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Mitidieri, M. Estudio De Patologías Óseas En Reptiles Marinos Mesozoicos De Patagonia Y Antártida

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Mitidieri, M. Estudio De Patologías Óseas En Reptiles Marinos Mesozoicos De Patagonia Y Antártida ESTUDIO DE PATOLOGÍAS ÓSEAS EN REPTILES MARINOS MESOZOICOS DE PATAGONIA Y ANTÁRTIDA Trabajo Final Licenciatura en Paleontología (UNRN 2021) Universidad Nacional de Río Negro Autor: Matías Mitidieri Universidad Nacional de Río Negro EEUU 750, General Roca, Río Negro, Argentina. Directora: Marianella Talevi Instituto de Investigación en Paleobiología y Geología Universidad Nacional de Río Negro - CONICET Av. Roca 1242, General Roca, Río Negro, Argentina. Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 AGRADECIMIENTOS A mis padres por haberme apoyado en cada etapa de mi vida y particularmente en la elección de mi carrera, así como al resto de mi familia (hermanos, tíos, primos y abuelos) por el interés mostrado en el desarrollo de esta Tesis. A mi directora, Dra. Marianella Talevi, por la lectura crítica de las sucesivas versiones de este Trabajo Final de Licenciatura, por los consejos dados y el apoyo incondicional durante el desarrollo del mismo. A la Universidad Nacional de Río Negro (UNRN), al Instituto de Investigación en Paleobiología y Geología (IIPG) y al Consejo Interuniversitario Nacional (CIN) por brindar el marco institucional y financiamiento necesarios para la realización de este trabajo. A mis amigos que me acompañaron durante el cursado de la Licenciatura en Paleontología: Gerardo, Lautaro, Lisandro, Lucas y Rocío. Finalmente, deseo agradecer a todos aquellos que, aunque no mencionados explícitamente, han colaborado de muchas maneras a lo largo de estos cinco años. 1 Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 ÍNDICE RESUMEN………………………………………………………………….……...………4 ABSTRACT……………………………………………………………….……….…..…..6 CAPÍTULO 1 – INTRODUCCIÓN 1.1. Introducción……………………………………………………………….….....……8 1.2. Hipótesis de trabajo……………………………………………….……….……...…9 1.3. Objetivos………………………………………………………….………….….......10 1.4. Plesiosaurios…………………………………………………….…………….........10 1.5. Reseña histórica de estudios patológicos en plesiosauria…......………..…….12 1.5.1. Necrosis avascular…………………………….………………………..…….12 1.5.2. Necrosis séptica……………………………….………………………..….....13 1.5.3. Marcas de mordedura……………………….………………………….....….14 1.5.4. Nódulos de Schmorl……………………….…………………………...….....16 1.5.5. Artrosis……………………………………..………………………….............17 1.5.6. Fusiones vertebrales debido a traumatismos……………………….…......18 1.6. Mosasaurios…………………………………………………………………..….....20 1.7. Reseña histórica de estudios patológicos en mosasaurios.............................22 1.7.1. Necrosis avascular…………………………………………...…………….....22 1.7.2. Neoplasia (tumores)……………………………………..……………….......23 1.7.3. Fracturas óseas………………………………………………..…………......25 1.7.4. Fusiones vertebrales debido a infecciones óseas……………..…..……...27 1.7.5. Fusiones vertebrales debido a traumatismos……………………………...31 1.7.6. Osteomielitis………………………………………………………….…...…..33 1.7.7. Artritis……………………………………………………..…………….……...35 CAPÍTULO 2 – MATERIALES Y MÉTODOS 2.1. Marco geológico…………………………………………………………………….37 2.1.1. Ejemplar MML-PV 1305. Vértebra cervical de plesiosaurio…...…..……..37 2.1.2. Ejemplar MLP 87-II-7-1. Escápula izquierda de mosasaurio.....…………39 2 Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 2.2. Elementos analizados……………………………………………………………...41 2.2.1. Plesiosaurio…………………………………………………………..………..41 2.2.2. Mosasaurio………………………………………………………..…………...41 2.3. Análisis y documentación……………………………………………………........42 2.3.1. Microtomografías computarizadas…………………………………...……..42 2.3.2. Fotogrametría………………………………………………………………....42 2.4. Abreviaturas institucionales……………………………………………………….43 2.5. Abreviaturas anatómicas…………………………………………………...…......44 CAPÍTULO 3 – RESULTADOS 3.1. Ejemplar MML-PV 1305. Vértebra cervical de plesiosaurio…………...……....45 3.1.1. Descripción general……………………………………………………...…...45 3.1.2. Análisis macroscópico………………………………………………………..46 3.1.3. Análisis de las microtomografías computarizadas…………...…………...47 3.2. Ejemplar MLP 87-II-7-1. Escápula izquierda de mosasaurio…………............49 3.2.1. Descripción general………………………………………………….............49 3.2.2. Análisis macroscópico……………………………………………….…….....49 3.2.3. Análisis de las microtomografías computarizadas………………………...50 3.3. Fotogrametría de los materiales……………………………………………..……51 CAPÍTULO 4 – DISCUSIÓN Y CONCLUSIONES 4.1. Diagnosis Patológica del ejemplar MML-PV 1305………………………..........54 4.2. Diagnosis Patológica del ejemplar MLP 87-II-7-1.……….…………….............57 4.3. Conclusiones……………….………...…………………………………..…………59 REFERENCIAS BIBLIOGRÁFICAS………………………………………..