232 research outputs found
Distichlis australis (Speg.) Villamil
Hab. In aridis subsalsis inter S. Julián et Río DeseadopublishedVersio
Draba australis R. Br. ex Hook. f.
Patagonia: Golfo de San JorgeFil: Ariza Espinar. Universidad Nacional de Cordoba. Facultad de Ciencias Exactas, Fisicas y Naturales; Consejo Nacional de Investigaciones Cientificas y Tecnicas. Instituto Multidisciplinario de Biologia Vegetal; Argentin
Exceptional skull of huayqueriana (mammalia, litopterna, macraucheniidae) from the late miocene of Argentina: Anatomy, systematics, and peleobiological implications
The Huayquerías Formation (Late Miocene, Huayquerian SALMA) is broadly exposed in westcentral Argentina (Mendoza). The target of several major paleontological expeditions in the first half of the 20th century, the Mendozan Huayquerías (badlands) have recently yielded a significant number of new fossil finds. In this contribution we describe a complete skull (IANIGLA-PV 29) and place it systematically as Huayqueriana cf. H. cristata (Rovereto, 1914) (Litopterna, Macraucheniidae). The specimen shares some nonexclusive features with H. cristata (similar size, rostral border of the orbit almost level with distal border of M3, convergence of maxillary bones at the level of the P3/P4 embrasure, flat snout, very protruding orbits, round outline of premaxillary area in palatal view, and small diastemata between I3/C and C/P1). Other differences (e.g., lack of sagittal crest) may or may not represent intraspecific variation. In addition to other features described here, endocast reconstruction utilizing computer tomography (CT) revealed the presence of a derived position of the orbitotemporal canal running below the rhinal fissure along the lateroventral aspect of the piriform lobe. CT scanning also established that the maxillary nerve (CN V2) leaves the skull through the sphenoorbital fissure, as in all other litopterns, a point previously contested for macraucheniids. The angle between the lateral semicircular canal and the plane of the base of the skull is about 26°, indicating that in life the head was oriented much as in modern horses. Depending on the variables used, estimates of the body mass of IANIGLA-PV 29 produced somewhat conflicting results. Our preferred body mass estimate is 250 kg, based on the centroid size of 36 3D cranial landmarks and accompanying low prediction error. The advanced degree of tooth wear in IANIGLA-PV 29 implies that the individual died well into old age. However, a count of cementum lines on the sectioned left M2 is consistent with an age at death of 10 or 11 years, younger than expected given its body mass. This suggests that the animal had a very abrasive diet. Phylogenetic analysis failed to resolve the position of IANIGLA-PV 29 satisfactorily, a result possibly influenced by intraspecific variation. There is no decisive evidence for the proposition that Huayqueriana, or any other litoptern, were foregut fermenters.Fil: Forasiepi, Analia Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: MacPhee, Ross D. E.. American Museum Of Natural History; Estados UnidosFil: Hernández del Pino, Santiago Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Schmidt, Gabriela Ines. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Amson, Eli. Universitat Zurich; SuizaFil: Grohé, Camille. American Museum Of Natural History; Estados Unido
An exceptionally well-preserved skeleton of Palaeothentes from the Early Miocene of Patagonia, Argentina: new insights into the anatomy of extinct paucituberculatan marsupials
International audienc
Between seas and continents: aspects of the scientific career of Hermann Von Ihering, 1850-1930
This paper covers some periods in Hermann von Ihering’s scientific trajectory: his training in zoology in Germany and Naples, his international activities based in Brazil, and his return to Germany. It deals with aspects of the formulation of his theories on land bridges. It focuses on the network of contacts he maintained with German émigrés like himself, and primarily with Florentino Ameghino, which allowed him to interact in international scientific circles. It mentions excerpts of his letters and his publications in the periods when he began corresponding with Ameghino (1890), when he travelled to Europe in search of support for his theories (1907), and when he published his book on the history of the Atlantic Ocean (1927).Facultad de Ciencias Naturales y Muse
The skull of Epidolops ameghinoi from the early Eocene Itaboraí fauna, southeastern Brazil, and the affinities of the extinct marsupialiform order Polydolopimorphia
The skull of the polydolopimorphian marsupialiform Epidolops ameghinoi is described
