Eldonia eumorpha Enigmatic Taxon from Chengjiang

This enigmatic creature from the Chenjiang Biota is known as Eldonia eumorpha. It is known from numerous specimens, and is one of the largest animals from the site, sometimes in four inches across, which are preserved as a nearly flat impressions. Distinct strands radiating from the center on both the ventral and dorsal surfaces are interpreted as radial canals.

Eldonia eumorpha was originally described as a medusoid with the name Stellostomites eumorphus, but was later assigned as a species of Eldonia, a genus represented in the somewhat younger Burgess Shale fauna by Eldonia ludwigi. Some scientists believe there is enough difference between them to justify a new genus for the Chengjiang Eldonia. Just as its affinities are enigmatic, so also is its lifestyle. While its medusoid shape suggests a pelagic lifestyle, other researchers believe it led a benthic and passive life on the sea bottom. The taxon is only known from the Chengjiang Biota.