Ankylosaurid dinosaur tail clubs evolved through stepwise acquisition of key features.
Ankylosaurid ankylosaurs were quadrupedal, herbivorous dinosaurs with abundant dermal ossifications. They are best known for their distinctive tail club composed of stiff, interlocking vertebrae (the handle) and large, bulbous osteoderms (the knob), which may have been used as a weapon. However, tail clubs appear relatively late in the evolution of ankylosaurids, and seemed to have been present only in a derived clade of ankylosaurids during the last 20 million years of the Mesozoic Era. New evidence from mid Cretaceous fossils from China suggests that the evolution of the tail club occurred at least 40 million years earlier, and in a stepwise manner, with early ankylosaurids evolving handle-like vertebrae before the distal osteoderms enlarged and coossified to form a knob.
Paleontology and Geology Research Laboratory, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.|Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.|Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
Victoria M
VM
Arbour
Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
Philip J
PJ
Currie
D000818:Animals; D005075:Biological Evolution; D025061:Dinosaurs / Q000033:anatomy & histology*; D005580:Fossils / Q000033:anatomy & histology*; D010802:Phylogeny; D013045:Species Specificity; D013131:Spine / Q000033:anatomy & histology*
Ankylosauria; Ankylosauridae; Cretaceous; Dinosauria