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Mar del Plata, Argentina

Haidr N.,Museo de la Plata. Paseo Del Bosque S n | Acosta Hospitaleche C.,CONICET
Alcheringa | Year: 2014

Fossil penguins (Aves, Spheniscidae) are widely recorded throughout the Southern Hemisphere and are especially well represented from the Eocene to present in Patagonia. There are currently three Miocene specimens that include preservation of part of the skull and mandibles: Paraptenodytes antarcticus, Madrynornis mirandus and MLG 3400 (cf. Spheniscus). Osteological appraisals relative to extant taxa and a morphometric analysis were employed to infer possible dietary preferences. The results suggest that Paraptenodytes antarcticus and cf. Spheniscus were piscivores but used different strategies for prey capture. Madrynornis, on the other hand, might have had a mixed diet comprising both small fish and crustaceans. © 2014 Association of Australasian Palaeontologists. Source

Torretta J.P.,University of Buenos Aires | Torretta J.P.,CONICET | Durante S.P.,Museo de la Plata. Paseo Del Bosque S n | Colombo M.G.,Museo de la Plata. Paseo Del Bosque S n | Basilio A.M.,University of Buenos Aires
Apidologie | Year: 2012

The nesting biology of the leafcutting bee Megachile (Pseudocentron) gomphrenoides Vachal (Hymenoptera: Megachilidae) was studied in an agro-ecosystem in the Province of Buenos Aires, Argentina. Data were obtained from trap-nests placed in the field margin during two agricultural years (2008/2009 and 2009/2010). Females made an average of 7.55 cells per nest, and used leaves of at least three plant species to build their nests. Provisions of cells were principally of Asteraceae pollen. Adult emergence showed a bimodal pattern suggesting a facultative bivoltinism life cycle. Approximately, 30 % of all offspring failed to complete development to the adult stage and an additional 10 % were killed by natural enemies. These included parasitic wasps (Eulophidae: Melittobia and Horismenus), a cleptoparasite bee (Megachilidae: Coelioxys), and a bristle beetle (Meloidae: Tetraonyx). The host/cleptoparasite association between M. gomphrenoides and Coelioxys remissa constitutes the first such record for both species, and the Megachile-Tetraonyx interaction was previously unknown. M. gomphrenoides possesses some characteristics that make it an interesting potential opportunity to use this species for pollination of commercial sunflowers in the Pampean region. © 2012 INRA, DIB and Springer-Verlag, France. Source

Abstract: Two species of Guerrerostrongylus Sutton and Durette-Desset, 1991, are reported in cricetid rodents from the Atlantic rain forest of Misiones, Argentina. Guerrerostrongylus zetta (Travassos, 1937) is redescribed on the basis of material collected from Oligoryzomys nigripes from Argentina and material loaned by CHIOC from Brazil. It is characterized by a synlophe with about 4045 (3548) well-developed cuticular ridges, caudal bursa with long rays 6 and dorsal ray divided at mid-length, and well-sclerotized spicules with marked twisting. It was found with a prevalence of 100 in O. nigripes (14 hosts examined); however, it was not found in its type host Nectomys squamipes (4 hosts examined). Guerrerostrongylus ulysi n. sp., which is described from Sooretamys angouya, differs from the remaining species in the genus mainly by a synlophe with a strong reduction of the cuticular ridges and struts on the right side, and by a heart-shaped caudal bursa, with short rays 6 and a dorsal ray divided distally. It was found with a prevalence of 100 in 5 hosts examined. © American Society of Parasitologists 2012. Source

Gallina P.A.,Maimonides University | Gallina P.A.,CONICET | Otero A.,Museo de la Plata. Paseo Del Bosque S n | Otero A.,CONICET
Ameghiniana | Year: 2015

The original material assigned to Laplatasaurus araukanicus Huene come from five different localities in northern Patagonia (Argentina) where the Upper Cretaceous (Campanian) lies exposed. This material includes several postcranial bones from multiple specimens and showing different conditions of preservation, often lacking anatomical overlap. The taxonomic status of the taxon is further obscured by the absence of quarry maps of the multiple localities (lacking the recognition of associated materials), and a proper designation of type material in its original description. After Huene, new material was assigned to this taxon, although none of it resolved the existing taxonomic issues. In 1979, the designation of a lectotype (one tibia and one fibula) was the first stage in the nomenclatural stabilization of the species. However, the assignment of the remaining material to L. araukanicus remained uncertain. Here we review all the material hitherto assigned to this taxon in order to clarify its taxonomic status. We also provide a re-description of the lectotype and discuss the taxonomic identification of material previously referred to this taxon. Lastly we include it for the first time in an updated phylogenetic data matrix. Laplatasaurus araukanicus is retained only for the lectotype. The material from Rancho de ávila is referred to cf. Bonitasaura sp. because they share diagnostic features and are stratigraphically congruent. The remaining material is referred as Lithostrotia indet. A phylogenetic analysis nests Laplatasaurus within Titanosauria in a clade formed by ((Laplatasaurus + Uberabatitan) + (Bonitasaura + (Futalognkosaurus + Mendozasaurus))). Source

Otero A.,Museo de la Plata. Paseo Del Bosque S n | Otero A.,CONICET | Pol D.,Museo Paleontologico Egidio Feruglio | Pol D.,CONICET
Journal of Vertebrate Paleontology | Year: 2013

The transition from basal sauropodomorphs to sauropods is one of the most dramatic evolutionary transformations in the history of dinosaurs. Constituent taxa of this transition were recorded mainly in South Africa and South America, and to a lesser extent in North America. We describe here the postcranial anatomy of four specimens of basal sauropodomorphs from the Late Triassic of Patagonia, Argentina, and identify them as adult individuals of Mussaurus patagonicus. The material is composed of one subadult and three adult specimens and was originally identified as Plateosaurus. The completeness of the material provides more complete knowledge of this taxon and allows us to introduce aspects of basal sauropodomorph anatomy that were poorly understood until now, such as the configuration and arrangement of the distal carpal elements. The phylogenetic relationships of Mussaurus patagonicus are tested through a cladistic analysis of basal sauropodomorphs based on the anatomy of these specimens rather than on the post-hatchling and juvenile specimens previously known for this taxon. Mussaurus is recovered as a non-sauropod anchisaurian, being the sister group of Aardonyx plus more derived sauropodomorphs and is depicted outside the quadrupedal clade, given the presence of plesiomorphic features such as a humerus/femur ratio <0.8, a curved femoral shaft in lateral view, and a nearly circular femoral midshaft cross-section. Mussaurus patagonicus adds new and valuable information that helps to clarify the core of the basal sauropodomorph-sauropod transition. SUPPLEMENTAL DATA - Supplemental materials are available for this article for free at www.tandfonline.com/UJVP © 2013 by the Society of Vertebrate Paleontology. Source

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