The taxonomic status of Parathrinaxodon proops (Therapsida: Cynodontia), with comments on the morphology of the palate in basal cynodonts

The holotype and only specimen of Parathrinaxodon proops, a cynodont from the Upper Permian Kawinga Formation, Tanzania, is redescribed. Upper postcanines from the middle of the tooth row are ovoid in outline, presenting a large main cusp and tiny anterior and posterior accessory cusps on the sectorial margin. Anterior and posterior lingual cusps on the crown indicate the presence of a lingual cingulum. The overall postcanine morphology is remarkably similar to that of Procynosuchus delaharpeae, a Late Permian cynodont particularly common in the lower Beaufort Group of South Africa. The presence of a complete osseous palate and a medial palatal opening between the maxillae (=vomerine fossa) in Parathrinaxodon proops remain the main differences previously reported between this species and Procynosuchus delaharpeae. Restudy of the palate of Parathrinaxodon proops indicates that there exists some degree of deformation, particularly notable in the broken and distorted vomer. The supposed presence of the complete secondary palate and of the medial palatal opening in Parathrinaxodon proops are interpreted as resulting from a slight horizontal displacement of the long, and originally free, palatal processes of the maxilla and palatine. It is concluded that Parathrinaxodon proops is synonymous with Procynosuchus delaharpeae. This synonymy is problematic because Parathrinaxodon proops Parrington 1936 would have priority over Procynosuchus delaharpeae Broom 1937, but the latter is the best known Late Permian cynodont. Consequently, we propose to conserve Procynosuchus delaharpeae as the valid name for this cynodont based on article 23, section 9 (Reversal of precedence) of the International Code of Zoological Nomenclature. An analysis of the Kawinga fauna, using genus as the taxonomic unit for comparison, indicates strong similarity (67%) with faunas from theTropidostoma, Cistecephalus and Dicynodon assemblage zones from the SouthAfrican Karoo.Financial support was provided by the University of the Witwatersrand through a Postdoctoral Research Fellowship awarded to FA. The Royal Society of London and PAST (Palaeontology Scientific Trust, Johannesburg) provided FAgrants that enabled a research visit to the United Kingdom

Taxonomic studies of the genus Phymaturus (IGUANIA: LIOLAEMIDAE): Description of four new species.

After the study of a diverse collection of Phymaturus from three Argentinian institutions and additional samples collected in the last two years we discovered several populations of uncertain taxonomic status. Based on 93 morphological characters of squamation, color pattern, gular and nuchal folds, precloacal pores, and morphometric data, we conclude that at least four of those are independent lineages which require formal description. Characters related to sexual dimorphism and dichromatism as well as the ontogenetic change of several others, from juvenile to adult specimens, are described. According to the most recent revision of the genus (Lobo and Quinteros, 2005a) and considering the descriptions made in the last four years, the taxonomic composition of the genus was raised to 23 species. In this study we provide the formal description of four additional new taxa, including their diagnosis and detailed comparisons with other members of their species groups. Two new species belong to the patagonicus group (provinces of Chubut and Rio Negro, in Patagonia between 46° and 41° of latitude) while the other two belong to the palluma group (Neuquén and Catamarca provinces, western Argentina, 39° and 27‑26°30’of latitude respectively). With the exception of one case for which four localities are reported, all new species are restricted to their type localities. This fact confirms a common historical distributional pattern for most species of the genusPhymaturus from three Argentinian institutions and additional samples collected in the last two years we discovered several populations of uncertain taxonomic status. Based on 93 morphological characters of squamation, color pattern, gular and nuchal folds, precloacal pores, and morphometric data, we conclude that at least four of those are independent lineages which require formal description. Characters related to sexual dimorphism and dichromatism as well as the ontogenetic change of several others, from juvenile to adult specimens, are described. According to the most recent revision of the genus (Lobo and Quinteros, 2005a) and considering the descriptions made in the last four years, the taxonomic composition of the genus was raised to 23 species. In this study we provide the formal description of four additional new taxa, including their diagnosis and detailed comparisons with other members of their species groups. Two new species belong to the patagonicus group (provinces of Chubut and Rio Negro, in Patagonia between 46° and 41° of latitude) while the other two belong to the palluma group (Neuquén and Catamarca provinces, western Argentina, 39° and 27‑26°30’of latitude respectively). With the exception of one case for which four localities are reported, all new species are restricted to their type localities. This fact confirms a common historical distributional pattern for most species of the genuspatagonicus group (provinces of Chubut and Rio Negro, in Patagonia between 46° and 41° of latitude) while the other two belong to the palluma group (Neuquén and Catamarca provinces, western Argentina, 39° and 27‑26°30’of latitude respectively). With the exception of one case for which four localities are reported, all new species are restricted to their type localities. This fact confirms a common historical distributional pattern for most species of the genuspalluma group (Neuquén and Catamarca provinces, western Argentina, 39° and 27‑26°30’of latitude respectively). With the exception of one case for which four localities are reported, all new species are restricted to their type localities. This fact confirms a common historical distributional pattern for most species of the genus.Fil: Lobo Gaviola, Fernando Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Abdala, Cristian Simón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Valdecantos, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentin

