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Separar los orígenes evolutivos de los dientes de la evidencia en fósiles de vertebrados con mandíbula
Moya Meredith Smith1, Zerina Johanson
1Craniofacial Development, Dental Institute, King's College London, Guy's Campus, London Bridge, London SE1 9RT, UK. moya.smith@kcl.ac.uk
Science (New York, N.Y.)
|February 22, 2003
Resumen
Los peces con mandíbulas fósiles llamados placodermos, que antes se pensaba que no tenían dientes, poseían filas de dientes. Estos dientes de placodermo se desarrollaron como otros vertebrados con mandíbula, lo que sugiere que los dientes evolucionaron convergentemente al menos dos veces.
Área de la Ciencia:
- Paleontología Paleontología.
- Evolución de los vertebrados Evolución de los vertebrados
- Biología del desarrollo Biología del desarrollo.
Sus antecedentes:
- Los placodermos (clase Placodermi) son vertebrados de mandíbula basal extintos.
- Los dientes generalmente se consideraban ausentes en los placodermos, con su origen posterior a la evolución de la mandíbula.
- El origen filogenético de los dientes en los vertebrados con mandíbula sigue siendo un área clave de investigación.
Objetivo del estudio:
- Para investigar la presencia y la naturaleza de los dientes en placódermos derivados, específicamente los artrodires.
- Para determinar si los dientes de placodermo exhiben características similares a los dientes de otros gnathostomes (vertebrados con mandíbula).
- Para reevaluar la historia evolutiva de los dientes en vertebrados con mandíbula.
Principales métodos:
- Análisis de especímenes fósiles de placódermos derivados (arthrodires).
- Examen microscópico de la morfología dental y la estructura histológica.
- Comparación de las características de desarrollo y composición con los vertebrados con mandíbula existentes.
Principales resultados:
- Descubrimiento de filas de dientes en placódermos derivados (arthrodires).
- Estos dientes recién identificados están compuestos de dentina de tipo gnathostome.
- Los dientes placodérmicos se desarrollan y se regulan de manera similar a los de otros vertebrados con mandíbula.
Conclusiones:
- La presencia de dientes en placódermos derivados desafía las suposiciones anteriores.
- El desarrollo de los dientes en los placodermos sugiere la evolución convergente de los dientes al menos dos veces.
- Este hallazgo impacta nuestra comprensión de la evolución temprana de los vertebrados con mandíbula y los orígenes dentales.
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