The long-running debate over where turtles sit on the tree of life has taken a decisive turn. A study published in Current Biology examined 226 fossil specimens using X-ray imaging and identified three skeletal traits—a laterosphenoid bone in the braincase, a hooked fifth metatarsal in the foot, and a floating stapes in the ear—that align the earliest turtles with archosauromorphs, the group that includes birds, crocodiles, and dinosaurs. The analysis, led by researchers at the American Museum of Natural History and the University of the Witwatersrand in Johannesburg, severs the previously proposed link to the ancient reptile Eunotosaurus africanus, which lacks all three features. The finding brings anatomical evidence into line with genetic data that had long pointed toward an archosaur connection, though some paleontologists, including the Denver-based scientist who first proposed the Eunotosaurus link, remain unconvinced.

In separate work, a crinoid fossil from Oklahoma has yielded only the second known example of preserved soft tissue in this group of marine invertebrates—and the oldest, at more than 450 million years. The specimen, Dendrocrinus simcoensis, retains its tube feet, structures that reveal feeding strategy and habitat, much as tooth shape does in mammals. University of Oklahoma paleontologists describe the preservation as a one-in-a-million event, made possible by environmental conditions that acted like a natural vacuum sealer. Meanwhile, a vertebra collected in 1985 on the Antarctic Peninsula and left unidentified in a Cambridge collection for four decades has been confirmed as the first sauropod bone from the continent. The caudal vertebra belonged to a titanosaur roughly 82 million years old, when Antarctica was a warm, forested landmass. The find, reported in Acta Palaeontologica Polonica, fills a gap in the sparsest dinosaur fossil record on Earth.

Astronomers, too, are pushing back temporal frontiers. Using the European Southern Observatory’s Very Large Telescope, an international team measured isotopic ratios of carbon and nitrogen in the gas around the interstellar comet 3I/ATLAS. The unusually high ratios, published in Nature Astronomy, indicate the comet formed in the outer regions of an ancient, low-metallicity star system—making it likely more than twice as old as the Sun. Separately, the European Space Agency’s Euclid telescope has identified 31 new quasars from the universe’s infancy, including two that date to just 670 million years after the Big Bang, doubling the known count of such ancient objects. Researchers at Leiden University and ESA say the quasars, embedded in dusty, star-forming galaxies, offer a direct view of how supermassive black holes grew so rapidly in the early cosmos.

On the ground, a new abelisaurid dinosaur from Argentine Patagonia, Koleken inakayali, described in the journal Cladistics, reveals that these large carnivores were diversifying vigorously 69 million years ago, shortly before the asteroid impact. The specimen, excavated from the La Colonia Formation in Chubut by CONICET paleontologists, challenges the view that abelisaurids were in decline. In a different register of longevity, biologists note that creatures such as the Turritopsis dohrnii jellyfish, tardigrades, and Hydra polyps can reset their life cycles or suspend metabolism, effectively escaping ageing—though they remain vulnerable to predation and disease. The next milestones to watch include further Euclid data releases that will refine the census of early quasars, and additional isotopic surveys of interstellar objects that may reveal whether 3I/ATLAS is typical of comets formed around ancient stars.