Bactrosaurus
Name:
Bactrosaurus
(club lizard).
Phonetic: Bak-tro-sore-us.
Named By: Charles W. Gilmore - 1933.
Synonyms: Cionodon kysylumensis?
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia, Ornithopoda, Hadrosauroidea.
Species: B. johnsoni
(type), B. kysylumensis?
Diet: Herbivore.
Size: About 6 meters long.
Known locations: China - Iren Dabasu Formation,
Zouyun Formation. Kazakhstan - Dabrazhin Formation. Mongolia
- Baynshire Formation.
Time period: Cenomanian to Campanian of the
Cretaceous.
Fossil representation: Several individuals,
including adults and juveniles.
Bactrosaurus
is one of the earliest hadrosauroids
known from Asia, and also one of
the best known. Bactrosaurus still had three
stacked teeth for each
tooth in the maxilla, an iguanodont feature that reveals the ancestry
of the genus. However, Bactrosaurus also has a
number of
hadrosauroid features, particularly those of lambeosaurines (hollow
crested like Lambeosaurus).
For most of its early taxonomic life,
Bactrosaurus was reconstructed as being crestless.
However, study
of one Bactrosaurus skull seems to show the early
development of a bony
crest. This could be a further indicator for Bactrosaurus
being
ancestral to lambeosaurines.
Some
Bactrosaurus skeletons show the presence of
tumours, mostly benign,
but also cancerous. Some later hadrosaurs such as Edmontosaurus
and
Brachylophosaurus
also show the common development of tumours, which
has led to speculation that at least some genera of hadrosaurs had a
genetic predisposition towards developing tumours and possibly even
cancer.
Further reading
- On the dinosaurian fauna of the Iren Dabasu Formation. -
Bulletin of the American Museum of Natural History
68(2-3):23-78. - Charles W. Gilmore - 1933.
- Some results of the studies of the Upper Cretaceous dinosaurian
fauna from the vicinity of the station Sary-Agach, South Kazakhstan.
Problems of Paleontology 4:125-135. - A. N. Riabinin -
1938.
- Epidemiologic study of tumors in dinosaurs. -
Naturwissenschaften 90 (11): 495–500. - B. M.
Rothschild, D. H. Tanke, M. Helbling II & L. D.
Martin. - 2003.
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