Instituto Miguel Lillo

San Miguel de Tucumán, Argentina

Instituto Miguel Lillo

San Miguel de Tucumán, Argentina
SEARCH FILTERS
Time filter
Source Type

Agnolin F.L.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Agnolin F.L.,Maimónides University | Powell J.E.,Instituto Miguel Lillo | Powell J.E.,CONICET | And 3 more authors.
Cretaceous Research | Year: 2012

The Alvarezsauridae represents a branch of peculiar basal coelurosaurs with an increasing representation of their Cretaceous radiation distributed worldwide. Here we describe a new member of the group, Bonapartenykus ultimus gen. et sp. nov. from Campanian-Maastrichtian strata of Northern Patagonia, Argentina. Bonapartenykus is represented by a single, incomplete postcranial skeleton. The morphology of the known skeletal elements suggests close affinities with the previously described taxon from Patagonia, Patagonykus, and both conform to a new clade, here termed Patagonykinae nov. Two incomplete eggs have been discovered in association with the skeletal remains of Bonapartenykus, and several clusters of broken eggshells of the same identity were also found in a close proximity. These belong to the new ooparataxon Arriagadoolithus patagoniensis of the new oofamily Arriagadoolithidae, which provides first insights into unique shell microstructure and fungal contamination of eggs laid by alvarezsaurid theropods. The detailed study of the eggs sheds new light on the phylogenetic position of alvarezsaurids within the Theropoda, and the evolution of eggs among Coelurosauria. We suggest that plesiomorphic alvarezsaurids survived in Patagonia until the latest Cretaceous, whereas these basal forms became extinct elsewhere. © 2011 Elsevier Ltd.


Simmons M.P.,Colorado State University | Goloboff P.A.,CONICET | Goloboff P.A.,Instituto Miguel Lillo
Molecular Phylogenetics and Evolution | Year: 2014

We re-analyzed 10 sparse supermatrices wherein the original authors relied primarily or entirely upon maximum likelihood phylogenetic analyses implemented in RAxML and quantified branch support using the bootstrap. We compared the RAxML-based topologies and bootstrap values with both superficial- and relatively thorough-tree-search parsimony topologies and bootstrap values. We tested for clades that were resolved by RAxML but properly unsupported by checking if the SH-like aLRT equals zero and/or if the parsimony-optimized minimum branch length equals zero. Four of our conclusions are as follows. (1) Despite sampling nearly 50,000 characters, highly supported branches in a RAxML tree may be entirely unsupported because of missing data. (2) One should not rely entirely upon RAxML SH-like aLRT, RAxML bootstrap, or superficial parsimony bootstrap methods to rigorously quantify branch support for sparse supermatrices. (3) A fundamental factor that favors thorough parsimony analyses of sparse supermatrices is being able to distinguish between clades that are unequivocally supported by the data from those that are not; superficial likelihood analyses that quantify branch support using the bootstrap cannot be relied upon to always make this distinction. (4) The SH-like aLRT and parsimony-optimized-minimum-branch-length tests generally identify the same properly unsupported clades; the latter is a more severe test. © 2014 Elsevier Inc.


Simmons M.P.,Colorado State University | Goloboff P.A.,CONICET | Goloboff P.A.,Instituto Miguel Lillo
Molecular Phylogenetics and Evolution | Year: 2013

Empirical and simulated examples are used to demonstrate an artifact caused by undersampling optimal trees in data matrices that consist mostly or entirely of locally sampled (as opposed to globally, for most or all terminals) characters. The artifact is that unsupported clades consisting entirely of terminals scored for the same locally sampled partition may be resolved and assigned high resampling support-despite their being properly unsupported (i.e., not resolved in the strict consensus of all optimal trees). This artifact occurs despite application of random-addition sequences for stepwise terminal addition. The artifact is not necessarily obviated with thorough conventional branch swapping methods (even tree-bisection-reconnection) when just a single tree is held, as is sometimes implemented in parsimony bootstrap pseudoreplicates, and in every GARLI, PhyML, and RAxML pseudoreplicate and search for the most likely tree for the matrix as a whole. Hence GARLI, RAxML, and PhyML-based likelihood results require extra scrutiny, particularly when they provide high resolution and support for clades that are entirely unsupported by methods that perform more thorough searches, as in most parsimony analyses. © 2013 Elsevier Inc.


Hayes F.E.,Pacific Union College | Capllonch P.,Instituto Miguel Lillo | Montero R.,CONICET
Revista Brasileira de Ornitologia | Year: 2016

Twelve species of birds have been reported to prey upon amphisbaenians (Squamata: Amphisbaenidae). We document the first report of predation on an amphisbaenian by a heron (Pelecaniformes: Ardeidae). On 1 November 2012 we photographed a Whistling Heron Syrigma sibilatrix preying on an Amphisbaena heterozonata at Tucumán, Argentina. © 2015, Sociedade Brasileira de Ornitologia. All rights reserved.


Goloboff P.A.,CONICET | Goloboff P.A.,Instituto Miguel Lillo | Catalano S.A.,CONICET
Cladistics | Year: 2012

This paper presents a pipeline, implemented in an open-source program called GB→TNT (GenBank-to-TNT), for creating large molecular matrices, starting from GenBank files and finishing with TNT matrices which incorporate taxonomic information in the terminal names. GB→TNT is designed to retrieve a defined genomic region from a bulk of sequences included in a GenBank file. The user defines the genomic region to be retrieved and several filters (genome, length of the sequence, taxonomic group, etc.); each genomic region represents a different data block in the final TNT matrix. GB→TNT first generates Fasta files from the input GenBank files, then creates an alignment for each of those (by calling an alignment program), and finally merges all the aligned files into a single TNT matrix. The new version of TNT can make use of the taxonomic information contained in the terminal names, allowing easy diagnosis of results, evaluation of fit between the trees and the taxonomy, and automatic labelling or colouring of tree branches with the taxonomic groups they represent. © The Willi Hennig Society 2012.


