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Photos: Ancient Marine Critter Had 50 Legs, 2 Large Claws

New fossils

ancient marine critter

(Image credit: Lars Fields/Copyright Royal Ontario Museum)

A large number of arthropods living today have mandibles, including flies, ants, crayfish and centipedes. But until now, it wasn't clear just when these unique appendages, which help animals grasp, crush and cut food, evolved.

Now, researchers have identified the first arthropod with mandibles on record. This marine creature, known as Tokummia katalepsis, was about 4 inches (10 centimeters) long and had 50 legs, two claws and an oversize shell. [Read the Full Story about the First Known Mandibulate]

Reconstructed

ancient marine critter

(Image credit: Lars Fields/Copyright Royal Ontario Museum)

An artist illustrates how Tokummia katalepsis may have looked. The creature had two large pincers (maxillipeds) for hunting prey and a hard shell protecting most of its multisegmented body. The animal's jaw was notably small and its other limbs had subdivided, spinose bases.

Cutting into fossil beds

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

At the Marble Canyon quarry at Kootenay National Park (Canadian Rockies), Cédric Aria sliced the fossiliferous beds open with a saw during the summer 2014 fieldwork season. The specimen is named for Tokumm creek (seen at the right, middle side of the image) with the species name katalepsis meaning "seizing" in Greek — Tokummia katalepsis.

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

Crew members work with Cédric Aria, in the foreground, hoping to find new fossils in layers of shale from the Marble Canyon quarry. Any new finds will be catalogued and examined more fully at the museum.

A second look

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

After discovery by a Royal Ontario Museum led-team in 2012, another team, led by Cédric Aria, seen in the foreground, returned in 2014 to the Marble Canyon locality in the Kootenay National Park. The team conducted a more thorough investigation for Burgess Shale fossils in the quarry.

Broken down

ancient marine critter

(Image credit: Danielle Dufault/Copyright Royal Ontario Museum)

Researchers provided a technical illustration notating the many parts of the Tokummia katalepsis, summarizing important structural characteristics of the fossils. Of particular note, the jaws are quite small.

[Read the Full Story about the First Known Mandibulate]

Strong legs, paddle-like limbs

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

This specimen represents the new genus, Tokummia, and new species, katalepsis. Clearly visible on the left of the image, several strong legs extend from the body. The creature's shell is bivalved and dozens of small, paddle-like limbs are discernible to the right.

Preserved fossil

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

In the field, the fossil of Tokummia ROM63823 was found at the Marble Canyon quarry in Kootenay National Park. This image displays the fossil before any preparations were completed.

Secrets revealed

ancient marine critter

(Image credit: Jean-Bernard Caron/Copyright Royal Ontario Museum)

The specimen here is preserved at such an angle that several front limbs are revealed, including antennules and pincers.

From above

ancient marine critter

(Image credit: Lars Fields/Copyright Royal Ontario Museum)

Another artist's illustration shows what the Tokummia katalepsis may have looked like from above with its hinged carapace (shell) and extending its large pincers.

Family tree

ancient marine critter

(Image credit: Copyright Royal Ontario Museum)

The Tokummia katalepsis is an arthropod. This cladogram — a diagram displaying the connection between several species — shows the creature's relationship to other arthropods.