Sign In


Products
   Fossils
     Ammonites
       Ammonites - England
       Ammonites - Madagascar
       Ammonites - South Dakota
         Acanthoscaphites
         Conglomerate
         Didymoceras
         Hoploscaphites
         Jeletzkytes
         Menuites
         Placenticeras costatum
         Placenticeras intercalare
         Placenticeras meeki
         Prionocyclus wyomingensis
         Sphenodiscus
         Rhaeboceras
         Trachyscaphites
         Eutrephoceras
       Ammonites - Russia
       Ammonites - Unknown location
     Trilobites
     Fossil Sets
     Other
     Wood
     Plants
     Copal
     Baculites
     Bivalves
     Original Casting Fossils
     Coprolites
     Teeth
     Bone
     Gastropods
     Blastoid plates
   Replicas
   Clothing
   Jewelry
   Fluorescent Minerals & Equipment
Brazil calcite and quartz
Perchoerus - peccary
Illinois
Dinosaur Eggshell
Crocodile teeth
Trematochamsid crocodile
Ginglymostoma moroccanum
Media
Brachiopods
Fossil Egg Shell
Echinoids
Echinoderms
Coral
Nautiloids
Elrathia kingii - fossil trilobite
Phacops
Bivalves - France

Prionocyclus was a cephalopod. Cephalopods are the most highly developed of the mollusks. They were carnivorous and at the top of the mollusk food chain. They possessed a distinct, well defined head and a circlet of eight or more arms. They used a funnel-like opening, called a hyponome, to eject water through, in order to propel themselves backwards or for turning side to side. They are fairly common as fossils and are used as index fossils to identify regional and international layers of rock.

The Class Cephalopoda is broken down into three subclasses: Nautiloidea, Ammonoidea, and Coleoidea. The representatives of the first two subclasses have and external shell. The representatives of the last subclass do not have a an external shell and are represented by only a few fossils(octopi and squip today). The most common differences between Nautiloidea and Ammonoidea are that the septum wall and suture pattern of the nautiloids is straighter or only gently curved, while those of the ammonoids are much more complex. Secondly, the siphuncle is usually centrally located on the septum wall for the nautiloids and is located towards the internal part of the coil for ammonoids. The siphuncle is the tube between the septum walls that allows the shell to be filled with gas or water, allowing the animal to raise or lower itself in the water.

Prionocyclus is characterized by a disc shape, it is compressed slightly, and has flattened sides. The whorls overlap only slightly. It has a large unbilicus (evolute). The venter, outside edge, is broad with a narrow keel in the center that is continuous and not bumpy. The ribs are well developed and are irregular in size and length, bending towards the front as they reach the keel.

Even though the age of Prionocyclus is given as Middle to Late Cretaceous, it is found only in a single stage within that period (the Turonian Stage), which lasted only a few million years. Therefore, when Prionocyclus is found, the age of the rocks can be identified with remarkable precision.

The following is the classification breakdown for Prionocyclus wyomingensis: Kingdom: Anamalia, Phylum: Mollusca, Class: Cephalopoda, Subclass: Ammonoidea, Order: Ammonitida, Family: ?, Genus: Prionocyclus, Species: wyomingensis.

Robust form.

This specimen is being offered from a private collection!

Prionocyclus wyomingensis
 
<i>Prionocyclus wyomingensis</i> Quantity in Basket: None
Code: FA-300
Price: $1,125.00
Shipping Weight: 3.67 pounds
 
 
Quantity:
 
Time: Upper Cretaceous, Turonian Member, approximately 94 million years ago.
Location: Carlile Shale, South-West South Dakota
Dimensions: 8-3/8 inches



Ecommerce Shopping Cart Software by Miva


Ecommerce Shopping Cart Software by Miva