New Evidence About the Emergence of New World Monkeys During the Oligocene Paleogene

Neotropics provide insights into the emergence of New World monkeys: New dental evidence from the late Oligocene of Peruvian Amazonia

Authors:

Marivaux et al

Abstract:

Recent field efforts in Peruvian Amazonia (Contamana area, Loreto Department) have resulted in the discovery of a late Oligocene (ca. 26.5 Ma; Chambira Formation) fossil primate-bearing locality (CTA-61). In this paper, we analyze the primate material consisting of two isolated upper molars, the peculiar morphology of which allows us to describe a new medium-sized platyrrhine monkey: Canaanimico amazonensis gen. et sp. nov. In addition to the recent discovery of Perupithecus ucayaliensis, a primitive anthropoid taxon of African affinities from the alleged latest Eocene Santa Rosa locality (Peruvian Amazonia), the discovery of Canaanimico adds to the evidence that primates were well-established in the Amazonian Basin during the Paleogene. Our phylogenetic results based on dental evidence show that none of the early Miocene Patagonian taxa (Homunculus, Carlocebus, Soriacebus, Mazzonicebus, Dolichocebus, Tremacebus, and Chilecebus), the late Oligocene Bolivian Branisella, or the Peruvian Canaanimico, is nested within a crown platyrrhine clade. All these early taxa are closely related and considered here as stem Platyrrhini. Canaanimico is nested within the Patagonian Soriacebinae, and closely related to Soriacebus, thereby extending back the soriacebine lineage to 26.5 Ma. Given the limited dental evidence, it is difficult to assess if Canaanimico was engaged in a form of pitheciine-like seed predation as is observed in Soriacebus and Mazzonicebus, but dental microwear patterns recorded on one upper molar indicate that Canaanimico was possibly a fruit and hard-object eater. If Panamacebus, a recently discovered stem cebine from the early Miocene of Panama, indicates that the crown platyrrhine radiation was already well underway by the earliest Miocene, Canaanimico indicates in turn that the “homunculid” radiation (as a part of the stem radiation) was well underway by the late Oligocene. These new data suggest that the stem radiation likely occurred in the Neotropics during the Oligocene, and that several stem lineages independently reached Patagonia during the early Miocene. Finally, we are still faced with a “layered” pattern of platyrrhine evolution, but modified in terms of timing of cladogeneses. If the crown platyrrhine radiation occurred in the Neotropics around the Oligocene–Miocene transition (or at least during the earliest Miocene), it was apparently concomitant with the diversification of the latest stem forms in Patagonia.

Panamacebus transitus: a Monkey in North America During the Miocene Neogene

Seven tiny teeth tell the story of an ancient monkey that made a 100-mile ocean crossing between North and South America into modern-day Panama - the first fossil evidence for the existence of monkeys in North America.

The find provides the oldest fossil evidence for the interchange of mammals between South and North America and challenges long-held views of South America as an island continent that evolved in isolation before the Isthmus of Panama was formed and animals began crossing between the continents about 3.5 million years ago, said Jonathan Bloch, curator of vertebrate paleontology at the Florida Museum of Natural History on the University of Florida campus. Study findings are detailed online today in the journal Nature.

Scientists uncovered the teeth belonging to the 21-million-year-old forest-dwelling primate during recent excavations related to the expansion of the Panama Canal. The new genus and species, dubbed Panamacebus transitus, received its name from the Latin word transit, meaning crossing.

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The Chimpanzee Stone Age has Begun

In the rainforests of west Africa, the woodlands of Brazil and the beaches of Thailand, archaeologists have unearthed some truly remarkable stone tools.

It's not the workmanship that makes them special. If anything, a casual observer might struggle to even identify them as ancient tools. It's not their antiquity that's exceptional either: they're only about the same age as the Egyptian pyramids.

What makes these tools noteworthy is that the hands that held them weren't human.

These stone tools were wielded by chimpanzees, capuchins and macaques. The sites where they have been unearthed are the basis of a brand new field of science: primate archaeology.

The tools are crude. A chimpanzee or monkey stone hammer is hardly a work of art to rival the beauty of an ancient human hand axe. But that's not the point. These primates have developed a culture that makes routine use of a stone-based technology. That means they have entered the Stone Age.

link.

The question is whether or not the stone tools have been worked or if they just stones picked up to be used.

