Tuesday, 7 July 2009

The Frog Mouthed Pterosaurs

Anurognathus ammoni, a pterosaur from the upper Jurassic Solenhofen limestones of Bavaria, was first published in 1923 by Dodderlein. This was recognised as a very unusual small pterosaur, having a very broad and short jaw. Nothing had been seen like this before. The specimen was poorly preserved and the bones were somewhat disarticulated, but the animal clearly has short blunt teeth which were not suited to tearing flesh. "Frog Jaw" was thought to be an insectivore, possibly catching is prey on the wing or on leaves and branches around forested areas.
A second, well articulated specimen of
Anurognathus ammoni was described by Bennet in 2002 and this specimen shows the skeletal anatomy of the pterosaur very clearly.
Another frog mouthed species,
Batrachognathus volans, is known from the Karatau Mountains, Upper Jurassic sediments of Kazakhstan. This species was described by Rjabinin in 1948. The specimen is a partial skeleton including a disarticulated skull which clearly shows a wide jaw. This specimen shows some similarities with Anuroghnathus, but enough differences to classify it as a different species.
Dendrorhynchoides curvidentatus is a Tithonian species that was collected from the Chaomidianzi Formation, Zhangijagou locality from the Lower Yixian Formation near Beipiao City, Western Liaoning Province, China. It was published in 1998 and is one of several fine specimens to come out of this part of China. This is a very good fossil of this type of pterosaur and it has been restored after a preparator doctored the fossil in an attempt to make it more salable.
Jaholopterus ninchengensis is a compete Anurognathid with some soft part preservation from the Lower Yixian Formation at Nincheng, Inner Mongolia. This specimen is known as the Nincheng Rehe Pterosaur and is in the Institute of Vertebrate Paleontology and Paleoathropology in Beijing. The specimen caused quite a stir when it was published in 2002.

These 5 specimens are the major contingent of the classification Anurognathidae. There are a few fragmentary remains, like a jaw fragment from the Middle Jurassic Stonesfield Slate which is in The National Museum of Wales, Cardiff. The Anurognathids were probably quite widespread in distribution, but I suspect that they were forest dwelling pterosaurs, living in places where fossilization is a rare process. The scientific community is probably quite lucky to have this many specimens of this pterosaur lineage to work with.

Döderlein L., 1923, Anurognathus ammoni, ein neuer Flugsaurier. Sitzungsberichte der Bayerischen Akademie Wissenschaften, math.-naturwiss. Klasse, 1923, München. Pp. 117- 64, figs. 1-7.

Bennett S. C., 2002, A second specimen of Anurognathus from the Solnhofen Limestone of South Germany. Journal of Vertebrate Paleontology 22 (supp. 3), 36A

Rjabinin A. N., 1948, Remarks on a flying reptile from the Jurassic of the Kara-Tau, Akademia Nauk, Paleontological Institute, Trudy, 15(1): 86-93, 1 plate, Moscow and Leningrad.

Ji S.-A. and Ji Q., 1998, A new fossil pterosaur (Rhamphorhynchoidea) from Liaoning. Jiangsu Geology 22(4): 199-206.

Wang X., Zhou Z., Zhang F. and Xu W., 2002, A nearly complete articulated rhamphorhynchoid pterosaur with exceptionally well-preserved wing membranes and "hairs" from Inner Mongolia, Northeast China. Chinese Science Bulletin vol. 47(3), pp. 226-232.

1 comment:

  1. Yesterday I saw a documentary on discovery about frogs pterosaurs. I believe there are plenty of them buried all around the world, I wouldn't ever like to run into one of these animals.