Taxonomy, phylogeny and biogeography of the marine sponge genus Rhabderemia Topsent, 1890 (Demospongiae, Poecilosclerida)
R.W.M. Van Soest, J.N.A. Hooper

The predominantly tropical-subtropical sponge genus Rhabderemia Topsent, 1890. is revised following examination of an almost comprehensive series of type and other published specimens. The generic names Rhabdosigma Hallmann, 1916, Hallmannia Burton, 1931, Nisibaris de Laubenfels, 1936, and Stylospira de Laubenfels, 1934, are considered junior synonyms of Rhabderemia, although the last of these may be a valid (sub-) generic sister group to Rhabderemia s.s. A reexamination of the widespread “species” Rhabderemia “minutula”/R. “pusilla” and R. “coralloides” revealed six new species: R. africana, R. antarctica, R. burtoni, R. gallica, R. topsenti, and R. uruguaiensis, most of which were hidden under incorrectly assigned specimens of previously described species. A further new species, R. destituta, was found in East-Pacific material conforming to the nominal genus Stylospira de Laubenfels. A total of 26 species is now recognized and each of them is diagnosed and discussed. Hypothesized phylogenetic relationships of the members of Rhabderemia are proposed on the basis of a morphological character analysis aided by the use of phylogenetic computer programs. Biogeographic observations are made from an areagram based on the Rhabderemia phylogeny. Frequent extinction events during the evolution of the genus, since at least the Oligocene, may explain the inferred disjunct sister-group distributions.

Keywords: Taxonomy, phylogeny, biogeography, marine sponges, Poecilosclerida, Rhabderemia
Contents of this volume Sci. Mar. 57(4) : 319-351 Back PDF
 
 
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