The earliest cynodont therapsids from the Late Permian of the Karoo Basin, South Africa

Non-mammaliaform cynodonts were a widespread and successful group of advanced therapsids that arose in the early late Permian. The oldest described species are Charassognathus gracilis and Abdalodon diastematicus, both of which are known from single specimens from the Endothiodon Assemblage Zone (Tropidostoma-Gorgonops Subzone) of the Beaufort Group of the Main Karoo Basin, South Africa. Here we present two undescribed cynodont specimens from the same subzone, which comprise a second specimen of A. diastematicus and a new species of a small-bodied cynodont, housed at the palaeontological collections of the Council for Geosciences, Pretoria, South Africa and the Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa, respectively. Three of these four early cynodont specimens, excluding Charassognathus, were CT scanned using a Nikon Metrology XTH 225/320 LC dual source industrial CT system at the Evolutionary Studies Institute at the University of the Witwatersrand (Johannesburg, South Africa), enhancing the assessment of their craniodental morphology. Remarkable features of the new species include: the presence of a platform on the dentary, lateral to the lower postcanines; the absence of a masseteric fossa; two forms of sectorial postcanine teeth, whereby the anterior postcanines possess a posterior accessory cusp and the posterior postcanines have an additional anterior accessory cusp; and the presence of two small, canine-like postcanines in the dentary immediately distal to the canines. X-ray images of the new material of A. diastematicus suggest alternating dental replacement of the complex upper postcanines, which also seems to be the case for the lower incisors. A preliminary phylogeny retrieves Abdalodon as closely related to a monophyletic clade formed by the cosmopolitan Procynosuchus and the Russian Dvinia, whereas the new taxon and Charassognathus are successive sister species of remaining cynodonts.Fil: Abdala, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Benoit, Julien. University of the Witwatersrand; SudáfricaFil: Jasinoski, Sandra C.. University of the Witwatersrand; SudáfricaFil: Gaetano, Leandro Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Day, Michael O.. National Museum of Natural History; Estados UnidosFil: Rubidge, Bruce S.. University of the Witwatersrand; SudáfricaXII Congreso de la Asociación Paleontológica ArgentinaArgentinaAsociación Paleontológica Argentin

Reptile species persistence under climate change and direct human threats in north-western Argentina

Protected areas have been established historically in residual places where the potential for extractive uses is low, implying that places at risk are usually underprotected. Argentina is no exception,with fewprotected areas established in productive regions that are prone to conversion. Here, using reptiles as a study group and considering the most important human threats in north-westernArgentina,we estimated priority conservation areas where we expect species to persist in the face of climate change and land conversion. Protected areas cover no more than 9% of the study region, but represent less than 15% of reptile distributions. There are great opportunities for improving the conservation status in the region by protecting only 8% more of north-western Argentina, with the level of species protection inside the protected area network increasing almost four-fold, reaching 43% of species distributions on average and 59% of the distributions of threatened reptiles. Fortunately, the highest diversity of reptiles in the region does not match the places targeted for agriculture expansion. Our findings suggest that future prioritization schemes should embrace other groups that are especially diverse in the Chaco ecoregion, which overlaps with our study area.FONCYT and SECYTUNC. RL’s research has been constantly funded by CNPq (grants #308532/2014-7, 479959/2013-7, 407094/2013-0 and 563621/2010-9), O Boticário Group Foundation for Nature Protection (grant #PROG_0008_2013) and CNCFlora. This paper is a contribution of the Brazilian Network on Global Climate Change Research funded by CNPq (grant #437167/2016-0) and FINEP (grant #01.13.0353.00). RLP acknowledges the support of the Australian Research Council

Fish fauna of the Pandeiros River, a region of environmental protection for fish species in Minas Gerais state, Brazil

The Area of Environmental Protection of the Pandeiros River is the largest unit for sustainable use in Minas Gerais state, Brazil. The Pandeiros Wetland in the lower part of this river is considered a nursery for most migratory fish species of the São Francisco River and it is currently threatened by the introduced peacock-bass Cichla piquiti (Kullander & Ferreira, 2006). In this study, a list of fish species from the Pandeiros River was developed and compared with data for populations from other regions in the São Francisco basin. The presence of a new species record for the São Francisco River basin in the Pandeiros, and the particular local biotic and abiotic conditions of that river, support its recognition as an important conservation unit within the basin. © 2015 Check List and Authors

Spin and orbital disordering by hole doping in Pr1-xCaxVO3

High-resolution powder x-ray diffraction and single-crystal neutron diffraction were used to investigate the crystal structure and magnetic ordering of the compound Pr1-xCax VO3 (0 <= x <= 0.3), which undergoes an insulator-to-metal transition for x similar to 0.23. Since the ionic radii of Pr3+ and Ca2+ are almost identical and structural disorder is minimal, Pr1-xCaxVO3 is a good model system for the influence of hole doping on the spin and orbital correlations in transition metal oxides. The end member PrVO3 is a Mott-Hubbard insulator, which exhibits a structural phase transition at T-S = 180 K from an orthorhombic to a monoclinic structure with space groups Pbnm and P2(1)/b, respectively. This transition is associated with the onset of orbital ordering and strong Jahn-Teller distortions of the VO6 octahedra. Antiferromagnetic C-type order with vanadium moments oriented in the ab plane is observed below T-N = 140 K. Upon cooling, the vanadium moments induce a progressive magnetic polarization of the praseodymium sublattice, resulting in a ferrimagnetic structure with coexisting modes (C-x, F-y) and (F-x, C-y). In the insulating range of the Pr1-xCaxVO3 phase diagram, Ca doping reduces both the orbital and magnetic transition temperatures so that T-S = 108 K and T-N = 95 K for x = 0.20. The Jahn-Teller distortions and ordered vanadium moments also decrease upon doping. In a metallic sample with x = 0.30, Jahn-Teller distortions and long-range orbital ordering are no longer observable, and the average crystal structure remains orthorhombic down to low temperature. However, broadening of some lattice Bragg reflections indicate a significant increase in lattice strain. Antiferromagnetic short-range order with a weak ordered moment of 0.14(3) mu(B) per vanadium atom could still be observed on the vanadium site below T similar to 60 K. We discuss these observations in terms of doping-induced spin-orbital polaron formation