Emmonsaspis
| Emmonsaspis Temporal range: [1]
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| File:Emmonsaspis.jpg | |
| Life restoration of Emmonsaspis | |
| File:Metaspriggina sp. (YPM IP 543315).jpg | |
| Fossil of Emmonsaspis | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Genus: | †Emmonsaspis Resser & Howell, 1938 |
| Species | |
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Emmonsaspis is a Cambrian chordate, and its fossils were found in the Cambrian-age Parker Slate of Vermont in the late 19th century.
Description
[edit | edit source]Emmonsaspis is a chordate related to Metaspriggina and Nuucichthys. It grew to roughly 4.5 cm (1.8 in) in length and probably fed on plankton in the water column. No trace of a spinal cord is present, although roughly 50 myomeres can be seen in the fossils. It had large eyes and a large organ behind its branchial chamber, probably a liver.
There are two species: Emmonaspis worthanella and Emmonaspis cambriensis (Walcott(?) 1886(?) 1911(?)).
E. cambrensis has been described as a graptolite, a chordate, an arthropod and as a frond-like organism.[2][3]
Affinities
[edit | edit source]It was interpreted by paleontologist C. D. Walcott in 1911 as a polychaete worm. Although some paleontologists regarded it as an early chordate allied with Pikaia et al., Conway Morris suggested in 1993 that it might be a Cambrian descendant of the Vendian form Pteridinium, and a frondose morphology was accepted,[4] until a 2024 study found Emmonsaspis to be in a polytomy with Metaspriggina and Nuucichthys as a stem-group vertebrate.[1]
Notes
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