STL Science Center

STL Science Center

07 March 2012

Many Discoveries of Anurognathus

Anurognathus has been defined and redefined every forty or fifty years it seems. Considering the interesting nature of the flying reptile, I do not find this amazing. The more interesting the fossil the more attention it gets after all. New studies still come out all the time on some of our favorite crowd pleasers, so it is not really all that amazing except for the fact that Anurognathus is not typically a known fossil. Despite that, the original fossil, which was a part of a slab with the other half of the slab having been lost along with a great deal of bone which, thankfully at least, left a little bit of an impression of the bones that disappeared with it, had been described and named in 1923 and re-described in 1975 by Peter Wellnhofer. Wellnhofer simply re-described the holotype specimen and confirmed Doderlein's measurements. The measurement of the wing was confirmed to be fifty centimeters or twenty inches of wingspan. Having a nine centimeter long body this was a tiny adult specimen of a flying reptile and in 2008 Mark Paul Witten estimated that a thirty five centimeter wingspan specimen weighed in at approximately forty grams.

©Jaime A. Headden

The juvenile or sub-adult specimen described by S. Christopher Bennett in 2007 was a much better representation of the skeleton than the original specimen. This was due mainly to the fact that both halves of the fossil slab existed and thus provided a nearly complete skeleton. In describing this specimen Bennett noted that what Wellnhofer marked as antorbital fenestra were actually the orbitals and that this meant that Anurognathus actually had enormous eyes for its size. Other characteristics emerged as well in this new description such as the fact that the wings attached to the ankles making it short and broad, there were bristly hair-like protrusions on the jaw, and that the fourth phalanx on the wing finger of the hand is missing. The tail vertebrae, rather than only being able to study an impression of vertebrae, show in this specimen as unfused bone, meaning that the tail was not completely unmovable. This, with a shorter and more robust wing has led to the conclusion that where Doderlein thought Anurognathus was a swift hunting flier, Bennett believes Anurognathus was a twilight hunter (crepuscular animals) that relied more on maneuvering and using its large eyes to see through the dawn or dusk darkness.

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