UNCOMMON ANDROGYNOCERAS AMMONITE IN MATRIX

Braunschweig, Germany

EARLY JURASSIC PERIOD (LIAS):  206 - 180 million years ago

This unique Androgynoceras maculatum ammonite specimen was collected during the construction of a highway near Braunschweig, Germany.  The layer where this specimen was found was exposed during the site excavation.  This is a unique and rare opportunity to acquire a specimen such as this as the layer is not accessible to collecting outside of such a project and these fossils are not mined nor available in any ordinary commercial manner.  Nice overall size and aesthetic preparation.  NO REPAIR AND NO RESTORATION.

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.

NICE OVERALL SIZE FOR DISPLAY OF THIS UNCOMMON TYPE AND SITE - RARE!

3.75" x 3.25" overall with matrix, ammonite 1.5" in width

$95     AMX-140    Actual Item - One Only

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