Paleontology

The fossils of Repenomamus robustus and Psittacosaurus lujiatunensis with insets showing some magnified details of their interactions that are considered among the evidence that they died during a fight

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An article published in the journal “Scientific Reports” describes what appears to all intents and purposes a fight in which a mammal of the species Repenomamus robustus attacked a dinosaur of the species Psittacosaurus lujiatunensis. A team of researchers examined fossils discovered in today’s China dating back to about 125 million years ago, in the Jurassic period, which offer the first evidence of a mammal hunting a dinosaur. The two animals engaged in a mortal fight became entangled in a flow of volcanic mud similar to the one called lahar in jargon, leaving evidence of that fight.

The KNM-ER 741 tibia with the cuts in the magnified area (Photo courtesy Jennifer Clark)

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An article published in the journal “Scientific Reports” offers evidence that hominins who lived at least 1.45 million years ago killed each other and possibly practiced cannibalism. Paleoanthropologist Briana Pobiner of the National Museum of Natural History led the study of the markings found on a fossil tibia discovered in northern Kenya. The examination of 3D models of the surface of this tibia indicates that 11 of those marks were left by stone tools and that their characteristics likely indicate butcher work much like that seen on fossil animal bones slaughtered by hominins for consumption.

A reconstruction of a Homo naledi skeleton in the position in which it was found (Image courtesy Berger et al., 2023)

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Three articles under peer review ahead of a publication in the journal “eLife” report different aspects of a study of what were defined as intentional burials of individuals belonging to the species Homo naledi. Various researchers including Dr. Lee Berger, who led the team that discovered these hominins, examined the cave called Rising Star, about 50 km northwest of Johannesburg, South Africa, in which their fossils were discovered and what were interpreted as engravings of symbols accompanying those burials. This would mean that Homo naledi buried their dead between 241,000 and 335,000 years ago, 100,000 years before Homo sapiens.

A schematic of the various evolutionary patterns of Homo sapiens including also an interbreeding with Neanderthals

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An article published in the journal “Nature” reports a study that relaunches the idea that the Homo sapiens species emerged not from a single population that had e linear evolution but from different groups of genetically similar hominins that diversified and then interbred again. A team of researchers led by Brenna Henn of the University of California-Davis, USA, and Simon Gravel of McGill University in Montreal, Canada, conducted a genetic analysis and a comparison with early Homo sapiens fossils to try and locate the origin of modern humans. The researchers tested different evolutionary and migratory models and the one that best matches the data points to ramifications of African populations that subsequently interbred again until they merged.

Photos of Rotadiscus grandis fossils and their interpretive drawings

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An article published in the journal “Current Biology” reports a study on exceptionally preserved Rotadiscus grandis fossils. A team of researchers led by Dr Imran Rahman of the Natural History Museum in London offered many new insights into these animals dating back to the Lower Cambrian period, about 518 million years ago. Previous studies had left a number of questions about their classification and lifestyle. The new study assigns them to the large Ambulacraria group, which includes the Echinoderms and Hemicordata phyla and is part of the superphylum Deuterostomia together with the phylum of Chordates. If this classification is correct, it indicates that certain characteristics of later animal species emerged independently several times.