…………61 3 Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 RESUMEN Los estudios paleopatológicos se han utilizado para comprender la historia de lesiones y enfermedades en el registro fósil, y permiten deducir el tipo de daño esquelético que ocurre en ejemplares fósiles, su causa aparente y por los aspectos relacionados con la paleoecología y de comportamiento. El análisis de las características patológicas de los reptiles marinos mesozoicos de Patagonia y Antártida, se presenta como un vasto campo de estudio aun escasamente explorado, y capaz de ofrecer información novedosa. El objetivo principal del trabajo es analizar elementos óseos de un plesiosaurio y un mosasaurio recuperados de Patagonia y Antártida respectivamente, los cuales presentan indicios de diversas paleopatologías. Los elementos de los ejemplares se analizaron macroscópicamente así como también mediante microtomografías computarizadas. Asimismo, a través de la técnica de fotogrametría se realizó una reconstrucción en 3D de los elementos, que luego fueron impresos mediante una impresora 3D (Creality Ender 3). El primer ejemplar (MML-PV 1305) consta de una vértebra cervical perteneciente a un plesiosaurio adulto, recuperado del Maastrichtiano superior de Patagonia (Bajo de Santa Rosa, Río Negro). Éste representa el primer informe de una paleopatología ósea en un reptil marino de Argentina. El análisis macroscópico reveló en la cara articular anterior del centro vertebral la presencia un nódulo de Schmorl acompañado de osteofitos en el borde inferior izquierdo del centro vertebral. El análisis de las microtomografías permitió evidenciar una depresión en la región central del centro vertebral, seguida de una erosión que se extendió internamente hasta la región media del mismo. Todas estas características observadas en el ejemplar resultan consistentes con el diagnóstico de un trauma por estrés mecánico, generado por esfuerzos de torsión y compresión producidos por la propia longitud del cuello o en momentos de alimentación. Esta condición patológica pudo generar dificultades en el movimiento y ocasionar dolores recurrentes en la región cervical del individuo. El segundo ejemplar (MLP 87-II-7-1) consta de una escápula izquierda perteneciente a un mosasaurio juvenil, recuperado del Maastrichtiano superior de Antártida (Isla Marambio), que representa el primer informe de una patología ósea en un reptil marino de Antártida. 4 Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 El análisis macroscópico reveló una expansión de la articulación glenohumeral, la cual se encontraba profundamente erosionada y remodelada, y un seno de drenaje a la altura del cuello escapular, el cual se encontraba rodeado de un delgado margen de hueso perióstico nuevo. El análisis de las microtomografías reveló tejido trabecular desorganizado y dos senos de drenaje. Todas estas características observadas en el ejemplar resultan consistentes con el diagnóstico de una artritis infecciosa. La articulación de la escápula y el húmero fue interrumpida por la erosión de la fosa glenoidea, comprometiendo su función normal. Aunque no está directamente relacionada con la muerte del mosasaurio, esta condición pudo haber contribuido a reducir su efectividad para obtener alimento o aumentar su susceptibilidad a enfermedades fatales, lesiones adicionales o incluso depredación. Los resultados obtenidos a partir del trabajo realizado complementan el estado de conocimiento sobre patologías actuales en formas extintas y su prospección evolutiva, así como aspectos paleoecológicos de los organismos estudiados. Palabras clave: Patología. Reptiles marinos. Cretácico. Patagonia. Antártida. 5 Mitidieri, M. Estudio de patologías óseas en reptiles marinos mesozoicos de Patagonia y Antártida. 2021 ABSTRACT Paleopathological studies have been used to understand the history of injuries and diseases in the fossil record, and allow deducing the type of skeletal damage that occurs in fossil specimens, its apparent cause, and aspects related to palaeoecology and behavior. The analysis of the pathological characteristics of the Mesozoic marine reptiles of Patagonia and Antarctica, is presented as a vast field of study still scarcely explored, and capable of offering novel information. The main objective of the work is to analyze bone elements of a plesiosaur and a mosasaur recovered from Patagonia and Antarctica which show signs of various paleopathologies. The elements of the specimens were analyzed macroscopically as well as by computerized microtomography. Also, through the photogrammetry technique, a 3D reconstruction of the elements was made, which were then printed using a 3D printer (Creality Ender 3). The first specimen (MML-PV 1305) consists of a cervical vertebra belonging to an adult plesiosaur, recovered from the upper Maastrichtian
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