Cretaceous Amniotes from Angola
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Abstract Book Progeo 2Ed 20
Abstract Book BUILDING CONNECTIONS FOR GLOBAL GEOCONSERVATION Editors: G. Lozano, J. Luengo, A. Cabrera Internationaland J. Vegas 10th International ProGEO online Symposium ABSTRACT BOOK BUILDING CONNECTIONS FOR GLOBAL GEOCONSERVATION Editors Gonzalo Lozano, Javier Luengo, Ana Cabrera and Juana Vegas Instituto Geológico y Minero de España 2021 Building connections for global geoconservation. X International ProGEO Symposium Ministerio de Ciencia e Innovación Instituto Geológico y Minero de España 2021 Lengua/s: Inglés NIPO: 836-21-003-8 ISBN: 978-84-9138-112-9 Gratuita / Unitaria / En línea / pdf © INSTITUTO GEOLÓGICO Y MINERO DE ESPAÑA Ríos Rosas, 23. 28003 MADRID (SPAIN) ISBN: 978-84-9138-112-9 10th International ProGEO Online Symposium. June, 2021. Abstracts Book. Editors: Gonzalo Lozano, Javier Luengo, Ana Cabrera and Juana Vegas Symposium Logo design: María José Torres Cover Photo: Granitic Tor. Geosite: Ortigosa del Monte’s nubbin (Segovia, Spain). Author: Gonzalo Lozano. Cover Design: Javier Luengo and Gonzalo Lozano Layout and typesetting: Ana Cabrera 10th International ProGEO Online Symposium 2021 Organizing Committee, Instituto Geológico y Minero de España: Juana Vegas Andrés Díez-Herrero Enrique Díaz-Martínez Gonzalo Lozano Ana Cabrera Javier Luengo Luis Carcavilla Ángel Salazar Rincón Scientific Committee: Daniel Ballesteros Inés Galindo Silvia Menéndez Eduardo Barrón Ewa Glowniak Fernando Miranda José Brilha Marcela Gómez Manu Monge Ganuzas Margaret Brocx Maria Helena Henriques Kevin Page Viola Bruschi Asier Hilario Paulo Pereira Carles Canet Gergely Horváth Isabel Rábano Thais Canesin Tapio Kananoja Joao Rocha Tom Casadevall Jerónimo López-Martínez Ana Rodrigo Graciela Delvene Ljerka Marjanac Jonas Satkünas Lars Erikstad Álvaro Márquez Martina Stupar Esperanza Fernández Esther Martín-González Marina Vdovets PRESENTATION The first international meeting on geoconservation was held in The Netherlands in 1988, with the presence of seven European countries. -
JVP 26(3) September 2006—ABSTRACTS
Neoceti Symposium, Saturday 8:45 acid-prepared osteolepiforms Medoevia and Gogonasus has offered strong support for BODY SIZE AND CRYPTIC TROPHIC SEPARATION OF GENERALIZED Jarvik’s interpretation, but Eusthenopteron itself has not been reexamined in detail. PIERCE-FEEDING CETACEANS: THE ROLE OF FEEDING DIVERSITY DUR- Uncertainty has persisted about the relationship between the large endoskeletal “fenestra ING THE RISE OF THE NEOCETI endochoanalis” and the apparently much smaller choana, and about the occlusion of upper ADAM, Peter, Univ. of California, Los Angeles, Los Angeles, CA; JETT, Kristin, Univ. of and lower jaw fangs relative to the choana. California, Davis, Davis, CA; OLSON, Joshua, Univ. of California, Los Angeles, Los A CT scan investigation of a large skull of Eusthenopteron, carried out in collaboration Angeles, CA with University of Texas and Parc de Miguasha, offers an opportunity to image and digital- Marine mammals with homodont dentition and relatively little specialization of the feeding ly “dissect” a complete three-dimensional snout region. We find that a choana is indeed apparatus are often categorized as generalist eaters of squid and fish. However, analyses of present, somewhat narrower but otherwise similar to that described by Jarvik. It does not many modern ecosystems reveal the importance of body size in determining trophic parti- receive the anterior coronoid fang, which bites mesial to the edge of the dermopalatine and tioning and diversity among predators. We established relationships between body sizes of is received by a pit in that bone. The fenestra endochoanalis is partly floored by the vomer extant cetaceans and their prey in order to infer prey size and potential trophic separation of and the dermopalatine, restricting the choana to the lateral part of the fenestra. -
