[D] Suzhousaurus megatherioides [sG] [T]
Li, Peng, You, Lamanna, Harris, Lacovara & Zhang, 2007
Cretaceous Early ?Aptian Albian
Saurischia Theropoda Tetanurae Coelurosauria Therizinosauroidea
Yujingzi Basin, northwestern Gansu Province, China. Xinminpu Group (= “Xinminbao”) Group, China
Genus - Typespecies
“Suzhou” (Chinese): ancient name of the Jiuquan area, where the specimen was discovered; “sauros” (Greek): lizard. “Megatherium”: genus of giant ground sloth; “-oides” (Greek): like.
FRDC-GSJB-99, an associated partial postcranial skeleton including 10 partial to nearly complete dorsal vertebrae; incomplete dorsal ribs; nearly complete right scapulocoracoid; complete right humerus; ? pubic peduncle of the left ilium; largely complete left and fragmentary right pubes; and several unidentified fragments.
Features of its humerus, such as strongly expanded proximal and distal ends, a well developed medial tuberosity, distal condyles expressed on the humeral cranial surface, and a hypertrophied entepicondyle, definitively establish the therizinosauroid affinities of the specimen.
It differs from other therizinosauroids in having a shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and a pubis with a strongly concave cranial margin.
Cladistic analysis recovers Suzhousaurus as the sister taxon of Nothronychus mckinleyi from the mid-Cretaceous of western North America; together, they are basal members of the Therizinosauroidea, more derived than the Early Cretaceous Falcarius and Beipiaosaurus but less derived than Alxasaurus and the Therizinosauroidea. Along with \\\"Nanshiungosaurus\\\" bohlini from possibly coeval beds in the Mazongshan area of northern-most Gansu, Suzhousaurus represents one of the largest-known Early Cretaceous therizinosauroids, demonstrating that this clade attained considerable body size early in its evolutionary history.
Large (humeral proximodistal length 550 mm) therizinosauroid characterized by the following autapomorphies: shallow, poorly demarcated glenoid fossa with a prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion, and pubis with a strongly concave cranial margin.