| Mei long | |
|---|---|
 | |
| Fossil specimen | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Family: | †Troodontidae |
| Subfamily: | †Sinovenatorinae |
| Genus: | †Mei Xu &Norell, 2004 |
| Species: | †M. long |
| Binomial name | |
| †Mei long Xu & Norell, 2004 | |
Mei (fromChinese:寐;pinyin:mèi;lit. 'sleepy') is agenus ofduck-sizedtroodontiddinosaur first unearthed bypaleontologists from theYixian Formation inLiaoning,China in 2004.Mei lived during the EarlyCretaceous period. Thebinomial name of its only species,Mei long (Chinese寐 mèi and龍 lóng), meanssleeping dragon.
Mei is atroodontid, a group of small, bird-like,gracilemaniraptorans. All troodontids have many unique features of the skull, such as closely spacedteeth in the lower jaw, and large numbers of teeth. Troodontids have sickle-claws andraptorialhands, and some of the highest non-avianencephalization quotients, meaning they were behaviourally advanced and had keen senses.[1] Thetype 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 betweenbirds and dinosaurs.[2] 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. Although DNHM D2154 exhibits several juvenile-like features including free cervical ribs, unfused frontals and nasals, and a short snouted skull, other attributes, full fusion of all neurocentral synostoses and the sacrum, and dense exteriors to cortical bone, suggest a small, mature individual. Microscopic examination of tibia and fibula histology confirms maturity and suggests an individual greater than two years old with slowed growth.Mei is notable as a distinct species of troodontid based on several unique features, including extremely largenares. It is most closely related to the troodontidSinovenator, which places it near the base of the troodontid (bird like) family.[3]
As a basal troodontid, unlike advanced troodontids, it has a bird like hip structure shared with many advanced maniraptorans.
Mei lived in the EarlyAptian stage of theCretaceous period, about 125.8 million years ago. At this time, the Liaoning area was dominated by numerous volcanoes in a landscape that was covered in coniferous forest, with an understory of ferns and other plants like largehorsetails. Several other trees were present, such asginkgos andaraucarias. Some of the earliest flowering plants were also found here. Rivers and streams coming down from the flanks of the volcanoes fed into lakes in the valleys.[citation needed]
There were many species of small birdlike theropod dinosaurs living in the area, although most of them were slightly larger thanMei. This probably led to a lot of niche partitioning. There were only five or six species of herbivorous non-theropod dinosaurs, however, and a large and varied fauna of earlymammals andpterosaurs. Theapex predator was the 9-meter-longtyrannosauroidYutyrannus, which would have preyed on the two or more species ofsauropod. Often, volcanoes erupted, entombing animals in ash and suffocating others with carbon monoxide, which accounts for the high level of preservation of fossils.[citation needed]
Mei probably fed on small lizards and insects on the forest floor. It probably climbed trees as well to shelter from larger predators, and was probably not omnivorous. Judging by the length of the legs, it was a fast runner. Nothing is known about its nesting habits.[citation needed]
When the first fossil ofMei was discovered, scientists were charmed to see the fossil in a birdlike sleeping posture.Mei long means 'sleeping dragon' in Chinese. The animal had probably died from carbon monoxide poisoning, then became entombed in ash.[citation needed]
The dictionary definition of寐 at Wiktionary
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