Ancient ape fossil discovery in India


This 13 February 2018 video from India is called Ramapithecus: Phylogenetic and Taxonomic status.

From PLOS:

Late Miocene ape maxilla (upper jaw) discovered in western India

Discovery extends the range of ancient apes in the subcontinent

November 14, 2018

An ape maxilla (upper jaw) from the Late Miocene found in the Kutch basin, in western India, significantly extends the southern range of ancient apes in the Indian Peninsula, according to a study published in November 14, 2018 in the open-access journal PLOS ONE by Ansuya Bhandari from the Birbal Sahni Institute of Palaeosciences, Lucknow, India, and colleagues.

Apes, or hominoids, are a group of primates from Africa and Southeast Asia that includes the gibbons and the great apes: chimps, orangutans, gorillas, and humans. Ancient ape remains from Miocene deposits in the Siwaliks of India and Pakistan have been key for understanding the evolution of great apes and humans. In this study, the researchers examined an ape jaw fragment excavated from the Kutch basin, in the Gujarat state of western India, about 1000 km south of the Siwaliks deposits.

X-ray computed-tomography revealed details of the preserved canine and cheek teeth, such as the tooth enamel and root structure. The ape mandible belonged to an adult individual of the Sivapithecus genus, but the species could not be identified. The authors dated the specimen to the basal Late Miocene, around 11 to 10 million years ago based on previous mammalian fossil findings in the site. The new finding is the first Miocene ape fossil to be discovered so far south in the Indian peninsula, and extends the southern range of ancient apes in the subcontinent by about 1000 km.

The authors add: “This is a landmark discovery of 11 million-year-old human ancestors in Kutch, Gujarat.”

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Chimpanzees, BBC video


This 7 November 2018 video says about itself:

Things to Know About Chimps | BBC Earth

Chimp behaviour can be surprisingly advanced, and sometimes incredibly violent: discover some of their impressive features with the best clip from our Natural History archive.

Wild chimpanzees share food with friends


This 10 October 2018 video from the Ivory Coast says about itself:

Honey sharing in wild chimpanzees of the Taï Forest – Taï Chimpanzee Project

From the Max Planck Institute for Evolutionary Anthropology in Germany:

Wild chimpanzees share food with their friends

October 10, 2018

Summary: Why share food with non-family members when there is no immediate gain? An international team of researchers conducted observations of natural food sharing behavior of the chimpanzees of the Tai National Park, Ivory Coast. They found that chimpanzees who possess large, desirable food items, like meat, honey or large fruit share food with their friends, and that neither high dominance status nor harassment by beggars influenced possessors’ decisions to share.

Sharing meat after hunting and exchanging other valued food items is considered key in the evolution of cooperation in human societies. One prominent idea is that humans share valuable foods to gain future favors, such that those we chose to share with are more likely to cooperate with us in the future. Despite regularly occurring in humans, sharing food outside of kinship or mating relationships is rare in non-human animals. Our two closest living relatives, chimpanzees and bonobos, are two of the rare exceptions, and because of the important role of food sharing in human evolution, examining the sharing patterns of chimpanzees can help to answer questions on how sharing food amongst adults evolved and how it may have shaped human cooperation.

Researchers from the MPI-EVA observed natural food sharing behavior of the chimpanzees of the Tai National Park, Ivory Coast, and found that chimpanzees are very selective in who they share desirable food items, like meat, honey or large fruits, with. They show that chimpanzees were more likely to share food with their friends, and that neither high dominance status nor harassment by beggars influenced their decision. This complements results from another study by the same team published last month that examined meat sharing after group hunting of monkeys. There they found that chimpanzees in possession of meat after successful hunts were likely to reward other hunters by sharing with them. “Collectively our research shows that the chimpanzees decide when to share food based on the likelihood that this favor will be returned in the future,” says Liran Samuni, first author of both studies. “Or, in case of sharing after group hunts, sharing of meat is returning the favor for helping out.”

Previous studies in another subspecies of chimpanzees have suggested that food sharing in chimpanzees mainly occurs because of harassment pressure from beggars. “This was not the case for the Tai chimpanzees”, Catherine Crockford, senior author on the studies, points out, “emphasizing the high variation in cooperation across chimpanzee populations.” Human populations also vary in how cooperative they are and research is ongoing in both humans and non-human animals assessing what might make some populations more cooperative than others. “The need to stay in a cohesive unit, because of high predation pressure, or the capability to exhibit strong cohesion, because of rich food sources, are two possible scenarios to promote the expression of cooperative acts”, suggests Roman Wittig, the second senior author of the studies.

