Chancelloria
pentacta
Phylum incertae
sedis, Order Chancelloriida, Family Chancelloriidae
Geologic
Time: Middle Cambrian
Size: The
Chancelloria is 3” in length
on a 5 x 2 3/4” plate
Fossil Site:
Wheeler Shale Formation, House Range, Utah
Code: PFO425
Price: Sold
Description:
Presented is an elegant Chancelloria pentacta. I fell in love
with this fossil when I saw it. The sponge is a bit ethereal,
almost floating on the plate. One of the characteristics of this
most aesthetic fossil is the star-shaped sclerites. The plate
was cracked and repaired. The primary collecting location for
Chancellorias at the classic pipe stone quarry has been exhausted
and abandoned by current diggers for many years now. This specimen
I begged and pleaded to obtain from the owner of a private collection.
I doubt you’ll ever find a larger or better-preserved specimen
of this rare enigmatic animal.
Chancelloria is a genus of early animal known from the Middle
Cambrian Burgess Shale and Wheeler Shale and elsewhere. It was
first described in 1920 by Charles Doolittle Walcott, who regarded
them as one of the most primitive groups of sponges. This appears
unlikely, and it is currently placed in the enigmatic group Coeloscleritophora.
Classifying the chancelloriids is difficult. Some paleontologists
classify them as sponges, an idea which chancelloriids' sessile
lifestyle and simple structure make plausible. Other proposals
suggest that they were more advanced, or at least originated from
more advanced ancestors; for example chancelloriids' skins appear
to be much more complex than those of any sponge. It has been suggested
that chancelloriids were related to the "chain mail" armored
slug-like halkieriids, which are important in analyses of the Cambrian
explosion. The chancelloriids had bag-like bodies with an orifice
at the top, and show no evidence of internal organs.
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