Oncoceratidae

From Palaeos.org

Jump to: navigation, search
m (Protected "Oncoceratidae" ([move=sysop] (indefinite)))
Line 1: Line 1:
 +
As defined by Sweet (1964), the Oncoceratidae is ancestral to a number of other oncocerid families; indeed, the oncoceratid lineage probably survives to the modern day in the Nautilidae. The Oncoceratidae excluding the descendant families were mostly cyrtoconic.
 +
 +
'''Characters''' (from Sweet 1964): Exogastric, ventromyarian brevicones and cyrtocones; siphuncle empty, on ventral side of chamber. Siphuncles suborthochoanitic and cylindrical in early stages of early forms, cyrtochoanitic with expanded segments in later stages and later forms. Connecting rigns thin. Conch usually compressed, few species with circular or depressed section. Actinosiphonate deposits in a few advance forms.
 +
 +
==Phylogeny/TAxonomy==
  [[Oncocerida|<==]]Oncoceratidae [Maelonoceratidae, Melonoceratidae, Ooceratidae, Oocerinidae, Oonoceratidae, Rizoceratidae]
  [[Oncocerida|<==]]Oncoceratidae [Maelonoceratidae, Melonoceratidae, Ooceratidae, Oocerinidae, Oonoceratidae, Rizoceratidae]
     |--+--[[Brevicoceratidae]] S64
     |--+--[[Brevicoceratidae]] S64

Revision as of 12:29, 18 January 2011

Personal tools