Additionally, the researchers collected urine samples from chimpanzees after hunting and food sharing events and measured the hormone oxytocin. “We know that oxytocin plays a strong role in lactation, which you could look at as an example of food sharing between mother and infant, and is generally involved in social behavior and bonding”, Liran Samuni explains. The researchers found high levels of oxytocin after chimpanzees shared meat and other valued foods, and after chimpanzee participated in hunting with others. “That we found higher oxytocin levels after both hunting and sharing adds to the idea that oxytocin is a key hormone involved in cooperation in general”, Liran Samuni points out.

The researchers conclude that like humans, Tai chimpanzee sharing is selective, and that friends and others that helped acquiring the food benefit more. Emotional connection, as is obvious amongst friends, likely played a crucial role in the evolution of human cooperation.

Primates, including humans, are usually thought of as visual animals with reduced reliance on the sense of smell. In behavioral experiments, biologists have now found that chimpanzees use olfaction as a prime mode of investigation, and that they recognize group members and kin using olfactory cues: here.

Chimpanzees react faster to cooperate than make selfish choices: here.

Apes have ‘human’ muscles too


Figure showing the striking similarities between the head muscles of common chimpanzees, bonobos and humans: the very rare exceptions are those shown in colors and with text. Credit: © Rui Diogo

From ScienceDaily:

‘Uniquely human’ muscles have been discovered in apes

Apes also have muscles long-believed to be only present in humans and used for walking on two legs, using complex tools, and sophisticated facial and vocal communication

May 23, 2018

Muscles once thought ‘uniquely human’ have been discovered in several ape species, challenging long-held theories on the origin and evolution of human soft tissues. The findings question the anthropocentric view that certain muscles evolved for the sole purpose of providing special adaptations for human traits, such as walking on two legs, tool use, vocal communication and facial expressions. Published in Frontiers in Ecology and Evolution, the study highlights that thorough knowledge of ape anatomy is necessary for a better understanding of human evolution.

“This study contradicts key dogmas about human evolution and our distinct place on the ‘ladder of nature’,” says Rui Diogo, an Associate Professor in the Department of Anatomy at Howard University, Washington, USA. “Our detailed analysis shows that in fact, every muscle that has long-been accepted as ‘uniquely human’ and providing ‘crucial singular functional adaptations’ for our bipedalism, tool use and vocal and facial communications is actually present in the same or similar form in bonobos and other apes, such as common chimpanzees and gorillas.”

Long-standing evolutionary theories are largely based on the bone structures of prehistoric specimens — and, according to Diogo, also on the idea that humans are necessarily more special and complex than other animals. These theories suggest that certain muscles evolved in humans only, giving us our unique physical characteristics. However, verification of these theories has remained difficult due to scant descriptions of soft tissues in apes, which historically have mainly focused on only a few muscles in the head or limbs of a single specimen.

Diogo explains, “There is an understandable difficulty in finding primate, and particularly ape, specimens to dissect as they are so rare both in the wild and museums.”

To find enough data to complete this research, Diogo compiled all previous information on ape anatomy based on studies with colleague Bernard Wood. He also conducted anatomical research on several bonobos that died of natural causes, together with colleagues at the University of Antwerp under the Bonobo Morphology Initiative 2016 — looking for the presence of seven different muscles thought to have evolved only in our species.

Diogo discovered that these seven muscles were present in apes in a similar or even exact form. For example the fibularis tertius muscle, said to be uniquely associated with human bipedalism (walking on two legs), was present in half the examined bonobos. Similarly, both the laryngeal muscle arytenoideus obliquus and the facial muscle risorius — thought to have evolved for our uniquely sophisticated vocal and facial communication, respectively — were present in at least some chimpanzees and/or gorillas.

These findings open crucial new directions for research and question our understanding of human evolution. “The picture emerging from this research is that the origin and evolution of human soft-tissue is clearly more complex — and not as exceptional — as first thought”, says Diogo.

“We need a more thorough examination of why these muscles are present in apes and, in some cases, in just part of a population within a certain species”, he says. “Are these muscles essential for the apes that have them, as adaptationist evolutionary scientists would argue? Or are they evolutionary neutral features related to how their bodies develop, or simply by-products of other features?”

He concludes, “Most theories of human evolution give the impression that humans are markedly distinct from apes anatomically, but these are unverifiable ‘just-so stories’. The real evidence shows we are not so different overall. This study highlights that a thorough knowledge of ape anatomy is necessary for a better understanding of our own bodies and evolutionary history.”

