Descrição do sincrânio de Cavia aperea (Rodentia, Caviidae) e comparação com as demais espécies do gênero no Brasil

The genus Cavia includes four species for Brazil, C.aperea (at least two subspecies, C.a.aperea and C.a.pamparum), C.magna, C.intermedia and C.fulgida. Aiming to contribute to the anatomy and to distinction of these species the syncranium (skull and mandible) of C.a.pamparum from Rio Grande do Sul State is described and compared with C.magna from Rio Grande do Sul and Santa Catarina States, C.intermedia from Moleques do Sul island on Santa Catarina's coast, and C.fulgida from Minas Gerais and Paraná States. Cavia aperea skull is lower and longer, with laterally compressed rostrum; marked interorbital constriction; elliptical orbit with broad communication with temporal fossa; broad and depressed infraorbital foramen; longer and lower mandible, with angular process not reflected laterally; dental formula 1I.0C.1P.3M; hypselodont teeth; molariforms formed for two prisms, the anterior laminar and the posterior cordiform. Cavia aperea distinguishes from C.magna by a less developed rostrum and ventral root of zygomatic process of maxilla; infraorbital foramen more depressed; posterior portion of dorsal surface of frontals and parietals less convex laterolaterally; paraoccipital apophysis shorter and more bent anteriorly; superior incisors narrower and generally opistodonts (proodonts in C.magna); external tertiary notch (fte) deeper with a thicker cement; anterior prolongation to fte more developed; and a constriction at the bottom of posterior prolongation. Cavia intermedia is distinguished by a shorter jugal; reduced/absent jugal fossa; more prominent depression in the interorbital region; larger sagittal crest; less marked lateral constriction in basisphenoid; wider magnum foramen; lower supraoccipital; fte less marked and its anterior prolongation little developed; the anterior prism of p4 as large as the posterior; anterior prism of m3 larger than posterior; shallow internal secondary notch in m3. Cavia fulgida differentiates by the smaller dimensions and a deeper fte. However southern Brazil specimens with these characters, but not typical coloration of C.fulgida, should belong to C.aperea. More studies are needed to clarify this issue.O gênero Cavia inclui quatro espécies no Brasil, C.aperea (pelo menos duas subespécies, C.a.aperea e C.a.pamparum), C.magna, C.intermedia e C.fulgida. Visando contribuir para o conhecimento da anatomia e para a distinção dessas espécies, descreve-se o sincrânio (crânio e mandíbula) de exemplares de C.a.pamparum do Rio Grande do Sul e compara-se com exemplares de C.magna deste estado e de Santa Catarina, C.intermedia da ilha de Moleques do Sul, na costa catarinense, e C.fulgida de Minas Gerais e Paraná. Cavia aperea possui crânio baixo e longo; rostro comprimido lateralmente; constrição interorbital marcada; órbita elíptica com ampla comunicação com a fossa temporal; forâmen infra-orbital amplo e deprimido; mandíbula longa e baixa, com processo angular não refletido lateralmente; fórmula dentária 1I.0C.1P.3M; dentes hipselodontes; molariformes formados por dois prismas, o anterior laminar e o posterior cordiforme. Cavia aperea distingue-se de C.magna pelo menor desenvolvimento da porção rostral do crânio e da raiz ventral do processo zigomático do maxilar; forâmen infraorbital mais deprimido; porção posterior dos frontais e parietais menos convexos; apófises paraoccipitais mais curtas e curvas anteriormente; incisivos superiores mais estreitos e geralmente opistodontes (proodontes em C.magna); fenda terciária externa (fte) mais profunda e com mais cemento; prolongamento anterior à fte mais desenvolvido e constrição na base do prolongamento posterior. Cavia intermedia possui jugal curto; fossa jugal reduzida/ausente; depressão na região interorbital bem marcada; crista sagital larga; constrição lateral no basisfenóide tênue; forâmen magno amplo; supra-occipital baixo; fte rasa e prolongamento anterior pouco desenvolvido; p4 com prisma posterior tão largo quanto o anterior; m3 com prisma anterior mais largo que o posterior e fenda secundária interna menos profunda. Cavia fulgida caracteriza-se por suas dimensões menores e fte muito profunda. Entretanto, exemplares do sul do Brasil com estes caracteres, mas coloração não típica de C.fulgida, podem pertencer à C.aperea, sendo necessários mais estudos para esclarecer esta questão

