Waptia
(Chuandianella) ovata
Phylum
Arthropoda (Crustaceanomorpha), Extinct Order Waptiida, Family
Waptiidae
Geological
Time: Early Cambrian (~525 million years ago)
Size: 18
mm long (plus antennae) shell: 10 mm long by 8 mm across
Fossil
Site: Changjiang Maotianshan Shales, Quiongzhusi Section, Yu’anshan
Member, Heilinpu Formation, Mafang Village , Anning, Kunming, Yunnan Province,
China
| Description:
This unusual arthropod is known as Waptia ovata. The species
is
known mostly from the distinctive wrinkled carapace, but this one
has much soft tissue preserved. The discovery of the Chengjiang
Biota by Hou Xian-guang in 1984 opened a window onto a remarkable
array of life forms 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.
The
systematic position of this taxon has undergone several revisions.
It was originally placed within the Ostracodiform genus Mononotella,
then later referred to a new genus Chaundianella. More recent
finds
of remains other than the carapace have shown it to be similar
to the Burgess Shale genus
Waptia. While the species is known from other Lower Cambrian
locations
in Yunnan, Sichuan, Guizhou, and
Shaanxi Provinces, only those from the Chengjiang Biota are known
to show soft part preservation. This one shows the antennae preserved
as well. The negative image makes the antennae
more apparent. Note as well the 3-D nature of the shells, as most
unusual preservation occurrence.
Also
see: Chengjiang
Biota, Chengjiang
Fossils, Cambrian
Explosion
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