Fig. 25From: The oldest described eurypterid: a giant Middle Ordovician (Darriwilian) megalograptid from the Winneshiek Lagerstätte of IowaOntogenetic changes in prosomal appendages of Pentecopterus decorahensis from juvenile to adult (coxa not shown). a Juvenile appendages II–V. b Adult appendage II. c Adult appendage III. d Adult appendage IV. e Adult appendage V. Homologous structures are color coded: red = distal denticulations, green = moveable ventral spines, blue = fixed lateral spinesBack to article page