Late Permian terrestrial faunal connections invigorated: the first whaitsioid therocephalian from China

The record of therocephalian therapsids from the late Permian of China has recently been greatly expanded by the discovery of severalnew taxa of Akidnognathidae, a group previously known principally from South Africa and Russia. Continuing this string of discoveries,we present here the first Chinese record of a whaitsiid therocephalian. This is also the first record published of a tetrapod fromJingtai, Gansu, a late Permian locality that also yields remains of other groups such as dicynodonts, captorhinids, and chroniosuchians.This is the third taxon of whaitsiid therocephalian recognized in North Pangea. The new therocephalian is similar to the RussianMoschowhaitsia vjuschkovi in overall appearance, and although they are only recovered as sister-taxa in 6 out of 30 most parsimonioustrees in our phylogenetic analysis, it is tentatively referred to Moschowhaitsia as a new species,M. lidaqingi. The phylogeny obtained islargely similar to previous hypotheses, recovering three main lineages of Eutherocephalia: Akidnognathidae, Whaitsioidea andBaurioidea. However, it differs from previous analyses in finding Chthonosauridae (comprising the Russian Chthonosaurus andZambian Ichibengops) to be deeply nested within Whaitsioidea. Therocephalians were among the largest carnivores in the late Permianof North China, and may have represented the top predators in some faunas.Fil: Liu, Jun. Chinese Academy of Sciences; República de ChinaFil: Abdala, Nestor Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. University of the Witwatersrand; Sudáfric

The emblematic South African therocephalian Euchambersia in China: A new link in the dispersal of late Permian vertebrates across Pangea

Therapsids were widely distributed in Pangea in the late Permian. South Africa in Gondwana and Russia in Laurasia are the principal areas recording tetrapods (including therapsids) of this age. More recent field explorations have increased the importance of Chinese late Permian fossil assemblages. This is clearly reflected in the discovery of several new therocephalians from the Naobaogou Formation in Nei Mongol. Here, we report a therocephalian from that unit identified as a new species of the emblematic South African taxon Euchambersia. The new species, Euchambersia liuyudongi, is represented by a well-preserved skull and mandible showing a well-developed maxillary fossa and the absence of postcanine teeth. This is the third akidnognathid therocephalian recovered from the Naobaougou Formation, but oddly, the two basal Chinese akidnognathids previously known were recovered from a younger unit of the formation than the derived E. liuyudongi. This is the first time that the same therocephalian genus has been recorded in northern and southern continents, making the record of the Naobaougou Formation key to understanding the evolution of late Permian continental fauna in general, and of akidnognathid therocephalians in particular.Fil: Liu, Jun. Chinese Academy of Sciences; República de ChinaFil: Abdala, Nestor Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Fundación Miguel Lillo; Argentina. University of the Witwatersrand; Sudáfric

