The first large, diverse lineage of short-tailed avialans to evolve were the enantiornithes, or "opposite birds", so named because the construction of their shoulder bones was in reverse to that of modern birds. Enantiornithes occupied a wide array of ecological niches, from sand-probing shorebirds and fish-eaters to tree-dwelling forms and seed-eaters. While they were the dominant group of avialans during the Cretaceous period, enantiornithes became extinct along with many other dinosaur groups at the end of the Mesozoic era. COUNT 4
QSN1 What were the first large, diverse lineage of short-tailed avialans to evolve? ANS1 enantiornithes QSN2 Because of the construction of their shoulder bones, what were the enantiornithes called? ANS2 opposite birds QSN3 What was the dominant group of avialans during the Cretaceous period? ANS3 enantiornithes QSN4 When did enantiornithes become extinct? ANS4 end of the Mesozoic era