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a herbivorous hadrosauroid dinosaur from the Late Cretaceous of China.
Pronunciation: BAK-tro-SOR-us
Meaning: Club lizard
Author/s: Gilmore (1933)
Synonyms: None known
First Discovery: Nei Mongol, China
Chart Position: 131

Bactrosaurus johnsoni

After the discovery of fossils by Albert F. Johnson in a quarry that would later be named in his honor, Barnum Brown coined "Paraiguanodon" (meaning alongside Iguanodon) in 1923, but the name wasn't attached to a description so it was never official. Tasked with describing these remains a decade later and realising that they didn't actually belong "alongside Iguanodon" in features or in age, Charles Whitney Gilmore chose a new name, Bactrosaurus, and trumpeted it as a member of Lambeosaurine; the hadrosaurs with head crests, which was a tad strange because his own eyes told him it didn't have one.

Since then, paleontologists have discovered a lump of bone that they think may be the remnant of a headcrest, though it wasn't actually attached to a head, and so the strangeness continues. Bactrosaurus sports features typical of lambeosaurine hadrosaurids but is small and of a suprisingly powerful build. Even with a mouthful of lozenge-shaped teeth and a bank of three available replacements for each it still had a lower tooth count than its more advanced brethren, and fewer sacral (hip) vertebrae too, and all things considered it seems to be straddling an evolutionary path with the primitive iguanodonts on one side and hadrosaurids proper on the other. In other words, it's probably a hadrosauroid.

Bactrosaurus is named for the club-shaped dorsal spines that formed a visible ridge down the mid-line of its back, not Bactria; an ancient country around abouts the location of modern-day Afghanistan, nor for prehistoric bacteria, but infection, it seems, was a problem. Of ten thousand dinosaur fossils which were subjected to fluoroscope screening Bactrosaurus and its closest kin were shown to be riddled with tumors - particularly the cancerous metatastic variety, and also hemangiomas, desmoplastic fibroma and osteoblastoma. Despite sounding like made-up words from cheats scrabble these are actual diseases and bad ones at that, the cause of which may have been environmental factors such as particular food-types, or perhaps gliches in their genetics in which case they were primed for extinction regardless.
Bactrosaurus gets its name from the Greek words "baktron" (club), referring to the club shaped spines projecting from some of its vertebrae, and "sauros" (lizard). The name is sometimes interpreted as "Lizard from Bactria" though quite what links this dinosaur to Bactria, an ancient country around abouts the location of modern-day Afghanistan and many miles from its fossil home, eludes us. The species epithet, johnsoni, is a nod to Albert Johnson (see discovery).
The first fossils of Bactrosaurus — possibly six individuals which seem to represent a clean sweep of growth stages from juvenile to geriatric — were discovered at Johnson Quarry (AMNH quarry 141) eight miles to the east of the Iren Dabasu telegraph station, in the Iren Dabasu Formation of China's Gobi Desert by Albert Johnson in 1923.
The holotype (AMNH 6553) is the largest partial skeleton found in the Quarry.
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Campanian
Age range: 84-71 mya
Est. max. length: 6 meters
Est. max. hip height: 2 meters
Est. max. weight: 1.4 tons
Diet: Herbivore
• Gilmore, Charles Whitney (1933) "On the dinosaurian fauna of the Iren Dabasu Formation". Bulletin of the AMNH; v.67, article 2.
• Godefroit P, Z Dong, P Bultynck, H Li and L Fenh (1998) "New Bactrosaurus (Dinosauria: Hadrosauroidea) material from the Iren Dabasu". Bulletin de l'Institut Royal des Sciences Naturelles de Belqique, Sciences de la Terre, Volume 68, Suppl., Pages 3-70.
• Rothschild BM, DH Tanke, M Helbling II and LD Martin (2003) "Epidemiologic study of tumors in dinosaurs". Naturwissenschaften. 2003 Nov;90(11):495-500.
• Horner JR, DB Weishampel and CA Forster (2004) "Hadrosauridae" in Weishampel, Dodson, and Osmólska (eds.) "The Dinosauria: Second Edition".
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To cite this page:
Atkinson, L. "BACTROSAURUS :: from DinoChecker's dinosaur archive".
›. Web access: 17th Jan 2018.