Perimecturus rapax
Late Mississippian
Bear Gulch Limestone
Fergus County, Montana, USA

Arthropd. Crustacean. Carboniferous.

70mm crustacean on 111mm slab. A nice high quality, large specimen of this unusual early relative of the mantis shrimp. Rare.

Perimecturus is a genus of extinct crustacean that has been informally called a “proto mantis shrimp though they didn’t have the “ballistic claws” and other adaptations of true mantis shrimp. In fact, Perimecturus was more like a flattened lobster in form – not directly related to lobsters either. It is known from the Early Carboniferous (Mississippian) of Montana.

Back in the 90’s, when Bear Gulch material was regularly available, Perimecturus specimens were uncommon.  These days, specimens are scarce with even fewer going on the market and the demand for oddball predators being about the same.

Well-preserved example of this ancient crustacean.

For reference see: F. R. Schram and J. Horner. 1978. Crustacea of the Mississippian Bear Gulch Limestone of Central Montana. Journal of Paleontology 52(2): 394-406.