Tag Archives: Australopithecus

New Study Suggests Remarkable South African Fossil Could Represent a New Australopithecus Species

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A recent study conducted by researchers from the University of Cambridge and La Trobe University questions the classification of the Littlefoot fossil, Australopithecus prometheus.

Littlefoot fossil from Sterkfontein Cave, central South Africa. Image credit: Purdue University.

The Littlefoot fossils were found in 1994 within a cave in Sterkfontein, central South Africa.

This specimen, referred to as StW 573, drew its name from the four small leg bones discovered in a box containing animal fossils, leading to the uncovering of the skeleton.

In the 2010s, paleoanthropologist Ronald Clark proposed that Littlefoot belonged to a hominin species known as Australopithecus prometheus.

Others argued that it was Australopithecus africanus, a hominid species first identified by Australian anatomist Raymond Dart in 1925 and already well-known in the region and across South Africa.

However, a new investigation by Dr. Jesse Martin and his team at La Trobe University has determined that Littlefoot does not exhibit a distinct set of traits linked to either species, suggesting it may be a completely new species.

“This fossil represents one of the most significant discoveries in human history, and its identity is crucial for understanding our evolutionary background,” stated Martin.

“We believe it’s evident that it does not belong to Australopithecus prometheus or Australopithecus africanus. This is likely a previously unidentified ancestor of humans.”

“Dr. Clark deserves recognition for discovering Littlefoot and for being among the few to suggest the presence of two hominin species in Sterkfontein.”

“Littlefoot indicates that this is likely true; there are indeed two species.”

Another forensic facial reconstruction of Australopithecus species – afarensis. Image credit: Cicero Moraes / CC BY-SA 3.0.

The researchers now intend to determine which species Littlefoot represents and how it fits within the human evolutionary tree.

Professor Andy Herries, a researcher at La Trobe University and the University of Johannesburg, remarked: “Littlefoot is one of the most complete and significant fossils ever discovered, providing valuable insights into early human diversity and how our ancestors adapted to various environments in southern Africa.”

“It is distinctly different from the designated specimen of Australopithecus prometheus, a classification based on the notion that early humans mastered fire, which we now understand was not the case.”

“Its unique significance compared to other contemporary fossils clearly indicates the necessity of defining it as a distinct species.”

Regarding this research, a paper was published in the December 2025 issue of the American Journal of Biological Anthropology.

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Jesse M. Martin et al. 2025. StW 573 Littlefoot fossil is Australopithecus prometheus. American Journal of Biological Anthropology 188 (4): e70177; doi: 10.1002/ajpa.70177

Source: www.sci.news

Two Australopithecus Species Coexisted in Ethiopia 3.4 Million Years Ago

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In 2009, paleoanthropologists uncovered eight foot bones from ancient human ancestors in 3.4 million-year-old deposits at the Wolanso Mir site in Ethiopia’s Afar Rift Valley. A new study reveals that this fossil, known as Brutele’s foot, belongs to Australopithecus deiremeda. This finding adds to the evidence that two hominin species, Australopithecus deiremeda and Australopithecus afarensis, coexisted in the same region at the same time.

Australopithecus deiremeda and Australopithecus afarensis. Image credit: Gemini AI.

“When we found this foot in 2009 and announced it in 2012, we recognized it was distinct from Lucy’s species, although Australopithecus afarensis has received significant attention since then,” stated Professor Johannes Haile Selassie from Arizona State University.

“Typically, naming a species based on postcranial elements is uncommon in our field, so we anticipated finding something distinctly linked to the feet from the neck up.

“Traditionally, the skull, jaw, and teeth are the primary markers for species identification.”

“When Bartele’s foot was first reported, some teeth had already been found in the same area, but we weren’t certain they were from the same deposit level.”

“Then in 2015, scientists classified a new species, Australopithecus deiremeda, from the same region, but the foot was not included, despite other specimens being unearthed nearby.”

