The shallow water sea anemone Phymanthus crucifer exhibits
three distinct morphotypes, characterized by the presence or absence of
protuberances on the marginal tentacles, as well as intermediate forms. The
taxonomic status of the different morphotypes and the diagnostic value of
protuberances on the tentacles have been debated for this species and the
family Phymanthidae. We analysed the external and internal anatomy, cnidae
and three mitochondrial molecular markers for representatives of each of the
three morphotypes. In addition, we address the putative monophyly of the
family Phymanthidae based on molecular data. With the exception of the
protuberances, our morphological and molecular results show no differences
among the three morphotypes; thus, we consider this feature to be
intraspecific variability within P. crucifer. Furthermore,
molecular data reveal that the family Phymanthidae is not monophyletic. In
addition, we discuss several diagnostic morphological features of the family
Phymanthidae.
