Pouched Killers Not Poor Cousins of Carnivores 24 November 2010, by Bob Beale

Pouched killers not poor cousins of carnivores 24 November 2010, By Bob Beale

most carnivorous niches on land. Today, these roles are mostly filled by placental meat-eaters, including such iconic species as the lion, tiger and grey wolf."

Computer model of a placental lion skull used in the analysis. Researchers compared 33 measurements taken from the skulls of 62 different mammalian carnivores. Computer model of a marsupial lion skull used in the analysis.

(PhysOrg.com) -- Marsupial predators are not the poor cousins of the carnivore world, as has long been thought: new research shows that they have "However, among the other major group of been just as diverse as placental carnivores over mammals, the pouched marsupials, predators are time. mostly small and few and far between. They display relatively little variation in shape or habit. Most are "We've looked at the deep-time perspective and found only in Australia and the largest - weighing shown that over evolutionary history marsupial only around 7 kilograms - is the Tasmanian devil, carnivores have been every bit as varied in shape which is now restricted to the Australian island of and habit as their placental counterparts," says Dr. Tasmania and under serious threat." Stephen Wroe, an author of a paper published in the journal Proceedings of the Royal Society B. The traditional explanation for this apparent lack of diversity has long been that the marsupial mode of "Their ranks have included creatures as bizarre as development, where the young are born at a very the Argentinean pouched sabretooth, which early stage, had seriously constrained their ability sported monstrous, self-sharpening canine teeth to adapt to new habits and environments. that extended almost back into its braincase, and Australia's own marsupial lion, which had teeth like "But if we consider species back through the last 60 bolt-cutters and the muscle power to match." million years or so it is clear that this was not always the case. For most of this time the "Throughout most of the Age of Mammals - a marsupial predator club contained a much wider period extending back some 65 million years - range of species that included some real giants, warm-blooded furry predators have dominated and the marsupials dominated South America - and

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probably Antarctica - as well as Australia." More information: rspb.royalsocietypublishing.or … b.2010.2031.abstract Working with Anjali Goswami of University College London, and Nick Milne of the University of Western Australia, Wroe looked at data collected from museums on five continents, including Provided by University of New South Wales members of a wide range of living and extinct mammalian carnivore families. Applying an approach known as geometric morphometrics to map out and analyse whole skulls of living and fossil species, they showed that the variation in shape of marsupial carnivores was actually greater than that observed in placentals.

Although superficially similar to the placental sabretoothed cats, like Smilodon fatalis, the extinct sabretoothed marsupial, Thylacosmilus atrox, shown here, is the only mammalian carnivore to have evolved ever-growing canines, making it one of the most formidable predators known in mammalian history. Image (c) UCL, Grant Museum of Zoology

"It seems likely that the diversity in skull shape among marsupial carnivores reflects a diversity in lifestyle that once was quite comparable to that of placentals," says Dr. Wroe, an expert in mammalian carnivore evolution. "Our results reinforce my own conclusion that the lack of marsupial predators in the world today has more to do with bad luck than bad genes."

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APA citation: Pouched killers not poor cousins of carnivores (2010, November 24) retrieved 1 October 2021 from https://phys.org/news/2010-11-pouched-killers-poor-cousins-carnivores.html

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