Trilobites and Crustaceans

Trilobites and crustaceans are arthropods, the group that includes arachnids, horseshoe crabs, millipedes, and the like. Arthropods molt as they grow. The result is common fragments and rarer complete animals. (Updated Feb. 10, 2022)

Photos of Trilobites and Other arthropods

Calymene breviceps Hall from the Waldron Shale of Clark Co., Indiana.

TRILOBITES   Period                                Location               Preservation

p = pygidium, t = thorax, c = cephalon

Arctinurus occidentalis pygidium resembles a palmetto leaf

Arctinurus occidentalis (Hall) – Waldron Shale, Middle Silurian, Clark Co., IN – C,2

Bumastus pygidium, a steinkern encrusted with sphalerite crystals

Bumastus sp. – Laurel Formation, Middle Silurian, Bardstown, Nelson Co., KY – C,2

Calymene breviceps with pyrite – this was found attached to the floor of the Atkin’s Quarry

Calymene breviceps Hall – Waldron Shale, Middle Silurian, Clark Co., IN – C,2

Cheirurus dilatatus has a spiny pygidium
Cheirurus dilatatus has a large glabella

Cheirurus dilatatus Raymond – Waldron Shale, Middle Silurian, Clark Co., IN – C,2

Cryptolithus bellulus cephalon with genial spines

Cryptolithus bellulus Ulrich – Kope Formation, Upper Ordovician, Carrol Co., KY – C,1,2

Eldridgeops sp. – complete, flat and made of quartz
Eldridgeops sp. – front of molted cephalon on trace fossil showing compound eyes (chert replacement)

Eldridgeops sp. (was Phacops) – Sellersburg Limestone, Givetian, Middle Devonian, Clark Co., IN – S,1,2

Flexicalymene granulosa – a small enrolled specimen through a microscope.

Flexicalymene granulosa  Foerste – Kope Formation, Upper Ordovician, Carrol Co., KY – C,1,2

Glyptambon verrucosus (p,c)            Middle Silurian                                  IN                          C,2

Kaskia chesterensis  (p)                      Upper Mississippian                         IN                          C,2

Litotix armatus (p,c)                            Middle Silurian                                IN                           C,2

Philibole conkini – cephalon
Philibole conkini – cephalon and pygidium
Philibole conkini – thorax and pygidium

Philibole conkini Hessler – Coral Ridge Member, New Providence Shale, Lowermost Middle Mississippian, Jefferson Co., KY – C,P,1,2

Sthenarocalymene celebra steinkern with manganese stain

Sthenarocalymene celebra (Raymond) – Laurel and Louisville Limestones, Middle Silurian, Jefferson & Nelson Cos., KY – C,1,2

Trimurus delphinocephalus cephalon
Trimurus delphinocephalus thorax and pygidium, prepped by Tom Johnson

Trimurus delphinocephalus (Green) – Waldron Shale, Middle Silurian, Clark Co., IN – C,2

Trilobite hash: C. bellus, F. granulosa, Acidapsis, Ceraurus, Isotelus, and other fossils, Up. Ordovician, KY, C,2


Dakoticancer australus (crab)           Upper Cretaceous                           MS                          C,1

Paguristes whitteni (crab)                  Upper Cretaceous                          MS                          C,1

Paraparchites sp. (Ostracod)          Middle Mississippian                          KY                          C,2

Unidentified ostracods               Late Eocene or early Oligocene       Colorado                   Carb,2