“Over the last decade, our repeated fieldwork has yielded more fossils, allowing us to confidently link Brutele’s foot to the species Australopithecus deiremeda.”

Australopithecus deiremeda exhibits more primitive foot structures compared to Lucy’s species, Australopithecus afarensis.

While retaining an opposable thumb useful for climbing, it is believed that Australopithecus deiremeda likely walked on two legs, with an emphasis on their second toes rather than their big toes, as is the case with modern humans.

“The presence of an opposable big toe in Ardipithecus ramidus was a surprising and unexpected finding, highlighting that 4.4 million years ago, early human ancestors still possessed opposable big toes,” remarked Professor Haile Selassie.

“Then, a million years later, the discovery of Brutele’s foot further amazed us.”

“Currently, we’re in an era where we can observe subsequent species. Members of Australopithecus afarensis had an adducted big toe and displayed complete bipedalism.”

“This indicates that bipedalism, or walking on two legs, manifested in diverse forms among these early human ancestors.”

“The discovery of specimens like Bartele’s foot conveys that there were multiple ways to walk bipedally. It wasn’t until later that a single method emerged.”

To gain insights into their dietary practices, researchers sampled eight of the 25 teeth found in the area related to Australopithecus deiremeda for isotope analysis.

This process involved cleaning the tooth to ensure only the enamel was analyzed.

“I extracted the tooth using a dental drill with a very small bit, similar to what dentists use,” explained Naomi Levin, a professor at the University of Michigan.

“Using this drill, we meticulously remove a small amount of powder, which we store in a vial and return to the lab for isotope analysis.”

“The results were intriguing: Lucy’s species displayed a mixed diet, consuming both C3 (from trees and shrubs) and C4 (tropical grasses and sedges) plants; while Australopithecus deiremeda primarily utilized resources from the C3 category.”

“We were taken aback by how distinctly clear the carbon isotope signal was, mirroring ancient hominin data from Australopithecus ramidus and Australopithecus anamensis.

“I considered the dietary differences between Australopithecus deiremeda and Australopithecus afarensis. Although identifying them was challenging, the isotopic data distinctly indicated that Australopithecus deiremeda was not exploiting the same range of resources as Australopithecus afarensis, known as the earliest hominin to consume C4 grass-based resources.”

Another significant analysis involved accurately dating the fossils and understanding the ancient environments inhabited by these early humans.

“We conducted extensive field research at Wolanso Mir to analyze how different fossil layers interrelate, which is essential for grasping when and in what environments different species thrived,” noted Professor Beverly Thaler from Case Western Reserve University.

In addition to the 25 teeth found at Bartele, researchers also recovered the jaw of a four-and-a-half-year-old child, displaying dental anatomy similar to that of a juvenile Australopithecus deiremeda.

Professor Gary Schwartz from Arizona State University commented: “In juvenile hominins of this age, we observed evident growth discontinuity between front teeth (incisors) and back chewing teeth (molars), akin to patterns in modern apes and early australopiths like Lucy.”

“The most surprising aspect was that, despite gaining a better understanding of the diversity within early australopith (and thus early hominid) species regarding size, diet, locomotion, and anatomy, these early forms appeared surprisingly uniform in growth patterns.”

Findings have been detailed in a paper published in this week’s edition of Nature.

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Y. Haile Selassie et al. New discovery illuminates the diet and lifestyle of Australopithecus deiremeda. Nature published online November 26, 2025. doi: 10.1038/s41586-025-09714-4

Source: www.sci.news

Paleontologists Reveal Significant Size Difference Between Male and Female Australopithecus

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Two extinct hominins, Australopithecus afarensis and Australopithecus africanus, exhibited much greater sexual dimorphism than chimpanzees and modern humans. According to Dr. Adam Gordon, a paleontologist at the University of Albany and Durham, Australopithecus afarensis displayed even higher levels of dimorphism.

Reconstructing the face of Australopithecus afarensis. Image credit: Cicero Moraes/CC by-sa 3.0.

