[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Irritator and Spinosaurids
I'd like to fly an highly speculative kite for the troops to take shots at.
I've just got hold of the description of Irritator and a few points
strikeme as very interesting. The authors note that there is a similarity
between the teeth of Irritator and those of Spinosaurids. I was also
struck by the similarity of Irritator to Baryonyx in gross skull shape,
mostly the long low shape, the placement of the nostrils far back from
the snout tip and the strong postero-lateral inclination of the ramus of
the lacrimal that forms the preorbital bar. Perhaps Irritator is indeed a
spinosaurid and spinosaurids are infact coelurosaurs (bullatosaurs even?)
rather than megalosauroids.This may help explain the Baryonyx-like
features seen in the jaw of the coelurosaur, Archaeornithoides. In the
Irritator paper it is also noted that saggital crest on the frontals and
parietals may have been an attachment site for an enlaged dorsal neck
musculature designed to pull the head back sharply (as a fisheater would
do when a fish had been caught). Might the unusal, derived necks of
spinosaurids be adapted for the same purpose? I would further speculate
that the small saggital eminance on the nasal of Baryonyx is part of a
larger Irritator-like crest. Under my scheme then the Spinosaurids
would be a Gondwanan radiation (with some incursions into Laurasia) of
large piscivorous coelurosaurs , possibly bullatosaurs, characterised
by long low heads, strong necks for pulling the head backwards and
conical unserrated teeth.
Of course the similarities between Irritator and Spinosaurids may be
due to convergence caused by a similar piscivorous lifestyle.
Hopefully the new Spinosaurus material will provide the answers.