WHITE PROCHELONICERAS AMMONITE SEA FOSSIL FROM THE CRETACEOUS OF NORTH AFRICA

Agadir, Morocco

MIDDLE CRETACEOUS PERIOD:  112 - 99.6 million years ago

This attractive ammonite is a member of the Procheloniceras species of Cretaceous ammonites from the coastal village of Agadir, Morocco.  Because of the stubbornness of the matrix and difficulty in removing it from the fossil, usually, these fossil ammonites need to be partially ground or reshaped during the preparation process.  This nice specimen shows natural original surface pigmentation and untouched chamber detail on the back side with other small ammonite impression in the rock.  It is in a larger than typical size and makes for an impressive yet, reasonably affordable specimen for its dimension and beautiful appearance.  Untouched side detail would make a great specimen for educational display.

Ammonites are extinct members of the Cephalopod class.  Modern members include nautilus, squid and octopus.  They first appeared during the Silurian Period (435 million to 410 million years ago) and were abundant and widespread in the seas of the Jurassic and Cretaceous periods (175 million to 65 million years ago).  Ammonites are important index fossils—that is, they often link the rock layer in which they are found to specific geological time periods.

Ammonites varied greatly in size.  The largest known as small as 2 cm (0.75 in) in diameter.  During the Jurassic and Cretaceous periods, ammonites evolved more streamlined shells for swimming and the structure of the shell became stronger.  Different shell shapes emerged as well, such as snail-like or uncoiled.   

The shells of ammonites had hollow chambers separated by walls called septa.  A tube called the siphuncle, connected the body with the chambers allowing the animal to fill them with water or air, changing its buoyancy in order to  rise or drop in the ocean.  Only the last and largest chamber was occupied by the living animal.  

Ammonites probably lived for one to six years, with the majority living two to four years.  They fed on plankton (tiny free-floating organisms), sea lilies, and smaller orthoceras.  Although many fed off the ocean floor, others may have caught plankton while floating or swimming via jet propulsion, expelling water through a funnel-like opening to propel themselves in the opposite direction.

Because ammonites lived exclusively in marine environments, their presence also indicates the location of prehistoric seas.

COMMON SPECIES BUT UNCOMMON WITH NATURAL PIGMENT AND CHAMBER DETAIL ON BACK SIDE

7.25" wide

SOLD     AM11X1     INCLUDES STAND     Actual Item - One Only

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