Patterns of morphological evolution in major groups of paleozoic temnospondyli (Amphibia: tetrapoda)

Ruta, Marcello (2009) Patterns of morphological evolution in major groups of paleozoic temnospondyli (Amphibia: tetrapoda). In: Patterns and Processes in Early Vertebrate Evolution. Special Papers in Palaeontology (81). Wiley-Blackwell / Palaeontological Association, Oxford, pp. 91-120. ISBN 9781405199209

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Abstract

A maximum parsimony analysis of a data
matrix including 42 temnospondyl species and 14 outgroup
species coded for 246 characters results in eight
shortest trees. Temnospondyls emerge as two distinct radiations:
one includes edopoids and eryopoids-basal archegosauriforms;
the other includes dissorophoids and
dvinosaurs. Both receive low statistical support. The
branching pattern of dissorophoids remains elusive and is
obscured by recurrent homoplasies. The two Micropholis
morphs appear as sister taxa near the base of the dissorophoid
clade. Perryella is either placed as sister taxon to
dvinosaurs or nested within them. Temnospondyls such as
the genera Balanerpeton and Dendrerpeton occur close to
the node that subtends the dvinosaur–dissorophoid separation.
Disparity analysis using Principal Coordinate Analysis
of both Manhattan and Euclidean intertaxon distance
matrices reveals that all major temnospondyl groups are
widely separated in morphospace. Levels of disparity are
comparable in the various clades examined, but the
dvinosaurs tend to be morphologically more diverse than
other groups when variance-derived metrics are used. For
range-derived metrics, dissorophoids are more disparate
than other groups. Overall disparity is similar in
edopopids and eryopoids-basal archegosauriforms, as is in
dissorophoids and dvinosaurs. However, the latter two
groups are invariably slightly more disparate than the
former two.

Item Type:Book Section
Additional Information:A maximum parsimony analysis of a data matrix including 42 temnospondyl species and 14 outgroup species coded for 246 characters results in eight shortest trees. Temnospondyls emerge as two distinct radiations: one includes edopoids and eryopoids-basal archegosauriforms; the other includes dissorophoids and dvinosaurs. Both receive low statistical support. The branching pattern of dissorophoids remains elusive and is obscured by recurrent homoplasies. The two Micropholis morphs appear as sister taxa near the base of the dissorophoid clade. Perryella is either placed as sister taxon to dvinosaurs or nested within them. Temnospondyls such as the genera Balanerpeton and Dendrerpeton occur close to the node that subtends the dvinosaur–dissorophoid separation. Disparity analysis using Principal Coordinate Analysis of both Manhattan and Euclidean intertaxon distance matrices reveals that all major temnospondyl groups are widely separated in morphospace. Levels of disparity are comparable in the various clades examined, but the dvinosaurs tend to be morphologically more diverse than other groups when variance-derived metrics are used. For range-derived metrics, dissorophoids are more disparate than other groups. Overall disparity is similar in edopopids and eryopoids-basal archegosauriforms, as is in dissorophoids and dvinosaurs. However, the latter two groups are invariably slightly more disparate than the former two.
Keywords:Carboniferous, characters, clades, disparity, Permian, phylogeny, Temnospondyli
Subjects:C Biological Sciences > C300 Zoology
C Biological Sciences > C182 Evolution
F Physical Sciences > F641 Palaeontology
C Biological Sciences > C181 Biodiversity
Divisions:College of Science > School of Life Sciences
ID Code:6436
Deposited By: Marcello Ruta
Deposited On:05 Oct 2012 08:41
Last Modified:13 Mar 2013 09:15

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