The sexual size dimorphism is not just a mere physical trait; it indicates deeper behavioral and evolutionary strategies.

In line with sexual selection theory, the sexual size dimorphism seen in modern primates typically correlates with intense male-male competition and social structures, fostering a one-sided mating system where one or more large males dominate access to multiple females.

Conversely, low sexual dimorphism is characteristic of species that exhibit paired social structures with lower competition for mating opportunities.

Contemporary human populations show low to moderate sexual size dimorphism, with males generally being slightly larger than females on average, although there is considerable overlap between the sexes.

Fossil data is often incomplete, making it exceedingly difficult to ascertain the gender of ancient individuals.

To overcome this issue, Dr. Gordon utilized a geometric averaging method for estimating size from multiple skeletal elements, including the upper arm, femur, and tibia.

Resampling techniques were then employed to simulate thousands of comparisons between fossil hominins and living primates, ensuring that the statistical model accounted for the incomplete and varied nature of fossil samples.

A comparative framework was developed using data from contemporary gorillas, chimpanzees, and humans with known genders and complete skeletons.

Unlike earlier studies where ambiguous or inconclusive statistical results were interpreted as signs of similarity, Dr. Gordon’s approach unveiled clear and significant differences, even with relatively small fossil samples.

To eliminate the potential of body size changes in Australopithecus afarensis reflecting broader evolutionary trends rather than gender distinctions, Dr. Gordon also analyzed time series trends over a 300,000-year span from the Khadar Formation in Ethiopia.

His analysis indicated no significant size increase or decrease over time, suggesting that the observed variations were more likely due to differences between males and females.

“These were not minor differences,” Dr. Gordon stated.

“In the case of Australopithecus afarensis, males were significantly larger than females—possibly more so than the great living apes.”

“Both of these extinct hominin species displayed gender-specific size distinctions from modern humans, yet differed from extant ape species in this regard.”

Australopithecus africanus. Image credit: JM salas/cc by-sa 3.0.

Dr. Gordon’s previous research indicates that the elevated sexual size dimorphism seen in living primates may correlate with considerable resource stress. In situations where food is scarce, smaller, healthier females can better meet their metabolic needs and reproduce quicker than larger females, leading to offspring with smaller mothers and greater size disparities between males and females.

The pronounced sexual size dimorphism observed in both Australopithecus afarensis and Australopithecus africanus suggests a high level of male competition, akin to differences noted in chimpanzees and gorillas. However, the distinctions between the two fossil species could reflect varying intensities of sexual selection or resource stress in their environments (e.g., differences in the length of dry seasons that could affect female body size).

In any event, the high sexual size dimorphism of these fossil hominins starkly contrasts with the more balanced sizes seen in modern humans, offering insights into different models of early human existence.

The implications of these findings are significant. Australopithecus afarensis, which inhabited the Earth between 3.9 and 2.9 million years ago, is often viewed as very closely related to the direct ancestors of modern humans.

However, its pronounced sexual dimorphism suggests that early human social systems may have been much more hierarchical and competitive than previously believed.

On the contrary, Australopithecus africanus—which appears slightly later in the fossil record—exhibits less dimorphism compared to Australopithecus afarensis. This could represent different evolutionary branches within the human lineage or perhaps reflect various social behavioral stages in the development of hominins.

“We often categorize these early hominins together as a single group called Gracile Australopithecines, believed to have interacted with their physical and social environments in similar ways,” Dr. Gordon explained.

“While there is some truth to this, the significant differences in dimorphism between the two species indicate that these closely related hominins were under distinct selection pressures, unlike those affecting modern human pair bonds.”

The survey findings will be published in the American Journal of Biological Anthropology.

