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Descripción y morfología de dos cráneos de tortugas terrestres del género chelonoidis del mioceno de La Venta, Huila, Colombia
No full textThe locality of La Venta is one of the most important paleontological sites in northern South America, characterized by its richness of fossils from the middle to late Miocene (~16-11 Ma). A great variety of vertebrate specimens have been found in this fossiliferous zone of the middle Miocene, including several species of turtles, belonging to the suborder Pleurodira and Cryptodira. The fossil record of turtles in La Venta indicates that most of the turtles of the middle Miocene were Pleurodira and had an aquatic lifestyle, but some specimens of terrestrial turtles (tortoises), belonging to the genus Chelonoidis have also been found, which represent the only cryptodiran (hidden-necked turtle) from this region. So far, two possible species of Chelonoidis existed in La Venta but only one has been partially described, C. hesterna. Still, much is unknown about these tortoises from the middle Miocene of Colombia. Therefore, this study aims to analyze and expand the morphological description of the Chelonoidis fossils with two new skull specimens found in the locality of La Venta, Huila, Colombia. In this study, we found that the two new Chelonoidis specimens resemble in size to Chelonoidis sp. indet, and that most of the cranial bones have typical contacts of the genus Chelonoidis in relation to the shape, proportion and sutural contact.La localidad de La Venta es uno de los yacimientos paleontológicos más importantes en el norte de Sudamérica, caracterizado por su riqueza de fósiles de la época Mioceno medio a tardío (~16?11 Ma). En esta zona fosilífera del Mioceno medio se han encontrado una gran variedad de especímenes de vertebrados, incluyendo varias especies de tortugas, que pertenecen al suborden Pleurodira y Cryptodira. El registro fósil de tortugas en La Venta, indica que la mayoría de las tortugas del Mioceno medio eran Pleurodira y tenían un estilo de vida acuático, pero en esta localidad también se han encontrado algunos ejemplares de tortugas terrestres del género Chelonoidis, que representa la única Cryptodira (tortuga de cuello oculto) de esta región. Hasta ahora, existen dos posibles especies de Chelonoidis en La Venta, pero solo una ha sido descrita parcialmente, C. hesterna. Aun así, se desconoce mucho sobre las tortugas terrestres del Mioceno medio de Colombia. Por lo tanto, este estudio pretende analizar y ampliar la descripción morfológica del material fósil de Chelonoidis con dos nuevos especímenes de cráneo hallados en la localidad de La Venta, Huila, Colombia. En este estudio, encontramos que los dos nuevos especímenes de Chelonoidis se asemejan en tamaño a Chelonoidis sp. indet, y que la mayoría de los huesos craneales tienen contactos típicos del género Chelonoidis en relación a la forma, proporción y contacto sutural.BiólogoPregrad
Amber and the Cretaceous Resinous Interval
No full textEl ámbar es resina fosilizada que preserva restos biológicos con un detalle excepcional, cuyo estudio ha revolucionado la comprensión de los organismos terrestres del pasado y de los hábitats desde el Cretácico Temprano hasta la actualidad. Los afloramientos de ámbar del Cretácico son más abundantes en el Hemisferio Norte y durante un intervalo de aproximadamente 54 millones de años, desde el Barremiense hasta el Campaniense. La extensa producción de resina que generó este notable registro de ámbar puede atribuirse a la biología de los productores de resina coníferos, al crecimiento de bosques resiníferos en proximidad a ambientes sedimentarios transicionales y a la dinámica del clima durante el Cretácico. Aquí discutimos el conjunto de factores abióticos y bióticos interrelacionados potencialmente involucrados en la producción de resina durante ese período. Nombramos a este período de producción masiva de resina por coníferas durante el Mesozoico tardío, fundamental como un archivo de vida terrestre, el 'Intervalo Resinoso del Cretácico' (CREI)
El registro fósil de las tortugas en Colombia; una revisión de los descubrimientos, investigaciones y futuros desafíos
No full textThis is a review article on the fossil record of turtles in Colombia that includes: the early Cretaceous turtles from Zapatoca and Villa de Leyva localities; the giant turtles from the Paleocene Cerrejón and Calenturitas Coal Mines; the early Miocene, earliest record of Chelus from Pubenza, Cundinamarca; the early to late Miocene large podocnemids, chelids and testudinids from Castilletes, Alta Guajira and La Venta; and the small late Pleistocene kinosternids from Pubenza, Cundinamarca. I also discuss here the current gaps in the fossil record of tropical South American turtles, as well as the ongoing research and future projects to be developed in order to understand better the evolutionary history of Colombian turtles.En este artículo resumo el registro fósil de tortugas de Colombia, incluyendo las tortugas del Cretácico temprano de Zapatoca y Villa de Leyva, las tortugas gigantes del Paleoceno en las minas de carbón de El Cerrejón y Calenturitas, el registro más antiguo de Chelus, proveniente del Mioceno temprano de Pubenza (Cundinamarca), los grandes podocnémidos, chélidos, y testudínidos del Mioceno temprano a tardío de Castilletes en la Alta Guajira y La Venta, y los pequeños kinostérnidos del Pleistoceno tardío de Pubenza, Cundinamarca. En este artículo discuto también los actuales intervalos para los cuales no se conocen registro fósil de tortugas en la parte tropical de Suramérica, así como también las investigaciones que se están desarrollando actualmente, c también los futuros proyectos a desarrollar con el fin de entender mejor la historia evolutiva de las tortugas en Colombia
