Macrobiological features have been cited as irreducibly complex, including animal joints and the trap mechanisms of carnivorous plants, even the cell itself.

Source

A new analysis of a set of 1.4-million-year-old fossilized footprints found along the shore of an ancient Kenyan lake revealed that the hominins responsible for leaving them were much larger than previously believed, with some specimens approaching the height and body size of modern humans.

The new analysis also determined that discovering a group of footprints belonging to eight different adult males from distant human ‘cousin’ species Paranthropus boisei walking together suggests a complex societal dynamic where males likely competed for females but also worked together for the group’s benefit.

1.4-Million-Year-Old Fossilized Footprints Reveal Unexpectedly Large Body Size

According to a statement announcing the new fossilized footprint analysis, the team behind the research had previously “pioneered” methods allowing science to accurately identify the footprints as belonging to Paranthropus boisei in 2024.

However, lead author Kevin Hatala, of Chatham University and an associated researcher of the Department of Human Origins at the Max Planck Institute for Evolutionary Anthropology in Leipzig, said the new approach, which analyzes foot anatomy and movement patterns based on the fossilized footprints, revealed much larger individuals than expected.

“The sizes of the footprints indicate human-like body sizes – up to 1.8 meters tall and around 75 kilograms”, Hatala said, noting that scientists studying the rare fossils available for Paranthropus boisei had previously assumed the species was much smaller than the modern human ancestor and contemporary hominin, Homo erectus.

For example, the researchers explain, the “overwhelming majority” of previously identified Paranthropus boisei fossils were skulls with massive jaws and teeth. However, they add, little is known about this ancient hominin’s anatomy from the neck down.

“A Window into Hominin Behavior and Group Dynamics”

Although indirect evidence compared to actual bones, the team notes that fossilized footprints form “very quickly.” This rapid formation helps preserve critical movement and anatomy data that the team notes “can be a useful window into hominin behavior and group dynamics.”

“The fact that eight, mostly adult male, Paranthropus boisei individuals seemingly traveled together as a group, without females or children, hints at a complex social structure in this species”, explained study co-author Neil Roach of Harvard University.

For example, Roach said the ancient footprint makers may have lived in large groups, “where males competed for mates.” However, he notes, the same footprints suggest these competing males “also tolerated each other at times for safety in a dangerous environment.”

“This discovery adds an important behavioral dimension to the fossil record of Paranthropus boisei, a species that lived alongside early members of the genus Homo, yet took a different evolutionary path,” they explain.

Proximity and Environmental Conditions Could Offer More Behavioral Clues

Although the study focused on the 1.4-million-year-old footprints found on the shore of an ancient Kenyan lake, the work joins a growing catalog of ancient hominin footprints left on equally ancient lake shores. To date, the team has documented hundreds of hominin footprints across more than a half-dozen sites in the local region.

When discussing the significance of their findings, the team noted that these 1.4-million-year-old footprints join this larger group in supporting ancient lakes as an “important habitat with critical resources” that our now-extinct relatives relied on for survival. Study co-author Kay Behrensmeyer of the Smithsonian Institution also highlighted the unexpected nature of the discovery of ancient footprint fossils so close to others from a similarly ancient time.

“To me, it is amazing that we have the same kind of lake margin deposits in two areas of East Turkana that are 40 kilometers apart, at about the same age”, the researcher explained.

Study co-author Anna K. Behrensmeyer from the Department of Paleobiology and Human Origins Program, National Museum of Natural History, Smithsonian Institution, said understanding the environment and local conditions when the footprints were left could fill in even more missing pieces about this enigmatic ancient hominin.

“If we can understand what geological conditions allowed these tracks to be preserved, we should know more about why hominins continued to return to the lake shore environment over more than 100,000 years,” Behrensmeyer said.

Building a Photo Album of Our Past

When detailing the significance of the new analysis, study co-author Purity Kiura of the National Museums of Kenya said finding these fossilized prints along the margins of Lake Turkana “reinforces the region’s global importance in understanding human evolution, preserving remarkable evidence of how our ancient relatives lived 1.4 million years ago.”

“It further strengthens Kenya’s position as one of the world’s leading paleoanthropological landscapes and highlights our responsibility to protect this irreplaceable heritage,” Kiura added.

From a methodology standpoint, the team noted the benefit of combining new analytical approaches with “exceptional” fossil footprints. They also point out that ancient tracks like the 1.4 million-year-old footprints found in Kenya “can reveal the anatomy and movement of extinct human relatives, while also providing rare insights into their social lives and environments.”

To follow up on their findings, the research team said they plan to return to Kenya later this year and conduct more analysis of the footprints. According to Hatala, this work will help archaeologists and anthropologists fill in missing pieces of hominin history, especially those extinct branches of the evolutionary tree.

“Each site represents a snapshot of our past, and we are quickly building a photo album with several different windows to hominin anatomy, locomotion, behavior, and environments during the Early Pleistocene,” the researcher explained.

