Mollusca

From Palaeos.org

Jump to: navigation, search
m (Systematics: Linnaean methodology self evident)
 
Line 55: Line 55:
Traditionally seven [[class]]es are recognized: [[Aplacophora]] (primitive worm-like shell-less forms), [[Polyplacophora]] (chitons, at one time included with the Aplacophora in the class [[Amphineura]]), [[Monoplacophora]] (primitive ancestral forms), [[Gastropoda]] (snails and slugs), [[Bivalvia]] (clams, mussels, oysters, etc), [[Scaphopoda]] (tooth and tusk shells), and [[Cephalopoda]] (squids, octopus, nautilus, cuttlefish), of which only Gastropoda, Bivalvia, and Cephalopoda have large numbers of species and a strong [[fossil record]].  However it is becoming increasingly recognized that there were more groups that have since died out.
Traditionally seven [[class]]es are recognized: [[Aplacophora]] (primitive worm-like shell-less forms), [[Polyplacophora]] (chitons, at one time included with the Aplacophora in the class [[Amphineura]]), [[Monoplacophora]] (primitive ancestral forms), [[Gastropoda]] (snails and slugs), [[Bivalvia]] (clams, mussels, oysters, etc), [[Scaphopoda]] (tooth and tusk shells), and [[Cephalopoda]] (squids, octopus, nautilus, cuttlefish), of which only Gastropoda, Bivalvia, and Cephalopoda have large numbers of species and a strong [[fossil record]].  However it is becoming increasingly recognized that there were more groups that have since died out.
-
With the [[cladistic revolution|falling out of favor of Linnaean methodology]], recent work in molluscan systematics is done via [[phylogenetics|cladistic analysis]]. The following is a recent cladogram showing molluscan relationships.
+
With the falling out of favor of Linnaean methodology, recent work in molluscan systematics is done via [[phylogenetics|cladistic analysis]]. The following is a recent cladogram showing molluscan relationships.
[[Image:Mollusc cladogram.gif]]
[[Image:Mollusc cladogram.gif]]

Latest revision as of 23:14, 8 March 2013

Personal tools