A new paper published recently in the journal Geology reports on peculiar conga party lines of our paleo-friend, the Trilobite. Gutierrez-Marco and colleagues discovered a quarry replete with marine invertebrate fossil, including potentially some of the largest trilobite specimens ever found. Curiously though, these capricious little critters were found exhibiting some rather gregarious behavior! They offer up 3 explanations:
(1) en masse mating, with monotaxic body clusters of adult specimens killed by sporadic anoxic fluctuations
(2) epibenthic mass molting, with large assemblages of monospecific exuviae
(3) hiding in burrows or under skeletal remains to escape predation while molting in a monotaxic to polytaxic cryptic behavior.
Those guys above? TOTALLY a paleo-orgy of epic proportions!! What a way to die, huh?
Gutierrez-Marco, J., Sa, A., Garcia-Bellido, D., Rabano, I., & Valerio, M. (2009). Giant trilobites and trilobite clusters from the Ordovician of Portugal Geology, 37 (5), 443-446 DOI: 10.1130/G25513A.1