|  Description:
This small brachiopod is known as Diandongia pista. The species
is a relatively common member of the biota, with most preserved
with some 3-dimensional detail. The discovery of the Chengjiang
Biota by Hou Xian-guang in 1984 brought to light an exceptional
largerstatte of the time 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.
It
is thought that this species lived epifaunally, attached by a short
pedicle. The  elongated
structure seen on the positive example is a member of the Hyolitha,
a phylum with problematic affinities, thought to be related to the
mollusks. They are thought to have lived on the substrate, resting
on the flatter side of the shell for stability. The two stabilizing
structures are termed the Helens. While Hyolthiods are a common
fossil of the Chengjiang Biota, many have not been described. This
one most looks like a member of the genus Ambrolinevitus. The linear
structure is thought to be the result of collapse of the shell postmortem.
Obviously, the brachiopod had greater structural integrity, leaving
you the fine specimen seen here.
Also
see: Chengjiang
Biota List Chengjiang
Fossils
|
