Tag Archives: Coexistence

New Crocodile Fossil Discovery in Ethiopia: Coexistence with Australopithecus afarensis Revealed

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Paleontologists examining fossils in Ethiopia have discovered a new species of crocodile, named Crocodylus lucivenator, that coexisted with the renowned hominid Australopithecus afarensis. This formidable predator likely thrived in the wetlands and forest watering holes during the Pliocene epoch, posing a significant threat to early hominins.

Crocodylus lucivenator cohabited with Lucy and her early ancestors, potentially preying on them. Image credit: Tyler Stone, University of Iowa.

Crocodylus lucivenator thrived between 3.4 and 3 million years ago, overlapping in time and place with the famous hominin Australopithecus afarensis.

This species measured approximately 3.7 to 4.6 meters (12 to 15 feet) in length and weighed between 270 and 590 kilograms (600 to 1,300 pounds).

As an ambush predator, it would remain camouflaged underwater, ready to strike at unsuspecting drinkers.

“It was the dominant predator in that ecosystem, surpassing lions and hyenas, representing the biggest threat to our ancestors,” stated Professor Christopher Brochu from the University of Iowa.

“It is highly likely that Crocodylus lucivenator preyed on Lucy’s kind.”

“The combination of anatomical features in Crocodylus lucivenator was quite extraordinary and surprising,” he added.

The species was identified from 121 specimens, primarily skulls, teeth, and jaw fragments, obtained from the Hadar Formation in Ethiopia’s Afar region.

One notable fossilized jaw exhibits signs of damage indicating potential combat with another crocodile.

“This specimen displayed several partially healed injuries, suggesting it likely engaged in a fight with another crocodile,” explained Dr. Stephanie Drumheller, a paleontologist at the University of Tennessee.

“Such face-biting behavior is a common trait in crocodilian species, with similar scars appearing in the fossil record of extinct groups.”

While it’s unclear which combatant emerged victorious, the healing suggests survival post-battle, regardless of the outcome.

Crocodylus lucivenator exhibits a unique blend of anatomical traits found across several extinct African crocodile species.

This crocodile shares features with two known Pleistocene species while also retaining more primitive characteristics.

Additionally, researchers found a distinctive ridge along the snout resembling traits in modern Neotropical crocodiles and late Miocene species from Libya and Kenya.

Similar fossilized features at the Pliocene Kanapoi site in Kenya had been previously misclassified under a different species.

New investigations reveal that these fossils closely relate to Crocodylus lucivenator and several other extinct East African crocodiles.

Phylogenetic analysis indicates that this ancient crocodilian population represents a distinct lineage.

Fossil evidence confirms that Crocodylus lucivenator was the sole crocodile inhabiting the Pliocene Hadar Formation.

In contrast, contemporary deposits in the Turkana Basin suggest four different crocodile species coexisted at that time, although the reason for this disparity remains unknown.

“During the Pliocene, Hadar featured diverse habitats, such as woodlands, wet grasslands, and river systems,” remarked Dr. Christopher Campisano, a paleontologist at Arizona State University.

“Remarkably, this crocodile was one of the few species successful in adapting.”

This discovery is detailed in the article: Journal of Systematic Paleontology.

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Christopher A. Brochu et al. Lucy’s Danger: A Pliocene crocodile from the Hadar Formation of northeastern Ethiopia. Journal of Systematic Paleontology published online on March 11, 2026. doi: 10.1080/14772019.2026.2614954

Source: www.sci.news

Coexistence of Two Coelurosaur Species in Cretaceous Brazil.

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Paleontologists have undertaken a thorough anatomical reevaluation of the fossilized remains of two coelurosaurian theropod dinosaurs that inhabited South America during the Early Cretaceous period: Santanaraptor Placidus and Milischia asymmetrica.

Hypothetical reconstruction of Milischia asymmetrica (left) and Santanaraptor Placidus (right), focusing on lizards that existed in what is now northeastern Brazil approximately 112 million years ago. Image credit: Guilherme Gehr.

Santanaraptor Placidus and Milischia asymmetrica thrived in Brazil during the Early Cretaceous period, roughly 112 million years ago.

The holotypes of these coelurosaurs were discovered in Romualdo Formation in 1996 and 2000, respectively.

Dr. Rafael Delcourt from the University of São Paulo and his team stated, “The Romualdo Formation is a renowned Early Cretaceous fossil hotspot situated along the edge of the Araripe Plateau in northwestern Brazil.”

“Its megafossil record encompasses plants, invertebrates, turtles, crocodiles, pterosaurs, theropod dinosaurs, as well as one of the most diverse and well-preserved ichthyofaunas from the Mesozoic era.”

“Spinosaurids are among the most notable Romualdian theropods, with numerous reference specimens including the well-preserved skull of Illitator Challenger and the snout of Illitator Challenger Angaturama Limai.”

“Both Santanaraptor Placidus and Milischia asymmetrica originate from the same deposits that produced Spinosaurus, specifically the upper carbonate condensation level of the renowned Romualdo Formation.”