The Incorporation of C4 Plants Into Hominin and Baboon Diets During the Early Pliocene Neogene

Dietary change among hominins and cercopithecids in Ethiopia during the early Pliocene

Authors:

Levin et al

Abstract:

The incorporation of C4 resources into hominin diet signifies increased dietary breadth within hominins and divergence from the dietary patterns of other great apes. Morphological evidence indicates that hominin diet became increasingly diverse by 4.2 million years ago but may not have included large proportions of C4 foods until 800 thousand years later, given the available isotopic evidence. Here we use carbon isotope data from early to mid Pliocene hominin and cercopithecid fossils from Woranso-Mille (central Afar, Ethiopia) to constrain the timing of this dietary change and its ecological context. We show that both hominins and some papionins expanded their diets to include C4 resources as early as 3.76 Ma. Among hominins, this dietary expansion postdates the major dentognathic morphological changes that distinguish Australopithecus from Ardipithecus, but it occurs amid a continuum of adaptations to diets of tougher, harder foods and to committed terrestrial bipedality. In contrast, carbon isotope data from cercopithecids indicate that C4-dominated diets of the earliest members of the Theropithecus oswaldi lineage preceded the dental specialization for grazing but occurred after they were fully terrestrial. The combined data indicate that the inclusion of C4 foods in hominin diet occurred as part of broader ecological changes in African primate communities.

Whoops! Australopithecus afarensis Lucy's Backbone Isn't Hers, Really a Baboon's!

Lucy's back: Reassessment of fossils associated with the A.L. 288-1 vertebral column

Authors:

Meyer et al

Abstract:

The Australopithecus afarensis partial skeleton A.L. 288-1, popularly known as “Lucy” is associated with nine vertebrae. The vertebrae were given provisional level assignments to locations within the vertebral column by their discoverers and later workers. The continuity of the thoracic series differs in these assessments, which has implications for functional interpretations and comparative studies with other fossil hominins. Johanson and colleagues described one vertebral element (A.L. 288-1am) as uniquely worn amongst the A.L. 288-1 fossil assemblage, a condition unobservable on casts of the fossils. Here, we reassess the species attribution and serial position of this vertebral fragment and other vertebrae in the A.L. 288-1 series. When compared to the other vertebrae, A.L. 288-1am falls well below the expected size within a given spinal column. Furthermore, we demonstrate this vertebra exhibits non-metric characters absent in hominoids but common in large-bodied papionins. Quantitative analyses situate this vertebra within the genus Theropithecus, which today is solely represented by the gelada baboon but was the most abundant cercopithecoid in the KH-1s deposit at Hadar where Lucy was discovered. Our additional analyses confirm that the remainder of the A.L. 288-1 vertebral material belongs to A. afarensis, and we provide new level assignments for some of the other vertebrae, resulting in a continuous articular series of thoracic vertebrae, from T6 to T11. This work does not refute previous work on Lucy or its importance for human evolution, but rather highlights the importance of studying original fossils, as well as the efficacy of the scientific method.

Two new Eocene Paleogene South American Platyrrhines Which Verify African Origin for New World Monkeys

Eocene primates of South America and the African origins of New World monkeys

Authors:

Bond et al

Abstract:

The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago, or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.

Monkeys Have a Human-like Thirst for Knowledge?

Monkeys are notoriously curious, and new research has quantified just how eager they are to gain new information, even if there are not immediate benefits. The findings offer insights into how a certain part of the brain shared by monkeys and humans plays a role in decision making, and perhaps even in some disorders and addictions in humans.

The study, by researchers at the University of Rochester and Columbia University, shows that rhesus macaques have such robust curiosity that they are willing to give up a surprisingly large portion of a potential prize in order to quickly find out if they selected the winning option at a game of chance.

link.

Basal Monkeys From Eocene Paleogene Amazonian Peru Link New World Monkeys to Old World Monkeys

Eocene primates of South America and the African origins of New World monkeys

Authors:

Bond et al

Abstract:

The platyrrhine primates, or New World monkeys, are immigrant mammals whose fossil record comes from Tertiary and Quaternary sediments of South America and the Caribbean Greater Antilles. The time and place of platyrrhine origins are some of the most controversial issues in primate palaeontology, although an African Palaeogene ancestry has been presumed by most primatologists. Until now, the oldest fossil records of New World monkeys have come from Salla, Bolivia, and date to approximately 26 million years ago , or the Late Oligocene epoch. Here we report the discovery of new primates from the ?Late Eocene epoch of Amazonian Peru, which extends the fossil record of primates in South America back approximately 10 million years. The new specimens are important for understanding the origin and early evolution of modern platyrrhine primates because they bear little resemblance to any extinct or living South American primate, but they do bear striking resemblances to Eocene African anthropoids, and our phylogenetic analysis suggests a relationship with African taxa. The discovery of these new primates brings the first appearance datum of caviomorph rodents and primates in South America back into close correspondence, but raises new questions about the timing and means of arrival of these two mammalian groups.

Common Marmoset Genome Sequenced

With the sequence of the marmoset, the team revealed for the first time the genome of a non-human primate in the New World monkeys, which represents a separate branch in the primate evolutionary tree that is more distant from humans than those whose genomes have been studied in detail before. The sequence allows researchers to broaden their ability to study the human genome and its history as revealed by comparison with other primates.

link.