Colonial Geology and Mineral Resources
COLONIAL GEOLOGY AND MINERAL RESOURCES VOLUME 4, NUMBER 3 LONDON: HER MAJESTY'S STATIONERY OFFIC 1954 P R I r. E 7.r fitl N F. T SOME NEW UPPER CRETACEOUS AMMONITES FROM NIGERIA1 By R. A. REYMENT, B.Sc. Geological Survey Department, Nigeria Abstract THREE NEW AMMONITE GENERA AND A NUMBER OF AMMONITE SPECIES ARE DESCRIBED from the Turonian and Coniacian of Nigeria. The new genera are Onitshoce,.as of Desmoceratidae, Kamerunoceras of Collignoniceratidae and Ezilloella of Vasco ceratidae. Some new species of Pseudaspidoceras Hyatt, Gombeoceras Reyment, Pachyvascoce,.as Furon and Solgerites Reeside are recorded. A discussion of the family Vascoceratidae appears. · Introduction IN A RECENT PAPER (Reyment, 1954) some new genera of Lower Turonian ammonites from Nigeria were established and their types and a few other species briefly described. The present paper contains descriptions of two further species of one of these new genera and of species of associated genera that have a wide distribution in both southern and northern Nigeria. Three new genera from the Turonian and Coniacian of southern Nigeria and the Cameroons are treated. This paper also includes a brief discussion of the family Vascoceratidae which provides an important element of the Lower Turonian faunas of many areas in Africa, Europe, Asia and North and South America. Both this and the previous work are preliminary to a larger review of the Upper Cretaceous-ammonites of southern Nigeria that is in active preparation;· but whose publication will in,evitably be delayed. Mean while, it is hoped that the new gehera described below and the informa tion on taxonomy and phylogeny becoming a\7ailable from studies of the Nigerian faunas will be of value both to palaeontologists and strati graphers. -
Classification of New Zealand Arionacea (Mollusca : Pulmonata
CLASSIFICATION OF NEW ZEA L AND ARIONACEA (MOLLUSCA: PULMONATA ) A REVISION OF SOME ENDODONTID GENERA ( ENDODONTIDAE PILSBRY, 1894 ) VOL. 1 F RANCIS MARTIN CLIMO 1 969 A T HESIS PRESENTED FOR THE D E GREE OF DOCTOR OF PHILOSOPHY IN Z OOLOGY AT CANTERBURY UN IVERSITY, CHRISTCHURCH, NEW ZEA L A ND "The creation of natural hierarchical systems of organisms is based on hierarchic combinative differentiation of characte rs, more precisely, of the systems of characte rs. None of the characters taken alone can s e r ve as a crite rion for the determination of the rank of a taxonomic category. Obj ective crite ria exist for the species only, due to the pres enc e of continuous variability within the species and in its absence b etween the species. " (B. A. Wainstein, Zool. Zh. , Vol. 39 (1960) p. 1 778) 1. GENERAL INTRODUCTION The following systematic revisions of New Zealand taxa within the Arionacean subfamilies F l ammulininae Climo, 1969, Otoconchinae Cockerell, 1893 and Endodontinae Suter, 1913 (family Endodontidae Pilsbry, 1894) are based on quantitative reappraisals of shell morphology and studi es on radular and soft-part morphology. The last major revision of these New Zealand pulmonate taxa was presented by Suter (1 913) i n hi s Manual of the New Zealand Mollusca, and illustra ted in hi s Atlas of Plates which appeared in 1915. Suter' s work was, as were the great majority of earlier pulmonate systematic studies, based on studies of shell and radular morphology, and was the major contribution towards the erection of a systematic hierarchy which illustrated the indigenous nature of the New Zealand endodontid fauna. -
Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas
Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas GEOLOGICAL SURVEY PROFESSIONAL PAPER 1253 Stratigraphy and Paleontology of Mid-Cretaceous Rocks in Minnesota and Contiguous Areas By WILLIAM A. COBBAN and E. A. MEREWETHER Molluscan Fossil Record from the Northeastern Part of the Upper Cretaceous Seaway, Western Interior By WILLIAM A. COBBAN Lower Upper Cretaceous Strata in Minnesota and Adjacent Areas-Time-Stratigraphic Correlations. and Structural Attitudes By E. A. M EREWETHER GEOLOGICAL SURVEY PROFESSIONAL PAPER 1 2 53 UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1983 UNITED STATES DEPARTMENT OF THE INTERIOR JAMES G. WATT, Secretary GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging in Publication Data Cobban, William Aubrey, 1916 Stratigraphy and paleontology of mid-Cretaceous rocks in Minnesota and contiguous areas. (Geological Survey Professional Paper 1253) Bibliography: 52 p. Supt. of Docs. no.: I 19.16 A. Molluscan fossil record from the northeastern part of the Upper Cretaceous seaway, Western Interior by William A. Cobban. B. Lower Upper Cretaceous strata in Minnesota and adjacent areas-time-stratigraphic correlations and structural attitudes by E. A. Merewether. I. Mollusks, Fossil-Middle West. 2. Geology, Stratigraphic-Cretaceous. 3. Geology-Middle West. 4. Paleontology-Cretaceous. 5. Paleontology-Middle West. I. Merewether, E. A. (Edward Allen), 1930. II. Title. III. Series. QE687.C6 551.7'7'09776 81--607803 AACR2 For sale by the Distribution Branch, U.S. -
Detrital Zircon Provenance and Lithofacies Associations Of
geosciences Article Detrital Zircon Provenance and Lithofacies Associations of Montmorillonitic Sands in the Maastrichtian Ripley Formation: Implications for Mississippi Embayment Paleodrainage Patterns and Paleogeography Jennifer N. Gifford 1,*, Elizabeth J. Vitale 1, Brian F. Platt 1 , David H. Malone 2 and Inoka H. Widanagamage 1 1 Department of Geology and Geological Engineering, University of Mississippi, Oxford, MS 38677, USA; [email protected] (E.J.V.); [email protected] (B.F.P.); [email protected] (I.H.W.) 2 Department of Geography, Geology, and the Environment, Illinois State University, Normal, IL 61790, USA; [email protected] * Correspondence: jngiff[email protected]; Tel.: +1-(662)-915-2079 Received: 17 January 2020; Accepted: 15 February 2020; Published: 22 February 2020 Abstract: We provide new detrital zircon evidence to support a Maastrichtian age for the establishment of the present-day Mississippi River drainage system. Fieldwork conducted in Pontotoc County,Mississippi, targeted two sites containing montmorillonitic sand in the Maastrichtian Ripley Formation. U-Pb detrital zircon (DZ) ages from these sands (n = 649) ranged from Mesoarchean (~2870 Ma) to Pennsylvanian (~305 Ma) and contained ~91% Appalachian-derived grains, including Appalachian–Ouachita, Gondwanan Terranes, and Grenville source terranes. Other minor source regions include the Mid-Continent Granite–Rhyolite Province, Yavapai–Mazatzal, Trans-Hudson/Penokean, and Superior. This indicates that sediment sourced from the Appalachian Foreland Basin (with very minor input from a northern or northwestern source) was being routed through the Mississippi Embayment (MSE) in the Maastrichtian. We recognize six lithofacies in the field areas interpreted as barrier island to shelf environments. Statistically significant differences between DZ populations and clay mineralogy from both sites indicate that two distinct fluvial systems emptied into a shared back-barrier setting, which experienced volcanic ash input. -
A Fossiliferous Spherule-Rich Bed at the Cretaceous–Paleogene (K–Pg) Boundary in 1 Mississippi, USA: Implications for the K
1 A fossiliferous spherule-rich bed at the Cretaceous–Paleogene (K–Pg) boundary in 2 Mississippi, USA: implications for the K–Pg mass extinction event in the Mississippi 3 Embayment and Eastern Gulf Coastal Plain 4 James D. Witts1, Neil H. Landman1, Matthew P. Garb2, Caitlin Boas2, Ekaterina Larina3, 5 Remy Rovelli4, Lucy E. Edwards5, Robert M. Sherrell6,7, and J. Kirk Cochran8 6 1Division of Paleontology (Invertebrates), American Museum of Natural History, New York, 7 NY 10024, USA 8 2Department of Earth and Environmental Sciences, Brooklyn College, Brooklyn, NY 11210, 9 USA 10 3University of Southern California, Department of Earth Sciences, Los Angeles, CA 90018, 11 USA 12 4Department of Earth and Planetary Sciences, The University of New Mexico, Albuquerque, 13 NM 87131, USA 14 5U.S. Geological Survey, Mail Stop 926A, Reston, VA 20192, USA 15 6Department of Marine and Coastal Sciences, Rutgers University, Piscataway, NJ 08901, 16 USA 17 7 Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08901, 18 USA 19 8School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, 20 USA 21 [The final, fully formatted version of this article is available online at Cretaceous Research: 22 https://doi.org/10.1016/j.cretres.2018.06.002 ] 23 Abstract 24 We describe an outcrop of the Cretaceous–Paleogene (K–Pg) boundary exposed due 25 to construction near New Albany, Union County, Mississippi. It consists of the Owl Creek 26 Formation and overlying Clayton Formation. The Owl Creek Formation is rich in the 27 ammonites Discoscaphites iris and Eubaculites carinatus, which, along with 28 biostratigraphically important dinoflagellate cysts and calcareous nannofossils, indicate 29 deposition occurred within the last 1 million years, most likely last 500 kyrs, of the 30 Cretaceous. -
Angola: Museum in the Ground
ANGOLA: MUSEUM IN THE GROUND Good Fossils Ocean Currents and Source Rocks Dinosaur Extinction (K-Pg Boundary) Angolasaurus (90 million year old marine lizard, also found in Texas) Louis L. Jacobs Roy M. Huffington Department of Earth Sciences Southern Methodist University, Dallas, Texas InIn 20052005 wewe wentwent toto AngolaAngola becausebecause fossilsfossils ofof giantgiant marinemarine lizardslizards (mosasaurs)(mosasaurs) hadhad beenbeen reportedreported inin thethe 1960’s.1960’s. CouldCould wewe findfind more?more? ColleaguesColleagues atat UniversidadeUniversidade Agostinho Agostinho Neto Neto were were contactedcontacted andand wewe brieflybriefly visitedvisited thethe field.field. BasedBased onon ourour preliminarypreliminary trip,trip, thethe NationalNational GeographicGeographic SocietySociety andand thethe PetroleumPetroleum ResearchResearch FundFund ofof thethe AmericanAmerican ChemicalChemical SocietySociety fundedfunded expeditionsexpeditions inin 20062006 andand 2007.2007. In cooperation with Universidade Agostinho Neto and ISPRA (Lubango). We have shown that: 1. The fossils of Angola are a “Museum in the Ground.” 2. The geologic context of the fossils gives clues to past ocean currents and productivity leading to petroleum source rocks. 3. The rocks of Angola record events of worldwide interest, such as the extinction of mosasaurs and dinosaurs, and the precise position of ancient shores. IEMBE (north of Luanda) 90 million years old Drawing of original specimen, 1964 Home of Discovery site of Angolasaurus in 1962 Angolasaurus Discovery site in 2006 The best specimen, 2006 Ammonite in Iembe cliff Angolasaurus before excavation Excavation of front flipper of Angolasaurus (note ammonite lying next to fingers) Shark Vertebrae, Iembe, 90 Million Years The first dinosaur, a sauropod, found in Angola, at Iembe. Excavation pit for front leg of sauropod dinosaur Professor Jacobs (SMU) excavating arm bone of Angolan dinosaur Unexcavated Turtle Skull BENTIABA 68 Ma, 15ºS Each red point is a good fossil. -