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Adam D. Gordon. 2025. Dimorphism of sexual size in Australopithecus africanus and A. afarensis in contrast to modern humans despite low power resampling analysis. American Journal of Biological Anthropology 187(3): E70093; doi: 10.1002/ajpa.70093

Source: www.sci.news

Studies Indicate Diverse Hand Grips Used by Australopithecus sediba and Homo naledi

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Australopithecus sediba – This small human species, which existed around 2 million years ago, displayed a blend of ape-like and human-like traits. Homona Lady – A recent study led by Dr. Samar Syeda from the American Museum of Natural History reveals that this newly identified species, dating back approximately 335,000 to 236,000 years, shows a distinct pattern of bone thickness, indicating diverse load applications and potential grip types.

A reconstruction depicting the life of Australopithecus sediba commissioned by the University of Michigan Museum of Natural History. Image credit: Elisabeth Daynes/S. Entressangle.

Dr. Syeda and her team explored variations in phalanx morphology, discovering that South African hominins might exhibit different dexterities along with varied climbing abilities.

They focused on two nearly complete fossil hand skeletons discovered in South Africa: the hands from Australopithecus sediba, dated at 2 million years old, and hand skeletons from the newly identified star cave system from 250,000 years ago.

While no direct associations with stone tools have been established for either species, certain aspects of their hand and wrist morphology imply a level of dexterity that aligns more closely with human hands than with those of chimpanzees and gorillas.

“Stone tools have been found in South Africa dating back at least 2.2 million years (and potentially as far back as 3.3 million years),” stated Dr. Tracy Kivell, a researcher at the Max Planck Institute for Evolutionary Anthropology and Witwatersrand University. “Many primates are adept stone tool users, as are Australopithecus sediba and Homona Lady.

“However, the exact nature of their tool usage and interaction remains unclear.”

Furthermore, both Australopithecus sediba and Homona Lady exhibit ape-like characteristics, especially within their upper limb bones, which could be advantageous for climbing.

The ongoing debate in paleontology considers whether these traits indicate actual climbing behaviors or if they are simply evolutionary remnants from climbing ancestors.

Reconstruction of Homona Lady‘s head by artist John Gurche, who spent around 700 hours recreating it from a bone scan, published in collaboration with the University of Witwatersrand, the National Geographic Society, and the South African National Research Foundation in the journal Elife. Image credits: John Gurche / Mark Thiessen / National Geographic.

To explore these inquiries, researchers examined variations in the internal composition of the fingers (cortical bone) in both Australopithecus sediba and Homona Lady.

Bones are dynamic tissues that can modify their structure based on usage and loading throughout life, thickening in high load areas while thinning in regions subjected to lesser loads.

As such, variations in internal cortical thickness can shed light on how these two hominin fossils utilized their hands during their lifetimes.

“Our findings indicate that both Australopithecus sediba and Homona Lady exhibit a range of functional signals within the cortical bone structure of their fingers,” remarked Dr. Syeda.

In Australopithecus sediba, the distribution of cortical bones within the proximal and intermediate phalanges of most fingers closely resembles that of apes. However, the thumb and pinky bones are more akin to human bones.

“These two digits appear to represent potential functional signals because they experience less frequent or lower loads during climbing or suspension,” noted Dr. Syeda.

“Combining these findings with a human-like thumb suggests that Australopithecus sediba employed its hands not just for climbing, but also for tool use and other dexterous activities.”

Homona Lady, in contrast, displays an unusual pattern where the proximal phalanx (the bone supported by the palm) shows human-like traits, while the intermediate phalanx (the bone in the middle of the finger) reflects ape-like characteristics.

Fossil hands of Australopithecus sediba and Homona Lady indicating that these South African hominins may have exhibited varying degrees of dexterity and climbing proficiency. Image credit: Tracy Kivell.

“This distinct pattern was unexpected and suggests that Homona Lady may have engaged different parts of its fingers for varied loading,” Dr. Syeda noted.

This unique loading pattern resembles certain grip types observed today, such as crimp grips used by rock climbers, where the surface is primarily grasped by the tips of the fingers.

Homona Lady also features unusually curved phalanges, particularly notable since this species coexisted with early members of our own species, Homo sapiens, indicating potential usage of hands for climbing.