Rede de coautoria sobre fósseis colombianos
Get PDFAnalyze the published literature on fossils found in Colombia to measure the degree of collaboration and co-authorship networks. We found 1412 documents published by 1411 authors, of which 68% were published as articles, they also found that 60% of this literature has been disseminated in English. It was found that 47% (668 documents) were published collaboratively, while 53% (744 documents) were published individually. The collaboration began in the 1980s. A complete co-authorship network was found by three components that are represented by Bermúdez, Hermann Darío; Honjo, S.; and Doubinger, Jeanne. The authors who have the highest centrality value or the highest recognition as a child can also be identified: Jaramillo Muñoz, Carlos Alberto; Cadena Rueda, Edwin Alberto; Guerrero Díaz, Javier; and Villarroel, Carlos.Analiza la literatura publicada sobre los fósiles encontrados en Colombia para medir el grado de colaboración y las redes de coautoría. Se encontraron 1412 documentos publicados por 1411 autores, de los cuales 68% fueron publicados como artículos, también se encontró que 60% de esta literatura se ha difundido en inglés. Se halló que 47% (668 documentos) se publicaron en colaboración, mientras que 53% (744 documentos) se publicaron individualmente. La colaboración comenzó a partir de la década de los 80. Se encontró una red de coautoría formada por tres componentes que están representados por Bermúdez, Hermann Darío; Honjo, S.; y Doubinger, Jeanne. También se identificaron a los autores que tienen el mayor valor de centralidad o mayor reconocimiento como son: Jaramillo Muñoz, Carlos Alberto; Cadena Rueda, Edwin Alberto; Guerrero Díaz, Javier; y Villarroel, Carlos.Analise a literatura publicada sobre fósseis encontrada na Colômbia para medir o grau de colaboração e redes de coautoria. Encontramos 1412 documentos publicados por 1411 autores, dos quais 68% foram publicados como artigos, eles também descobriram que 60% dessa literatura foi divulgada em inglês. Verificou-se que 47% (668 documentos) foram publicados colaborativamente, enquanto 53% (744 documentos) foram publicados individualmente. A colaboração começou nos anos 80. Uma rede completa de coautoria foi encontrada por três componentes representados por Bermúdez, Hermann Darío; Honjo, S.; e Doubinger, Jeanne. Os autores que têm o maior valor de centralidade ou o maior reconhecimento quando criança também podem ser identificados: Jaramillo Muñoz, Carlos Alberto; Cadena Rueda, Edwin Alberto; Guerrero Díaz, Javier; e Villarroel, Carlos
Recognition and characterization of potential soft tissue from a fossil ichthyosaur found in the Early Cretaceous (Barremian - Aptian) of Colombia
No full textThe Early Cretaceous of Colombia presents a rich, abundant, and well-preserved fossil vertebrate record of marine reptiles related to the Alto Ricaurte Marine Reptile Lagerstätte. However, despite the growing number of studies on soft tissue preservation worldwide in recent years, few have explored this remarkable preservation in this region. This study aims to identify and characterize the potentially preserved soft-tissue remains in the ichthyosaur specimen CIP-0107, addressing the question of how the taphonomic conditions of the Paja Formation contributed to exceptional soft-tissue preservation. In this context, samples of an Aptian ichthyosaur from the Paja Formation of Colombia were analyzed using techniques such as EDTA demineralization, thin section preparation, transmitted and polarized light microscopy, SEM-EDS, and ATR-FTIR spectroscopy. These analyses revealed net-like structures interpreted as potential keratinized epithelium in the stratum spinosum of epidermis, and skin-like tissues. The findings indicate preservation facilitated by rapid burial in “soupy” sediments, microbial activity, and dysoxic-anoxic marine conditions, and highlights the potential of Colombia as a key region for paleontological studies.Pregrad
Notoemys zapatocaensis, a new side-necked turtle (Pleurodira, Platychelyidae) from the early Cretaceous of Colombia
No full textno.3470 (2005
Notoemys zapatocaensis, a new side-necked turtle (pleurodira: platychelyidae) from the Early Cretaceous of Colombia
Get PDFNew side-necked turtle
No full text19 p. : ill., maps ; 26 cm.Includes bibliographical references (p. 19).A carapace and posterior plastral lobe from the early Cretaceous Valanginian of northeastern Colombia is a new species of the pleurodire Notoemys. It is a pleurodire based on the sutured pelvis and xiphiplastral notch. Notoemys zapatocaensis, n.sp., differs from the other two species of Notoemys, N. oxfordiensis and N. laticentralis, in having a slightly serrated posterior margin, a very small third peripheral, no contact of costal 1 and peripheral 3, and protuberances developed on the pleural and vertebral scale areas. Notoemys zapatocaensis, n.sp., extends the distribution of Notoemys from Argentina and Cuba to Colombia geographically, and from the 156 mya Oxfordian late Jurassic to the 135 mya Valanginian early Cretaceous. Reanalysis based on morphology of the new shell suggests that Notoemys is the sister taxon to the late Jurassic European Platychelys based on the common possession of a very large costovertebral tunnel, tubercle on anterior margin of first thoracic rib, wide, flat thoracic ribs, and a first thoracic centrum that is wider than high
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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