| Naraoia Temporal range: Cambrian |
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|---|---|
| Naraoia spinosa | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | †Trilobita |
| Order: | Nectaspida |
| Family: | Naraoiidae |
| Genus: | Naraoia Walcott, 1912 |
| Type species | |
| N. compacta |
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| Species | |
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Naraoia is a genus of trilobites (or trilobite-like arthropods) found in Cambrian strata of the Burgess Shale and the Maotianshan shales Lagerstätte. They were flattened, oval-shaped animals, with an uncalcified shield that was divided into two regions, a smaller region covering the head, and a larger section covering the body. There are no hint of lobes, as in true trilobites. All species were blind, showing no trace of eyes.
Naraoia fossils range between 2 and 4 centimetres in length. 392 specimens of Naraoia are known from the Greater Phyllopod bed, where they comprise 0.74% of the community.[1]
The name is derived from Narao, the name of a group of small lakes in Cataract Brook canyon, above Hector on the Canadian Pacific Railway, British Columbia, Canada."[2]
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When the fossil was first discovered in Canada's Burgess Shale, it was believed to be a crustacean, such was the difference between this and other trilobites. Its continuous shield hid most of its structure, interfering with proper classification. When Harry B. Whittington began dissecting some specimens (Naraoia was among the most populous of the Burgess Shale animals), he discovered that the legs (and gills) of the beasts were very similar, if not identical to those of trilobites, thus the current placement of Naraoia in Class Trilobita.
Misszhouia longicaudata was initially placed with Naraoia, but was later assigned to its current genus.[1]