Further research is necessary to ascertain whether Homona Lady utilized crimp-like grips for climbing; however, it is evident that throughout human evolution, there has been an ongoing requirement for using tools with enhanced dexterity for food processing on trees and rocks within the ancient South African landscape.

“This research offers greater evidence that human evolution is characterized by various ‘experiments’ balancing the demands of manipulation and movement within these historical environments, rather than a straightforward transition from upright walking to increasingly advanced tool use,” Dr. Kivell stated.

Survey results will be published this week in the journal Advances in Science.

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Samar M. Syeda et al. 2025. Bone distribution in the Faranjour cortex reveals variations in dexterity and climbing behaviors in Australopithecus sediba and Homona Lady. Advances in Science 11 (20); doi:10.1126/sciadv.adt1201

Source: www.sci.news

New study reveals Australopithecus did not regularly consume meat

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Australopithecus had a varied but plant-based diet, as indicated by stable isotope data analysis from seven human specimens collected in Sterkfontein, South Africa, 3.5 million years ago.

Lüdecke others. claim that Australopithecus In Sterkfontein, mammalian meat was not regularly consumed. Image credit: Cicero Moraes / CC BY-SA 3.0.

“Tooth enamel is the hardest tissue in the mammalian body and can preserve the isotopic fingerprint of an animal’s diet for millions of years,” says geochemist Dr Tina Lüdecke from the University of the Witwatersrand. said.

“When animals digest food, a biochemical reaction involves light isotopes of nitrogen (14yeah). ”

“Therefore, the breakdown products produced in their bodies include a high proportion of 14N.”

“When these light nitrogen compounds are excreted in urine, feces, or sweat, the proportion of heavy nitrogen increases (15N) It ​​provides the body with this light nitrogen compared to the food it takes in. ”

“This means that herbivores have higher nitrogen isotope ratios than the plants they consume, and carnivores have higher nitrogen isotope ratios than their prey.”

“Therefore, the higher the 15From N 14The higher the N ratio in the tissue sample, the higher the trophic position of the organism in the food web. ”

Nitrogen isotope ratios have long been used to study the diet of hair, nails, bones, and many other organic materials in modern animals and humans.

However, in fossil materials, these measurements have until now been limited to samples only tens of thousands of years old, as the organic material degrades over time.

In the new study, Luedecke and colleagues used a new technique to measure nitrogen isotope ratios in the enamel of fossilized teeth that are millions of years old.

They found that the nitrogen isotope ratio in tooth enamel was Australopithecus Abundances varied but were consistently low, similar to herbivore populations, and much lower than modern carnivore populations.

They conclude that the diets of these hominins, although diverse, consisted largely or exclusively of plant-based foods.

Therefore, Australopithecus did not regularly hunt large mammals, as Neanderthals did millions of years later, for example.

Although researchers cannot completely rule out the possibility that they occasionally consumed animal protein sources such as eggs or termites, there is evidence that their diet was primarily vegetarian.

“Our method opens up exciting possibilities for understanding human evolution and has the potential to answer important questions, such as when did our ancestors start incorporating meat into their diets?” And was the onset of meat eating associated with an increase in brain volume?” said Dr. Alfredo Martínez García, a researcher at the Max Planck Institute for Chemistry.

“This study represents a major step in extending our ability to better understand the diets and nutrient levels of all animals to multi-million-year scales.”

“This study provides clear evidence that the diet did not include large amounts of meat.”

“A pioneering application of this new method was pioneered at the Sterkfontein site, which continues to make fundamental contributions to science 89 years after the first hominin fossils were discovered there by Robert Bloom. We are honored to have received this recognition,” said Professor Dominic Stratford, Director of the Center. Research in Sterkfontein Cave.

of study Published in a magazine science.

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Tina Ludecke others. 2025. Australopithecus In Sterkfontein, very little mammalian meat was consumed. science 387 (6731): 309-314;doi: 10.1126/science.adq7315

Source: www.sci.news