| Changmiania | |
|---|---|
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| The possible sleeping position of aChangmiania specimen | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Ornithopoda |
| Genus: | †Changmiania Yanget al.,2020 |
| Species: | †C. liaoningensis |
| Binomial name | |
| †Changmiania liaoningensis Yanget al., 2020 | |
Changmiania (from the Chinese "changmian", meaning "eternal sleep") is agenus of basalornithopoddinosaur that lived in what is nowChina during theEarly Cretaceous. It contains a single species,Changmiania liaoningensis.
The taxon is represented by two near-complete articulated skeletons: theholotype specimen, PMOL AD00114; and a referred specimen, PMOL LFV022. These remains were discovered in theBarremian age, 123.2 million years old, Lujiatun Beds of theYixian Formation by local farmers and partially prepared. They were acquired by thePaleontological Museum of Liaoning atShenyang, which completed the preparation. No indications were found that the fossils had been tampered with by fossil thieves. The perfect life-like positions of these specimens suggest that they were buried alive, possibly in their own burrows due to a volcanic eruption.[1]
In 2020, thetype speciesChangmiania liaoningensis was named and described byYang Yuqing,Wu Wenhao,Paul-Emile Dieudonné andPascal Godefroit. The generic name is derived from 長眠 (cháng mián), "eternal sleep" in Chinese, referring to the possible sleep position the fossils were found in. Thespecific name refers to the provenance fromLiaoning.[1]
The holotype specimen has a preserved length of 117 centimetres.[1]
The describing authors established some distinguishing traits. Some of these wereautapomorphies, unique derived characters. Thefrontal bones are elongated, over four times longer than wide. The parietals do not share a midline crest. The front branch of thesquamosal bone is straight and elongated. On the upper rear corner of the squamosal a distinctive boss is present. The lower edge of the dentary is convex but the edge of theangular bone is strongly concave, resulting in a sinuous profile for the lower jaw as a whole. The neural spines of the sacral vertebrae are fused into a continuous elongated plate. Both the lower and upper end of the shoulder blade is asymmetrically expanded. The paired ilia are upwards and inwards inclined, covering the sacrum in top view. The upper part of the calfbone is as robust as that of the shinbone.[1]
The neck was very short, with only six vertebrae; other ornithischians usually have nine.[1]
In their phylogenetic analysis, Yanget al. (2020) recoveredChiangmiania as the basalmost ornithopod. The cladogram below follows their results:[1]
| Neornithischia |
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Changmiania probably dug burrows, like several other small ornithischians such asOryctodromeus. Several of its anatomical features, such as its short neck, short forearm and hands, and enlarged shoulder bones are probably adaptations for digging.[1]
