National University of Comahue

About: National University of Comahue is a education organization based out in Neuquén, Argentina. It is known for research contribution in the topics: Population & Species richness. The organization has 2242 authors who have published 4498 publications receiving 87157 citations. The organization is also known as: UNCOMA & UNCo.

Evolution of titanosaurid sauropods. 1:phylogenetic analysis based on the postcranial evidence

Abstract: "The phylogenetic relationships of titanosaurid sauropods are examined by means of a clodistic parsimony analysis based on postcranel features. Eusauropoda tBarapasaurus tagorei + Neosauropoda) have, at least, two synapomorphies. The Camarasauromorpha (Camarasauridae + Titanosauriformes) have five synapomorphies. The Titanosauriformes [Brachiosaurus brancai + tChubunsaurus insignis + Titanosauria)] share six derived characters (e.g., presence of medial prespinallamina in posterior trunk vertebrae, neural arches positioned anteriorly in mid and posterior caudal centra, c1aw on manual digit 1reduced or absent). Chubutisaurus insignis Del Corro shares with Titanosauria one apomorphy. Titanosauria is rediagnosed based on five synapomorphies (e.g., eye-shape pleurocoels in trunk vertebrae, anterior caudals procoelous, pubis considerably longer than ischium). Titanosauridae comprises titanosaurids with: absence of hyposphene-hypantrum articulation in posterior trunk vertebrae, six sacral vertebrae, anterior caudals strongly procoelous having ""ball and socket"" articular faces, mid and posterior caudals strongly procoelous, semilunar sternal plates, claw on manual digit I absent, manual phalanges absent and preacetabular lobe of ilium nearly horizontal, outwardly projected. Titanosaurids more derived than Epachthosaurus sciuttoi Powell and Malawisaurus dixeyi Haughton have medial prespinal lamina formed down to the base of neural spine in posterior trunk vertebrae and quadrangular coracoids. Argentinosaurus huinculensis Bonaparte and Coria, Opisthocoelicaudia skarzynskii Borsuk-Bialynicka and Titanosauridae indet*(DGM ""Serie B"") form a monophyletic group characterized by presence of accesory spino-diapophyseallaminae in trunk vertebrae. Aeolosaurus Powell shares with Alamosaurus sanjuanensis Gilmore and the Saltasaurinae biconvex first caudal and presence of dorsal prominence on inner face of scapula. Alamosaurus sanjuanensis is the sister-taxon of the Saltasaurinae."

Interspecific Pollen Transfer: Magnitude, Prevalence and Consequences for Plant Fitness

Abstract: Interspecific pollen transfer (IPT) is one of the mechanisms underlying potential competition among plants for pollinators, and it refers to movement of pollen between different plant species by pollinators that visit their flowers simultaneously. Two components of IPT, related to each other, are distinguished: (a) heterospecific pollen deposition (HPD) on conspecific stigmas, which may interfere with fertilization by conspecific pollen; and (b) conspecific pollen loss (CPL) on heterospecific flowers, which may reduce the amount of pollen transferred between conspecific flowers. Thus, IPT may lead to reciprocal losses for male and female functions of the plant, with potentially important ecological and evolutionary consequences. In this review, we explore the magnitude and prevalence of IPT, examining documented mechanisms and evaluating such potential ecological and evolutionary consequences. We compiled existing evidence of interspecific pollinator sharing and interspecific pollinator switching between ...

Comprehensive phylogeny of ray-finned fishes (Actinopterygii) based on transcriptomic and genomic data.

Abstract: Our understanding of phylogenetic relationships among bony fishes has been transformed by analysis of a small number of genes, but uncertainty remains around critical nodes. Genome-scale inferences so far have sampled a limited number of taxa and genes. Here we leveraged 144 genomes and 159 transcriptomes to investigate fish evolution with an unparalleled scale of data: >0.5 Mb from 1,105 orthologous exon sequences from 303 species, representing 66 out of 72 ray-finned fish orders. We apply phylogenetic tests designed to trace the effect of whole-genome duplication events on gene trees and find paralogy-free loci using a bioinformatics approach. Genome-wide data support the structure of the fish phylogeny, and hypothesis-testing procedures appropriate for phylogenomic datasets using explicit gene genealogy interrogation settle some long-standing uncertainties, such as the branching order at the base of the teleosts and among early euteleosts, and the sister lineage to the acanthomorph and percomorph radiations. Comprehensive fossil calibrations date the origin of all major fish lineages before the end of the Cretaceous.

Asymmetric specialization: a pervasive feature of plant-pollinator interactions

Abstract: Although specialization in species interactions has usually been equated to reciprocal specialization, asymmetric specialization (i.e., a specialist interacting with a generalist) is also likely. Recent studies have suggested that asymmetric specialization in species interactions could be more common than previously thought. We contrasted patterns of asymmetric specialization observed in 18 plant-pollinator interaction webs with pre- dictions based on null models. We found that asymmetric specialization is common in plant-pollinator interactions, and that its occurrence is more frequent than expected under a simple null model that assumed random interactions among species; furthermore, large assemblages with many pairs of interacting species tend to have more asymmetric inter- actions than smaller assemblages. A second null model, which incorporated a correlation between species frequency of interaction and degree of specialization observed in most data sets produced patterns that were generally closer to those present in the data. At least three kinds of explanations could account for the observed asymmetric specialization, including random interactions among individuals (rather than species), adaptive conse- quences of specialization, and artifacts, such as data aggregation and sampling biases. Future studies should be aimed at understanding the relative importance of each of these alternative explanations in generating asymmetric specialization in species interactions.

Flexible and practical modeling of animal telemetry data: hidden Markov models and extensions

Abstract: We discuss hidden Markov-type models for fitting a variety of multistate random walks to wildlife movement data. Discrete-time hidden Markov models (HMMs) achieve considerable computational gains by focusing on observations that are regularly spaced in time, and for which the measurement error is negligible. These conditions are often met, in particular for data related to terrestrial animals, so that a likelihood-based HMM approach is feasible. We describe a number of extensions of HMMs for animal movement modeling, including more flexible state transition models and individual random effects (fitted in a non-Bayesian framework). In particular we consider so-called hidden semi-Markov models, which may substantially improve the goodness of fit and provide important insights into the behavioral state switching dynamics. To showcase the expediency of these methods, we consider an application of a hierarchical hidden semi-Markov model to multiple bison movement paths.