Saturday, February 2, 2013

Dimorphodon: Prehistoric Animal of the Week

This week we will be taking a look at Dimorphodon macronyxDimorphodon was a pterosaur, a prehistoric flying reptile related to the dinosaurs.  Pterosaurs, the first ever animals to fly after insects, had wings consisting of skin membrane attached to the animal's hands much like modern bats.  Unlike bats, however, who's wings are supported by four of their five fingers, pterosaurs only had one super elongated, sturdy finger (digit four) that supported each wing with digits one through three free.  Dimorphodon was about three feet long from snout to tail and had about a six foot wingspan (roughly the same overall size as a modern Bald Eagle).  It lived in what is now England during the early Jurassic period.  The genus name, Dimorphodon, translates to "Two kinds of teeth" in reference to the fact that this pterosaur had...two kinds of teeth.  (long ones in the front of the jaws and smaller ones in the back) The species name, macronyx, means "long claw" in reference to the three imposing claws on each of the animal's hands.

Life reconstruction of Dimorphodon eating a dobsonfly.

The most striking feature about this creature is its gigantic head full of sharp, pointed teeth.  Despite its appearance, however, the skull of Dimorphodon was extremely light thanks to a series of large holes called fenestre causing it to be hollow.  These are present in all pterosaurs and dinosaurs (amongst other archosaurs) but are particularly large in DimorphodonDimorphodon's wings were also proportionally shorter compared to its body as oppose to many other known pterosaurs that had much longer wings for soaring long distances.  This leads some scientists to believe that Dimorphodon may not have been as strong of a flier as some of its later relatives.  It had a long, somewhat stiffened tail with a veined leaf-shaped rudder at the tip to aid in steering during flight and the fifth digit on each of its feet was extremely long which would have anchored another membrane between it's legs, called a uropatagium.

Dimorphodon skeleton in quadrupedal stance.

Shortly after the time of its discovery in the 1800s and then later again in the 1980s, some scientists proposed that Dimorphodon would have been able to run on its hind legs much like a bird.  This theory has been mostly discredited since trackways of pterosaurs (not of Dimorphodon, however) have been discovered that clearly show quadrupedal (four legs) locomotion.  Another source of debate about this animal is its diet.  Some scientists think it was a fish eater since its long, pointed teeth seem to be perfect for the task plus the shape of its head strongly resembles that of a modern puffin's which eat almost exclusively marine prey.  Other scientists have suggested Dimorphodon may have specialized more for hunting insects and other land prey since its anatomy appears to be adapted more to flying from tree to tree, rather than over the open ocean.

Puffin.  Its a dinosaur and thus not that closely related to Dimorphodon (a pterosaur) despite the resemblance.


That's all for this week!  As always if you would like to request an animal for me to review feel free to comment below or on our facebook page.

Works Cited

Osi, A. (2010). "Feeding-related characters in basal pterosaurs: implications for jaw mechanism, dental function and diet." Lethaia, doi:10.1111/j.1502-3931.2010.00230.x

Wellnhofer, Peter (1996) [1991]. The Illustrated Encyclopedia of Pterosaurs. New York: Barnes and Noble Books. p. 69. ISBN 0-7607-0154-7

Witton, Mark P. Pterosaurs: Natural History, Evolution, Anatomy. N.p.: n.p., n.d. Print.

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