A recent discovery of dinosaur footprints in southern Italy may disprove a conventional theory which held that southern Italy was a group of islands during the Cretaceous. Instead, according to Alfonso Bosellini, a professor at the University of Ferrera, this land was likely connected to northern Africa.
Earlier this year Bosellini and his team of students discovered about sixty dinosaur footprints in early Cretaceous sediments in southern Italy, in a cave near San Giovanni Rotondo, an area of the country that is commonly referred to as 'the boot's spur.' These tracks, several of which neared 18 inches long, were believed to be made by an Iguanadon, or another mid-sized early Cretaceous plant eater. Iguanadon, which was first discovered in England by early paleontologist William Buckland, was a herbivorous dinosaur which lived about 130 million years ago. A typical Iguanadon was about nine meters (29 feet) long and five meters (17 feet) tall at the hips.
Conventional tectonic and paleogeographical theories tell us that the area that now comprises southern Italy was an archipelago, or chain of volcanic islands, during the early Cretaceous, about the time the land rose from the sea. A current example of an archipelago is the U.S. island chain of Hawaii. It was thought that southern Italy once resembled Hawaii, but only larger.
According to Bosellini, the size of the prints are too large to represent an island-dwelling dinosaur species. A principle of biology is that dwarfism usually occurs on islands, making animals smaller, but the prints of this Iguanadon approached 18 inches, a typical size for Iguanadon species already known that were found on the continents of Europe and North America, both of which were mostly large landmasses during the Cretaceous. Also, Bosellini says, these 60 prints resemble another trackway discovered in northern Africa. After a long research project, Bosellini has concluded that southern Italy was likely connected to the main continent of Africa during the early Cretaceous.
This theory makes sense to plate tectonic experts because the modern day country of Italy is not part of the European plate, as many assume, but rather part of the African plate. Because of the formation of the Mediterranean sea over part of the African plate, the landmass of Italy was somewhat isolated from the main continent of Africa. But, about 85 million years ago, this outlet of the African plate pushed into Europe, causing a massive mountain-building process. This process continues today, and is responsible for the tall peaks of the Alps Mountain range, which occurs along the point where Italy crashed into Africa.
Earlier this decade a dinosaur trackway was discovered in late Cretaceous sediments in the town of Rovereto in northern Italy. Unlike the Iguanadon tracks, these northern tracks were likely made by small and fast moving predatory dinosaurs. The typical print length of these northern prints is about six inches long, only about a third of the Iguanadon tracks. It is unknown how these prints, which have been studied by the Trento, Italy Museum of Natural Science, relate to their slightly older southern cousins.
Bosellini plans to continue his project, and a published paper is due out shortly.
© 1997 brusatte@theramp.net
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