An asteroid (Echinodermata) faunule from the Oxfordian Swift Formation (Upper Jurassic) of Montana

Abstract

AbstractA new Late Jurassic (Oxfordian) asteroid (Echinodermata) faunule from the Swift Formation of Montana includes representatives of four genera including the new genus and speciesAtalopegaster gundersoni(Stichasteridae),Eokainastersp. indet. (Astropectinidae), an indeterminate probable member of the Goniasteridae, and a species indeterminate beyond the class level. Because of weathering at the outcrop, preservation is poor.Although representing an unusual depositional occurrence, overall faunule composition appears comparable to that found in a similar modern environment. The faunule is comparable in age and regional location to earlier Jurassic asteroid discoveries, suggesting wide distribution during a geologically brief time interval of favorable conditions. Asteroids are only rarely reported from the Mesozoic of the North American continental interior, and co-occurrence of multiple fossil taxa is unusual on a global basis.