Late Permian terrestrial faunal connections invigorated: the first whaitsioid therocephalian from China

The record of therocephalian therapsids from the late Permian of China has recently been greatly expanded by the discovery of severalnew taxa of Akidnognathidae, a group previously known principally from South Africa and Russia. Continuing this string of discoveries,we present here the first Chinese record of a whaitsiid therocephalian. This is also the first record published of a tetrapod fromJingtai, Gansu, a late Permian locality that also yields remains of other groups such as dicynodonts, captorhinids, and chroniosuchians.This is the third taxon of whaitsiid therocephalian recognized in North Pangea. The new therocephalian is similar to the RussianMoschowhaitsia vjuschkovi in overall appearance, and although they are only recovered as sister-taxa in 6 out of 30 most parsimonioustrees in our phylogenetic analysis, it is tentatively referred to Moschowhaitsia as a new species,M. lidaqingi. The phylogeny obtained islargely similar to previous hypotheses, recovering three main lineages of Eutherocephalia: Akidnognathidae, Whaitsioidea andBaurioidea. However, it differs from previous analyses in finding Chthonosauridae (comprising the Russian Chthonosaurus andZambian Ichibengops) to be deeply nested within Whaitsioidea. Therocephalians were among the largest carnivores in the late Permianof North China, and may have represented the top predators in some faunas.Fil: Liu, Jun. Chinese Academy of Sciences; República de ChinaFil: Abdala, Nestor Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. University of the Witwatersrand; Sudáfric

Evolution and identity of synapsid carpal bones

To date there is little information on carpal bone homology in late Palaeozoic and Mesozoic Synapsida. Crucial to the understanding of homology in synapsid carpal elements is the fact that different nomenclatures are used for the carpals of non-mammaliamorph Synapsida (Gegenbauer?s canonical nomenclature) and Mammaliaformes (mammalian nomencla-ture). The homologies of the carpals of non-mammaliamorph synapsids and mammals were established early last century and have not been reviewed since then. Here we provide a detailed study of the carpal bones of synapsids ranging in age from the early Permian to Late Cretaceous. The mammaliamorph lunate, previously considered the homologue of the intermedium of non-mammaliamorph synapsids, is interpreted here as homologous to their lateral centrale. We interpret the single mammaliamorph centrale as a homologue of the medial centrale of non-mammaliamorph synapsids. In some synapsid specimens, we found that one or two centralia are fused to the radiale (e.g., the gorgonopsian Arctognathus and tritylodontid Bienotheroides), supporting a digging habit. A third centrale is present in the therocephalian Theriognathus, very likely an abnormal duplication. An additional medial bone in a biarmosuchian was interpreted as a prepollex/sesamoid. A cartilaginous prepollex/sesamoid may also have been present in several non-mammaliamorph synapsids, which have an open space proximal to distal carpal I. Distal carpal V is completely lost in dicynodonts and it is mainly fused to distal carpal IV in the adult stage of most other therapsid groups, but showed a delayed development in most non-mammaliamorph cynodonts. In mammaliamorphs, distal carpal V is not present. Our observations provide an up-dated revision of synapsid carpal homologies, mainly on the basis of position and anatomical contacts and also taking into account the results of embryological studiesFil: Kummell, S.. University Witten/herdecke; AlemaniaFil: Abdala, Nestor Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Sassoon, J.. University Of Bristol; Reino UnidoFil: Abdala, Virginia Sara Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; Argentin

Las formas de intervenir en la escuela de las familias de sectores populares : El caso de una institución educativa urbano marginal de la ciudad de Tunuyán, Mendoza

