Phylum Arthropoda; Ercaicunia multinodosa
Time: Early Cambrian, (~525 million years ago)
inch): 11 mm long by 8 mm wide on a 36 mm by 28 mm matrix
Ghengjiang, Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation,
Ercaicun Village, Anning, Kunming, Yunnan Province, China
This unusual arthropod is known as Ercaicunia multinodosa. The species
is known mostly from the thin-shelled carapace, with this one showing
both the segmented abdomen, and the tail fan, seen here in dorsal
aspect. 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.
systematic position of this taxon has undergone several revisions.
It was established as the sole member of the Family Clypercarididae,
and was originally known from only one specimen. Those from Chengjiang
have been called Ercaicunia multinodosa, but some scientists believe
that to be a junior synonym of Clypecaris. It differs from the more
common genus Waptia in having a higher number of body segments.