- Source: Emmonsaspis
Emmonsaspis is a Cambrian chordate, and its fossils were found in the Cambrian-age Parker Slate of Vermont in the late 19th century.
Description
Emmonsaspis is described as a tadpole or worm-like animal. No trace of a spinal cord is present, although myomeres can be seen in the fossils.
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.
Affinities
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, until a 2024 study found Emmonsaspis to be in a polytomy with Metaspriggina and Nuucichthys as a basal chordate.
