A very Peculiar Pterosaur

Pterodaustro is represented by a number of specimens from Argentina. There is a complete skeleton, a partial juvenile and an egg, just to mention a few. This unusual pterosaur is quite well represented in the fossil record, certainly enough is known to make a convincing reconstruction.
Most unusually, this was a filter feeder with a fine sieve of unusually adapted teeth that would have been ideal for filter feeding on small aquatic living organisms. This was the Flamingo of the ancient world!
The diagram of the skull shows the peculiar nature of this animals jaw. This pterosaur has more teeth than any other pterosaur. It is likely that it has more teeth than any other Dinosauromorph. It is also the first pterosaur where gizzard stones have been observed to be present.

The holotype, which was originally described by Bonaparte, is PLV 2571 and is a right humerus in the Institute Miguel Lillo, Universitat Nacional Tucuman, Argentina. Most of the specimens come from South America which is probably where the species evolved within a specific shallow water habitat, where zooplankton and phytoplankton were abundant.

In 2004 un-hatched egg containing a juvenile Pterodaustro, from the Lagarcito Formation in Central Argentina was described. The lacustrine deposits in which it was found are called the Loma del Pterodaustro and they are dated to about 100 million years ago. The specimen MHIN-UNSL-GEO-V 246 has been studied using electron micrographs of the egg shell suggesting a leathery shell. Ghosting of proteins can be interpreted within the shell structure which has yealded a significant amount of information about this pterosaurs eggs.

Bonaparte J F, 1970 Pterodaustro guinazui gen.et sp.nov.. Pterosaurio de la formacion Lagarcito, Provincia de San Luis, Argentina, Acta Geologica Lilloana, 10(10):207-226

Bonaparte J F, 1971 Descripcion del craneo y mandibulas de Pterodaustro guinazi (Pterodactyloidea - Pterodaustriidae), de la Formacion Lagarcito, San Luis, Argentina, Publ. Mus. Mun. Cienc. Nat. Mar del Plata, Pp. 63-272

Bonaparte J F & Sanches T M, 1975 Restos de um Pterosaurio,Puntanipterus globosus de foracion la Cruz, provincia de San Luis, Argentina, Actas Primeiro Cong. A

L. M. ChiappeA. Chinsamy, 1996, Pterodaustro's true teeth, Nature 379, 211 - 212 (18 January 1996)rgentino Paleont. Biostretigr., 2:105-113

Frey E., Martill D. M., Chong-Diaz G. and Bell M., 1997, New pterosaurs from the Lower Cretaceous of Chile. J. Vert. Paleont. 17 (3)

Codorniú L, Chiappe L.M. Early juvenile pterosaurs (Pterodactyloidea: Pterodaustro guinazui) from the Lower Cretaceous of central Argentina. Can. J. Earth Sci. 2004;41:9–18

Chiappe L.M., Codorniú L., Grellet-Tinner G. and Rivarola D., 2004, Palaeobiology: Argentinian unhatched pterosaur fossil, Nature. 432, pp. 571-572 (2 Dec 2004)

A Chinsamy, L Codorniú, and L Chiappe, 2008, Developmental growth patterns of the filter-feeder pterosaur, Pterodaustro guiñazui, The Royal Society, Biol Lett. 2008 June 23; 4(3): 282–285