page_title: Albertonykus
section_title: Description
hierarchical_section_title: Albertonykus / Description
caption_attribution_description: English: Albertonykus borealis ( Dinosauria - Theropoda - Coelurosauria - Alvarezsauridae ) from the late Cretaceous ( Maastrichtian aged ) Horseshoe Canyon Formation of Dry Island Buffalo Jump, Alberta, Canada. Original pencil, graphite, and charcoal on paper by Nick Longrich. Additional digital editing by Nick Longrich
context_page_description: Albertonykus is an alvarezsaurid dinosaur from the Maastrichtian-age rocks of the Horseshoe Canyon Formation of Alberta, Canada. It is known from forelimb and hindlimb remains from multiple individuals. All but two of the specimens come from a bonebed dominated by Albertosaurus, located located at the top of Unit 4 of the Horseshoe Canyon Formation, dating to ~68.5 million years ago.
  Albertonykus is interpreted as having fed on wood-nesting termites because the forelimbs appear specialized for digging, but are too short for burrowing. Albertonykus is the earliest-known North American alvarezsaurid. Isolated bones of alvarezsaurids are known from late Maastrichtian rocks in Montana and Wyoming.
  The type species is A. borealis, described by Nicholas Longrich and Philip Currie in 2009. The specific name means "north".
context_section_description: Albertonykus is the smallest known alvarezsaurid ever discovered in North America, measuring only 70 centimeters (2.5 ft) in length. Other estimates are 1.1 meters and 5 kg. Alvarezsaurs typically had slender hind legs, long rigid tails, and unusually short arms that were powerfully built to support a large claw. Although no skull bones of Albertonykus have been found, related animals from Mongolia show that they likely had long, slender snouts filled with tiny teeth similar to those of armadillos and anteaters. It is likely that Albertonykus ate insects, using its large thumb claw to tear open rotten logs to find its prey. As in other alvarezsaurs, the forelimbs of Albertonykus were specialized for digging, but were too short to permit burrowing. Unfortunately at this time the skeleton of Albertonykus is not complete, but its Mongolian relatives give us a distinct idea of what the rest of the skeleton would have looked like.
  Possible prey items were evaluated and compared with the fossil record of social insects. Ants were not an important part of the ecosystem during the Cretaceous, and mound-building termites do not appear until the Eocene. This leaves the possibility that Albertonykus preyed on wood-nesting termites. This hypothesis was tested by examining petrified wood from the Horseshoe Canyon Formation, where Albertonykus was found. The wood found there frequently contains borings, which resemble those of termites.
caption: Albertonykus borealis foraging for termites
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