A 86.6-millimetre Tennessee crayfish tops North America’s record list
A Tennessee bottlebrush crayfish in West Liberty University’s collection has been identified as the largest known in North America, with a carapace measuring 86.6 millimetres, excluding its tail, claws and antennae. Researchers ranked 20 specimens across 18 species after a colleague’s challenge prompted Caitlin Bloomer of the University of Illinois Urbana-Champaign to search museum collections; the study appeared in Ecology.
Bottom line — The measurements suggest North American crayfish tend to top out near 80 millimetres, but the reason remains unconfirmed.
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The record-holder was collected by West Liberty University researchers in 2011, according to the university’s Zackary Graham.
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Bloomer’s Crawzilla made the top 20 and was the only burrowing crayfish on the list, she said.
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The Illinois Natural History Survey supplied six of the 20 specimens; the Smithsonian’s National Museum of Natural History supplied four.
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Researchers found no clear link between maximum size and latitude, oxygen availability or habitat type, Bloomer said.
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The team suspects exoskeleton structure or muscle anatomy may limit growth, but says those ideas need testing.
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The ranking relied on museum specimens measured with calipers, according to the study’s coverage.