Eoredlichia
intermedia
Trilobites
Order Redlichiida, Family Redlichiidae Geological
Time: Early
Cambrian (~525 million years ago)
Size: Trilobite
is 20 mm long and 17 mm across on a 41 mm by 41 mm matrix
Fossil Site:
Chengjiang Maotianshan Shales -
Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Haiyi
Village, Anning, Yunnan Province, China
Description:
This trilobite is a member of the Order Redlichiida, Family Redlichiidae
from the Early Cambrian Heilinpu Formation deposits near Anning,
in Kunming County, Yunnan Province, China, known as Eoredlichia
intermedia. The species is one found in several locations within
Yunnan Province in what is termed the Chegjiang Biota by Hou Xian-guang
in 1984. 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
Redlichioids of this type are considered to be the sister-group
comprising all of the “higher” (non-Olenelloid) trilobites
by Richard Fortey. Eoredlichia is thought to have lived on or close
to the seafloor. Based upon its spinose limb bases and braced hypostome,
it is thought by some researchers to have led a predatory existence.
Missing only the axial spine, this is a highly desirable specimen
due to its association with the Chengjiang Biota that made up a
glimpse of the Cambrian Explosion some 5-10 million years before
the Burgess Shale fauna came into being. Notice the sweeping spines
that have been preserved. I have included an artist’s (my
daughter’s) rendition of its appearance in life.
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