Oxford University Uses MRIs of Humans and Monkeys to Identify Unique Human Brain Areas

Oxford University researchers have identified an area of the human brain that appears unlike anything in the brains of some of our closest relatives.

The brain area pinpointed is known to be intimately involved in some of the most advanced planning and decision-making processes that we think of as being especially human.

'We tend to think that being able to plan into the future, be flexible in our approach and learn from others are things that are particularly impressive about humans. We've identified an area of the brain that appears to be uniquely human and is likely to have something to do with these cognitive powers,' says senior researcher Professor Matthew Rushworth of Oxford University's Department of Experimental Psychology.

MRI imaging of 25 adult volunteers was used to identify key components in the ventrolateral frontal cortex area of the human brain, and how these components were connected up with other brain areas. The results were then compared to equivalent MRI data from 25 macaque monkeys.

This ventrolateral frontal cortex area of the brain is involved in many of the highest aspects of cognition and language, and is only present in humans and other primates. Some parts are implicated in psychiatric conditions like ADHD, drug addiction or compulsive behaviour disorders. Language is affected when other parts are damaged after stroke or neurodegenerative disease. A better understanding of the neural connections and networks involved should help the understanding of changes in the brain that go along with these conditions.

link.

Pre Monkey-Ape Split Primates From Chattian Oligocene Tanzania Found?

From the human perspective, few events in evolution were more momentous than the split among primates that led to apes (large, tailless primates such as today's gorillas, chimpanzees, and humans) and Old World monkeys (which today include baboons and macaques). DNA studies of living primates have estimated that the rift took place between 25 million and 30 million years ago, but the earliest known fossils of both groups date no earlier than 20 million years ago. Now, a team working in Tanzania has found teeth and partial jaws from what it thinks are 25-million-year-old ancestors of both groups. If the interpretations hold up, the finds would reconcile the molecular and fossil evidence and possibly provide insights into what led to the split in the first place.

Researchers have long been frustrated by a paucity of fossils from this key period in evolution, which sits at the borderline between two major geological epochs: the Miocene (about 23 million to 5 million years ago) and the Oligocene (about 34 million to 23 million years ago). The earliest known fossils of early apes and Old World monkeys date from the early Miocene and have been found in just a handful of sites in Kenya, Uganda, and North Africa. Meanwhile, molecular studies of existing primates consistently suggest that these two groups arose during the Oligocene, leading scientists to wonder whether the molecular dates are wrong or if paleontologists have been looking in the wrong places.

For more than a decade, researchers from the United States and Tanzania have been combing Tanzania's Rukwa Rift Basin, searching for fossils of all kinds. During the 2011 and 2012 seasons, a team led by Nancy Stevens, a vertebrate paleontologist at Ohio University in Athens, discovered fossils that it identified as belonging to two previously unknown species of primates: one, an apparent ape ancestor the team has named Rukwapithecus fleaglei; the other, a claimed Old World monkey ancestor dubbed Nsungwepithecus gunnelli. (The species were named after two notable primatologists, John Fleagle of Stony Brook University in New York, and Gregg Gunnell, who is now at Duke University in Durham, North Carolina.)

Both specimens, consisting of teeth and partial jaws, were found in Rukwa Rift sediments dated by several techniques, including the often used argon-argon method, to 25.2 million years ago. The team identified them as ape and Old World monkey ancestors from the features of their molars, which paleontologists routinely use to tell primates apart. For example, Stevens says, Nsungwepithecus "has a much more triangular outline" of its last lower molar than Rukwapithecus, and there are "a number of other major differences in the shape and position of the cusps and crests that run along the chewing surface of the teeth." The two species also show other dental features that group them with later Old World monkeys and apes, but are still different enough to be classified as separate—and more ancient—species.

paper link.

Its Not Just What You Have, But How You use It: Epigenetics Very Different Between Humans, Chimps & Rhesus Monkeys

Humans share over 90% of their DNA with their primate cousins. The expression or activity patterns of genes differ across species in ways that help explain each species' distinct biology and behavior.

DNA factors that contribute to the differences were described on Nov. 6 at the American Society of Human Genetics 2012 meeting in a presentation by Yoav Gilad, Ph.D., associate professor of human genetics at the University of Chicago.

Dr. Gilad reported that up to 40% of the differences in the expression or activity patterns of genes between humans, chimpanzees and rhesus monkeys can be explained by regulatory mechanisms that determine whether and how a gene's recipe for a protein is transcribed to the RNA molecule that carries the recipe instructions to the sites in cells where proteins are manufactured.

In addition to improving scientific understanding of the uniqueness of humans, studies such as the investigation conducted by Dr. Gilad and colleagues could have relevance to human health and disease.

