiated; diagnoses of some genera (Paramedlicottia, Parasicanites, Miklukhoceras) and geochronological ranges of others (Neouddenites and Medlicottia) are emended. The phylogenetic reconstructions of some medlicottiid lineages in the subfamilies Medlicottiinae, Sicanitinae, and Episageceratinae are revised.

The Permian brachiopods of the superfamily Richthofenioidea Waagen, 1885 (order Productida) were obtained from the Gundara formation, Kubergandian regional stage of the Darvaz Range, Tajikistan. The collection contains Gundaria insolita Angiolini et al., 2016, Hercosestria sp., Coscinarina sp., and Proteguliferina sp. The peculiarities of the shell preservation are described. An individual age of the brachiopods is determined by the growth rings. The shell interior and exterior were studied using various techniques including the X-ray microtomography.

A new study of the holotype of Riabininohadros weberae from the Upper Cretaceous (upper Maastrichtian) of Crimea (Besh-Kosh) reveals previously unknown fragments of femur, astragalus, and calcaneus. This taxon is characterized by a complex of primitive characters found in Iguanodontia and basal Ornithischia and its phylogenetic position can be defined as Styracosterna indet. The second dinosaur record from Crimea (Aleshino) is represented by a fragmentary skeleton, including cervical and dorsal vertebrae. It may belong to a derived iguanodontian or a primitive hadrosauroid. Thus, at least two species of dinosaurs coexisted in the Maastrichtian of Crimea.

A new species of Hyaenodontinae is described from a horizontal ramus of the mandible, the smallest Asian species of the subfamily, Hyaenodon pumilus sp. nov. from the upper Eocene of the Ergilin Dzo Formation of southwestern Mongolia. New specimens of H. chunkhtensis Dashzeveg, 1985 are described from the localities Khoer Dzan (Ergilin Dzo Formation, upper Eocene) and Tatal Gol (Shand Gol Formation, upper Oligocene). The specimens of H. chunkhtensis can be divided into two morphotypes.