This extinct ten-armed fossil may be earliest known ancestor of vampire squid

Paleontologists believe they have discovered a new genus and species of extinct cephalopod with ten functional arms, similar to a vampire squid. The 328-million-year-old fossil is the earliest known example of a vampyropod (ancient soft-bodied cephalopods) to date, pushing back the earliest evidence by 82 million years, according to a new paper published in the journal Nature Communications. Other paleontologists aren't so sure, believing the specimen might represent a different known species of ancient cephalopods and calling for a full chemical analysis to confirm the species one way or the other.

The fossil was excavated from Bear Gulch Limestone in Montana. The fossils found there tend to be exceptionally well-preserved—sometimes even showing vascularization—thanks to the impact of seasonal monsoons. That heavy rainfall rapidly deposited sediments and other biological matter into the bay, in turn feeding algal blooms. Those algal blooms resulted in temporary oxygen-deprived zones, while the sudden infusion of fresh water from the rain would have lowered saline levels, according to the authors.

The fossil was donated to the Royal Ontario Museum in 1988, and there it sat, unnoticed for decades, until co-author Christopher Whalen, a postdoc in paleontology at the American Museum of Natural History in New York City, was perusing the collection and spotted the arms. When he looked at the specimen more closely under the microscope, he noticed small suckers on those arms, making this an incredibly rare find, since suckers are typically not preserved.