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Dientes fuera de la mandíbula: Evolución y desarrollo del cierre dentado de la cabeza en las quimeras
Karly E Cohen1,2, Michael I Coates3, Gareth J Fraser1
1Department of Biology, University of Florida, Gainesville, FL 32611.
Resumen
Las chimeras, o tiburones fantasma, poseen unos dientes faciales únicos. Estos dientes extraorales se desarrollan dentro del tenaculo, se asemejan más a los dientes orales del tiburón que a los denticles dérmicos.
Área de la Ciencia:
- Ictiología
- Biología del desarrollo
- Biología evolutiva
Sus antecedentes:
- Las quimeras (Holocephali) son peces cartilaginosos con estructuras dentales únicas, incluidos los dientes extraorales en el tenaculo masculino.
- El origen evolutivo y la base del desarrollo de los dientes tenaces siguen siendo poco conocidos.
Objetivo del estudio:
- Investigar la ontogenia del tenaculo y sus dientes en el pez rata manchado (Hydrolagus colliei).
- Evaluar la homología y la convergencia de los dientes tenacos con las mandíbulas orales.
- Caracterice los genes y tejidos involucrados en el desarrollo de los dientes tenaces.
Principales métodos:
- Análisis ontogenético detallado del tenaculo y del desarrollo de los dientes en Hydrolagus colliei.
- Análisis comparativo de los dientes tenacos, los dientes orales y los dentículos dérmicos.
- Integración de datos de desarrollo con evidencia fósil de holocefalos del Carbonífero.
Principales resultados:
- Las quimeras machos juveniles desarrollan el tenaculo antes de que se complete el desarrollo de los dientes; los machos maduros tienen el tenaculo completamente dentado.
- Los dientes tenaculares surgen de dentro del tenaculo, no del epitelio circundante.
- La dentición tenacular muestra un parecido con los giros dentales orales del tiburón, no con los denticles dérmicos.
Conclusiones:
- El tenaculo está estrechamente asociado con la mandíbula superior.
- Los dientes tenaculares probablemente representan una vía evolutiva distinta en lugar de los dentículos modificados.
- Este estudio arroja luz sobre el desarrollo craneofacial único y la evolución de las quimeras.
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