Moluscos Del Perú
Rev. Biol. Trop. 51 (Suppl. 3): 225-284, 2003 www.ucr.ac.cr www.ots.ac.cr www.ots.duke.edu Moluscos del Perú Rina Ramírez1, Carlos Paredes1, 2 y José Arenas3 1 Museo de Historia Natural, Universidad Nacional Mayor de San Marcos. Avenida Arenales 1256, Jesús María. Apartado 14-0434, Lima-14, Perú. 2 Laboratorio de Invertebrados Acuáticos, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Apartado 11-0058, Lima-11, Perú. 3 Laboratorio de Parasitología, Facultad de Ciencias Biológicas, Universidad Ricardo Palma. Av. Benavides 5400, Surco. P.O. Box 18-131. Lima, Perú. Abstract: Peru is an ecologically diverse country, with 84 life zones in the Holdridge system and 18 ecological regions (including two marine). 1910 molluscan species have been recorded. The highest number corresponds to the sea: 570 gastropods, 370 bivalves, 36 cephalopods, 34 polyplacoforans, 3 monoplacophorans, 3 scaphopods and 2 aplacophorans (total 1018 species). The most diverse families are Veneridae (57spp.), Muricidae (47spp.), Collumbellidae (40 spp.) and Tellinidae (37 spp.). Biogeographically, 56 % of marine species are Panamic, 11 % Peruvian and the rest occurs in both provinces; 73 marine species are endemic to Peru. Land molluscs include 763 species, 2.54 % of the global estimate and 38 % of the South American esti- mate. The most biodiverse families are Bulimulidae with 424 spp., Clausiliidae with 75 spp. and Systrophiidae with 55 spp. In contrast, only 129 freshwater species have been reported, 35 endemics (mainly hydrobiids with 14 spp. The paper includes an overview of biogeography, ecology, use, history of research efforts and conser- vation; as well as indication of areas and species that are in greater need of study. -
(Squamata: Mosasauridae) from the Late Cretaceous Of
C. R. Palevol 14 (2015) 483–493 Contents lists available at ScienceDirect Comptes Rendus Palevol www.sci encedirect.com General Palaeontology, Systematics and Evolution (Vertebrate Palaeontology) An halisaurine (Squamata: Mosasauridae) from the Late Cretaceous of Patagonia, with a preserved tympanic disc: Insights into the mosasaur middle ear Un halisauriné (Squamata : Mosasauridae) du Crétacé supérieur de Patagonie, à disque tympanique conservé : un aperc¸ u de l’oreille moyenne des mosasaures a,∗ b Marta S. Fernández , Marianella Talevi a CONICET - División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina b CONICET - Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Isidro Lobo y Belgrano, 8332 General Roca, Río Negro, Argentina a b s t r a c t a r t i c l e i n f o Article history: Halisaurinae is a subfamily of enigmatic, small- to medium-sized mosasauroids, which Received 15 September 2014 retain a mosaic of primitive and derived features. The first record of a South American Hal- Accepted after revision 13 May 2015 isaurus with precise stratigraphic information includes a quadrate carrying a tympanic disc together with twelve vertebrae, collected in the Late Maastrichtian of Jagüel Formation Handled by Nathalie Bardet in northern Patagonia (Argentina). The preservation of a tympanic disc allows exploring and discussing the mechanisms of sound transmission in these mosasauroids. The loca- Keywords: tion of the tympanic disc resembles that one formed by the extracolumella of aquatic Halisaurus turtles and at least one extant lizard. Based on morphological comparison of the middle Patagonia ear we discuss previous hypotheses on the modification of the tympanic middle ear system Late Maastrichtian of mosasauroids for underwater hearing, in a manner similar to that observed in aquatic Cretaceous turtles. -
