Echinoderms are a phylum of marine animals that include sea stars, urchins, sand dollars, and the like. They are an ancient group going back to the Cambrian if not the Ediacaran. A number of classes existed for a short geological interval before going extinct. The most common echinoderm fossils in my region are crinoids and blastoids.
I’ve been involved in research in Middle Mississippian crinoids with Dr. William Ausich and Dr. Thomas Kammer. I will eventually post that research and photos of specimens. Most of the important ones were donated to the Smithsonian (U.S. National Museum) and the Orton Geological Museum at The Ohio State University.
Echinoderm Photos (organized by class – Crinozoa, Blastozoa, etc.)
Preservation Key: C = Calcified, Ph = Phosphatic, P = Pyritized, S = Silicified, 1= w/o, matrix, 2 = w/ matrix
# Not available for sale, just for identification
BLASTOIDS & CORONOID
Cuplocorona gemmiformis (Hall)# – formerly Stephanocrinus gemmiformis, from the Waldron Shale, Middle Silurian, Clark Co., IN – C,1,2
Decaschisma pentalobus (Hall)# – an uncommon Waldron Shale blastoid, most common in Shelby Co., Indiana.
Diploblastus glaber (Meek & Worthen)# – is a tiny blastoid, rare but often found in groups. Upper Mississippian, IL,IN,KY – C,1
Diploblastus incurvatus Weller# – pretty rare, Upper Mississippian, IL,IN,KY – C,1
Elaeacrinus verneuili (Roemer) – Jeffersonville Limestone Middle Devonian IN, MO C,S,1,2
Elaeacrinus sp.# – Beechwood Limestone, Givetian, Middle Devonian, IN – S,1
Euryocrinus veryi Ausich & Meyer # – from the pyritized Coral Ridge fauna, basal New Providence Shale, considered early or mid-Mississippian depending on reference. KY, IN? – Goethite,1
Granatocrinus kentuckyensis (Conkin)# – from the pyritized Coral Ridge fauna, basal New Providence Shale, considered early or mid-Mississippian depending on reference. KY, IN? – P,1
Hadroblastus sp., [H. kentuckyensis (Shumard)?] – same data as Granatocrinus kentuckyensis, though extremely rare instead of very rare. KY, IN? – P,1 Coral Ridge fauna article will be posted under articles… eventually.
Metablastus sp. # – rare, Middle Mississippian, KY – C,2
Pentremites is restricted to the Mississippian Period, primarily in North America. There are dozens of names in Galloway & Kaska’s monograph Genus Pentremites and its Species (1957). However, Dr. Alan Horowitz considered them to be overly split and that most were variations on a hand full of species.
Pentremites buttsi Ulrich?# – rare, Indian Springs Shale Mbr., Big Clifty Fm., Upper Mississippian, Crawford Co., Indiana.
Pentremites conoideus Hall – Salem Ls., Middle Mississippian, IN,KY – C,1,2
Pentremites fohsi Ulrich – Glen Dean Fm., Upper Mississippian, Grayson Co., Kentucky – C,1
Pentremites girtyi Ulrich – Upper Mississippian formations, IN,KY – C,1,2
Pentremites godoni (Defrance) – Upper Mississippian formations, IL,KY – C,S,1,2 This species has been further sub-divided. Two examples below.
Pentremites ovoides Ulrich# – Ste. Genevieve Ls., Mississippian, Hastie’s Quarry, Cave in Rock, Illinois. Collected ~1987, at the Oxford-West Morrison cut that no longer exists.
Pentremites patei Ulrich# – Indian Springs Shale Mbr., Big Clifty Fm., Upper Mississippian, Crawford Co., Indiana.
Pentremites platybasis Weller# – Indian Springs Shale Mbr., Big Clifty Fm., Upper Mississippian, Crawford Co., Indiana
Pentremites pulchellus Ulrich# – Renault Fm., Upper Mississippian, Shetlerville, Illinois
Pentremites pyramidatus Ulrich# – Renault Fm., Upper Mississippian, Shetlerville, Illinois
Pentremites pyriformis Say – Upper Mississippian formations, IN,KY – C,1,2
Pentremites robustus Lyon# – Glen Dean Fm?, Upper Mississippian, Madison Co., Kentucky
Pentremites springeri Ulrich# – Indian Springs Shale Mbr., Big Clifty Fm., Upper Mississippian, Crawford Co., Indiana IN,KY
Pentremites symmetricus Hall – Upper Mississippian formations, IL, IN, KY – C,S,1,2
Pentremites welleri Ulrich – Indian Springs Shale Mbr., Big Clifty Fm., Upper Mississippian, Crawford Co., Indiana
Pentremites growth series available
Tricoelocrinus woodmani (Meek & Worthen)# – extremely rare, this specimen found on the family farm near Lanesville, Indiana, shortly before it was sold. Salem Ls. (Somerset Shale Mbr.), Middle Mississippian, IN, KY – C,1
Troosticrinus reinwardi (Troost)# – from the Waldron Shale, Middle Silurian, in Tennessee. Similar to Decaschisma.
Comments about Pentremites
It’s possible to find more than the theca (body) and other features – including brachioles (feeding “bristles”), internal hydrospire folds (part of the respiratory system), and growth defects. No specimens like these are available for sale. Here are some examples:
Perhaps the smallest complete embryonic Pentremites ever found. It will be featured in an upcoming monograph on blastoids written by the world’s experts. Found at the Sulphur exit road cut, Crawford Co., IN. Indian Springs Member of the Big Clifty Formation, Chesterian, Upper Mississippian.
The simplest technique is to get them wet. The problem is that they reflect light. Compare these Pentremites platybasis below.
CYSTOID / RHOMBIFERAN Period Location Preservation
Caryocrinus persculptis Springer from the Waldron Shale, Middle Silurian, Jeffersonville, Clark Co., Indiana. C,1,2