The type fossil is a young juvenile about 53 centimetres (21 in) long, complete and exceptionally well preserved in three-dimensional detail, with the snout nestled beneath one of the forelimbs and the legs neatly folded beneath the body, similar to the roosting position of modern birds. This posture provides another behavioral link between birds and dinosaurs. The chemistry of the matrix stone and the resting pose indicate the living animal was probably buried instantly in volcanic ash. A second specimen, DNHM D2154, was also preserved in a sleeping posture.
Mei is notable as a distinct species of troodontid based on several unique features, including extremely large nares. It is most closely related to the troodontid Sinovenator, which places it near the base of the troodontid family.
As a basal troodontid, unlike advanced troodontids, it has a bird like hip structure shared with many advanced maniraptorans.
In popular cultureEdit
Mei long were featured in the third episode of the ITV series Prehistoric Park, where they were depicted attacking a member of the fictional documentary crew, looking for the food in his pack. In the story, several M. long were later found dead near a volcano, suffocated by the toxic gasses, based on one hypothesized explanation for the 'sleeping' posture of the fossil. The program also erroneously depicted Mei without feathers and coexisting with the dromaeosaurid Microraptor, which lived later and is known from younger rocks of the Jiufotang Formation, rather than the older Yixian Formation where Mei was found.