Maiasaura ‭(‬Caring/Good mother lizard‭)‬

Short Info

Maiasaura ‭(‬Caring/Good mother lizard‭)‬

Phonetic : My-ah-sore-ah.

Named By : Jack Horner‭ & ‬Robert Makela‭ ‬-‭ ‬1979

Diet : Herbivore

Size : Estimated 9 meters long

Type of Dinosaur : Euornithopod

Type Species : M.‭ ‬peeblesorum‭ (‬type‭)

Found in : USA‭ ‬-‭ ‬Montana‭ ‬-‭ ‬Two Medicine Formation

When it Lived : Late Cretaceous, 80-75 million years ago

Maiasaura, derived from the Greek maia and the feminine form Latin saurus meaning “good mom reptile or lizard”, is a large herbivorous saurolophine dinosaur genus called “duck-billed” that lived in Canada’s Upper Cretaceous Period (76.7 million years ago).


Maiasaura skeletonMeridas (Vladimír Socha), CC BY-SA 4.0, via Wikimedia Commons


In 1978, the first remains of Maiasaura’s were found. In 1979, the genus was named. Named after the discovery of nests containing eggs, embryos, and young animals in a nesting colony. These evidence showed that Maiasaura had fed its young while they were nesting, which was the first time such evidence has been found for a dinosaur. Maiasaura bones have been found in hundreds.

Maiasaura measured approximately 9m (30ft) in length. The young animals were able to walk on their hind legs while the adults walked on all fours. Brachylophosaurus was likely Maiasaura’s close relative.

Maiasaura were tall, reaching a maximum length of 9 meters (30 ft). Their flat, hadrosaurid-like beak was complemented by thick, broad noses. The crest was small and spiky, just in front of their eyes. This crest could have been used to headbutt between males during the breeding seasons.

Maiasauras were herbivores. They could walk on either two (quadrupedal), or four (bipedal), legs. The stress patterns in healed bones have shown that younger juveniles were primarily bipedal and switched to a more quadrupedal style when they got older. Like most hadrosaurs Maiasaura lacked any obvious weapons, but could likely defend themselves with kicks or stomps or their muscular tails. They likely fled from danger using their large herds as cover. The herds could have been as large as 10,000. Maiasaura lived within an inland habitat.

Laurie Trexler discovered a Maiasaura skull, specimen PU 22205 (now in Yale Peabody Museum of Natural History’s collections as YPM/PU 22205 after the transfer of Princeton University’s vertebrate paleontology collections). Jack Horner and Robert Makela described it as the holotype of an entirely new species. The type species was named Maiasaurapeeblesorum. The generic name refers the Greek goddess Maia, also known as “Good Mother”, and they used saura to emphasize this. The family of John and James Peebles on whose land these finds were made is the reason for the specific name. Marion Brandvold discovered a nest containing eggshells and large babies in 1978. These discoveries led to other discoveries, and the area was named “Egg Mountain” in the rocks of the Two Medicine Formation in western Montana. This was the first evidence of giant dinosaurs feeding and raising their young.

More than 200 specimens of all ages have been discovered. The discovery of Maiasaura drew renewed scientific attention to the Two Medicine Formation. Many other types of dinosaurs were also discovered due to this increased interest. The remains of Choteau Maiasaura are found in higher strata that their Two Medicine River counterparts.

Source: Wikipedia