Acaban de publica un interesante artículo sobre el mundialmente conocido Archaeopteryx en el que discuten si ya es un ave, o si sigue siendo un dinosaurio.
El equipo liderado por Erickson hace un meticuloso estudio osteológico concluyendo que el tipo de crecimiento de Archaeopteryx es más propio del de un dinosaurio no aviano, que el de un ave propiamente dicho. Os dejo con el resumen del trabajo publicado en la revista PLoS One:
Background
Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs.
Methodology/Principal Findings
We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates.
Conclusions/Significance
The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.
Citation:
Erickson GM, Rauhut OWM, Zhou Z, Turner AH, Inouye BD, et al. (2009) Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx. PLoS ONE 4(10): e7390. doi:10.1371/journal.pone.0007390
El equipo liderado por Erickson hace un meticuloso estudio osteológico concluyendo que el tipo de crecimiento de Archaeopteryx es más propio del de un dinosaurio no aviano, que el de un ave propiamente dicho. Os dejo con el resumen del trabajo publicado en la revista PLoS One:
Background
Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs.
Methodology/Principal Findings
We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates.
Conclusions/Significance
The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.
Citation:
Erickson GM, Rauhut OWM, Zhou Z, Turner AH, Inouye BD, et al. (2009) Was Dinosaurian Physiology Inherited by Birds? Reconciling Slow Growth in Archaeopteryx. PLoS ONE 4(10): e7390. doi:10.1371/journal.pone.0007390
Imagen:
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-FXa5GPwJR_O02JOl-wy9blBsU0K7CqHd_AupaO1BEkdisiD-O5pss1u9QR3Lud_-bwPXPqH0xWmNIzLzUjQyUvox2jShQGvM9lNjbxD97sVs8Mbw6EVvLi6_PDQ-Xs2p1Q8-YLUdf8Q/s400/archaeopteryx+D.jpg
“Es posible volar sin motores, pero no sin conocimiento y habilidad. Considero que es esto algo afortunado para el hombre, por causa de su mayor intelecto, ya que es más razonable la esperanza de igualar a los pájaros en conocimiento, que igualar a la naturaleza en la perfección de su maquinaria.” Wilbur Wright
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-FXa5GPwJR_O02JOl-wy9blBsU0K7CqHd_AupaO1BEkdisiD-O5pss1u9QR3Lud_-bwPXPqH0xWmNIzLzUjQyUvox2jShQGvM9lNjbxD97sVs8Mbw6EVvLi6_PDQ-Xs2p1Q8-YLUdf8Q/s400/archaeopteryx+D.jpg
“Es posible volar sin motores, pero no sin conocimiento y habilidad. Considero que es esto algo afortunado para el hombre, por causa de su mayor intelecto, ya que es más razonable la esperanza de igualar a los pájaros en conocimiento, que igualar a la naturaleza en la perfección de su maquinaria.” Wilbur Wright
Humm... un trabajo interesante. A ver si me lo pillo. Y por cierto, muy buena la imagen! Bocetos de Ice Age, no? ;)
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