Entity

Time filter

Source Type

Buenos Aires, Argentina

Amargatitanis macni Apesteguía, 2007 was described as a purported titanosaur sauropod. That referral is significant because Amargatitanis would represent one of the oldest known members of Titanosauria. However, this referral and even the systematic validity of the taxon were questioned. Here, all the available remains of the taxon are evaluated including a description of unpublished elements. The identity of the type material is discussed based on a first-hand examination of the specimens and evaluation of the original field notes as reliable evidence for bone association. The original holotype of Amargatitanis is a chimaera, as pointed out by previous authors. Herein a new, modified holotype for Amargatitanis is proposed. This analysis presents a revised diagnosis for Amargatitanis macni as a valid taxon, and description of unpublished material clarifies the anatomy of this sauropod dinosaur. The inclusion of Amargatitanis macni in an updated phylogenetic analysis revealed the presence of a second species of the family Dicraeosauridae in the La Amarga Formation, suggesting that, at present, there is no record of titanosaur body fossils in Patagonia prior to Cenomanian times. © 2016 Elsevier Ltd. Source


Lisboa M.S.,University of Maryland University College | Lisboa M.S.,Maimonides University | Lansing S.,University of Maryland University College
Waste Management | Year: 2013

Co-digestion of food waste with dairy manure is increasingly utilized to increase energy production and make anaerobic digestion more affordable; however, there is a lack of information on appropriate co-digestion substrates. In this study, biochemical methane potential (BMP) tests were conducted to determine the suitability of four food waste substrates (meatball, chicken, cranberry and ice cream processing wastes) for co-digestion with flushed dairy manure at a ratio of 3.2% food waste and 96.8% manure (by volume), which equated to 14.7% (ice-cream) to 80.7% (chicken) of the VS being attributed to the food waste. All treatments led to increases in methane production, ranging from a 67.0% increase (ice cream waste) to a 2940% increase (chicken processing waste) compared to digesting manure alone, demonstrating the large potential methane production of food waste additions compared to relatively low methane production potential of the flushed dairy manure, even if the overall quantity of food waste added was minimal. © 2013 Elsevier Ltd. Source


Apesteguia S.,Maimonides University | Jones M.E.H.,University College London
Cretaceous Research | Year: 2012

Rhynchocephalia achieved a global distribution during the Mesozoic but the history of sphenodontines, the clade containing the extant genus Sphenodon (the New Zealand tuatara), remains poorly understood. Here, we describe a partial maxilla from the Late Cretaceous of Argentina bearing teeth that closely resemble those of modern Sphenodon. This material helps to fill in a notable gap in the fossil history of lepidosaurs because it represents the first evidence of a sphenodontine from South America and increases the number of known Late Cretaceous rhynchocephalian taxa from that region. The morphological disparity encompassed by these records is consistent with suggestions that rhynchocephalians remained diverse in the Late Cretaceous of South America despite a concurrent disappearance from Laurasia. Moreover, the new record supports the hypothesis that sphenodontines were once found widely throughout Gondwana, before its constituent landmasses began to separate about 80 million years ago. The extant Sphenodon probably represents a biogeographic remnant of this distribution, but whether its relatively large size and its ability to remain active at cold temperatures reflects a high latitude ancestry requires further examination. © 2011 Elsevier Ltd. Source


Ezcurra M.D.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Agnolin F.L.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Agnolin F.L.,Maimonides University
Systematic Biology | Year: 2012

Late Mesozoic palaeobiogeography has been characterized by a distinction between the northern territories of Laurasia and the southern landmasses of Gondwana. The repeated discovery of Gondwanan lineages in Laurasia has led to the proposal of alternative scenarios to explain these anomalous occurrences. A new biogeographical model for late Mesozoic terrestrial ecosystems is here proposed in which Europe and Gondwanan territories possessed a common Eurogondwanan fauna during the earliest Cretaceous. Subsequently, following the Hauterivian, the European territories severed from Africa and then connected to Asiamerica resulting in a faunal interchange. This model explains the presence of Gondwanan taxa in Laurasia and the absence of Laurasian forms in the southern territories during the Cretaceous. In order to test this new palaeobiogeographical model, tree reconciliation analyses (TRAs) were performed based on biogeographical signals provided by a supertree of late Mesozoic archosaurs. The TRAs found significant evidence for the presence of an earliest Cretaceous Eurogondwanan fauna followed by a relatively short-term Gondwana-Laurasia dichotomy. The analysis recovered evidence for a biogeographical reconnection of the European territories with Africa and South America-Antarctica during the Campanian to Maastrichtian time-slice. This biogeographical scenario appears to continue through the early Tertiary and sheds light on the trans-Atlantic disjunct distributions of several extant plant and animal groups. © 2012 The Author(s). Source


Sangeeta Devi Y.,Michigan State University | Halperin J.,Maimonides University | Halperin J.,CONICET
Molecular and Cellular Endocrinology | Year: 2014

Prolactin (PRL) is a polypeptide hormone with a wide range of physiological functions, and is critical for female reproduction. PRL exerts its action by binding to membrane bound receptor isoforms broadly classified as the long form and the short form receptors. Both receptor isoforms are highly expressed in the ovary as well as in the uterus. Although signaling through the long form is believed to be more predominant, it remains unclear whether activation of this isoform alone is sufficient to support reproductive functions or whether both types of receptor are required. The generation of transgenic mice selectively expressing either the short or the long form of PRL receptor has provided insight into the differential signaling mechanisms and physiological functions of these receptors. This review describes the essential finding that both long and short receptor isoforms are crucial for ovarian functions and female fertility, and highlights novel mechanisms of action for these receptors. © 2013 Elsevier Ireland Ltd. Source

Discover hidden collaborations