Plenocaris
Extinct genus of arthropods
From Wikipedia, the free encyclopedia
Plenocaris plena is a genus of extinct bivalved hymenocarine arthropod that lived in the Cambrian aged Burgess Shale[1] and Chengjiang.[2] Originally described as a species of Yohoia by Walcott in 1912, it was placed into its own genus in 1974.
| Plenocaris Temporal range: | |
|---|---|
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| Fossil of Plenocaris plena from the Burgess shale | |
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| Life restoration | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Clade: | Mandibulata |
| Order: | †Hymenocarina |
| Family: | †Waptiidae |
| Genus: | †Plenocaris Whittington, 1974 |
| Species: | †P. plena |
| Binomial name | |
| †Plenocaris plena (Walcott, 1912) | |
| Synonyms | |
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The head has a pair of simple antennae. The body has 13 tergites, with trunk tergites 2 to 4 having pairs of elongate and uniramous appendages, with appendages absent from the other body segments.[3] The body terminates with paired tail flukes. Unlike waptiids, but similar to Synophalos, the tail flukes lack segmentation.[4] 106 specimens of Plenocaris are known from the Greater Phyllopod bed, where they comprise 0.20% of the community.[5] It has been suggested to be a member of Hymenocarina, which contains numerous other Cambrian bivalved arthropods.[6] Some specimens have been found with sediment within the gut tract, suggesting it was a deposit feeder. The lack of swimming appendages means that swimming was likely primarily accomplished with movement of the trunk and tail fan.[3]
