Published online by Cambridge University Press: 20 May 2016
Large collections of Glyptopleura costata (McCoy, 1844) from the Maxville Limestone in central Ohio contain four instars and adults. The juveniles provide a basis for understanding the orderly development of the complex ornamentation of costae characteristic of Glyptopleura. Dimorphism is prominent with heteromorphs and adult tecnomorphs readily identifiable, primarily in adults. Progressive development of the ornamentation in juveniles, significant variation in adult ornamentation, and dimorphism has led to a proliferation of proposed taxa.