This fine trilobite specimen comes from what has been termed the
“Guanshan Fauna”, found in the Wulongqing Formation.
The Guanshan Fauna shares many genera with the slightly older Chengjiang
Biota, but differs at the species level. With the discovery of the
Chengjiang Biota in 1984 a window on the Cambrain Explosion in China
was opened. 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.
trilobite is a Redlichia species, the patronymic genus of the Family
Redlichiida. Trilobites from this timeframe were members of the
Redlichiida, Ptychopariida, Corynexochida, and the Agnostida, with
the balance of the orders appearing later in time. What is most
unusual about this one is that the whip-like antenna on the right
side has been preserved; the left antenna shows only a trace. This
is the first example with antennal preservation I have had.