Pronunciation: yoo-AHN-moo-SOR-us
Meaning: Yuanmou lizard
Author/s: Lu, Li, Ji, Wang, et al. (2006)
Synonyms: None known
First Discovery: Yunnan, China
Discovery Chart Position: #599
Yuanmousaurus jingyiensis
When tasked with diagnosing a new dinosaur species, most experts would love to have a skull to play with, but Yuanmousaurus, as is the case with many sauropods, is suffering from a rather nasty case of LNS (lost noggin syndrome). Fortunately, there's quite a lot of the rest of it. After studying its four types of vertebrae, a pair of shoulder blades, a partial hip bone, limb bones, a foot claw, and other odds and sods, Junchang Lü concluded that Yuanmousaurus was a Euhelopodid standing somewhere between the primitive Omeisaurus and the derived Euhelopus, with features that suggest it was closest to Patagosaurus from Argentina, though not geographically, of course.
Unfortunately, Euhelopodidae has since fallen out of favour and is rarely used by palaeontologists, due in no small part to the uncertainty surrounding its name-bearer, Euhelopus. During a 2006 restudy of Chuanjiesaurus anaensis and other Chinese sauropods, Toru Sekiya reclassified Yuanmousaurus jingyiensis as a member of Mamenchisauridae; the sauropods with insanely long necks, though its remains only include a single neck vertebra and even that one is incomplete.
Lü also coined Eomamenchisaurus in 2008 and chose this name (dawn Mamenchisaurus) because he thought it was similar to, but older than, the noodle-necked mamenchisaurid anchor, Mamenchisaurus. Although closely related, this may be a case of mistaken identity and chances are the former may actually be a specimen of Yuanmousaurus: one of the largest Middle Jurassic dinosaurs and possibly the first truly huge sauropod.
Unfortunately, Euhelopodidae has since fallen out of favour and is rarely used by palaeontologists, due in no small part to the uncertainty surrounding its name-bearer, Euhelopus. During a 2006 restudy of Chuanjiesaurus anaensis and other Chinese sauropods, Toru Sekiya reclassified Yuanmousaurus jingyiensis as a member of Mamenchisauridae; the sauropods with insanely long necks, though its remains only include a single neck vertebra and even that one is incomplete.
Lü also coined Eomamenchisaurus in 2008 and chose this name (dawn Mamenchisaurus) because he thought it was similar to, but older than, the noodle-necked mamenchisaurid anchor, Mamenchisaurus. Although closely related, this may be a case of mistaken identity and chances are the former may actually be a specimen of Yuanmousaurus: one of the largest Middle Jurassic dinosaurs and possibly the first truly huge sauropod.
(Yuanmou Lizard from Jiangi)
Etymology
Yuanmousaurus is derived from "Yuanmou" (the Chinese county) and the Greek "sauros" (lizard). The species epithet, jingyiensis, is derived from "Jiangi" (a Latinization of "Zhange", the formation and town within Yuanmou County where it was found) and the Latin "ensis" (from).
Discovery
The remains of Yuanmousaurus were discovered in the Zhanghe Formation, Jiangyi, Yuanmou County, Yunnan Province, China, by a team of paleontologists from the Yunnan Provincial Institute of Cultural Relics and Archaeology, the Yuanmou Museum and the Chuxiong Museum, in 2000.The holotype (YMV 601, housed at the Yuanmou Museum) is a partial skeleton including 9 dorsal (back), 3 sacral (hip) and 7 caudal (tail) vertebrae, a partial cervical (neck) vertebra, a partial ilium (hip bone), a humerus (upper arm or "funny" bone), an ulna and radius (forearm bones), a femur (thigh bone), a tibia (shin), a fibula (calf), an astragalus (ankle), a claw from the hind foot, and some unidentifiable fragments.
