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Maiasaura is an extinct genus of hadrosaurid dinosaur that lived during the Late Cretaceous in Montana.

History[]

Maiasaura is derived from the Greek μαία, the female variation of the Latin 'saur' meaning lizard or reptile. The name means 'good mother lizard' or 'good mother reptile' in its entirety.

Description[]

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Credit: Skye McDavid.

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Two juvenile Maiasaura mounts at the Royal Ontario Museum.
Credit: Clumsystiggy on DeviantArt.

Maiasaura had a flat beak, with thick nasal cavities. Males had a small spiky crest above their eyes, possibly for head butting competitions for females. Maiasaura was capable of standing in both bipedal and quadrupedal. Studies on the feet show that juveniles used a bipedal gait, and switched to a quadrupedal gait as they grew older. Maiasaura had no defense to their predators, lived inland, with herds of up to 10,000 individuals.

Paleoecology[]

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An extremely speculative Maiasaura x Hypacrosaurus infertile hybrid (right) and a Maiasaura (left) created via drought, making the two species integrate more than normal.
Credit: Emily Stepp.

Maiasaura lived in Montana during the Late Cretaceous. Individuals lived in massive herds, that laid eggs once every month. Maiasaura cared for their young. Males bore a head crest for headbutting competitions, though had no defenses against predators.

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Supposed M. sp. from Hell Creek; this is probably not the case.

A specimen auctioned off by Heritage Auctions, labelled as M. sp., is stated to be from the Hell Creek Formation. The specimen was inferred to be closer to but earlier than M. peeblesorum; however, Maiasaura lived millions of years before the Hell Creek fauna, so this must be untrue. The skull and jaw is in good condition with all teeth present and preserved in the upper jaw. The skull, after preparation, is reportedly 25 inches long. The braincase was also found, 5.5 inches long, with intact large, round olfactory lobes. It was found by a fossil collector whose daughter located a strange object, which turned out to be the skull. It was found disarticulated, the braincase partially embedded in rock. However, it is unlikely Maiasaura are present in Hell Creek. Some have noted a majority of the skull looks restored, with the presumed fossil parts assumed to be lambeosaurine, possibly of the Hell Creek lambeosaur. It may also be an amateur mistake or a lie used by the auction house used because Hell Creek is a popular geologic formation. Nonetheless, the skull was sold on September 28, 2014.

Classification[]

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A Maiasaura (background) and Gryposaurus (foreground) mount at the Royal Ontario Museum.
Credit: Clumsystiggy on DeviantArt.

Maiasaura classification per Horner et al., 2004 (top) and Gates and Sampson, 2007 (bottom).

 Hadrosaurinae 

Lophorhothon





Prosaurolophus




Gryposaurus




Edmontosaurus




Brachylophosaurus



Maiasaura








Secernosaurus/"Kritosaurus"



Naashoibitosaurus



Saurolophus





Hadrosaurinae

Lophorhothon





Edmontosaurus




Prosaurolophus



Saurolophus






Naashoibitosaurus




Gryposaurus




Brachylophosaurus



Maiasaura







References[]

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