FIGURE 11 in Two new species of Australoheros (Teleostei: Cichlidae), with notes on diversity of the genus and biogeography of the Río de la Plata basin

FIGURE 11. Phylogeny of all valid and one putative species of Australoheros based on 38 morphological characters. Ottoni and Costa (2008), Ottoni et al. (2008), Ottoni and Cheffe (2009) and Ottoni (2010) have diagnosed the Brazilian coastal species by a unique combination of 14 + 12 vertebrae. Our examination of material from some of the drainages (see Figs E and F) instead shows a combination of 13 + 13 vertebrae, which is not unique among Australoheros. Our phylogenetic analyses have thus been performed with both combinations (14 + 12 in Figs A and B; 13 + 13 in Figs C – F). The three upper Figs (A, C, E) show maximum parsimony (MP) topologies, the lower three show neighbour joining (NJ) topologies (with branch lengths showing amount of morphological divergence; B, D, F). Numbers at nodes show bootstrap support. Bold black nodes and branches show agreement between all analyses (MP and NJ separately), bold grey nodes and branches agreement between two of three analyses. The interrupted-line boxes show the relationships and branch lengths among the northern Brazilian coastal species. Notable is the collaps of their relationships under the 13 + 13 scenario (Figs C – F) and the markedly short branches separating these species (Figs B, D, F). The short branches separating these species are much more similar to intraspecific variability among other species of Australoheros (grey boxes in Fig. F) than to interspecific branch lengths (grey-line boxes in Fig. F). This low differenciation of the northern Brazilian coastal species is also evident from Fig. E, where the morphological matrix (Appendices 1 and 2) is mapped onto the phylogeny (geographical distribution of the species is also shown). Most species, with the exception of the northern Brazilian coastal species, are diagnosed by unique characters or unique combinations of characters. The average number of changes among interspecific pairs described by Říčan and Kullander (2003, 2008, this study) is 98.5, while among intraspecific comparisions it is 20.7. The average for comparisons among the species described by Ottoni and Costa (2008), Ottoni et al. (2008), Ottoni and Cheffe (2009) and Ottoni (2010) is 20.5, i.e. corresponding to variation within species of Říčan and Kullander (op. cit.). Based on these considerations we believe that the number of described species from the northern Brazilian coastal drainages is a case of excessive splitting and that the species diversity is actually much lower.