Suarez G.M.,Instituto Miguel Lillo | Suarez G.M.,CONICET | Larrain J.,University of Concepción | Schiavone M.M.,Instituto Miguel Lillo
Boletin de la Sociedad Argentina de Botanica | Year: 2013

Broth. allowed the detailed examination of this forgotten endemic taxon of NW Argentina, and its comparison with other South American species. We present a redescription of the species, together with its first illustration. A lectotype for this name is here designated.


Goloboff P.A.,CONICET | Goloboff P.A.,Instituto Miguel Lillo | Catalano S.A.,CONICET
Cladistics | Year: 2011

This paper describes algorithms for optimizing two- or three-dimensional landmark data onto trees directly. The method is based on a first approximation using grids, and subsequent iterative refinement of the initial point estimates. Details of the implementation are discussed, as well as an empirical example. © The Willi Hennig Society 2010.


Ordonez R.M.,National University of Tucuman | Ordonez R.M.,Instituto Miguel Lillo | Cardozo M.L.,National University of Tucuman | Zampini I.C.,National University of Tucuman | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

Cyphomandra betacea ripe fruits can be a source of value-added byproducts and products such as antioxidant supplements, Ingredients for food processing or alternative medical products. The aims of the present study were to obtain different preparations of C. betacea fruits, such as juice, decoction, and maceration and to characterize them in terms of microbiological stability, sensorial and chemical parameters, antioxidant potential (DPPH and ABTS .+ radical scavenging, β-carotene bleaching, nitrite scavenging activities), capacity to prevent oxidative stress-induced cell death, and genotoxicity. The best antioxidant activity was found in C. betacea fruit maceration, probably as a consequence of the high flavonoid and anthocyanin content. Nevertheless, all preparations analyzed proved to be good as free radical scavengers (SC50 values between 1.88 and 44 μg/mL) and exerted protection against β-carotene oxidation. Total phenolic compounds and flavonoids showed a better correlation than anthocyanins with the free radical scavenging effect of the assayed foods. The Insoluble matters (pomace) obtained after juice preparation showed antioxidant activity by quenching free radicals. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-dlphenyltetrazolium (MTT) reduction assay showed that C. betacea preparations prevent oxidative stress-induced cell death in HepG2 cells in a dose-dependent manner. Salmonella microsome assays show no mutagenic effect. The data presented in this study demonstrate that C. betacea ripe fruits, aqueous and ethanolic preparations, and pomace may be a good source of antioxidant compounds in nutraceutical or functional-food products. © 2009 American Chemical Society.


Babot J.,Fundacion Miguel Lillo | Lopez D.A.G.,Instituto Miguel Lillo | Gaudin T.J.,University of Tennessee at Chattanooga
Journal of Vertebrate Paleontology | Year: 2012

In this study we describe an isolated petrosal from the middle Eocene of northwestern Argentina assigned to Dasypodinae (Mammalia, Xenarthra, Cingulata). The specimen was recovered from the Geste Formation, Antofagasta de la Sierra, Catamarca, Argentina. The material is an incomplete right petrosal preserving the pars cochlearis and the anterior third of the pars canalicularis. It is described in detail and compared with extant and fossil cingulates. Additionally, we performed a cladistic analysis in order to define its phylogenetic position. The most remarkable traits of this petrosal include an anteromedially-posterolaterally elongated promontorium, open cavum supracochleare, wide and smooth crista interfenestralis, roof of the post-promontorial tympanic sinus triangular, reduced, and well separated from the stapedius fossa, and poorly developed epitympanic wing and crista petrosa. The phylogenetic analysis reveals affinities with Dasypus and Stegotherium that are supported by the weakly developed crista petrosa and the reduced dorsal and ventral extension of the cerebellar surface of the pars cochlearis in relation to the size of the internal acoustic meatus. The information provided by this element indicates the existence of several characters that were already present in the Eocene, such as an elongated promontorium, and a step between the stapedius fossa and the roof of the post-promontorial tympanic sinus. We propose hypotheses of evolutionary change in the auditory region of cingulates, including the medial expansion of the roof of the post-promontorial tympanic sinus and the emergence of a conspicuous crista petrosa. © 2012 Taylor & Francis Group, LLC.


Martin P.R.,Instituto Miguel Lillo | Gibon F.-M.,French Natural History Museum | Molina C.I.,Higher University of San Andrés
Zootaxa | Year: 2011

Six new species of Oecetis are described from Bolivia: O. carlibanezae, O. chipiriri, O. dominguezi, O. oberdorffi, O. pseudoamazonica and O. traini. Eight previously described species are recorded from Bolivia and northwestern Argentina: O. amazonica (Banks 1924), O. avara (Banks 1895), O. exisa Ulmer 1907, O. inconspicua (Walker 1852), O. knutsoni Flint 1981, O. paranensis Flint 1982a, O. punctipennis (Ulmer 1905) and O. rafaeli Flint 1991b. This work contains an identification key for males of Oecetis species from Mexico, Central and South America.

Loading Instituto Miguel Lillo collaborators
Loading Instituto Miguel Lillo collaborators