Giants of the Paleozoic

Giants of the Paleozoic

Update! Invertebrate Paleontology will be back at Bug Fair! Come visit our booth at the museum the weekend of May 19-20, 2018.

Looking for a little more information about the fossil insects and other arthropods you saw at Bug Fair? You’ve come to the right place!


The largest insects that ever lived were the griffenflies. These animals were not dragonflies, although they look similar to the Odonata. The largest of these insects had wingspans of about 2.3 feet!




Arthropleura was one of the largest arthropods to have ever lived. While one species of this animal may have reached up to 6.5 ft in length during the Paleozoic, it’s living relatives are typically less than 3 millimeters long.





Jaekelopterus rhenaniae is estimated to have reached up to 8 feet long, making it the largest arthropod to have ever lived. With claws (chelicerae) that were 1.5 feet long, it was likely at the top of the food chain in the ocean.





“Rex” means “king”, and Isotelus rex lived up to its name. At about 2.4 feet long, this animal dwarfed all other trilobites scurrying around the ancient continental shelf.





While most anomalocaridids lived during the Cambrian, some larger species have been recently discovered in rocks of Ordovician age. The largest of these animals may have grown up to 3 feet long, and some species probably ate trilobites.

Want to learn more? You can listen to interviews with experts on these fossils at

Thank you for visiting our exhibit at Bug Fair 2017! – Team LACMIP

Further reading: 

Braddy, S. J., Poschmann, M., & Tetlie, O. E. (2008). Giant claw reveals the largest ever arthropod. Biology Letters, 4(1), 106-109.

Grimaldi, D., & Engel, M. S. (2005). Evolution of the Insects. Cambridge University Press.

Hahn, G., Hahn, R., & Brauckmann, C. (1986). Zur kenntnis von Arthropleura (Myriapoda; Ober-Karbon). Geologica et Palaontologica, 20, 125-137.

Lucas, S. G., Lerner, A. J., Hannibal, J. T., Hunt, A. P., & Schneider, J. W. (2005). Trackway of a giant Arthropleura from the Upper Pennsylvanian of El Cobre Canyon, New Mexico. In Geology of the Chana Basin. New Mexico Geological Society, 56th Field Conference Guidebook (pp. 279-282).

Rudkin, D. M., Young, G. A., Elias, R. J., & Dobrzanski, E. P. (2003). The world’s biggest trilobite—Isotelus rex new species from the Upper Ordovician of northern Manitoba, Canada. Journal of Paleontology, 77(1), 99-112.

Van Roy, P., & Briggs, D. E. (2011). A giant Ordovician anomalocaridid. Nature, 473 (7348), 510.