- Naraoia
-
Naraoia
Temporal range: CambrianNaraoia spinosa Scientific classification Kingdom: Animalia Phylum: Arthropoda Class: †Trilobita Order: Nectaspida Family: Naraoiidae Genus: Naraoia
Walcott, 1912Type species N. compacta Species - N. compacta Walcott, 1912
- N. spinifer Walcott 1931
- N. spinosa
Zhang & Hou, 1985 - N. halia
Simonetta & Delle Cave 1975 - N. pammon
Simonetta & Delle Cave 1975
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]
Classification
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.
Related Fossil Species
Misszhouia longicaudata was initially placed with Naraoia, but was later assigned to its current genus.[1]
References
- ^ Caron, J. -B.; Jackson, D. A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS 21 (5): 451–465. doi:10.2110/palo.2003.P05-070R.
- ^ Charles D. Walcott, "Middle Cambrian Branchiopoda, Malacostraca, Trilobita, and Merostomata," in Cambrian Geology and Paleontology II (Smithsonian, 1914), p. 175.
Categories:- Burgess Shale fossils
- Maotianshan shales fossils
- Trilobites
Wikimedia Foundation. 2010.