A coluna vertebral de Brazilosaurus sanpauloensis Shikama & Ozaki, 1966 da Formação Irati, Permiano da Bacia do Paraná (Brasil) (Proganosauria, Mesosauridae)

Este trabalho trata da descrição da coluna vertebral de Brazilosaurus sanpauloensis. O Áxis, e a coluna vertebral como um todo, mostram caracteres semelhantes àqueles de alguns dos mais antigos Amniota. No espécime mais completo, o número de vértebras pré-sacrais é trinta e cinco; a região cervical - com costelas fusionadas - exibe pelo menos treze vértebras (ou no máximo quinze); a primeira vértebra tóraco-lombar típica é a décima-sexta, apresentando esta região entre vinte, e vinte e duas vértebras; a região sacral tem duas vértebras fusionadas; e há cerca de sessenta e seis vértebras caudais. Em trabalhos prévios há erros, tais como: na interpretação do áxis como sendo o atlas; nos parâmetros para determinar os limites entre as regiões cervical e tóraco-lombar nos Mesosauridae. O melhor caráter para determinar os limites entre as regiões cervical e tóraco-lombar poderia ser o fusionamento costo-vertebral na primeira, se este caráter for constante nesta espécie. Outros e mais completos espécimes são necessários para esclarecer as dúvidas remanescentes. ABSTRACT This work deals with the description of the vertebral column of Brazilosaurus sanpauloensis. The axis, and vertebral column as a whole, present similar characters to those of some of the earliest Amniota. In the most complete specimen, the number of presacral vertebrae is thirtyfive; the cervical column - with fused ribs - exhibits at least thirteen vertebrae (or fifteen at the maximum); the first typical thoraco-lumbar vertebra is the sixteenth, this region presents twenty to twenty-two vertebrae; the sacral column has two fused vertebrae; and there are about sixty-six caudal vertebrae. There are mistakes in previous works such as: in the interpretation of the axis as being atlas; in the parameters to determine the limits between cervical and thoraco-lumbar regions in the Mesosauridae. The best character to determine the limits between cervical and thoraco-lumbar regions might be the costovertebral fusion in the first, if this character is constant in this species. Other and more complete specimens are needed to clarify the remaining doubts. RÉSUMÉ Ce travail traite de la description de la colonne vertébrale de Brazilosaurus sanpauloensis. LAxis et tout la colonne vertébrale montrent les caractères semblables a ceux de les Amniota plus anciènnes. Dans le spécimen le plus complet, le nombre de vertèbres du presacral est trente-cinq; la colonne cervicale avec les côtes amorcé expose au moins treize vertèbres (ou quinze au maximum); la première vertèbre thoraco-lombaire typique cest la seizième; cette région présente vingt à vingt-deux vertèbres; la colonne du sacral a deux vertèbres amorcé; et il y a approximativement soixante-six vertèbres caudales. Il y a des erreurs dans les travaux antérieurs tel que: dans linterprétation de lAxis comme être Atlas; dans les paramètres déterminer les limites entre cervical et régions thoraco-lombaires dans le Mesosauridae. Le meilleur caractère à déterminer les limites entre régions cervicales et thoraco-lombaires serait la fusion du costovertebral dans le premier, si ce caractère est constant dans cette espèce. Les spécimens plus complets sont necessaire à clarifier les doutes restants

Mesosaur taxonomy reappraisal: are Stereosternum and Brazilosaurus valid taxa?

