Scaphites Ammonite Fossil Unrolled Sea Shell Prehistoric Cretaceous Collection (2)

Description

Origin : Madagascar

Geological era : Lower Cretaceous (Albian)

Age : 110 million of years

Size : 34 gr - cm 4 x 3.3 x 2.2

Ammonite Fossil Heteromorphic Seashell mm 40 x 33 x 22 gr 34 Scaphites equalis Extinct Prehistoric Molluscs Cephalopod Mesozoic Cretaceous Collecting Paleontology Museum.

Interesting fossil sample of Heteromorphic Ammonite (with unrolled shell) from the Lower Cretaceous, a representative collectible find of fair quality, with evident and appreciable details of the unwrapped coils and the ornamental ribs.
No restored at all. Only a piece, as in photos.

Scaphites is a genus of Cephalopod Molluscs belonging to the Ammonidea. Unlike most of the Ammonites, it had a shell uncoliled. He lived between the lower and upper Cretaceous (between 110 and 94 million years ago). Its remains are found in much of the world, particularly in Europe (England, France) and in North America.
The appearance of this small ammonite was definitely curious: the shell was in fact partially coiled, with a front U-shaped, thick and swollen, with a particular symmetry. The general form is called scafitoid (from the name of this animal) and presented the first turn coil closely umbilicated; subsequent rounds, however, were unrolled in a slightly curved stick and, in the end, it fell back to the starting point.
The ornamentation of this ammonite was made up of smooth or ribbed collated with knots; the region of the stick has less dense ornamentation. The head of the animal, probably protruded from the shell with a considerable angle.
Like other ammonites of the Cretaceous, Scaphites presented a regressive form, both as regards the spiralizzation both for sutures simplified. Because of the particular shape of the shell, it seems that this ammonite was not able to exercise an active swimming, probably filled with water the various rooms to go up or down along the water column, leading a kind of planktonic life.
It is possible that Scaphites was closely related to other warned of more traditional look, as Kosmoceras. Other Ammonites uncoiled, with look vaguely similar (Macroscaphites, Ancyloceras) may not have been close relatives of Scaphites.

The Ammonites are an extinct group of Cephalopods, which appeared in the Lower Devonian about 400 million years ago and extinguished at the end of the Cretaceous, together with the Dinosaurs (65 million years ago), leaving no known descendants. Like all cephalopods known this organisms were carnivorous: active predators of marine animals, microphagous (plankton), scavengers, and even cannibals. The shell of ammonites in general has the form of a spiral wound on a plan (although some species, such heteromorphy, have a more complex three-dimensional winding) and it is this feature that has given their name. The appearance infact resembles a coiled horn, like that of a ram (the Egyptian god Amon was commonly depicted as a man with ram's horns). Pliny the Elder described the fossils of these animals ammonis cornua, "horns of Ammon." Often the name of the species of Ammonites ends with -ceras, from a greek word (κέρας) whose meaning is, in fact, "horn" (eg. Pleuroceras etymologically means horn with the coast).
The shell was divided by septa into several rooms, including the clam occupied only the last. The others were used as "air chambers" filled with gas and liquid to control the floating body. The ammonite could well change its depth in a manner similar to the current Nautilus.
Because of their extraordinary variability and distribution in marine sediments around the world the ammonites are considered fossils for excellence and guide-fossils of exceptional value, used for dating in stratigraphy of the sedimentary rocks.
The classification of ammonites is made on the basis of morphology and ornamentation of the shell, and the shape of septa, depending on the suture line.