Canistrocrinus typus
Compsocrinus harrisi
Glyptocrinus decadactylus
Glyptocrinus fornshelli
Glyptocrinus nodosus
<=== New Species
Pycnocrinus dyeri
Pycnocrinus subglobosus
Xenocrinus baeri
Canistrocrinus typus  10 mm scale, back and front. Photos by Jack Kallmeyer |
Canistrocrinus has prominently raised
rays
and anal series on the calyx. The plates between the rays are large
compared to those in Xenocrinus. The five
rays of the cup branch to
produce four free arms per ray. The arms are
pinnulate. Canistrocrinus is found in the Waynesville and Liberty Formations. |
 10 mm scale Photo by Jack Kallmeyer |
The stem of Canistrocrinus is round in cross-section with alternating large diameter nodals and smaller diameter internodals. Mid-stem nodals have radial nodes projecting from them. |
Pycnocrinus dyeri   10 mm scale Photos by Jack Kallmeyer |
The somewhat globular cup of this species is ornamented with
stellate ridges making it look superficially like
Glyptocrinus decadactylus. Originally described as
Glyptocrinus dyeri, it was moved in to the genus
Pycnocrinus by Bassler & Moodey in 1943 based
upon cup morphology. The most obvious difference between
Pycnocrinus and Glyptocrinus is
the location of ray branching – the five prominent rays branch only once
on the calyx in Pycnocrinus but they branch
twice on the calyx in Glyptocrinus. The arms
are heavily pinnulate.
This crinoid is found in the Maysvillian Stage and lower Richmondian Stage.   Columns are round in cross-section with large diameter nodals alternating with multiple smaller diameter internodals. |
 10 mm scale Pychnocrinus distal coil holdfast Photo by Jack Kallmeyer |
 Attachment of the relatively short (up to about 20 cm) column is by coiling of the distal stem around another object. |
Pycnocrinus subglobosus  10mm scale (#1) Probable juvenile Pycnocrinus subglobosus (#2) Cincinnati Museum Center CMCIP 39948 with permission of Brenda Hunda Photos Jack Kallmeyer |
The morphology of Pycnocrinus subglobosus
is as with other members of this genus (see
P. dyeri
for more detail). The only exception is that the
calyx plates are smooth
and without ornamentation. This crinoid was found in the Corryville Formation |
Glyptocrinus decadactylus  10 mm scale Photos and artwork by Jack Kallmeyer |
The cup of this species is ornamented with stellate ridges making it
look like Pycnocrinus dyeri (see the
P. dyeri description for details of the differences).
Columns are round in cross-section with large diameter nodals alternating with multiple smaller diameter internodals. Attachment of the relatively short (up to about 20 cm) column is by coiling of the distal stem around another object. This species is found in the Fairmount Member of the Fairview Formation. |
Glyptocrinus fornshelli 10mm scale Miami University MUGM 28121 With permission of Kendall Hauer Photo Jack Kallmeyer |
The cup plates of this species are very thin with distinctive
ornamentation comprised of fine ridges and small nodes. The Richmondian
Glyptocrinus fornshelli is one of the largest
crinoids in the Cincinnatian with cup heights around 75 mm, not
including the arms. The heavily pinnulate
arms themselves branch three times above the cup making for what had to
be a very impressive and bushy crinoid. The large size coupled with the
thin cup plates makes preservation of complete specimens rare. Most are
found as masses of disarticulated arms and cups. This species appears in the Waynesville and Liberty Formations. |
 The stem of G. fornshelli is comprised of very thin columnals that are sharply pentagonal in outline. 10 mm scale Photo by Jack Kallmeyer
|
 The holdfast of G. fornshelli is of the distally coiled stem variety. 10 mm scale Miami University MUGM 28121 With permission of Kendall Hauer Photo by Jack Kallmeyer |
Glyptocrinus nodosus
<=== New Species Holotype CMCIP 71396 10 mm Scale bar Photo by Jack Kallmeyer The cup plates are adorned with small nodes (small conical points) rather than stellate ridges like other local Glyptocrinus species. Ray branching is variable with some rays producing four free arms while others produce only three free arms. The arms are heavily pinnulate. This condition produces a crinoid with 17 free arms. |
An unusual glyptocrinid has recently been discovered in the Southgate Member of the Kope Formation. Glyptocrinus nodosus was described as a new species by Kallmeyer & Ausich (2015) in the Journal of Paleontology, Volume 89, issue 6, http://dx.doi.org/10.1017/jpa.2015.72
|
 CMCIP 72242 10 mm Scale bar Photo by Jack Kallmeyer |
The stem and holdfast are typical of other Glyptocrinidae with the
exception of radial projections on the nodals of the mesistele; proximal and distal parts of the column are without these projections. The
holdfast is of the distal coil type.  |
Compsocrinus harrisi  10 mm scale Courtesy of Steve Brown Photo by Jack Kallmeyer |
Compsocrinus harrisi is roughly similar to
Glyptocrinus in ray branching in that they
divide twice on the cup producing four free arms per ray. The arms do
not branch above the cup. Unlike Glyptocrinus,
the basal plates do not all touch each other - the primanal plate
separates the basal plate series. The anal series of plates proceeds up
the side of the cup as a raised ridge. The Treatise on Invertebrate Paleontology indicates that the column can be quadrangular or round. A portion of a round column is visible on the specimen pictured. Holdfast type is presumably a distal coil although that cannot be determined from the material currently available. Compsocrinus is known from the Waynesville Formation although the specimen pictured here was collected in the Liberty Formation. The specimen illustrated was provided by Steve Brown for inclusion on this webpage. |
  5 mm scale Photos by Jack Kallmeyer |
At first glance this crinoid may look like a small
Gaurocrinus. However, Xenocrinus
is a monobathrid camerate having only two circlets of plates in the cup
rather than three like the diplobathrid
Gaurocrinus.
There are four basal plates at the base of the cup. It has prominent
ray
ridges that branch once on the calyx. The anal series is a prominent
vertical ridge on the calyx.
Calyx plates between the
rays and
anal
series are small and irregular. Xenocrinus is found in the Liberty and Whitewater Formations. The genus is also found in the U.K. |
 10 mm scale Photo by Jack Kallmeyer |
By far, the most distinguishing
feature of Xenocrinus is its quadrangular
stem. No other crinoid in the Cincinnatian has a square stem. Since
echinoderms in general have five-part symmetry this is even more
unusual.  See more Xenocrinus stem sketches The holdfast of X. baeri is of the distally coiled stem variety. |
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