Cricocosmia jinningensis Nematomorph Worm Death Assemblage

Cricocosmia jinningensis


Geologic Time: Early Cambrian (~525 million years ago)

Size: 50 and 51 mm

Fossil Site: Chengjiang Maotianshan Shales Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Jianshan, Anning, Kunming County, Yunnan Province, China

Cricocosmia jinningensisThis Nematomorph worm is known as Cricocosmia. The species is known from numerous specimens, many of Cricocosmiawhich have preserved details such as this fine example. The intestine is often preserved as a dark film as seen here, indicative of its deposit-feeding lifestyle. What is not typically seen preserved are the cone-shaped sclerites seen in paired longitudinal rows.

This group of worms is commonly known as the horsehair worms, and is represented by some 300 extant species. Cricocosmia was originally thought to be a priapulid worm, a view still held by some researchers. Cricocosmia is only known from the Lower Cambrian of Yunnan Province.

Also see: Chengjiang Biota Chengjiang Fossils Cambrian Explosion

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