Re: Ichthyovenator, new spinosaurid from Early Cretaceous of Laos

[Tim Williams <tijawi@gmail.com>]

Robert Schenck <schenck.rob@gmail.com> wrote:

> Since Allain is involved in this, presumably there will be some
> isotopic analysis to follow, he's done a lot of good work on that.
> IIRC Allain was the one to demonstrate isotopically that Spinosaurids
> were fish-eaters.


Amiot &c used teeth for their isotopic studies on theropods and
crocodilians.  No teeth are known for _Ichthyovenator_.


BTW, the name "fish hunter" was based on the inferred piscivorous
habits of Spinosauridae in general.  It is unknown whether
_Ichthyovenator_ has the craniodental specializations associated with
piscivory seen in other spinosaurids.  Allain &c regard
_Chilantaisaurus_ as a spinosaurid.  A theropod tooth referred by Hu
(1964) to _Chilantaisaurus_because it was associated with the holotype
is recurved, serrated and transversely compressed - atypical of
spinosaurids.  So either this tooth does not belong to
_Chilantaisaurus_ (which Benson & Xu, 2008, rate as a good
possibility), or _Chilantaisaurus_ had teeth unlike those of (other)
spinosaurids.  Either way, it cannot be assumed that all spinosaurids
had the characteristic piscivorous adaptations of the group.  The fact
that Allain &c's analysis has _Ichthyovenator_ inside Baryonychinae
makes it more likely; but the "fish hunter" habits inferred for
_Ichthyovenator_ are not based directly on the fossil itself.
Theropod teeth have been found associated with the sauropod
_Tangvayosaurus_, also from the Grès supérieurs Formation of Laos.


> How come dinosaur@usc.edu isn't pre-set as the automatic,
> pre-populated ' reply-to ' address for the list? Other lists can do
> this no? I figure this must've come up before in the long history of
> the list and was curious.


I don't know the answer, but I can say that it's perhaps a good idea
that dinosaur@usc.edu isn't set as the default.  There is less chance
that off-list replies intended for individuals are not sent
inadvertently to the whole list.






Cheers

Tim