in detail for the first time, based on a single well-preserved cranium and associated left
and right dentaries plus additional craniodental fragments, all from the early Eocene
(53-50 million year old) Itaboraí fauna in southeastern Brazil. Notable craniodental
features of E. ameghinoi include absence of a masseteric process, very small
maxillopalatine fenestrae, a prominent pterygoid fossa enclosed laterally by a
prominent ectopterygoid crest, an absent or tiny transverse canal foramen, a simple,
planar glenoid fossa, and a postglenoid foramen that is immediately posterior to the
postglenoid process. Most strikingly, the floor of the hypotympanic sinus was
apparently unossified, a feature found in several stem marsupials but absent in all
known crown marsupials. "Type II" marsupialiform petrosals previously described from
Itaboraí plausibly belong to E. ameghinoi; in published phylogenetic analyses, these
petrosals fell outside (crown-clade) Marsupialia. "IMG VII" tarsals previously referred to
E. ameghinoi do not share obvious synapomorphies with any crown marsupial clade,
nor do they resemble those of the only other putative polydolopimorphians represented
by tarsal remains, namely the argyrolagids. Most studies have placed
Polydolopimorphia within Marsupialia, related to either Paucituberculata, or to
Microbiotheria and Diprotodontia. However, diprotodonty almost certainly evolved
independently in polydolopimorphians, paucituberculatans and diprotodontians, and
Epidolops does not share obvious synapomorphies with any marsupial order.
Epidolops is dentally specialized, but several morphological features appear to be
more plesiomorphic than any crown marsupial. It seems likely Epidolops that falls
outside Marsupialia, as do morphologically similar forms such as Bonapartherium and
polydolopids. Argyrolagids differ markedly in their known morphology from Epidolops
but share some potential apomorphies with paucituberculatans. It is proposed that
Polydolopimorphia as currently recognised is polyphyletic, and that argyrolagids (and
possibly other taxa currently included in Argyrolagoidea, such as groeberiids and
patagoniids) are members of Paucituberculata. This hypothesis is supported by
Bayesian non-clock phylogenetic analyses of a total evidence matrix comprising DNA
sequence data from five nuclear protein-coding genes, indels, retroposon insertions
and morphological characters: Epidolops falls outside Marsupialia, whereas
argyrolagids form a clade with the paucituberculatans Caenolestes and Palaeothentes,
regardless of whether the Type II petrosals and IMG VII tarsals are used to score
characters for Epidolops or not. There is no clear evidence for the presence of crown
marsupials at Itaboraí, and it is possible that the origin and early evolution of
Marsupialia was restricted to the "Austral Kingdom" (southern South America,
Antarctica, and Australia)
Shark fossil diversity (Squalomorphii, Squatinomorphii, and Galeomorphii) from the Langhian of Brielas (Lower Tagus Basin, Portugal)
The fossiliferous marine Miocene sediments of the Lower Tagus Basin (Portugal) present
a great diversity of Chondrichthyes forms. The current study focuses on the fossil
sharks from the Langhian Vc unit of the Brielas section, located in the Setúbal
Peninsula. A total of 384 isolated fossil teeth were analysed and ascribed to 17 species from the Orders Hexanchiformes, Squaliformes, Squatiniformes, Lamniformes,
and Carcharhiniformes. Centrophorus granulosus and Iago angustidens are described
for the first time in Portuguese sediments, whereas Pachyscyllium dachiardii and
Rhizoprionodon ficheuri represent only their second reported occurrence. Galeorhinus
goncalvesi was already known from the Portuguese uppermost Miocene (Alvalade
Basin), but it is now recognized in older sediments. Furthermore, the new material
seems to include the first reported occurrence of Hexanchus cf. agassizi in Miocene
sediments. As a whole, these new findings support the previous palaeoenvironment
characterization of a warm infralittoral setting gradually deepening to a circalittoral
one, where seasonal upwelling phenomena could have occurred
The spatial structure of lithic landscapes : the late holocene record of east-central Argentina as a case study
Fil: Barrientos, Gustavo. División Antropología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Catella, Luciana. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Oliva, Fernando. Centro Estudios Arqueológicos Regionales. Facultad de Humanidades y Artes. Universidad Nacional de Rosario; Argentin
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