Description: 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 problematic forms are known as well, some of which may
have represented failed attempts at diversity that did not persist
to the present day.
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 unusual, and quite rare;
it was originally known from only four incomplete specimens, and
was given the generic name Paucipodia (few feet) because it was
thought to have 3 fewer pairs of legs than other members. A scant
few recent examples show a complement of nine leg pairs. Each leg
bears curved claws which are thought to have served the creature
as an adaptation to crawling on other organisms. Indeed, some have
been found in close association with Eldonia. It is most closely
related to Aysheaia from the younger Burgess Shale. While not complete,
it is quite rare, especially as a part/counterpart example. There
may be more of the limbs still contained within the matrix, as turned
out to be the case with an Onychodictyon I had from the same region.
I will leave further preparation to the one fortunate enough to
acquire such a unique specimen.
Biota List Chengjiang