Volumetric Body Mass Estimate and in vivo Reconstruction of the Russian Pareiasaur Scutosaurus karpinskii

Pareiasaurs (Amniota, Parareptilia) were characterized by a global distribution during the Permian period, forming an important component of middle (Capitanian) and late Permian (Lopingian) terrestrial tetrapod biodiversity. This clade represents an early evolution of sizes over a ton, playing a fundamental role in the structure of middle and late Permian biodiversity and ecosystems. Despite their important ecological role and relative abundance around the world, our general knowledge of the biology of these extinct tetrapods is still quite limited. In this contribution we provide a possible in vivo reconstruction of the largest individual of the species Scutosaurus karpinskii and a volumetric body mass estimate for the taxon, considering that body size is one of the most important biological aspects of organisms. The body mass of Scutosaurus was calculated using a 3D photogrammetric model of the complete mounted skeleton PIN 2005/1537 from the Sokolki locality, Arkhangelsk Region, Russia, on exhibit at the Borissiak Paleontological Institute, Russian Academy of Sciences (Moscow). By applying three different densities for living tissues of 0.99, 1, and 1.15 kg/1,000 cm3 to reconstructed “slim,” “average” and “fat” 3D models we obtain average body masses, respectively, of 1,060, 1,160, and 1,330 kg, with a total range varying from a minimum of one ton to a maximum of 1.46 tons. Choosing the average model as the most plausible reconstruction and close to the natural condition, we consider a body mass estimate of 1,160 kg as the most robust value for Scutosaurus, a value compatible with that of a large terrestrial adult black rhino and domestic cow. This contribution demonstrates that barrel-shaped herbivores, subsisting on a high-fiber diet and with a body mass exceeding a ton, had already evolved in the upper Palaeozoic among parareptiles, shedding new light on the structure of the first modern terrestrial ecosystems.

Deep mourning with the loss of Ekaterina Alekseevna (Katya) Sidorchuk (09.07.1981–20.01.2019), an excellent and promising palaeontologist

Ekaterina Alekseevna Sidorchuk (Katya to all that knew her) (Fig.1) was born in Moscow into a family of scientists: her father was a geomorphologist and her mother a Quaternary palynologist. Soil/peat microsamples from the North Russian Quaternary, the main research material of her mother, are commonly rich in oribatid mites, which Katya started to study when she entered the Geographical Faculty of Moscow State University after completing her high school education in 1998. In the Department of Biogeography, her study of Quaternary oribatids was guided by the known Russian acarologist, the late Prof. Dmitry Krivolutsky. Katya graduated from the University in 2004 and post-graduated in 2007 when she obtained her PhD degree for the study titled “Oribatid mites as bio-indicators of environmental change during the Holocene (modern and fossil bog communities of Northern European Plain)”. The next year, 2008, she entered the A.A. Borissiak Paleontological Institute and worked at the Arthropoda Laboratory until her recent untimely departure.

THE HISTORY OF GEOLOGICAL AND PALEONTOLOGICAL STUDY OF BOLSHOYE BOGDO MOUNTAIN

The history of the geological and paleontological study of Bolshoye Bogdo mountain, as well as the evolution of the views on their geological structure, has been considered.The first descriptions of the rocks composing the Bolshoye Bogdo mountain, published in the 18th century by academicians S.G. Gmelin and P.S. Pallas, have been given. A particular attention has been paid to the results obtained during the expedition conducted under the guidance of the English geologist R.I. Murchison in 1841. A great contribution to the knowledge of the geological structure and paleontological characteristics of Bolshoye Bogdo mountain was made by A.B. Auerbach, who discovered here the remains of Triassic temnospondyl amphibians and fish for the first time for the territory of European Russia. A new stage in the study of the paleontology of the Bolshoye Bogdo mountain, which began in 1912, has been characterized. A well-known paleontologist and writer LA. Efremov worked there in the 1926th and 1928th years and conducted scientific research and searches for vertebrate remains. Later, the study of the geological structure of the Bolshoye Bogdo mountain was carried out by the staff of the Saratov State University, Borissiak Paleontological Institute and other scientific institutions of Russia.