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Tejido reproductivo específico del género en ratites y Tyrannosaurus rex
Mary H Schweitzer1, Jennifer L Wittmeyer, John R Horner
1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA. schweitzer@ncsu.edu
Science (New York, N.Y.)
|June 4, 2005
Resumen
Los investigadores descubrieron el hueso medular, un tejido exclusivo de las aves hembras, en un fósil de Tyrannosaurus rex. Este hallazgo ofrece un nuevo método para determinar el género de los dinosaurios y fortalece el vínculo evolutivo dinosaurio-pájaro.
Área de la Ciencia:
- Paleontología Paleontología.
- Biología evolutiva Biología evolutiva.
- Biología Reproductiva Biología Reproductiva.
Sus antecedentes:
- La fosilización generalmente resulta en la pérdida de la anatomía de los tejidos blandos, lo que dificulta la determinación del género en especies extintas.
- El dimorfismo sexual en los dinosaurios no aviares se entiende mal debido a la escasez de indicadores inequívocos.
- El hueso medular es un tejido reproductivo especializado que se encuentra exclusivamente en las aves hembras.
Objetivo del estudio:
- Para investigar la presencia de tejidos óseos derivados endostéticamente en los elementos de las extremidades traseras de Tyrannosaurus rex.
- Para determinar si estos tejidos son homólogos al hueso medular aviar.
- Establecer un método potencialmente objetivo para la diferenciación de género en dinosaurios extintos.
Principales métodos:
- Examen histológico de tejidos óseos de los elementos de las extremidades traseras de Tyrannosaurus rex (MOR 1125).
- Comparación de microestructuras óseas fósiles con tejidos óseos medulares aviares conocidos.
- Análisis de la ubicación y el origen del hueso derivado endostealmente.
Principales resultados:
- Se identificaron tejidos óseos derivados endosticamente que recubrían las cavidades de la médula de los huesos de las extremidades posteriores de Tyrannosaurus rex.
- Estos tejidos óseos fósiles exhiben características consistentes con el hueso medular encontrado en las aves hembras modernas.
- La presencia de este tejido sugiere una estrategia reproductiva compartida entre los dinosaurios terópodos y las aves.
Conclusiones:
- El descubrimiento del hueso medular en Tyrannosaurus rex proporciona una fuerte evidencia de su homología con el hueso medular aviar.
- Este hallazgo solidifica el vínculo evolutivo entre los dinosaurios y las aves.
- El hueso medular ofrece un método confiable y objetivo para determinar el género de los dinosaurios extintos.
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