Leanchoilia
illecebrosa (Chengjiang)
Phylum Arthropoda
Geological
Time: Early Cambrian (~525 million years ago)
Size (25.4mm=1
inch): 40 mm long (with antennae) on a 50 mm by 33 mm matrix
Fossil
Site: Chengjiang Maotianshan Shales, Quiongzhusi Section, Yu’anshan
Member, Heilinpu Formation Yuxi, Chengjiang County, Yunnan Province, China
Description:
This unusual arthropod is known as Leanchoilia. The taxon is known
from a number of locations within the Chengjiang region. 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
specimen is a member of the “great appendage arthropods”
known as the
after Opabinia from the Burgess Shale Fauna. Other members from
Chengjiang are Jianfengia and Alalcomenaeus (see my other offerings
for examples). The exceptional detail of the appendages is readily
apparent in this fine specimen, and is indicative of the fact that
this was a strong swimmer. This is a truly exceptional specimen,
showing a portion of the flagellate antennae believed to have performed
a sensory function, and as such is quite uncommon. The artistic
picture of the taxon shows what they likely looked like in life.
Also
see: Chengjiang
Biota List Chengjiang
Fossils
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