Hadrosaurids seemingly nest among a clade of iguanodontian ornithopods, possessing 'thumb' spikes, or spurs, like those of the 'thumbs up' dinosaur, Iguanodon. However, they lost the spurs. I'm perplexed why: did they evolve with interspecific behavior, of sociobiological relevance, that was somehow lost in hadrosaurs? Lower interspecific agonism? Less mate or nest site competition?

#ankylopollexians #iguanodontians #hadrosaurs #thumbspikes #ornithopods #evolution

Some ornithopod art in various styles, because ornithopods are great. #Paleoart #Dinosaurs #Ornithopods