South America is a continent of reversals, with giant armored turtles, lanky false-sauropods, and tiny, fleet-footed tyrannosaurs.  Of these last, the meter-long stalky (Papillotyrannius pauli) is the most common, a ubiquitous small predator of the pampas.

    Stalkies range from just south of the Amazon to Patagonia, and eat a variety of small dinosaurs, mammals, reptiles, and invertebrates.  These solitary predators have even been observed to eat poisonous snakes, stragling the reptiles with their powerful feet before biting off the head.  During the mating season, male stalkies develop a yellow tinge to their head and neck feathers, while their brow ridges turn blue and their tiny, atrophied arms flush red.  This trait has earned the stalky its generic name.