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

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

TRILOBITES Period Location Preservation

p = pygidium, t = thorax, c = cephalon

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

Arctinurus occidentalis pygidium resembles a palmetto leaf — *Arctinurus occidentalis* (Hall) pygidium resembles a palmetto leaf

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

Bumastus pygidium, a steinkern encrusted with sphalerite crystals — *Bumastus* pygidium, a steinkern encrusted with sphalerite crystals

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

Calymene breviceps with pyrite - this was found attached to the floor of the Atkin's Quarry — *Calymene breviceps* Hall with pyrite – this was found attached to the floor of the Atkin’s Quarry

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

Cheirurus dilatatus has a spiny pygidium — *Cheirurus dilatatus* Raymond has a spiny pygidium

Cheirurus dilatatus has a large glabella — *Cheirurus dilatatus* (Raymond) has a large glabella

Cryptolithus bellulus Ulrich – a blind trilobite from the Kope Formation, Upper Ordovician, Carrol Co., KY – C,1,2

Cryptolithus bellulus cephalon with genial spines — *Cryptolithus bellulus* Ulrich – cephalon interior with genial spines

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

Eldridgeops sp. - complete, flat and made of quartz — *Eldridgeops* sp. – complete, flat and made of quartz

Eldridgeops sp. - front of molted cephalon on trace fossil showing compound eyes (chert replacement) — *Eldridgeops* sp. – front of molted cephalon on trace fossil showing compound eyes (chert replacement)

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

Flexicalymene granulosa - a small enrolled specimen through a microscope. Kope Formation, Upper Ordovician, — *Flexicalymene granulosa* Foerste – a small enrolled specimen through a microscope.

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

Philibole conkini Hessler - Coral Ridge Member, New Providence Shale, Lowermost Middle Mississippian, cephalon view — Philibole conkini – cephalon

Philibole conkini Hessler - Coral Ridge Member, New Providence Shale, Lowermost Middle Mississippian, cephalon and pygidium — Philibole conkini – cephalon and pygidium

Philibole conkini Hessler - Coral Ridge Member, New Providence Shale, Lowermost Middle Mississippian, thorax and pygidium — Philibole conkini – thorax and pygidium

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

Sthenarocalymene celebra - steinkern with manganese stain — *Sthenarocalymene celebra* (Raymond) – steinkern with manganese stain

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

Trimurus delphinocephalus cephalon — *Trimurus delphinocephalus* (Green) – cephalon

Trimurus delphinocephalus thorax and pygidium, prepped by Tom Johnson — *Trimurus delphinocephalus* (Green) – thorax and pygidium, prepped by Tom Johnson

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

CRABS / OSTRACODS

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