The study “Insights into hominin body size, locomotion, and behavior from Early Pleistocene trackways in northern Kenya” was published in the Proceedings of the National Academy of Sciences.

Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org

An international research team led by Harvard scientists has announced the first-ever detection of an atmosphere on an Earth-like rocky exoplanet, LHS 1140 b, orbiting within its star’s habitable zone, only 48 light-years away.

The researchers behind the historic discovery, which they are calling “a major milestone in the search for life on other planets,” said the detection of an atmosphere on an Earth-like rocky exoplanet offers the strongest evidence to date that worlds with similar compositions and temperatures to Earth that are also capable of supporting life could exist beyond our solar system.

Models Predicted First Earth-like Rocky Habitable Zone Exoplanet Atmosphere

In a statement announcing the detection of an atmosphere around a habitable-zone rocky exoplanet, the discovery was motivated by theoretical predictions suggesting that LHS 1140 b may contain an atmosphere. The planet was even more tantalizing because its orbit around its host red dwarf star allows for liquid water on its surface, a key ingredient for life as we know it.

Although thousands of exoplanets have been confirmed since 1995, including habitable-zone rocky worlds similar in size and composition to Earth, the team notes that determining whether any of these potential Earth analogs maintain an atmosphere. Like water, an atmosphere is considered a likely necessity for life to emerge.

“An atmosphere is essential for a planet to support life as we know it,” explained Collin Cherubim, the lead author of a study detailing the findings, who recently earned his Ph.D. in Earth and Planetary Sciences from Harvard University.

Robin Wordsworth, the Gordon McKay Professor of Environmental Science and Engineering and Professor of Earth and Planetary Sciences at Harvard, said that as recently as twenty years ago, astronomers still didn’t know if other, terrestrial-type planets “even existed.” However, he explained, they quickly found that this type of planet was common, including some orbiting within their star’s habitable zone.

“The next question was whether any of them had managed to keep an atmosphere,” the professor added.

Infrared Observations Confirm Historic First  

Before performing any direct observations, the team used computer models to predict what they might find on LHS 1140 b. As noted, those models predicted an upper atmosphere rich in helium. The models also suggested that the atmospheric helium was slowly escaping into space.

To test the model’s predictions, Cherubim and colleagues gained access to the Warm Infrared Echelle (WINERED) Spectrograph on the Magellan Observatory in Chile. The team noted that this powerful telescope allowed them to observe an alignment of LHS 1140 b and another planet transiting its star “on the same night.”

When analyzing the data, the team found that one of the planets appeared to lack any measurable atmosphere. However, as their models had predicted, helium was actively escaping from LHS 1140 b. The finding confirmed that this rocky exoplanet orbiting within its star’s habitable zone was actively maintaining an atmosphere.

David Charbonneau, the head of the Harvard Department of Astronomy and an astronomer at the Center for Astrophysics | Harvard & Smithsonian, and Cherubim’s co-advisor with Wordsworth, was initially skeptical because the entire concept was based on a mathematical prediction of a phenomenon astronomers had never witnessed directly. However, Professor Charbonneau ended up praising the student’s determination and follow-through, which led to the historic detection.

“Collin analyzed the planets we knew about and predicted that this one would have a helium atmosphere,” Charbonneau said. “Then he organized telescope time, got the data, and the detection was statistically rock solid.”

“Hopefully it’s just the First of Many More Observations to Come”

When discussing the implications of the findings, Cherubim noted that “this is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star.” Professor Wordsworth agreed, once again noting that until now, planets in these categories with atmospheres had been purely theoretical.

“Now we know at least one has,” the professor said.

The data also suggest that LHS 1140 b’s atmosphere has likely survived for more than three billion years, roughly three-quarters of Earth’s existence. This durability makes LHS 1140 b an excellent candidate for future exoplanet atmosphere studies.

More broadly, the team said that using ground-based observatories to search for escaping gases, such as the helium detected leaving LHS 1140 b, “may become an important tool for studying atmospheres on rocky exoplanets.” They also note the potential value of atmospheric detection for astrobiologists searching for signs of life in the cosmos.

As for Cherubim, he plans on following up his historic discovery with a more detailed analysis of the planet’s atmospheric composition. He also said he would like to investigate the possible presence of surface oceans or other planetary characteristics typically associated with habitability and life. The entire team also said they would like to use Cherubim’s model to search for similar Earth-like, habitable-zone rocky exoplanets.

“This has been a model validation, and hopefully it’s just the first of many more observations to come,” Cherubim said.

The study, “Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone,” was published in Science.

Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.

Harvard researchers found that adding a little randomness to robot movements can prevent gridlock and dramatically boost efficiency in crowded swarms. Imagine a swarm of robots sent into a tight space to handle an urgent job, such as cleaning up an oil spill or assembling complex equipment. At first, adding more robots speeds things up. [...]