Anurognathus: Beast of the Week

This week we will be checking out a unique little pterosaur, Anurognathus ammoni!  Anurognathus lived in what is now Germany during the late Jurassic period, about 150 million years ago.  It was tiny, sporting a 14 inch (35.5 cm) wingspan, and would have likely eaten insects.  It's genus name translates to "Frog Jaw" since its skull was similar looking to a frog's, being extremely blunt with a wide mouth.  

Watercolor reconstruction of Anurognathus ammoni by Christopher DiPiazza.

Anurognathus' skull was unusually short and broad for a pterosaur, being wider than it was long. It had huge eye sockets, suggesting it had strong vision, and needle-like teeth.  Experts think it was likely hunting flying insects, possibly at night, by flying into them with its mouth open.  This is similar to the hunting strategies of some modern birds, like swifts and swallows, which also independently evolved extremely wide jaws to do the same thing.  There were even some small bumps found lining the mouth of Anurognathus' jaws, suggesting there were whiskers growing there in life, another trait that could have possibly helped it capture fling prey in the air.  

Anurognathus skeleton that was described in 2007.

Thanks to a well preserved skeleton known of Anurognathus, we not only know about its bones, but also some of its other softer body parts that usually disappear before fossilization.  Paleontologists were able to see some of its limb muscles as well as the membrane of skin that made up its wing.  Perhaps most interesting, is we even know that Anurognathus would have had fuzzy feathers covering most of its body, including its wings! 

Pterosaurs are basically divided into two major groups.  The pterodactyloids are known for their long skulls, longer necks, and short tails.  This includes famous pterosaurs, like Pteranodon, Pterodactylus, and Quetzalcoatlus. The rhamphorhynchoids are characterized by smaller skulls, shorter necks, long tails, and an elongated fifth toe on each foot, which a membrane between their legs, used for maneuvering in the air, anchored to.  This group includes Rhamphorhynchus and Dimorphodon.  Anurognathus, despite having a proportionally short tail, has been found to be more closely associated to the rhamphorhynchoid branch of pterosaurs, due to its shorter neck and large fifth toe.  

References

Bennett, S. C. (2007). "A second specimen of the pterosaur Anurognathus ammoni", Paläontologische Zeitschrift, 81: 376-398

Döderlein, L. (1923). "Anurognathus Ammoni, ein neuer Flugsaurier". Sitzungsberichte der Mathematisch-Naturwissenschaftlichen Abteilung der Bayerischen Akademie der Wissenschaften zu München, 1923, 306-307.

Witton, M.P. (2008) "A new approach to determining pterosaur body mass and its implications for pterosaur flight". Zitteliania B28: 143-159