Octopus origins
Tiny, ancestral cephalopod had just two tentacles
By Sid Perkins
Some of the earliest relatives of today’s octopuses, squid and cuttlefish had only two tentacles and measured no longer than a child’s little finger, a new study suggests.
Previously, scientists didn’t know where to put Nectocaris pteryx on life’s family tree because the species was known only from one fragmentary, poorly preserved fossil unearthed from the 505 million-year-old Burgess Shale of British Columbia, says Jean-Bernard Caron, a paleontologist at the Royal Ontario Museum in Toronto. “That specimen had some characteristics of arthropods and some of chordates,” the group that includes vertebrates, he notes. “No one knew how to classify it.”
Now, after scrutinizing more than 90 additional fossils of the creature, including many that are more complete and better preserved, Caron and museum colleague Martin Smith suggest in the May 27 Nature that Nectocaris belongs near the base of the cephalopod family tree. That group includes today’s octopi and squids, as well as long-extinct creatures such as ammonites and belemnites.