Pregnant bonobos get a little delivery help from their friends. Observations of captive apes suggest they, like humans, have ‘social’ births. By Bruce Bower, 1:26pm, May 24, 2018.

While humans and other species share some of the same genetic information, new research found that humans are unique among mammals when it comes to the types and diversity of microorganisms on our skin. This difference could have implications for our health and immune systems: here.

Chimpanzee brains similar to human ancestors’


This video says about itself:

How different are human and chimpanzee brain stem cells?

27 January 2017

We share between 94 and 99% of our DNA with our chimpanzee cousins, but how do our brains compare? Watch this video by Felipe Mora-Bermúdez to find out what he has learned from studying brain stem cells from humans and chimps.

You can read his full publication on this work in the journal eLife here.

Felipe is a postdoc in the lab of Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany.

By Bruce Bower, 3:00pm, March 26, 2018:

Modern chimp brains share similarities with ancient hominids

Scans suggest certain folding patterns don’t mark humanlike neural advances after all

Groove patterns on the surface of modern chimpanzee brains throw a monkey wrench into proposals that some ancient southern African hominids evolved humanlike brain characteristics, a new study suggests.

MRIs of eight living chimps reveal substantial variability in the shape and location of certain features on the brain surface. Some of these brains showed surface creases similar to ones that were thought to have signaled a turn toward humanlike brain organization in ancient hominids hundreds of thousands, if not millions, of years ago. Paleoanthropologist Dean Falk of Florida State University in Tallahassee and colleagues report their findings online March 13 in Brain, Behavior and Evolution.

The study casts doubt on a 2014 paper by Falk that was based on casts of the inside of fossil braincases, called endocasts, which preserve impressions of these surface features. At the time, Falk argued that four endocasts from southern African hominids — three Australopithecus africanus and one Australopithecus sediba — showed folding patterns that suggested that brain reorganization was underway as early as 3 million years ago in a frontal area involved in human speech production.

But MRIs of three of the chimp brains reveal comparable creases, the researchers found. Two other chimps display other frontal tissue furrows that Falk had also previously described as distinctly humanlike.

“I was really wrong about the handful of Australopithecus endocasts”, Falk says. The endocasts were made from A. africanus and A. sediba fossils dating to between roughly 2 million to 3 million years ago (SN: 8/10/13, p. 26).

And in one chimp, the new study finds, a pair of grooves correspond with those on a Homo naledi endocast that were described in 2017 as humanlike (SN Online: 4/25/17). H. naledi, a small-brained species with many humanlike skeletal features, inhabited southern Africa close to 300,000 years ago (SN: 6/10/17, p. 6).

Still, researchers have spent decades debating the implications of partially preserved brain surface features on hominid endocasts. And the new findings based on MRIs are also controversial.

Nothing in the new chimp study undermines the original finding of humanlike folds in H. naledi’s frontal brain, says biological anthropologist Shawn Hurst of Indiana University Bloomington. The frontal brain grooves on a H. naledi endocast, like those in modern humans, lie farther back than the grooves seen in the chimp MRI scan, Hurst contends. Expanded tissue folds around those grooves also follow a distinctly humanlike pattern not observed [in] chimps, he argues. Those features indicate H. naledi had a humanlike capacity for pride and other complex social emotions and possibly verbal communication of some type, Hurst says. What’s more, the new study fails to consider that the A. sediba endocast shows furrows and folding patterns found in humans but not chimps, he says.

Endocast researchers need to study the range of brain surface characteristics in a larger sample of living chimps and other apes to make more accurate comparisons, Falk says. Until now, line drawings published in 1950 of only five chimp brain hemispheres, she notes, have provided the most accurate and comprehensive look at furrow patterns on chimps’ brains.

How specific folds and creases on the brain’s surface relate to inner structures, such as those involved in speech and language, also remains poorly understood, Falk says.

Can chimpanzee vocalizations reveal the origins of human language? While closely related to humans, researchers discover that chimpanzees’ vocalizations resemble human language less than you’d expect: here.

Chimpanzees (Pan troglodytes) appear to keep tidier sleeping arrangements than humans do. That’s one finding of a recent study that evaluated the microbes and arthropods found in the treetop beds that chimpanzees make each night: here.

An international team of scientists has studied the physiological parameters of savanna and rainforest chimpanzees and compared their water and energy budgets as well as their stress levels. They found that the stress of maintaining their body temperature is a tremendous burden on chimpanzees living in the savanna: here.

