Valcouroceratidae

From Palaeos.org

The Valcouroceratidae were mostly breviconic (short-shelled) oncocerid cephalopods from the Middle to Upper Ordovician. In mature individuals, bladelike lamellae called actinosiphonate deposits developed within the siphuncle (Sweet 1964).

Characteristics (from Sweet 1964): Exogastric cyrtocones and brevicones with ventral, actinosiphonate siphuncle; conch changes during ontogeny from compressed to depressed or subtriangular section.

Taxonomy

<==Valcouroceratidae
   |--Actinomorpha Flower 1943 S64
   |    `--*A. pupa Flower 1943 S64
   |--Augustoceras Flower 1946 S64
   |    `--*A. shideleri Flower 1946 S64
   |--Kindleoceras Foerste 1924 S64
   |    `--*K. reversatum Foerste 1924 S64
   |--Manitoulinoceras Foerste 1924 S64
   |    `--*M. lysander (Billings 1865) [=Cyrtoceras lysander] S64
   |--Minganoceras Foerste 1938 S64
   |    `--*M. subturbinatum (Billings 1857) [=Cyrtoceras subturbinatum] S64
   |--Staufferoceras Foerste 1932 S64
   |    `--*S. featherstonhaughi (Clarke 1897) [=Cyrtoceras featherstonhaughi] S64
   |--Valcouroceras Flower 1943 S64
   |    |--*V. bovinum Flower 1943 S64
   |    `--V. elongatum Flower 1952 P68
   `--Fayettoceras Foerste 1932 S64
        |--*F. thompsoni (Miller 1894) [=Cyrtoceras thompsoni] S64
        |--F. beloitense Foerste 1932-1933 P68
        `--F. canyonense Foerste 1935 P68

* Type species of generic name indicated

References

Purnell, L. R. 1968. Catalog of the Type Specimens of Invertebrate Fossils. Part I: Paleozoic Cephalopoda. United States National Museum Bulletin 262: 1-198.

Sweet, W. C. 1964. Nautiloidea – Oncocerida. In Treatise on Invertebrate Paleontology pt. K. Mollusca 3. Cephalopoda – General Features – Endoceratoidea – Actinoceratoidea – Nautiloidea – Bactritoidea (R. C. Moore, ed.) pp. K277-K319. The Geological Society of America and the University of Kansas Press.

Credits

Christopher 22:46, 14 January 2011 (UTC)