Human evolution: early mammalian evolution (Introduction)

by David Turell , Wednesday, September 25, 2024, 20:04 (23 days ago) @ David Turell

New South American fossils:

https://www.sciencedaily.com/releases/2024/09/240925123653.htm

"These fossils, belonging to the mammal-precursor species Brasilodon quadrangularis and Riograndia guaibensis, offer critical insights into the development of the mammalian jaw and middle ear, revealing evolutionary experiments that occurred millions of years earlier than previously thought.

"Mammals stand out among vertebrates for their distinct jaw structure and the presence of three middle ear bones. This transition from earlier vertebrates, which had a single middle ear bone, has long fascinated scientists. The new study explores how mammal ancestors, known as cynodonts, evolved these features over time.

***

"These findings suggest that mammalian ancestors experimented with different jaw functions, leading to the evolution of 'mammalian' traits independently in various lineages. The early evolution of mammals, it turns out, was far more complex and varied than previously understood.

"Lead author James Rawson based in Bristol's School of Earth Sciences explained: "The acquisition of the mammalian jaw contact was a key moment in mammal evolution.

"What these new Brazilian fossils have shown is that different cynodont groups were experimenting with various jaw joint types, and that some features once considered uniquely mammalian evolved numerous times in other lineages as well."

"This discovery has broad implications for the understanding of the early stages of mammal evolution, illustrating that features such as the mammalian jaw joint and middle ear bones evolved in a patchwork, or mosaic, fashion across different cynodont groups.

"Dr. Agustín Martinelli, from the Museo Argentino de Ciencias Natural of Buenos Aires, stated: "Over the last years, these tiny fossil species from Brazil have brought marvellous information that enrich our knowledge about the origin and evolution of mammalian features. We are just in the beginning and our multi-national collaborations will bring more news soon.'"

Comment: mammals are very different unique branch of evolution that led to us. What was the natural necessity that drove these developments? There is none that is obvious. Still an evidence for design with purpose.