Re: VENOMOUS THERAPSID

[Jeff Hecht <jeff@jeffhecht.com>]

At 2:00 PM +0100 8/21/02, darren.naish@port.ac.uk wrote:
> Steve asked....
>
> ---------------
> Sometime ago (years, that is) I read an article in Discover
> magazine (I think) about therapsid predators who seemed to
> have hollow fangs and may have been venomous. I've never
> seen this mentioned since, so I was wondering if anybody
> could provide any information on the actuality of this.
> ---------------

A possibly venomous theropod based on a tooth from Baja California 
was described at the SVP meeting in 2000. Here's a draft of what I 
wrote for New Scientist at the time:


ID: Venomous theropod

A tooth from Baja California hints that venomous dinosaurs may have 
lived outside the fictional Jurassic Park. The two-centimeter tooth 
contains a longitudinal groove like those in the venom-carrying teeth 
of snakes, two Mexican paleontologists reported late last month at a 
meeting of the Society for Vertebrate Paleontology in Mexico City.

No other evidence of venomous dinosaurs has ever been discovered. The 
small poison-spitting predators of Jurassic Park were based on real 
dinosaurs called dilophosaurs, but their venom was fictional.

The curved blade-like tooth came from a small "theropod" dinosaur, 
the family of two-legged predators that included Velociraptor and 
Tyrannosaurus rex. "The general features of this tooth could be found 
in most theropod taxa," says Francisco Aranda-Manteca of the 
University of Baja California in Enselada. However, the groove-like 
structure is unique among dinosaurs. Aranda-Manteca says it resembles 
structures in the venom-delivering teeth of snakes and the two extant 
groups of poisonous (helodermatid) lizards -- the Gila monster and 
the Mexican beaded lizard. Neither group is closely related to 
dinosaurs, whose closest living relatives are birds and crocodiles.

So far, paleontologists have identified only one isolated tooth, 
missing its tip, in rocks 70 to 80 million years old. Measuring 5.6 
by  9.5 millimeters at its base, the tooth could have come from 
several types of theropods, but lacks distinctive features found in 
others, such as tyrannosaurs, which are among the few other dinosaurs 
known from the same deposits.

Other paleontologists at the meeting were intrigued, but share the 
caution of Aranda-Manteca and his colleague Ruben Rodriguez-de la 
Rosa. "It is not unquestionable evidence of venomous theropods," says 
Tom Holtz of the University of Maryland in College Park. "However, it 
does have an inverted serration pattern and groove down the back edge 
of the tooth, and indeed other animals which have a groove in that 
position are known to be poisonous."
--
Jeff Hecht, science & technology writer
jeff@jeffhecht.com; http://www.jeffhecht.com
Boston Correspondent: New Scientist magazine
Contributing Editor: Laser Focus World,  WDM Solutions
525 Auburn St., Auburndale, MA 02466 USA
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