Phylogeny, Diversity, and Ecology of the Ammonoid Superfamily Acanthoceratoidea Through the Cenomanian and Turonian
PHYLOGENY, DIVERSITY, AND ECOLOGY OF THE AMMONOID SUPERFAMILY ACANTHOCERATOIDEA THROUGH THE CENOMANIAN AND TURONIAN DAVID A.A. MERTZ A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2017 Committee: Margaret Yacobucci, Advisor Andrew Gregory Keith Mann © 2017 David Mertz All Rights Reserved iii ABSTRACT Margaret Yacobucci Both increased extinction and decreased origination, caused by rising oceanic anoxia and decreased provincialism, respectively, have been proposed as the cause of the Cenomanian Turonian (C/T) extinction event for ammonoids. Conflicting evidence exists for whether diversity actually dropped across the C/T. This study used the ammonoid superfamily Acanthoceratoidea as a proxy for ammonoids as a whole, particularly focusing on genera found in the Western Interior Seaway (WIS) of North America, including Texas. Ultimately, this study set out to determine 1) whether standing diversity decreased across the C/T boundary in the WIS, 2) whether decreased speciation or increased extinction in ammonoids led to a drop in diversity in the C/T extinction event, 3) how ecology of acanthoceratoid genera changed in relation to the C/T extinction event, and 4) whether these ecological changes indicate rising anoxia as the cause of the extinction. In answering these questions, three phylogenetic analyses were run that recovered the families Acanthoceratidae, Collignoniceratidae, and Vascoceratidae. Pseudotissotiidae was not recovered at all, while Coilopoceratidae was recovered but reclassified as a subfamily of Vascoceratidae. Seven genera were reclassified into new families and one genus into a new subfamily. After calibrating the trees with stratigraphy, I was able to determine that standing diversity dropped modestly across the C/T boundary and the Early/Middle Turonian boundary. -
Universidad Autónoma De Nuevo León Facultad De Ciencias De La Tierra
UNIVERSIDAD AUTÓNOMA DE NUEVO LEÓN FACULTAD DE CIENCIAS DE LA TIERRA "ANÁLISIS DE MICROFACIES Y PALEOICTIOLOGÍA DE LA FORMACIÓN AGUA NUEVA (CRETÁCICO SUPERIOR) EN LA SIERRA DE SAN CARLOS, TAMAULIPAS, MÉXICO" TESIS QUE COMO REQUISITO PARCIAL PARA OBTENER EL GRADO DE MAESTRO EN CIENCIAS GEOLÓGICAS PRESENTA: LAURA ALEJANDRA SANTANA SALAS LINARES, NUEVO LEÓN JUNIO 2012 UNIVERSIDAD AUTÓNOMA DE NUEVO LEÓN FACULTAD DE CIENCIAS DE LA TIERRA HDA. DE GUADALUPE, CARR. A CERRO PRIETO KM 8, A.P. 104 67700 LINARES, NUEVO LEÓN, MÉXICO TELS. Y FAX (821) 214 20 10, 214 20 20 Y 214 20 30 “ANÁLISIS DE MICROFACIES Y PALEOICTIOLOGÍA DE LA FORMACIÓN AGUA NUEVA (CRETÁCICO SUPERIOR) EN LA SIERRA DE SAN CARLOS, TAMAULIPAS, MÉXICO” PRESENTA: LAURA ALEJANDRA SANTANA SALAS HA SIDO ACEPTADA COMO REQUISITO PARCIAL PARA OBTENER EL GRADO DE: MAESTRO EN CIENCIAS GEOLÓGICAS Vo. Bo. DIRECTOR DE TESIS ___________________________________ Dr. José Guadalupe López Oliva LINARES, NUEVO LEÓN JUNIO 2012 UNIVERSIDAD AUTÓNOMA DE NUEVO LEÓN FACULTAD DE CIENCIAS DE LA TIERRA HDA. DE GUADALUPE, CARR. A CERRO PRIETO KM 8, A.P. 104 67700 LINARES, NUEVO LEÓN, MÉXICO TELS. Y FAX (821) 214 20 10, 214 20 20 Y 214 20 30 “ANÁLISIS DE MICROFACIES Y PALEOICTIOLOGÍA DE LA FORMACIÓN AGUA NUEVA (CRETÁCICO SUPERIOR) EN LA SIERRA DE SAN CARLOS, TAMAULIPAS, MÉXICO” PRESENTA: LAURA ALEJANDRA SANTANA SALAS HA SIDO ACEPTADA COMO REQUISITO PARCIAL PARA OBTENER EL GRADO DE: MAESTRO EN CIENCIAS GEOLÓGICAS COMITÉ DE REVISIÓN Vo. Bo. ___________________________________ Dr. José Guadalupe López Oliva Director de Tesis ____________________________ ________________________ Dr. Juan Alonso Ramírez Fernández M. C. Andres Ramos Ledezma Co-Director de Tesis Co-Director de Tesis ______________________________ Dra.