Description:
This unusual arthropod is known as Kuamaia lata, and at 150 by 100
mm, represents a huge specimen compared to others that have been
found. The species is known from some 100 examples as of 2004,
some of which show many exquisite details.
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.
The
taxon has a relatively wide and flat dorsal exoskeleton (hence the
generic name) which is differentiated into a cephalic shield (CS),
a thorax (T1-T8), and a pygidium (Py). Note also the eyes, hypostome
(H), and central gut as highlighted in the interpretive drawing.
It bears some resemblance to the younger Burgess
Shale genus Hemetia, which has led some to place them in the
Helmetidae along with several other similar arthropods. The body
shape suggests that Kuamaia was a benthic animal which was possibly
carnivorous. The species is only known from the Chengjiang
Biota.
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