Named By: Stephen L. Wick, Thomas M. Lehman & Alyson Brink - 2014.
Classification: Chordata, Reptilia, Varanoidea.
Species: D. shilleri (type).
Known locations: USA, Texas - Aguja Formation.
Time period: Campanian of the Cretaceous.
Fossil representation: Teeth.
the time of the genus description and writing of this, Dryadissector
is known only from teeth, but these teeth are nonetheless very
interesting indeed. At a glance these teeth are very similar to those
of small theropod dinosaurs, laterally compressed and serrated like
knives, while recurved so that prey that was impaled upon them could
not pull itself free out of the mouth. However, these teeth have a
bulge near the base on the inside surface, something that is unheard
of in theropod dinosaurs, but common in varanid lizards which would
have also been around at this time. This has led the describers to
conclude that Dryadissector would have been a
(possibly similar to a modern day monitor lizard), but with teeth
exceptionally well adapted to slicing through the flesh of animals.
Reptiles are known to shed and regrow their teeth throughout their lives, and so far all the teeth of Dryadissector seem to have been shed by living individuals, which by extension helps explain why no actual bones have been so far found. This makes Dryadissector a tooth taxon, and traditionally tooth taxons are problematic because it is very difficult to infer additional non tooth remains to the genus. However it is not impossible, the dinosaur genus Troodon was first named from teeth, and was later attributed skeletal remains thanks entirely to the teeth being so unique. Likewise, because the teeth of Dryadissector are so specialised, it may be easier to attribute skeletal fossil remains to this genus, especially jawbones with teeth still attached.
On a further note about the teeth, when you count up the number of Dryadissector teeth known from lower Aguja Formation, they actually outnumber the teeth of all the known teeth from theropod dinosaurs from the Aguja Formation combined. This raises a speculative but very interesting question, were varanid lizards like Dryadissector actually outcompeting the smaller theropod dinosaur predators, at least in Texas anyway?
- A theropod tooth assemblage from the lower Aguja Formation (Early Campanian) of West Texas, and the roles of small theropod and varanoid mesopredators in a tropical lizard predator guild. Palaeogeography, palaeoclimatology. - Palaeoecology - Stephen L. Wick, Thomas M. Lehman & Alyson Brink - 2014.