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Ancestor of All Placental Mammals Revealed

sciencehabit writes "The ancestor of all placental mammals—the diverse lineage that includes almost all species of mammals living today, including humans—was a tiny, furry-tailed creature that evolved shortly after the dinosaurs disappeared, a new study suggests. The hypothetical creature, not found in the fossil record but inferred from it, probably was a tree-climbing, insect-eating mammal that weighed between 6 and 245 grams—somewhere between a small shrew and a mid-sized rat. It was furry, had a long tail, gave birth to a single young, and had a complex brain with a large lobe for interpreting smells and a corpus callosum, the bundle of nerve fibers that connects the left and right hemispheres of the brain. The period following the dinosaur die-offs could be considered a 'big bang' of mammalian diversification, with species representing as many as 10 major groups of placentals appearing within a 200,000-year interval."

2 of 123 comments (clear)

  1. Re:No intermediate steps to prove! by Aardpig · · Score: 5, Informative

    Within the past 200,000 years of human history, we're aware that Homo Sapiens Sapiens existed alongside other members of the Homo genus, including Homo Neanderthalis and Homo Floresiensis.

    --
    Tubal-Cain smokes the white owl.
  2. Re:More Info Please... by dbug78 · · Score: 5, Informative

    science doesn't deal with facts

    Uh, what? Facts are the foundation of science. If science has any issue with facts it's that Joe Sixpack thinks the hierarchy is...

    Hypothesis -> Theory -> Facts

    In actuality, it's...

    Facts -> Hypothesis -> Theory

    Hypotheses and theories are built on facts. Maybe you meant science doesn't deal with proof?