Tokummia Temporal range:
| |
---|---|
![]() | |
Life restoration | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Order: | †Hymenocarina |
Family: | †Protocarididae |
Genus: | †Tokummia |
Species: | †T. katalepsis
|
Binomial name | |
†Tokummia katalepsis Aria & Caron, 2017
|
Tokummia is a genus of fossil hymenocarine arthropod, known only by one species, Tokummia katalepsis, from the middle Cambrian (508 million years old) Burgess Shale as found in a quarry in Marble Canyon in Canada.[1]
The genus name Tokummia named after Tokumm Creek which runs through the Marble Canyon where it was found. The species name katalepsis means Greek word for "seizing", "gasping" or "holding".[1]
Tokummia has a cylindrical body, with the anterior half covered by a 8.78 cm (3.46 in) long bivalved carapace. At the front of the animal, there are a pair of antennae, possible eyes, mouthparts (mandibles, maxillule and maxilla) and prominent pincer-like maxillipeds. These shows the oldest record of arthropod pincers. Posterior to the maxillipeds are 50 leg-bearing trunk segments. Each of its biramous leg has 5-segmented basipods, followed by an exopod (flap-like outer branch) and 7-segmented endopod (leg-like inner branch). The anterior 10 leg pairs have basipodal endites (inner spines) while the remaining leg pairs have widen exopods. The trunk terminated with a pair of caudal rami.[1]
Tokummia is suggested to be a bottom feeder, being able to walk on the sea floor, and to occasionally swim, and used its pincers to catch prey.[2]
According to the original description of Tokummia, hymenocarines like Tokummia, Branchiocaris, Canadaspis and Odaraia are stem group Mandibulata, the group includes myriapods, hexapods and crustaceans,[1] and this theory is supported in multiple subsequent studies.[3][4][5][6]