The discovery of the Chengjiang Biota by Hou Xian-guang in 1984
resulted in a clear window on what is known as the Cambrian Explosion.
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
are known as well, some of which may have represented failed attempts
at diversity that did not persist to the present day.
The Lobopodians are small marine and terrestrial
animals termed colloquially “velvet worms” or “worms
with legs”. While all Recent forms are terrestrial, most fossil
Lobopodians are marine, and are known primarily from the Cambrian.
Six named genera, each with a single species, are known from the
Chengjiang Biota, making it the richest source of fossils of the
type on Earth. This is one of the most striking, and quite rare;
as of 2004, only some 15 examples were known. The maximum length
is 70 mm. It possesses a sclerotized head shield with 10 paired
sclerotic plates, each associated with a pair of legs. Each leg
bears curved claws which are thought to have served the creature
as an adaptation to crawling on other organisms. It is most closely
related to Aysheaia from the younger Burgess Shale.