It is believed that the birds arose from a lineage of reptiles. A fossil was discovered having the size of a crow with a skull not unlike that of modern birds except that the beaklike jaws bore small bony teeth in sockets like those of reptiles. The skeleton is that if a reptile with a long bony tail, clawed fingers and abdominal ribs. There was the presence of imprint of feathers and it was the Archaeorptorex lithographica.
Frontiers, E. (2022). ZOO 313- Class Aves. Afribary. Retrieved from https://afribary.com/works/zoo-313-class-aves
Frontiers, Edu "ZOO 313- Class Aves" Afribary. Afribary, 04 Jul. 2022, https://afribary.com/works/zoo-313-class-aves. Accessed 19 May. 2024.
Frontiers, Edu . "ZOO 313- Class Aves". Afribary, Afribary, 04 Jul. 2022. Web. 19 May. 2024. < https://afribary.com/works/zoo-313-class-aves >.
Frontiers, Edu . "ZOO 313- Class Aves" Afribary (2022). Accessed May 19, 2024. https://afribary.com/works/zoo-313-class-aves