Few things can delight an adult more easily than the uninhibited, effervescent laughter of a baby. Yet baby laughter, a new study shows, differs from adult laughter in a key way: Babies laugh as they both exhale and inhale, in a manner that is remarkably similar to nonhuman primates: here.

‘Chimpanzees more playful than gorillas’


This video from the USA says about itself:

How Do Chimps and Gorillas Play?

9 December 2014

In the second of three episodes with Lincoln Park Zoo, we learn about how the zoo promotes play at the Regenstein Center for African Apes.

From PLOS:

Adult chimpanzees play more than adult lowland gorillas in captivity

In adult animals, play is a sign of social cohesion and is inhibited by strong competition

March 7, 2018

Play is more frequent in captive adult chimpanzees than in captive adult lowland gorillas, according to a study published March 7, 2018 in the open-access journal PLOS ONE by Giada Cordoni and Elisabetta Palagi from Univerity of Pisa in collaboration with Ivan Norscia from University of Turin.

In many adult animals, play is thought to reflect a species’ degree of social cohesion, and is usually more frequent in species with low levels of competition and high levels of social affiliation. Cordoni and colleagues compared adult play in chimpanzees and lowland gorillas, two ape species with different social structures. Chimpanzees live in highly cohesive, co-operative groups that can have several adult males.

However, lowland gorilla groups are dominated by a single silverback male and have low levels of social affiliation. The researchers observed 15 chimpanzees and 11 gorillas in the ZooParc de Beauval, France. Altogether, observations were made over more than 129 hours for chimpanzees and 135 hours for gorillas, with play including “peek a boo” and “tug-of-war” games as well as “rough and tumble” play fights.

The researchers found that adult play was more frequent in chimpanzees than in gorillas, and play sessions lasted longer. In addition, in gorillas play was more likely to escalate into real aggression. It appeared that the more players, the more unstable a play session and the more difficult to manage. While future work will show if affiliative relationships really determine differences in social play amongst great apes, the researchers’ findings are in keeping with the differences in social structure of chimpanzees and lowland gorillas.

A study of the microbiomes of wild gorillas and chimpanzees offers insights into the evolution of the human microbiome and might even have implications for human health: here.

Bonobos, chimpanzees understand each other’s gestures


This 2015 video is called Chimpanzees & Bonobos – The Differences.

From PLOS Biology:

Bonobo and chimpanzee gestures overlap extensively in meaning

Kirsty E. Graham, Catherine Hobaiter, James Ounsley, Takeshi Furuichi, Richard W. Byrne

February 27, 2018

Abstract

Cross-species comparison of great ape gesturing has so far been limited to the physical form of gestures in the repertoire, without questioning whether gestures share the same meanings. Researchers have recently catalogued the meanings of chimpanzee gestures, but little is known about the gesture meanings of our other closest living relative, the bonobo.

The bonobo gestural repertoire overlaps by approximately 90% with that of the chimpanzee, but such overlap might not extend to meanings. Here, we first determine the meanings of bonobo gestures by analysing the outcomes of gesturing that apparently satisfy the signaller. Around half of bonobo gestures have a single meaning, while half are more ambiguous. Moreover, all but 1 gesture type have distinct meanings, achieving a different distribution of intended meanings to the average distribution for all gesture types. We then employ a randomisation procedure in a novel way to test the likelihood that the observed between-species overlap in the assignment of meanings to gestures would arise by chance under a set of different constraints.

We compare a matrix of the meanings of bonobo gestures with a matrix for those of chimpanzees against 10,000 randomised iterations of matrices constrained to the original data at 4 different levels. We find that the similarity between the 2 species is much greater than would be expected by chance. Bonobos and chimpanzees share not only the physical form of the gestures but also many gesture meanings.

Author summary

Bonobos and chimpanzees are closely related members of the great ape family, and both species use gestures to communicate. We are able to deduce the meaning of great ape gestures by looking at the ‘Apparently Satisfactory Outcome’ (ASO), which reflects how the recipient of the gesture reacts and whether their reaction satisfies the signaller; satisfaction is shown by the signaller ceasing to produce more gestures. Here, we use ASOs to define the meaning of bonobo gestures, most of which are used to start or stop social interactions such as grooming, travelling, or sex.

We then compare the meanings of bonobo gestures with those of chimpanzees and find that many of the gestures share the same meanings. Bonobos and chimpanzees could, in principle, understand one another’s gestures; however, more research is necessary to determine how such gestures and gesture meanings are acquired.

This research is important for getting to know about the common ancestors of bonobos, chimpansees and humans.