| 词条 | Emmonsaspis |
| 释义 |
| taxon = Emmonsaspis | authority = 1886 }} Emmonsaspis is a fossil that was found in the Cambrian-age Parker Slate of Vermont in the late 19th century. DescriptionEmmonsaspis is described as a tadpole or worm-like animal. No trace of a spinal cord is present. 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.[1][2]AffinitiesIt was interpreted by paleontologist C. D. Walcott in 1911 as a polychaete worm. Although some paleontologists regard 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 is the current vogue.[3] Notes1. ^{{cite web|url=http://www.fossilmuseum.net/Cambrian-Explosion/Chordate/Chordate.htm|title=Cambrian Primitive Chordate Fossil|author=|date=|website=www.fossilmuseum.net|accessdate=29 May 2018}} {{Taxonbar|from=Q5373604}}{{Cambrian-animal-stub}}2. ^{{cite web|url=http://www.biology.ualberta.ca/courses.hp/biol606/OldLecs/Lecture2K.08.Duffy.html|title=Duffy: Chordate Origins|author=|date=|website=www.biology.ualberta.ca|accessdate=29 May 2018}} 3. ^{{Cite journal | last1 = Shu | first1 = D. -G. | last2 = Morris | first2 = S. C. | last3 = Zhang | first3 = X. -L. | doi = 10.1038/384157a0 | title = A Pikaia-like chordate from the Lower Cambrian of China | journal = Nature | volume = 384 | issue = 6605 | pages = 157–158 | year = 1996 | pmid = | pmc = }} 3 : Prehistoric incertae sedis animal genera|Cambrian animals of North America|Fossil taxa described in 1886 |
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