2013-12-10 17:14:54
About fifteen million years ago, in the middle of the Miocene, the level of the Mediterranean sea rose sharply, and the Gargano Promontory and its surroundings became an island or a group of islands in the Adriatic. The Gargano Promontory is the mountainous cape that forms the spur of the boot of Italy. The climate on the rocky island of Gargano was semi-arid, with herbaceous or shrubby vegetation, dotted with small trees. As in many islands, in the past and in the present, a very particular fauna lived in Gargano, different from that of the mainland.
The oldest inhabitants of the island of Gargano were not very different from their relatives on the mainland. There were mice, dormouse, hamsters, shrews, and gymnuros. Giant, furry rat-like relatives of the hedgehog, gymnuros are found today only in the jungles of Southeast Asia, but during the Miocene their range was wider, and they were abundant in Europe. There were also pigeons, swifts, owls, sandpipers, woodpeckers, ibis, ducks and small birds of prey in Gargano, as well as lizards, snakes, turtles and crocodiles, probably the last crocodiles in Europe.
With the passage of time, all the species that also live on the continent will disappear from Gargano, except for a field mouse that survived until the end. At the same time, the specific species of the island were evolving, almost all of them increasing in size until they became true giants. Although it wasn’t always that simple; sometimes large and small species coexisted at the same time, and in other cases, evolutionary lineages bifurcated, and while some species grew, others evolved adapting to changes in the environment, but without increasing in size.
Many endemic Gargano rodents grew over time: the Hattomys giant hamster reached two feet in length, while the Stertomys giant dormouse, with thick molars adapted to a harsh and abrasive diet, reached two feet in length. The largest specimens of the Mikrotia burrowing mouse, meanwhile, had skulls four inches long.
Pikes were also abundant in Gargano. Pikas are relatives of rabbits, with short legs and ears, and no tail, that live in cold climates in Eurasia and North America. Until recently, a family of giant pikes existed around the Mediterranean; the last, the Sardinian pike, which measured up to 25 centimeters in length, became extinct in the 17th century. XVIII; the first settlers of that island considered it a delicacy. Gargano pikes belong to two species, and one of them, Prolagus imperialis, is even larger than the Sardinian pike. Like the giant dormouse Stertomys, Prolagus imperialis has very thick and complex molars, adapted to an abrasive diet.
One of the largest mammals on Gargano is the giant gymnuro Deinogalerix. There were five species. The largest of the five has a skull eight inches long, with a long, narrow snout, strong, sharp incisors, and large premolars for crushing. The structure of the jaw indicates that it is capable of opening its mouth at a fairly large angle and that it can close it abruptly and forcefully. The total length of Deinogalerix exceeds two feet; it was bigger than the biggest living gymnuro. Deinogalerix’s legs are short and strong and the tail is long and bare, like a rat’s. It is probably a scavenger, or perhaps a predator specializing in the capture of fish and crustaceans, or small mammals, birds, and reptiles. The smaller species are insectivorous.
As is the case on many islands, predatory mammals were rare on Gargano. Apart from Deinogalerix, only the very rare fossil remains of a coastal otter have been found, somewhat larger than its mainland relatives, and specialized in eating molluscs.
Gargano’s big predators are birds. The Garganoaetus eagle, related to the booted eagle, is the size of a golden eagle: one meter long and two meters wide. There are also two owls, descendants of the giant owl Tyto balearica, weighing three kilos and having a wingspan of more than a meter and a half, which lived in the Iberian Peninsula, southern France, the Balearic Islands, Corsica and Italy. But the two Gargano’s owls, Tyto robusta and Tyto gigantea, got even bigger. The last, and also the most recent, Tyto gigantea, at 75 centimeters in length, was larger than an eagle owl, which can reach a wingspan of 1.7 meters. As still happens today, the eagle and the owls shared the hours of activity. The Garganoaetus eagle hunts during the day; owls, which probably nest on the ground, or in crevices between rocks, do so at night.
Some birds, as frequently occurs on islands, in the absence of terrestrial predators, have lost the ability to fly. Like Garganornis, a goose weighing 15 to 20 kilos and two meters in length, bigger than a swan.
But the most spectacular inhabitant of Gargano is a ruminant. A ruminant that has forced paleontologists to create a family for itself, since it does not fit into any of the ruminant families described so far. None of his characteristics are unique on their own, but the combination of him is. It is Hoplitomeryx, an animal with a short, thick snout and five horns on its head: one on the upper part of the snout, between the eyes, and two pairs further back, above the eye sockets. The three innermost horns are longer and curve backwards, while the outermost pair, curved forwards, is shorter. Viewed from the front, the antlers fan out in the shape of a diadem or crown, reminiscent of that of the Statue of Liberty. Hoplitomeryx also has prominent upper fangs, and two lacrimal orifices in each eye. Not a good runner, probably had a goat-like lifestyle. Due to the differences in size between the fossil remains found, it seems that there were four or five species of Hoplitomeryx; two of them were very small; the largest, about the size of a deer or elk, though more slender, had very long legs. Hoplitomeryx was very abundant, and was probably the main prey of the large birds of prey on the island.
But the inhabitants of Gargano are not as isolated as it may seem. Some migratory birds visit the island regularly. Like Palaeortyx, a small galliforme similar to a quail, which breeds in Gargano. There the chicks are born and there they remain, protected from the predators of the mainland, until they learn to fly.
Five and a half million years ago, at the end of the Miocene, the Strait of Gibraltar closed, in what is known as the Messinian salt crisis. Due to the coincidence of a tectonic rise in the region of the strait and a global drop of between 10 and 20 meters in sea level, the Mediterranean was isolated from the Atlantic Ocean, and became a lake. The contribution of water from the rivers could not compensate for evaporation, and the almost complete drying of the Mediterranean occurred. The Gargano islands were attached to the Italian peninsula, and were colonized by continental fauna. It was the end of the animals of Gargano.
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