Mesosaurs are basal amniotes that lived at the beginning of the Permian or close to the Permo–Carboniferous boundary. Despite the several hundred specimens that have been found, including complete skeletons of adult and juvenile individuals, mesosaur taxonomy has been subjected to a high controversy over time. Currently, three monotypic genera, Mesosaurus tenuidens Gervais, Stereosternum tumidum Cope, and Brazilosaurus sanpauloensis Shikama & Ozaki are recognized, but identification of new specimens using the available diagnostic characters are arbitrary and influenced by high subjectivity. We performed anatomical and morphometric analyses to look for statistical support to these previously suggested basic diagnostic characters through an exhaustive anatomical revision of these characters and also of some new attributes discovered during the course of our study. We found a notable influence of taphonomic features in most of the diagnostic characters used to differentiate the three monotypic genera, including strong bias derived from the preservation of individuals in different ontogenetic stages, whose size and degree of ossification could have been controlled by particular environmental conditions that resulted in subtle polymorphisms of these and other few characters. Other features may even represent sexual dimorphism. After the detailed revision of the type specimens of the three currently acepted mesosaur taxa, for which we include here good-quality photographs, and considering the lack of statistical support for the most applied putative diagnostic features such as the different ratio found when comparing skull and cervical region lengths and the low or higher intensity of pachyosteosclerosis observed in dorsal ribs, which can be controlled by taphonomic and ecological conditions, we recognize Mesosaurus as the only mesosaurid taxon in the Paraná and Karoo basins, probably including dwarf individuals. Therefore, S. tumidum and B. sanpauloensis are suggested here as nomina dubia taking into account that the autapomorphies that supported these taxa cannot be confirmed to be absent in Mesosaurus.Mesossauros são amniotas basais que viveram no início do Permiano ou próximo ao limite Permo–Carbonífero. A despeito das centenas de espécimes encontrados, incluindo esqueletos completos de indivíduos adultos e juvenis, a taxonomia dos mesossauros tem sido tema de muita controvérsia ao longo do tempo. Hoje, três gêneros monotípicos, Mesosaurus tenuidens Gervais, Stereosternum tumidum Cope, e Brazilosaurus sanpauloensis Shikama & Ozaki são reconhecidos, mas a identificação de novos espécimes utilizando os caracteres diagnósticos disponíveis é arbitrária e influenciada por alta subjetividade. Nós realizamos análises anatômica e morfométrica, tendo em vista obter um suporte estatístico para estes caracteres sugeridos como diagnósticos básicos por meio de uma exaustiva revisão anatômica destes caracteres, e de alguns novos caracteres descobertos durante o desenvolvimento de nosso estudo. Nós notamos uma notável influência de fatores tafonômicos na maioria dos caracteres diagnósticos utilizados para os três táxons monotípicos e incluindo uma forte preconcepção derivada da preservação dos indivíduos em diferentes estágios ontogenéticos, cujos tamanho e grau de ossificação poderiam ser controlados por condições ambientais que resultaram em sutis polimorfismos destes poucos caracteres. Outros aspectos podem mesmo representar dimorfismo sexual. Considerando a falta de suporte estatístico para a maioria dos putativos caracteres diagnósticos, tais como as diferentes relações entre comprimento do crânio e da coluna cervical e a pressão das condições tafonômicas e ecológicas, que podem ter controlado um menor ou maior grau de paquiosteoesclerose nas costelas dorsais, nós reconhecemos Mesosaurus como o único táxon de mesosaurídeo nas bacias do Paraná e Karoo, provavelmente incluindo populações anãs, e sugerimos que S. tumidum e B. sanpauloensis devem ser considerados como nomen dubium, levando em conta que as autapomorfias que suportam estes táxons não podem ser confirmadas como não estando presentes em Mesosaurus.Fil: Piñeiro, Graciela. Universidad de la República. Facultad de Ciencias; UruguayFil: Ferigolo, Jorge. Museu de Ciências Naturais; BrasilFil: Mones, Alvaro. Ministerio de Educación y Cultura. Museo Nacional de Historia Natural; UruguayFil: Núñez Demarco, Pablo Andrés. Universidad de la República. Facultad de Ciencias; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin

Isometry in mesosaurs: Implications for growth patterns in early amniotes

Mesosaurs were small amphibious tetrapods that lived in western Gondwana during the Early Permian or even earlier, when temperate Permo-Carboniferous conditions initiated after the glaciations that affected the southern region of Pangea. In this contribution, we applied traditional linear regression morphometrics to analyse proportions of both the skull and limb bones in more than 100 mesosaur specimens. The analyses revealed that all mesosaur bones scale remarkably close to a model of geometrical similarity (isometry), and that this pattern is particularly strong in long bones and also in the skull. These results indicate that juvenile and adult mesosaurs do not display appreciable change in bone proportions, meaning that there are few or no noticeable differences between them during growth. The well-defined isometry, and particularly, the high interrelation between metatarsals and phalanges permit us to suggest that the mesosaur hind limb is subject to notable modularity. This evidence strongly argues that the differences previously described to support three mesosaur species in Western Gondwana, might instead reflect natural intraspecific variability, taphonomic features or even possible sexual dimorphism, as recently suggested. Our study also reinforces the general plesiomorphic structure of the mesosaur skeleton, which along with some cranial specializations for ecological fitness and the evidence of strong isometric growth as we demonstrate herein, may suggest new hypotheses of relationships for mesosaurs which thus would position them as more basal amniotes than previously thought

Gregariousness in the giant sloth Lestodon (Xenarthra): multi-proxy approach of a bonebed from the Last Maximum Glacial of Argentine Pampas

