Cenozoic Reprise

Because birds are likely a specialized clade of theropods (Gauthier and Gall, 2001), the fossil record of dinosaur predation does not end with the K/T boundary. A diversity of Cenozoic birds has evolved as important predators of invertebrates and small vertebrates. At certain times and places, however, avian faunas have been particularly evocative of the Mesozoic glory days. For example, the phorusrhacoids of Tertiary South America (Andrews, 1901), and possibly the gastornithids of Paleogene Europe and North America (Witmer and Rose, 1991), were big, flightless, predatory birds startlingly reminiscent of their Mesozoic theropod predecessors.

The real Cenozoic lost world of dinosaurs, however, was New Zealand. In the absence of significant mammalian competition, a host of large and small birds, both volant and flightless, dominated the terrestrial vertebrate fauna (Worthy and Holdaway, 2002). Eleven species of moa, turkey to ostrich-plus in size, clumped through forest and field, cropping the vegetation like scaled-down sauropodomorphs or ornithischians. No ground-based tyrannosaur-avatar threatened the moa. Instead their chief predator was a huge eagle that attacked with talons from the air (Fig. 4), an entirely different style of dinosaurian predator-prey interaction than seen in the Mesozoic world. Dinosaurian dominance of New Zealand remained unchallenged until about a thousand years ago and the arrival of a bipedal, predatory primate far deadlier than any theropod, at which time this faraway land, too, finally fell under mammalian sway.

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