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.