Herbstosaurus Herbstosaurus Herbstosaurus is the name given to a genus of pterosaur that lived during the Jurassic period, in what is now Argentina. In 1969 Argentine paleobotanist Rafael Herbst in the province Neuquén at Picun Leufú dug up a piece of sandstone holding a number of disarticulated bones of a small reptile. At the time it was assumed the rock dated from the Middle Jurassic (Callovian), about 163 million years ago. In 1974/1975 paleontologist Rodolfo Magín Casamiquela named the find as a new genus. The type species is "Herbstosaurus pigmaeus". The genus name honours Herbst and connects his name to Greek
Cretaceous local subdivisions are still in use. As with other older geologic periods, the rock beds of the Cretaceous are well identified but the exact age of the system's base is uncertain by a few million years. No great extinction or burst of diversity separates the Cretaceous from the Jurassic. However, the top of the system is sharply defined, being placed at an iridium-rich layer found worldwide that is believed to be associated with the Chicxulub impact crater, with its boundaries circumscribing parts of the Yucatán Peninsula and into the Gulf of Mexico. This layer has been dated at 66.043 Ma.