[D] Monkonosaurus lawulacus [dG] [T]
Describer
Zhao vide Dong, 1990
Time
(?Jurassic Late) Cretaceous Early
Classification
Ornithischia Thyreophora Stegosauria Stegosauridae Wuerhosaurinae Nomina Dubia
Diet
Herbivore
Fossilsite
Loe-ein Formation, Monko County, Qamdo District, Tibet
Length
5 meter
Info
Genus - Typespecies
Two incomplete vertebrae, sacrum, three dorsal plates
Holotype
IVPP unnumbered, comprising two partial vertebrae, three dermal plates and a complete ilio-sacral block
Current location of material
The ilio-sacral block was located in the collections of the IVPP in September 2004. The whereabouts of the remainder of the holotype is unknown.
Original diagnosis Zhao in Dong (1990) used the following characters to diagnose Monkonosaurus:
(1) dermal plates large and thin and similar to those of Stegosaurus in shape;
(2) five sacral vertebrae with fenestrae between the sacral ribs entirely closed;
(3) sacral neural spines broad and lower than those of Stegosaurus, Kentrosaurus and Wuerhosaurus.
New descriptive data. Ilio-sacral block – The ilio-sacral block is substantially reconstructed having been broken since it was figured previously (Dong, 1990, fig. 19.17), and it is hard to distinguish the original material from the reconstructed areas. The ventral surface is cemented firmly to a metal stand, making study difficult.
Since it was figured in Dong (1990, fig. 19.17), the right anterior iliac process has been lost and it is cracked anteroposteriorly along the sacral ribs of the left side. There are five sacral ribs and five fused vertebrae. The first rib is slender and would have either been free or fused to the anterior process of the ilium (the latter has now been lost on both sides).
Dorsally, the ribs are not fused together, and there are clear and large fenestrae between them (contra Dong, 1990), although it is possible that the fenestrae are the result of the breakage of the ilio-sacral block. The posterior set of ribs angle posterolaterally.
The supraacetabular processes of the ilia are flattened and do not curve ventrally in lateral view. The acetabula are shallow, and posterior to them is a prominent tubercle, positioned between the posterior edge of the supraacetabular process and anterior part of the posterior iliac process.
\\\'Monkonosaurus lawulacus\\\' is based on fragmentary and undiagnostic material
(Maidment & Wei, 2006)
References
Chao S., 1983. \\\"Phylogeny and Evolutionary Stages of Dinosauria,\\\" Acta Palaeontologia Polonica 28(1/2): 295-306 [author\\\'s name spelled Zhao Xijin in this article].
Dong, 1990. Stegosaurs of Asia. in Carpenter and Currie, eds. Dinosaur Systematics: Approaches and Perspectives, pg. 255-268.
Maidment, S.C.R., and Wei, G. (2006) A review of the Late Jurassic stegosaurs (Dinosauria, Stegosauria) from the People\\\'s Republic of China. Geological Magazine 143(5):621-634