Calcaronea, Bidder, 1898

Alvizu, Adriana, Eilertsen, Mari Heggernes, Xavier, Joana R. & Rapp, Hans Tore, 2018, Increased taxon sampling provides new insights into the phylogeny and evolution of the subclass Calcaronea (Porifera, Calcarea), Organisms Diversity & Evolution (New York, N. Y.) 18 (3), pp. 279-290 : 286

Phylogeny of Calcaronea using 18S rRNA

The phylogenetic tree obtained with the 18S rRNA dataset showed a low resolution at all taxonomic levels, rendering most relationships inconclusive. This is due to the small number of informative sites in this gene when compared to the Cregion (16.3 vs. 52% variable sites), as also previously found by Manuel et al. (2003; Manuel 2004). This finding together with the larger overlap observed between intra- and interspecific variation further emphasizes 18S as containing very limited phylogenetic information in Calcaronea.