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Re: Dromaeosaur dorsal attacks led to ceratopsian shields and other dino gear? (free pdf)
Well it's not the wackiest idea I've heard. Not quite. To give
credit where credit's due, this is a brave attempt at reconciling the
apparent gliding adaptations of dromaeosaurids and early birds
(avialans) with their lack of arboreal adaptations. This "gliding
dismount" hypothesis is just the same as the arboreal ("trees-down")
hypothesis, except that the pro-avians ('parasites') are climbing and
leaping from large herbivores ('hosts'), rather than from trees.
A similar hypothesis was proposed on the DML ("Micropredatory Microraptorids").
It's also worth noting that the hypothesis that dromaeosaurids used
their enlarged sickle-claws as crampons (such as for climbing large
prey) was rebutted by Fowler et al. (2011).
On Tue, Jun 10, 2014 at 2:47 AM, Ben Creisler <firstname.lastname@example.org> wrote:
> From: Ben Creisler
> A new paper:
> Garnet Fraser (2014)
> “Bizarre Structures” Point to Dromaeosaurs as Parasites and a New
> Theory for the Origin of Avian Flight.
> The Journal of Paleontological Sciences: JPS.C.2014.01
> Ceratopsian neck frills, lambeosaurine crests, hadrosaur scales,
> stegosaur plates, cranial dome horns of Pachycephalosaurus
> (=Stygimoloch), diplodocid “whip” tails, sauropod dermal spikes,
> elaborate osteoderms, and elongated neural spines are considered
> bizarre dinosaur structures. Species identification, thermoregulation,
> sexual selection and display functions are theorized to explain these
> structures, not mechanically suitable for defense against large
> theropods. I propose that bizarre structures may have served to defend
> against parasitic dorsal attacks from riding dromaeosaurs. Removal of
> soft tissues by dromaeosaurs may have caused desiccation necrosis,
> callus formation and osteomyelitis, consistent with deformities in
> fossilized bone. Frequent dismounts from large living dinosaurs may
> explain the origin of feathers, gliding and avian flight. Plausibility
> of dorsal dromaeosaur riding is theorized from extant models
> including: the accipitrids (eagles), Geospiza difficilis
> septentrionalis (vampire finch), Gulo gulo (wolverine), Isistius sp.
> (cookie cutter shark), and vampire bat. Geologist Davidson-Arnott
> questions the “lethal sandslide” burial of the Mongolian “fighting
> pair,” a Velociraptor and Protoceratops, found locked in battle.
> Re-evaluation of their deposition favors a solitary approach to
> feeding in dromaeosaurs.