All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids.
Pterygotid eurypterids have traditionally been interpreted as active, high-level, visual predators; however, recent studies of the visual system and cheliceral morphology of the pterygotid Acutiramus contradict this interpretation. Here, we report similar analyses of the pterygotids Erettopterus, Jaekelopterus and Pterygotus, and the pterygotid sister taxon Slimonia. Representative species of all these genera have more acute vision than A. cummingsi. The visual systems of Jaekelopterus rhenaniae and Pterygotus anglicus are comparable to that of modern predatory arthropods. All species of Jaekelopterus and Pterygotus have robust crushing chelicerae, morphologically distinct from the weaker slicing chelicerae of Acutiramus. Vision in Erettopterus osiliensis and Slimonia acuminata is more acute than in Acutiramus cummingsi, but not to the same degree as in modern active predators, and the morphology of the chelicerae in these genera suggests a grasping function. The pterygotids evolved with a shift in ecology from generalized feeder to specialized predator. Pterygotid eurypterids share a characteristic morphology but, although some were top predators, their ecology differs radically between genera.
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA victoria.mccoy@yale.edu.
Victoria E
VE
McCoy
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA.
James C
JC
Lamsdell
Referat Erdgeschichte, Direktion Landesarchäologie, Generaldirektion Kulturelles Erbe RLP, Große Langgasse 29, 55116 Mainz, Germany.
Markus
M
Poschmann
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA.
Ross P
RP
Anderson
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA Yale Peabody Museum of Natural History, 170 Whitney Avenue, New Haven, CT 06520, USA.
Derek E G
DE
Briggs
D000818:Animals; D001181:Arthropods / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology; D005075:Biological Evolution; D054910:Compound Eye, Arthropod / Q000033:anatomy & histology*; D005580:Fossils; D006724:Hoof and Claw / Q000033:anatomy & histology*; D011235:Predatory Behavior
arthropod vision; chelicerae; eurypterid; predation; pterygotid