Si bien la participación de las familias es un derecho según la Ley de Educación Nacional, en las escuelas que atienden a sectores populares los docentes señalan como problema la ausencia de los padres. Por otro lado, estudios etnográficos dan cuenta de “otras maneras de intervenir” de estos sectores. En este trabajo presentamos los avances del proyecto de investigación “Las familias de sectores populares y sus relaciones con la escuela. El caso de una institución educativa urbano marginal de la ciudad de Tunuyán, Mendoza” desarrollado en el IES T_004 Normal de Tunuyán (INFD Convocatoria 2013/ N° 2054). Su objetivo es comprender las relaciones con la escuela de las familias de sectores populares. ¿En qué actividades escolares participan los padres? ¿Cómo interpretan sus vínculos con la escuela? ¿Cuáles son sus maneras de intervenir? ¿Cómo se articulan sus prácticas de intervención en la institución escolar con sus estrategias familiares, sus trayectorias sociales y los recursos económicos y culturales que poseen? La estrategia metodológica es el estudio de caso. Las técnicas utilizadas son el análisis de documentos escolares y datos de los registro, la observación de situaciones escolares y entrevistas abiertas a docentes y a integrantes de las familias.Mesa 16: Estructura social de la Argentina. Desigualdades, estructura y movilidad social en la Argentina contemporáneaFacultad de Humanidades y Ciencias de la Educació

Nueva especie del grupo de <i>Liolaemus darwinii</i> (Iguania: Liolaemidae) del noroeste de Argentina

Dentro del género Liolaemus hay un grupo de especies que se caracteriza por la presencia de un parche de escamas agrandadas en la cara posterior del fémur, este conjunto de especies es llamado "grupo de L. boulengeri". Integrando este grupo de especies, se reconoce entre otros, un clado monofilético denominado grupo de L. darwinii, caracterizado entre otras particularidades por presentar las coronas de los dientes posteriores con bordes rectos y un marcado dicromatismo sexual. Dentro de este grupo se diferencia un conjunto natural de especies que habitan principalmente la región fitogeográfica de la puna y prepuna de la Argentina distinguiéndose por ser Liolaemus vivíparos, mayormente herbívoros, con elevado número de poros precloacales en las hembras. Este conjunto de especies ha sido denominado como grupo de L. ornatus (el cual estaría integrado por L. albiceps, L. irregularis, L. calchaqui y L. ornatus). En este trabajo se describe una nueva especie del género Liolaemus, integrante del grupo de L. ornatus colectada en los departamentos de Chicoana, La Poma y Cachi de la provincia de Salta entre 2.800 y 4.100 msnm. Este nuevo lagarto presenta dicromatismo sexual, con un patrón de coloración dorsal en los machos en donde se destaca la presencia de dos bandas dorsolaterales muy marcadas con coloración que varía del castaño muy claro al amarillo, garganta manchada y vientre color amarillo o pardo rojizo. Al igual que las demás especies del grupo, esta nueva forma es vivípara. La especie que aquí se describe estaba confundida con Liolaemus ornatus, pero las diferencias en el patrón de coloración y escamación, indican que es una nueva especie del grupo de L. ornatus.Within the lizard genus Liolaemus there is a group of species characterized by the presence of a patch of enlarged scales on the posterior proximal surface of the thigh called the "boulengeri group". Within the boulengeri group is a clade called the "darwinii group" characterized by, among other things, the presence of posterior marginal teeth with straight borders, and marked sexual dichromatism. Within the darwinii group is subgroup called the "ornatus group" that lives in the Puna and Prepuna phytogeographic regions of Argentina, and may be distinguished by its viviparity, mainly herbivorous diet, and a high number of precloacal pores in females. The species currently included in the ornatus group are L. albiceps, L. irregularis, L. calchaqui, and L. ornatus. In this paper a new species of the ornatus group of Liolaemus is described from the departments of Chicoana, La Poma and Cachi in the Salta province, Argentina, from elevations between 2,800 and 4,100 m. This species exhibits marked sexual dichromatism, with the a dorsal pattern more prominent in males, dorsolateral bands well marked, a variety of colors including very light brown to yellow, a pigmented throat, and yellow or reddish-brown abdomen. As in other species of the ornatus group the new species is viviparous. This species been confused with Liolaemus ornatus in the past, but may be distinguished from that species by its coloration and scutellation.Asociación Herpetológica Argentina (AHA

A non-mammaliaform cynodont from the Upper Triassic of South Africa: a therapsid Lazarus taxon?

