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THE FABLED TEETH OF BARYONYX



Regarding comparisons of 'Megaraptor' with other theropods, Brian 
Choo writes..

> You are right in that the Australian dromaeosaur material is based 
> solely on teeth (over 30 teeth known from Dinosaur Cove and Flat 
> Rocks in Victoria) However the teeth of spinosaurs (Baryonyx, 
> Irritator) are extremely distinctive in being slender,conical 
> structures with no serrations visible to the naked eye and would 
> have been immediately recognised as such.

Excuse me for being out of 'the loop', but is 'Megaraptor' now a 
valid name? Refer me to the archives if I've missed an important 
paper.

As for Brian's comments on the teeth of _Baryonyx_ et al, his 
description of is not really satisfactory. Charig and Milner (1990) 
pointed out that Greg Paul's (1988) description of _Baryonyx_ and 
_Spinosaurus_ teeth as 'semi-conical' (I think that was the tern he 
used) is not accurate - _Baryonyx_ teeth actually have a gentle 
backwards curve as do many other theropod teeth: they are not 
straight and cannot be described as conical (where a straight central 
axis is a necessity, cf. Charig and Milner, 1990). Having examined 
_Baryonyx_ teeth myself (we now have them on the Isle of Wight as 
well as the mainland), I would argue that the serrations on them are 
very much visible to the naked eye: certainly I could see them. The 
number of serrations varies according to the tooth position - I can't 
remember off the top of my head which teeth have most serrations, but 
the density of them varies from 5 per mm to an amazing 35 per mm I 
think. The latter could truly be described as microscopically fine.

I've also examined _Spinosaurus_ teeth. They aren't that similar to 
those of _Baryonyx_ with their stout tubular form and absent 
serrations. Russell's new _S. maroccanus_ definitely has teeth with 
carinae, but the carinae bear no serrations. It's worth noting here, 
however, that teeth are unreliable in diagnoses of theropods. 

Charig and Milner's (or is it Milner and Charig's?) new BMNH paper on 
_Baryonyx_ uses much the same arguments as they did in the _Dinosaur 
Systematics_ paper. With _Baryonyx_ teeth in Wealden Isle of Wight 
rocks (Martill and Hutt, 1996), you'd expect postcrania on 
the Isle of Wight too, wouldn't you. I'd best say no more. Also, did 
any of you ever hear those rumours of a supposed miniature 
baryonychid, also from the Isle of Wight? I did. It turns out that 
this rumour has a basis in fact: it is a tiny ungual that belongs to 
notorious fossil collector and lobster expert Martin Simpson (who 
spent the day watching football when Luis Rey went to visit him). The 
ungual is apparently just like the type of _Baryonyx_ (I haven't seen 
it) but is only about 5 cm long. Munt and Hutt (Sandown Museum of 
Isle of Wight Geology) refer to it as 'Weenyonyx' ('weeny' is 
vernacular for tiny here in England).

One further thing - in the new _Baryonyx_ paper Milner and Charig 
decided to rename Maniraptora 'Manuraptora', on the basis that 
Gauthier's (1986) etymology was incorrect. I have advised other 
workers to ignore this as you can't change the spelling of a name 
once it's been published (witness _Erlikosaurus_ vs. _Erlicosaurus_, 
yes?) - am I right? Fingers crossed.

"He can't sing to save his life, and they're the most tedious  
group of all time.. mind you, some of their songs are good"

DARREN NAISH
darren.naish@port.ac.uk