In their new study, Dr. Delcourt and collaborators from Brazil, Argentina, and Germany revised and compared the anatomy of Santanaraptor Placidus and Milischia asymmetrica to examine their phylogenetic relationships and potential synonymy.

Their analysis positions both species within an early-divergent group of maniraptoromorph dinosaurs, alongside Juratirant Rangami and Taniko Lagreus Topwilsoni, dating back to the Late Jurassic of Laurasia, indicating an early diversification of coelurosaurs in this region.

While there is some skeletal overlap, notable anatomical differences affirm their classification as separate species.

“The clade containing Juratirant Rangami, Milischia asymmetrica, Taniko Lagreus Topwilsoni, and Santanaraptor Placidus appears to extend back to at least Laurasia in the Late Jurassic, prior to the formation of the Apulian sea route that facilitated faunal exchange in the Early Cretaceous,” noted the paleontologists.

“At that time, a variety of coelurosaurs existed in both Laurasia and Gondwana, including Megaraptorra and branches such as ornithomimosaur, alvarezaurid, and dromaeosaurid.”

“Our phylogenetic model aligns more closely with the existing biogeographical data than one that confines Romualdocoelurosaurids primarily within Laurasian compsognathids or tyrannosaurids.”

“However, further studies and extensive fieldwork are necessary to clarify the early radiation of Coelurosaurus and its affinities with Romualdo morphology.”

A paper detailing these findings was published on November 18, 2025, in Anatomical Records.

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Rafael Delcourt and colleagues. Coelurosaurian theropods of the Romualdo Formation of the Early Cretaceous (Aptian) of Brazil: Santanaraptor Placidus meets Milischia asymmetrica. Anatomical Records, published online on November 18, 2025. doi: 10.1002/ar.70085

Source: www.sci.news

Ancient Foot Bones Uncover Evidence of Coexistence Between Two Human Species

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Bones arranged in the approximate anatomical position of the right foot

The ancient human foot bones have puzzled scientists since their discovery in 2009.

Johannes Haile-Selassie

The origins of a 3.4-million-year-old foot bone uncovered in Ethiopia may finally be elucidated, prompting a reevaluation of how various ancient human ancestors cohabited.

In 2009, Johannes Haile-Selassie and his team at Arizona State University unearthed eight hominin bones that previously constituted a right foot at a site known as Burtele in northeastern Ethiopia’s Afar region.

This discovery, dubbed Bartele’s foot, features opposable big toes akin to those of gorillas, indicating that any species could have had arboreal capabilities.

Another ancient human species, Australopithecus afarensis, was known to inhabit the vicinity, with the well-known fossil of Lucy—also discovered in the Afar region—but Bartele’s foot appeared to belong to a different species. “From the outset, we realized it was not part of Lucy’s lineage,” Haile Selassie states.

There were two primary hypotheses that intrigued Haile Selassie: whether the foot was associated with another species within the genus Australopithecus or perhaps an older, more primitive group known as Ardipithecus, which existed in Ethiopia more than a million years ago and also possessed opposable thumbs.

Meanwhile, in 2015, scientists announced the identification of a previously unknown hominid species, named Australopithecus deiremeda, after jaw and tooth remains were found in the same region. Initially, there was uncertainty about whether the enigmatic leg bone was part of A. deiremeda, as its age differed from that of the jaw and tooth remains.

However, in the subsequent year, researchers made a crucial discovery. The lower jaw of A. deiremeda was located within 300 meters of Bartele’s foot, and both sets of remains were dated to the same geological era. This led the research team to conclude that Bartele’s foot belonged to A. deiremeda.

Bartele’s foot (left) and bones shaped like a gorilla’s foot (right), similar to Australopithecus deiremeda

Johannes Haile-Selassie

In a separate part of the study, researchers analyzed Earth’s carbon isotopes. They found that A. deiremeda primarily consumed materials from trees and shrubs, while human teeth were more adapted for a diet rich in grasses than those of afarensis.

Haile Selassie noted that this finding suggests that both hominin species occupied the same ecological niche without competing for resources. He believes these groups could have coexisted harmoniously, engaging in separate activities. “They must have crossed paths and interacted within the same habitat, each doing their own thing,” he remarked. “While members of Australopithecus deiremeda may have spent time in trees, afarensis was likely wandering the adjacent grasslands.”

This revelation enhances our understanding of human evolution. “Historically, some have argued that only a single hominid species existed at any given time, with newer forms emerging eventually,” Haile Selassie explained. “We are now realizing that our evolutionary path was not straightforward. Multiple closely related hominid species coexisted at the same time, indicating that coexistence was a fundamental aspect of our ancestors’ lives.”

Carrie Mongul, a professor at Stony Brook University in New York, expressed enthusiasm about these developments. “Understanding more about the diversity of Pliocene hominins is truly exciting,” she stated. “This period, around 3 million years ago, was rich in evolutionary significance.”

Topics:

  • Human evolution/
  • Ancient humans

Source: www.newscientist.com