The tetrapod record of the ‘Stormberg Group’, including the Lower Elliot Formation, in the South African Karoo is widely dominated by archosaurian reptiles, contrasting with the therapsid dominion of the subjacent Beaufort Group. The only therapsids represented by skeletal remains in the Upper Triassic Lower Elliot Formation are the large traversodontid cynodont Scalenodontoides macrodontes and the recently described tritheledontid cynodont Elliotherium kersteni. Here we present a fragmentary lower jaw that provides evidence of a third type of cynodont for the Upper Triassic of South Africa. The fossil is tentatively assigned to the Diademodontidae. The latter representative of this family is known from the Late Anisian, and its tentative record in the Norian Lower Elliot Formation, if confirmed, will represent a case of Lazarus taxon. Thus, Diademodontidae apparently disappeared from the fossil record by the end of the Anisian and then reappeared in the Norian of South Africa, a stratigraphic interval of some 21 million years. This new cynodont record, together with the recently described Tritheledontidae, show that cynodonts are now the second most diverse tetrapod group in the Lower Elliot fauna.The University of the Witwatersrand, the National Research Foundation of South Africa, the Royal Society of London and PAST

Paleobiogeography of non-mamaliaform cynodonts: telling a mainly Triassic history from the southern hemisphere

We present herein the first paleobiogeographic analysis of non-mammaliaform cynodonts through the Reconstruct Ancestral State in Phylogenies (RASP) v4 software. The study is based in a composite phylogenetic tree of 118 taxa, eight from the Late Permian, 85 from the Triassic and 25 from the Jurassic. The tree was temporally calibrated using the PaleoTree package in an R interface. A Bayesian Binary Markov Chain Monte Carlo (BBM) analysis of 100,000 cycles and 100 chains was performed, including 12 a priori determined areas of provenance and allowing the maximum number of areas per node. The results indicate that the paleobiogeographic history of non-mammaliaform cynodonts was dominated by dispersions (62 events), followed by vicariances (43 events), and only a few extinctions (5 events). Cynodontia originated in South Africa, a fact supported by the vast majority of Late Permian cynodonts being represented in that area, with only two exceptions: Dvinia prima (Russia) and Nshimbodon muchingaensis (Tanzania-Zambia) and with Procynosuchus being the first cosmopolitan cynodont, represented in Africa and Eurasia. Our analysis suggests that Epicynodontia and Eucynodontia were also originated in South Africa; Cynognathia in an area consisting of South Africa, Tanzania-Zambia, Namibia, and Argentina; and Gomphodontia was restricted to the Africa in a common area conformed by South Africa, Tanzania-Zambia, and Namibia. Traversodontidae had South Africa as the most likely ancestral area, whereas the speciose clades Massetognathinae and Gomphodontosuchinae most probably originated in Brazil. Probainognathia had its origin in South Africa but soon dispersed towards Argentina, where the chiniquodontids and allies originated. More derived probainognathians are interpreted to have had their center of diversification and dispersal in Brazil, with later dispersions to South Africa, where Chalimininae originated, and to China, with the impressive diversification of Tritylodontidae at the Early Jurassic. Finally, Brazil is identified as the ancestral area of hypothetical ancestor of Brasilodon + Botucaraitherium, the sister group of Mammaliaformes. Our results show that the vast majority of non-mammaliaform cynodont clades had ancestral areas in the Southern Hemisphere, with the sole exception of Tritylodontidae. Likewise, although the origin of Cynodontia dates back to the Permian, the origin of the main non-mamaliaform cynodont lineages (i.e., Eucynodontia, Cynognathia, and Probainognathia) took place during Triassic.Fil: Seoane, Federico Damián. 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: 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: Abdala, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaXII Congreso de la Asociación Paleontológica ArgentinaArgentinaAsociación Paleontológica Argentin