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Baryonyx walkeri description



It's finally out:

Charig, A. J. & Milner, A. C., 1997. "Baryonyx walkeri, a fish-eating
dinosaur from the Wealden of Surrey," Bulletin of The Natural History Museum,
Geology Series, 53(1): 1170 [June 26, 1997].

Taken from the first page is

Synopsis: The well-preserved skeleton of a large theropod dinosaur, Baryonyx
walkeri Charig & Milner, 1986, from the Wealden (Barremian, Lower Cretaceous)
of Surrey, is described in detail. It is a large theropod with some
resemblance to Megalosaurus or Allosaurus, but is sufficiently different to
merit its earlier designation as the type of the new family Baryonchidae. Its
distinguishing characters include: the prenarial extension of its snout into
a spatulate rostrum, a unique increase in the number of the dentary teeth
(which are more than twice as numerous per unit length of jaw as the opposing
maxillary teeth), an unusually robust fore-limb, and at least one pair of
 huge manual talons. Lack of fusion between the components of both skull and
vertebrae suggests that this 10 metre long animal was immature.

Few other specimens might be referred to Baryonyx: a maxilla fragment of B.
walkeri is recorded from the Barremian of Spain; two snout fragments from the
Aptian of Niger, which are virtually identical to the conjoined premaxillae
of Baryonyx; two isolated tooth crowns, one from the Hauterivian of East
Sussex, and one from Surrey; and seven from the Barremian of the Isle of
Wight are compared to the genus. On the evidence of the jaws and teeth only,
the families Baryonychidae and Spinosauridae (Spinosaurus, Angaturama, and
perhaps Irritator) are placed in the superfamily Spinosauroidea. An
investigation of the wider affinities of Baryonyx, based on a modified
version of Holtz's 1994a data-matrix on the Theropoda, suggests that the
Spinosauroidea is a basal member of the Tetanurae and sister-group to the
whole of the Neotetanurae (i.e. the Coelurosauria sensu Gauthier plus a
variable collection of 'allosauroids''), with Megalosaurus and Torvosaurus as
progressively more distant outgroups.

The associated fossil fauna is dominated by Iguanodon and many insects, which
lived in the vicinity of a sub-tropical delta. Baryonyx was terestrial, a
fish-eater, probably a scavenger, and possibly an active predator of small to
medium-sized land animals. It made greater use of its fore-limbs and talons
in attack and defense than its jaws and teeth, which were used mainly for
seizing fish and entrails. The taphonomy of the holotype suggests that the
animal is unlikely to have been transported from elsewhere and probably died
where found. Its skeletal remains lay in sediments that were mostly submerged
in shallow water but exposed to the air for brief periods; the bones were
trampled and broken before fossilization.

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The character matrix and clastic analyses should make Tom Holtz's mouth
water. Or, perhaps, foam up. Heh heh.