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Gavin "frogfoot" wrote;
Its a name that ive only ever seen a few times,
mentioned alongside other "Spinosaurs" such as Becklespinax and
Acrocanthosaurus. Not something Ive ever seen a picture of or any specs
(height, weight, etc) either. Can anone tell me more about this
creature? The species Yangchuanosaurus shangyouensis (a
sinraptorid allosauroid, from the Late Jurassic of China) was once included in
the genus Metriacanthosaurus, by G.S. Paul in his excellent "Predatory Dinosaurs
of the World". Some 10 years later, few workers now accept this
referal.
The original (and only valid species) of Metriacanthosaurus is
M. parkeri (details below)
Species described by von Huene (1923) as Megalosaurus
parkeri, Walker (1964) later created the separate genus
Metriacanthosaurus
Age : Late Jurassic (Oxfordian), some 160 MYA
Location : Corallian Oolite Formation, Dorset County,
England
Size estimate : up to 8 meters ( 26 ft )
Available fossil remains : (holotype, UMO 12144) partial
postcranium including dorsal & caudal vertebrae; ilium, fragmentary ischium
& pubis, right femur, proximal tibia
The remains don't reveal much, and it's difficult to
establish a reliable relationship with other dinosaur taxa.
M. parkeri has been considered as a neoceratosaur, a
"megalosaur", a sinraptorid or a spinosaurid. Classification as a spinosaurid
was based on the elongate dorsal neural spines, seen in the holotype of M.
parkeri, but their length is similar to the dorsal neural
spines of Allosaurus fragilis. In fact, the dorsal "spines" are
the main reason why Acrocanthosaurus atokensis and Becklespinax
altispinax (the other 2 taxa mentioned in your question) were considered to
be spinosaurs. Acrocanthosaurus is now classified as an allosaurid (probably
closely related to carcharodontosaurines), while Becklespinax (from the Wealden
of Sussex, England) remains a mystery, the remains ( 3 articulated dorsal
vertebrae) don't seem to belong to Baryonyx walkeri or Neovenator
salerii ( 2 other large - but better known - theropods from the
Wealden of England).
My guess is that Metriacanthosaurus parkeri may turn
out to be a basal allosauroid. Other allosauroids are known from Europe
including Lourinhanosaurus antunesi (from Portugal, Late Jurassic),
M. parkeri may be an ancestral form. Basal allosauroid characters seen
in the remains of M. parkeri may be the reason why it has been
considered as a sinraptorid.
Regards,
Gunter Van Acker
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