| The
discovery of the Chengjiang Biota by Hou Xian-guang in 1984 opened
a window onto a remarkable array of lifeforms from what is termed
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. 
This
is the grasping arm of the “Terror Of The Cambrian”,
Anomalocaris saron. The members of this group of enigmatic creatures
are known from Asia, Australia, Europe, and North America, and are
thought by many to be closely allied with the Arthropda, as position
not held by all researchers. As of the publication of Hou’s
book in 2004, some 20 examples were known, most being grasping arms
like this one. The spiniferous grasping appendages are strongly
suggestive of its carnivorous habits; some trilobites from Utah
bear evidence of bite marks that have been attributed to Anaomalocaris.
Known only from the Chengjiang biota, this species is closely related
to A. canadensis, the type species, from the younger Burgess Shale.
The genus derives its name from “anomalous shrimp” which
was what the describer thought the appendage was.
Also
see: Chengjiang Biota
|