TY - JOUR
T1 - Cephalopod origin and evolution
T2 - A congruent picture emerging from fossils, development and molecules: Extant cephalopods are younger than previously realised and were under major selection to become agile, shell-less predators
AU - Kröger, Björn
AU - Vinther, Jakob
AU - Fuchs, Dirk
N1 - Copyright © 2011 WILEY Periodicals, Inc.
PY - 2011
Y1 - 2011
N2 - Cephalopods are extraordinary molluscs equipped with vertebrate-like intelligence and a unique buoyancy system for locomotion. A growing body of evidence from the fossil record, embryology and Bayesian molecular divergence estimations provides a comprehensive picture of their origins and evolution. Cephalopods evolved during the Cambrian (∼530 Ma) from a monoplacophoran-like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus. During the mid-Palaeozoic (∼416 Ma) cephalopods diverged into nautiloids and the presently dominant coleoids. Coleoids (i.e. squids, cuttlefish and octopods) internalised their shells and, in the late Palaeozoic (∼276 Ma), diverged into Vampyropoda and the Decabrachia. This shell internalisation appears to be a unique evolutionary event. In contrast, the loss of a mineralised shell has occurred several times in distinct coleoid lineages. The general tendency of shell reduction reflects a trend towards active modes of life and much more complex behaviour.
AB - Cephalopods are extraordinary molluscs equipped with vertebrate-like intelligence and a unique buoyancy system for locomotion. A growing body of evidence from the fossil record, embryology and Bayesian molecular divergence estimations provides a comprehensive picture of their origins and evolution. Cephalopods evolved during the Cambrian (∼530 Ma) from a monoplacophoran-like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus. During the mid-Palaeozoic (∼416 Ma) cephalopods diverged into nautiloids and the presently dominant coleoids. Coleoids (i.e. squids, cuttlefish and octopods) internalised their shells and, in the late Palaeozoic (∼276 Ma), diverged into Vampyropoda and the Decabrachia. This shell internalisation appears to be a unique evolutionary event. In contrast, the loss of a mineralised shell has occurred several times in distinct coleoid lineages. The general tendency of shell reduction reflects a trend towards active modes of life and much more complex behaviour.
U2 - 10.1002/bies.201100001
DO - 10.1002/bies.201100001
M3 - Article (Academic Journal)
C2 - 21681989
SN - 1521-1878
VL - 33
SP - 602
EP - 613
JO - BioEssays
JF - BioEssays
IS - 8
ER -