So scientists have tried to determine whether there was one rafting event with rodents and monkeys together on a bed of entangled plants, or several. Surviving a cross-continent journey on a mass of vegetation seems like a one-in-a-million chance. Paleontologists have also found that the ancestors of capybaras and other rodents, called hystricognaths, likely rafted from Africa to South America as well. There were no land bridges connecting South America and Africa during the relevant time, nor was there any evidence that the primates took a circuitous overland route.Īnd monkeys were not the only animals to make the trip. Since the 1970s, paleontologists have pondered whether primates might have traveled across the ancient Atlantic on rafts of floating vegetation. “All our assumptions and scenarios are based on our knowledge of the fossil record,” Marivaux says. Regardless of whether Ashaninkacebus is an early platyrrhine or represents a distinct group, there is still the question of how the primates hopped between continents multiple times. “If this turns out to be the case, then there would only be evidence of two dispersals,” Seiffert says. Rather than representing a group of primates that arrived in South America only to became extinct, he says, the molar might document when the earliest ancestors of the continent’s monkeys arrived. “My suspicion is that Ashaninkacebus could be a stem platyrrhine,” says University of Southern California paleontologist Erik Seiffert, who was not involved in the new study. But there is another possibility, one that connects the new find to the monkeys living in South America today, known as platyrrhines. If Ashaninkacebus is an eosimiid, then it would represent a third, distinct primate group that rafted between the continents. “As such, this becomes another example of a primitive lineage from Africa turning up in South America,” says University of Toronto paleontologist Mary Silcox, who was not involved in the new study. Eosimiids were present in Africa as well as Asia. While the molar is certainly that of a primate, other experts are not entirely sure of its relationships. Based on fossils of eosimiids found elsewhere, Marivaux and colleagues expect Ashaninkacebus was a small species, about the size of a common marmoset at roughly half a pound, that primarily dined on insects and fruit. The arrangements of cusps on the tooth identify it as both a primate and possibly an eosimiid. ![]() Named Ashaninkacebus simpsoni by Marivaux and colleagues, the new fossil primate is known only from a single upper molar found along Brazil’s Juruá River. Primates must have made the journey from Africa to South America at least twice, then, and the new tooth might indicate that a third group also journeyed across the ancient ocean. In 2020 paleontologist Erik Seiffert and colleagues announced the discovery of a monkey in Peru called Ucayalipithecus that had ancestral ties to ancient Africa, rather than being part of the modern South American lineage. The new species is not the first strange animal to show up in South America’s prehistory. The 34-million-year-old tooth, described by Marivaux and colleagues in the journal PNAS, doesn’t look like it came from a South American monkey, instead resembling the teeth of early monkeys called eosimiids found in South Asia. ![]() “Immediately, when one of my Brazilian colleagues showed me this tiny tooth emerging, my heart began to beat very fast,” says Laurent Marivaux, a paleontologist at the University of Montpellier in France. The latest evidence of these ancient transatlantic excursions is a tiny fossil tooth uncovered from rocks in the Brazilian Amazon. This appears to have happened at least twice-and perhaps more. South America was home to a broader array of primates than previously known, hinting at a key prehistoric time when rafts of vegetation ripped up by intense storms swept ancient monkeys across the sea. The leading theory is the ancestors of these monkeys somehow rafted across the Atlantic Ocean between 40 and 32 million years ago.Īs new fossils have been discovered, however, the story’s become much more complex. ![]() The continent’s spider monkeys, capuchins, and marmosets form their own primate group, separate from those in Africa and Asia. For decades, paleontologists have wondered exactly how primates made it to South America.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |