Jh. Won et al., A phylogenetic study of the Anthozoa (phylum Cnidaria) based on morphological and molecular characters, CORAL REEF, 20(1), 2001, pp. 39-50
The phylogenetic relationships within the Anthozoa were re-evaluated based
on 41 morphological characters and nuclear sequences of 18S ribosomal DNA (
29 anthozoans as ingroups and 3 hydrozoans as outgroups). The parsimony tre
es derived from the morphological data did not coincide closely with the mo
lecular data, and the presence of several polytomies at some nodes of the t
rees resulted in ambiguities among the systematic relationships. On the oth
er hand, the combined analysis using total evidence presents a more resolve
d and highly supported topology, as is indicated by higher bootstrap values
and decay indices than either analysis alone. However, strict and semi-str
ict consensus trees derived from taxonomic congruence show a poorer resolut
ion for the phylogeny of Anthozoa. The trees constructed from the molecular
data, using neighbor-joining and maximum-likelihood methods, are nearly co
ngruent with the result from the total evidence. Based on these results, An
thozoa is divided into three subclasses: Alcyonaria, Zoantharia, and Cerian
tipatharia. The Ceriantipatharia now includes only one order, Ceriantharia,
since the order Antipatharia is more closely related to orders within the
Zoantharia. The Alcyonaria is a monophyletic group, in which the order Penn
atulacea is basal, and orders Alcyonacea and Telestacea branch later. The o
rder Gorgonacea is divided into two suborders, Holaxonia and Scleraxonia. B
ellonela is more related to order Stolonifera, forming a monophyletic group
. In Zoantharia, the order Zoanthinaria is basal, and the remaining taxa ar
e divided into two clades: one includes the order Actiniaria and the other
includes orders Antipatharia, Corallimorpharia, and Scleractinia. The latte
r two orders form a monophyletic group. This study presents a different phy
logeny of actiniarians from the earlier hypothesis of scleractinian ancestr
y.