Megamammals constituted an important component in the Pleistocene faunal communities of South America. Paleobiological and paleoecological studies involving different megamammal taxa have increased significantly in the last years, but there are still several poorly-known issues of its life history. In this work, we analyze an assemblage composed of 13 individuals of different ontogenetic stages, and possibly different sex, belonging to the giant ground sloth Lestodon armatus (Xenarthra, Folivora), recovered from Playa del Barco site (Pampean Region, Argentina). A dating of 19,849 years Cal BP allows assigning this assemblage to a period of the MIS (Marine Isotope Stage) 2 related to the end of the Last Glacial Maximum. Based on multiple lines of research (e.g. taphonomy, paleopathology, osteohistology, isotopy), we interpret the origin of the assemblage and diverse paleobiological and paleoecological aspects (e.g. social behavior, ontogenetic changes, sexual dimorphism, diseases, resource and habitat use, trophic relationships) of L. armatus. Evidence suggests that the assemblage was formed by a local single event of catastrophic mortality, which affected different members of a social group. This record represents the first accurate evidence of gregariousness for this ground sloth, providing new data on a poorly-known behavior among extinct Folivora

New sauropodomorph and cynodont remains from the Late Triassic Sacisaurus site in southern Brazil and its stratigraphic position in the Norian Caturrita Formation

Sacisaurus agudoensis is the only silesaurid known from the Triassic beds of the Santa Maria Supersequence and the correlation of its type locality to the other Triassic deposits of south Brazil has always been controversial. In an attempt to improve this, a handful of dinosaur and cynodont remains found associated to S. agudoensis are here described and compared. The anatomy of the sauropodomorph is more similar to that of Norian forms such as Pantydraco caducus and Unaysaurus tolentinoi than to that of Carnian taxa such as Saturnalia tupiniquim and Pampadromaeus barberenai. The cynodonts recovered based on isolated teeth include a brasilodontid and a Riograndia-like form. This assemblage is consistent with a Norian age, as is also suggested by local stratigraphic correlation, which positions the site in the Caturrita Formation

O final dos reinos: Diálogos entre Tiwanaku e La Aguada

Este escrito pone de nuevo a dialogar las iconografías de Tiwanaku (altiplano del Titicaca, Bolivia) y La Aguada (Noroeste de la Argentina), a más de 40 años de los trabajos de Rex González y de Ponce Sanginés. Lo hace en un contexto enteramente diferente con un énfasis decolonial. Objetos, imágenes, información etnográfica y arqueólogos de ambos lados de una frontera entre "naciones", se ensamblan con la clara intención de cuestionar supuestos subyacentes muy profundos de la arqueología. Metodología: a partir de los caminos que plantean las imágenes y colores, se amarran en estos nudos también los humanos y las cosas, las experiencias chamánicas y los fenómenos meteorológicos, todos enlazados de modo relacional. Conclusiones: tras poner a dialogar a La Aguada y Tiwanaku, con base en nuestras trayectorias investigativas, la discusión desemboca en una reflexión acerca de las consecuencias presentes de naturalizar miradas segmentadas y funcionalistas de los mundos animales y vegetales en el pasado, que se originan en los subyacentes ontológicos de nuestra propia modernidad. Originalidad: el texto apunta a abordar la crítica decolonial a partir del estudio de casos concretos y a aportar a esos debates desde materialidades arqueológicas.This paper once again brings the iconographies of Tiwanaku (Titicaca high plateau, Bolivia) and La Aguada (Northwest of Argentina) into discussion, more than 40 years after the works of Rex González and Ponce Sanginés. It does so in an entirely different context with a decolonial emphasis. Objects, images, ethnographic information and archaeologists from both sides of a border between “nations” are assembled with the clear intention of questioning very deep underlying assumptions of archaeology. Methodology: Beginning with the paths posed by images and colors, these knots also bind humans and things, shamanic experiences and meteorological phenomena. Conclusions: After bringing La Aguada and Tiwanaku into dialogue, based on our research trajectories, the discussion leads to a reflection on the present consequences of naturalizing segmented and functionalist gazes of the animal and plant worlds in the past, which originate in the ontological underpinnings of our own modernity. Originality: The text aims to approach decolonial criticism from the study of concrete cases and to contribute to these debates on the basis of archaeological materiality.Fil: Marconetto, María Bernarda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Villanueva Criales, Juan Eduardo. Museo Nacional de Etnografía y Folklore; Bolivi