Dichocrinus ficus
The crinoids, or sea lilies, or uncommonly encountered
in the fossil record having complete crowns (heads) attached to articulated
stems. Upon death, most crinoid heads fell apart rapidly due to decay of
soft tissues. The famous Crawfordsville crinoid fauna of Indiana, USA is famous
for its abundance of exceptionally preserved, articulated fossil crinoids
(& other echinoderms). This crinoid occurrence is one of the most
spectacular on Earth. The Crawfordsville crinoid fauna contains at least
63 different crinoid species (Ausich, 1999), many of which are quite sizable.
Shown below is a Dichocrinus ficus Lyon &
Casseday, 1862, a relatively small crinoid species from Crawfordsville.
The cup is reasonably well preserved, with arms attached and pinnules along the
lengths of the arms.
Classification: Animalia, Echinodermata, Crinoidea, Camerata,
Monobathrida, Compsocrinina, Dichocrinidae
Stratigraphy: Edwardsville Formation, Osagean Stage, upper Lower Mississippian
Locality:
near Crawfordsville, Montgomery County, western Indiana, USA
Dichocrinus ficus Lyon & Casseday, 1862 articulated crown &
stem (total preserved length 4.35 cm) in fossiliferous calcisiltite from the
Crawfordsville crinoid fauna (Edwardsville Formation, Lower Mississippian) near
Crawfordsville, Indiana, USA.
Reference
cited:
Ausich, W.I. 1999. Lower Mississippian
Edwardsville Formation at Crawfordsville, Indiana, USA. pp. 145-154 in
Fossil Crinoids. Cambridge, U.K. Cambridge University Press.