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sl8

(16,245 posts)
Fri Sep 29, 2023, 06:44 AM Sep 2023

Digging up ancient animals in Amazonia

Last edited Fri Sep 29, 2023, 08:01 AM - Edit history (1)

https://www.nature.com/articles/d41586-023-03004-7



SPOTLIGHT | 28 September 2023

Digging up ancient animals in Amazonia

Laurent Marivaux works to identify ancient mammals to understand evolutionary history in South America.

Magali Reinert

With his team, Laurent Marivaux, a palaeontologist at the Institute of Evolutionary Sciences of Montpellier, France, has been discovering primates and rodents that emerged in South America more than 35 million years ago.

His latest find, a small primate named Ashaninkacebus simpsoni, was published1 this July. After crossing the Atlantic Ocean in enigmatic circumstances, this mammal evolutionarily diverged into a diverse array of species. Nature spoke to Marivaux about working deep in the rainforest to discover these fossils. He says that his research relies on fruitful collaborations with scientists as well as with Indigenous people — and on a willingness to work hard physically and endure discomfort in the field.

What does the discovery of mammals that emerged in South America more than 35 million years ago tell us about animal evolution?

Over the past 15 years, our international team of palaeontologists and geologists has found teeth from several species of rodent2 and primate3 in Amazonia. Dating to 35 million to 40 million years ago, the fossils are among the first traces of mammals in South America. The primate species that we have discovered are probably closely related to the ancestors of platyrrhines [New World monkeys], such as capuchins and marmosets. And caviomorph rodents, including guinea pigs and chinchillas, are descendants of rodents that emerged in the region at the same time as the primate species.

These discoveries have taught us that these species originally came from Africa and South Asia, where fossilized animals in these groups date to earlier times, around 45 million years ago. These animals evolutionarily diverged on the South American continent, resulting in the richest mammalian biodiversity on the planet. The conditions and constraints in South America over time were entirely different from those in Africa, leading to entirely different evolutionary development. This has led to distinct evolutionary results, such as the absence of great apes in the Americas. Comparisons such as these help us to understand animal evolution.

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Digging up ancient animals in Amazonia (Original Post) sl8 Sep 2023 OP
I've almost finished reading Prothero's "Princeton Field Guide to Prehistoric Mammals" .... eppur_se_muova Sep 2023 #1
Looks like a good book, thanks for the reference. nt sl8 Sep 2023 #2

eppur_se_muova

(37,436 posts)
1. I've almost finished reading Prothero's "Princeton Field Guide to Prehistoric Mammals" ....
Fri Sep 29, 2023, 09:50 AM
Sep 2023

and have been just absolutely amazed at how much has been discovered recently, and how much reinterpretation has been forced by new fossil finds as well as genetic analysis. Modern cladistics has completely revised our views on the interrelatedness of various genera. I remember memorizing the old kingdom-phylum-class-order-family-genus-species heirarchy back in grade school, and it seems almost useless now.

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