Following hot on the heels โ or is that fins? โ of the filter-feeder Aegirocassisโ Yawunikย kootenayi is the latest ancient invertebrate to make us ask โWhat the heck is that thing?โ Described by paleontologists Cรฉdric Aria, Jean-Bernard Caron, and Robert Gaines from 42 fossils found in Canadaโs Kootenay National Park, the Cambrian critter adds to the wonderful and perplexing spread of body plans that had evolved by this chapter in Earthโs history โ jutting out from beneath the invertebrateโs tough exoskeletal hood are paired, pinching appendages arrayed with long wisps. The overall effect is of a lobster tail thatโs out for revenge on those who drew butter against it.
At the time that Yawunik swam around delivering deadly pinches to worms and other small prey, though, there werenโt lobsters yet. Aria, Caron, and Gaines propose that Yawunik belonged to a lineage of invertebrates called leanchoiliids โ a group so obscure they donโt even have a Wikipedia page summarizing what they are โ that fit near the base of the arthropod family tree. This doesnโt mean that Yawunik was an ancestor to todayโs insects, crustaceans, and arachnids, but rather that it was part of an evolutionary explosion from which the true arthropod ancestors emerged.
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Read full original article: Scientists Uncover Yet Another Cambrian Weirdo
