Conularida
indet
Phylum
Cnidaria (?), Conulariidae
Geological
Time: Mississippian (~ 320 million years old)
Size (25.4
mm = 1 inch): Fossil is 85 mm long by 37 mm across Matrix: 95 mm by
135 mm
Fossil Site:
Heath Shale Formation, Bear Gulch Limestone, Fergus County, Montana
Code: BGF706
Price: Sold
Description:
The Bear Gulch Limestone is a deposit of some 70 square km in
extent and 30 m in depth that has been a source of one of the
most diverse assemblages of fossil fish with some 110 species
having been described over the past 30 years. Most were new to
science, and provided a unique view of the marine environment
of Mississippian times. Fine preservation of both fish and invertebrates
is a hallmark of these deposits, presumably due to an anoxic
depositional environment. This specimen is a Conularid. Conularids
have been a subject of speculation for over a century and a half.
They ranged from the Middle Ordovician to the Triassic. Exactly
what they were is still not settled. Because of their fourfold
symmetry, they have often been placed in the Cnidaria. However,
their skeleton was very different from anything known in the
Cnidaria, and they may represent a separate, extinct phylum The
Conularids had elongated, pyramidal exoskeletons, made up of
rows of calcium phosphate rods. Most were square or rectangular
in cross section, with prominent grooves at the corners. They
lived attached to hard objects by a flexible stalk, and often
lived in groups. They are thought to have been filter feeders;
how they reproduced is not known. This one is found with several
brachiopods and bivalves making for an interesting association
piece.
Reference: Babcock, L.E. 1991. The enigma of conulariid
affinities. Pp. 133-143 in A.M. Simonetta and S. Conway Morris
(eds.). The
Early
Evolution
of Metazoa and the Significance of Problematic Taxa. Cambridge
University Press, Cambridge. |
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