Rare Priapulid Worm Fossil from Chengjiang

Description: This is an example of the priapulid worm Acosmia maotiania. The species is known from very few specimens, with the taxon named after, Maotianshan (Mao Tian Hill), site of the discovery of the Chengjiang Biota by Hou Xian-guang in 1984. The intestine is often preserved as a dark film, indicative of its deposit-feeding lifestyle. The diversity of soft-tissue fossils is astonishing: algae, medusiforms, sponges, priapulids, annelid-like worms, echinoderms, arthropods (including trilobites), hemichordates, chordates, and the first agnathan fish make up just a small fraction of the total. Numerous problematic forms are known as well, some of which may have represented failed attempts at diversity that did not persist to the present day.

Some specimens have been found tightly curved, suggesting it may have lived in a U-shaped burrow. This is a monospecfic genus, known only from the Chengjiang Biota. The fine example preserved here in exquisite detail makes this a highly unique specimen of life from 525 million years ago.

Also see: Chengjiang Biota List Chengjiang Fossils