"Through inter-species' comparisons at the DNA sequence and expression levels, we hope to identify the genetic basis of human specific traits and in particular the genetic variations underlying the higher susceptibility to certain diseases such as malaria and cancer in humans than in non-human primates," said Dr. Gilad.

Dr. Gilad and his colleagues studied gene expression in lymphoblastoid cell lines, laboratory cultures of immortalized white blood cells, from eight humans, eight chimpanzees and eight rhesus monkeys.

They found that the distinct gene expression patterns of the three species can be explained by corresponding changes in genetic and epigenetic regulatory mechanisms that determine when and how a gene's DNA code is transcribed to a messenger RNA (mRNA) molecule.

Dr. Gilad also determined that the epigenetics process known as histone modification also differs in the three species. The presence of histone marks during gene transcription indicates that the process is being prevented or modified.

"These data allowed us to identify both conserved and species-specific enhancer and repressor regulatory elements, as well as characterize similarities and differences across species in transcription factor binding to these regulatory elements," Dr. Gilad said.

Among the similarities among the three species were the promoter regions of DNA that initiated transcription of a particular gene.

In all three species, Dr. Gilad's lab found that transcription factor binding and histone modifications were identical in over 67% of regulatory elements in DNA segments that are regarded as promoter regions.

Antillothrix bernensis Fossil Found via Scuba Diving

Scientists have examined fossilised remains of a tiny, extinct monkey that were retrieved from an underwater cave in the Dominican Republic.

The researchers believe the fossil to be around 3,000 years old, but say the species itself could be very ancient.

This reveals clues about the origin of primates in the region.

It also suggests that many ecologically valuable treasures could be discovered by the unusual field of "underwater palaeontology".

Dr Alfred Rosenberger from Brooklyn College in New York, US, led the examination of the creature's bones, the results of which were published in the Royal Society journal Proceedings B.

[...]



Dr Rosenberger said the monkey - only the second specimen of the species Antillothrix bernensis ever found - probably measured about 30cm (12in) from head to toe.

The divers packed the fragile little skeleton into tupperware boxes

But the shape of the legs came as a surprise.

"Its femur or thigh bone was very thick. So it had sort of stout legs, which is something we didn't expect.

"We don't really have any living examples of New World monkeys that have stout legs like that."
Continue reading the main story
“Start Quote

It's now possible to reconstruct what this mysterious animal looked like and how it evolved”

End Quote Dr Sam Turvey Zoological Society of London

Dr Rosenberger thinks the creature went extinct relatively recently.

He said that it may have behaved similarly to a koala - clinging to the trunks of trees, rather than leaping from branch to branch.

"That's a very rough analogy, he said.

"But there's something very interesting about the ecological niche it inhabited."

The fossil also adds to evidence that there were several lineages of primates in the Caribbean, instead of one ancestor that moved into the region millions of years ago from which all modern species evolved.

Dr Rosenberger said it was likely that several species travelled "over the water" to inhabit the island of Hispaniola.

"And even though these particular bones might be relatively young, we're pretty sure that the arrival of these animals occurred well over 10 million years ago.

"That's an exciting part of the story - if you compare the dental remains of our monkey to other fossils that we know of, we see strong similarities with Patagonian fossils that are around 15 million years old."

no time.

Saadanius hijazensis: an exciting Saudi Oligocene Primate

The rust-coloured plateau above Mecca in Saudi Arabia may soon attract pilgrims of palaeontology. The hills, which overlook the Red Sea, have disgorged the 29–28-million-year-old partial skull fossil of an early primate that possesses features both of apes and monkeys. The skull could help palaeontologists to answer questions about the life of primates in a period that until now has provided few fossils.

When he caught sight of the skull during an expedition in search of ancient whale fossils last year, Iyad Zalmout wondered whether it belonged to a monkey or an ape. "It turns out it's not an ape, it's not a monkey, it's something intermediate," says Zalmout, a palaeontologist at the University of Michigan in Ann Arbor, and an author of a paper published in Nature today1.

The primate, dubbed Saadanius hijazensis, shares characteristics with Propliopithecoidea, an ancestor of apes and monkeys which existed more than 30 million years ago, as well as with more recent primates found to have lived from 23 million years ago. Saadanius lacks the advanced sinuses of the modern apes and monkeys that are collectively called catarrhines, but has a bony ear tube that was not yet fully developed in the Propliopithecoidea.

"This fossil is really key because it has that bony tube," says Erik Seiffert, an anatomist at Stony Brook University in New York. Comparison of the tube and other features, such as the teeth and the position of the eye sockets on the partial skull, with those of other primates could help palaeontologists to reconstruct the branches of the catarrhine family tree, between 30 and about 23 million years ago, says Seiffert.

Interesting. Again, no time.

Paper here.