Ptychagnostus atavus
| Ptychagnostus atavus Temporal range: Drumian | |
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Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | †Trilobita |
| Order: | †Agnostida |
| Family: | †Ptychagnostidae |
| Genus: | †Ptychagnostus |
| Species: | † P. atavus |
| Binomial name | |
| Ptychagnostus atavus (Tullberg, 1880) | |
| Synonyms | |
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Ptychagnostus atavus is a species of agnostid trilobite. It belongs to the genus Ptychagnostus in the family Ptychagnostidae. It was originally described by Swedish paleontologist Sven Axel Tullberg as Agnostus atavus in 1880.[1] It is used in biostratigraphy as an index fossil. Its first appearance at the GSSP section in the Wheeler Shale of Utah is defined as the beginning of the Drumian Age (around ~504.5 million years ago) of the Cambrian Series 3 (Middle Cambrian).[2][3]
References
- ↑ "Ptychagnostus atavus". Paleobiology Database. Retrieved 16 November 2012.
- ↑ Babcock, L. E.; Robison, R. A.; Rees, M. N.; Peng, S.; Saltzman, M. R. (2007). "The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA" (PDF). Episodes 30 (2): 85–95.
- ↑ Ogg, G. "GSSP for Drumian Stage". Geologic TimeScale Foundation. Retrieved 16 November 2012.
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