Peronopsis
sp.
Class
Trilobita (Trilobites); Trilobite
Order Agnostida; Family Peronopsidae
Geological
Time: Early Middle Cambrian Peronopsidae
Size: 2 mm
across by 4 mm long
Fossil
Site: Kaili Formation, Maiobanpo Section, Taijiang County, Kaili,
Guizhou Province, China
The
Kaili Biota of Guiznou Province China, like the fantastic Chengjiang
and Burgess Shale Fauna, preserve some of the earliest radiations
of complex life known on the planet. The formation is some 220 m
in thickness and spans the Late Early to Early Middle Cambrian.
As such it is intermediate in age between the Changjiang and Burgess
Shale Faunas. Representatives of some 110 genera are known, representing
11 phyla. The Kaili Biota includes both soft-bodied and skeletonized
animals, and is dominated by trilobites, with eocinoids as the second
most common fossil. It shares roughly 30 genera in common with Chengjiang
and nearly 40 with the Burgess Shale. The presence of Burgess Shale–like
fauna over a large part of southwestern China shows that the faunal
community was quite cosmopolitan in nature, indicating that preservation
was more of a factor in finding these concentrations of animals
than was the existence of isolated communities suitable for harboring
these myriad life forms.
This
trilobite is a species of Peronopsis, a member of the Order Agnosida.
Trilobites from this timeframe were members of the Redlichiida,
Ptychopariida, Corynexochida, and the Agnostida, with the balance
of the orders appearing later in time. The agnostids are well known
for the reduced number of thoracic segments, as well as their “pushme-pullyou”
appearance; it is hard to decide which was the cephalon and which
the pygidium.
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