Fig. 2.

Phylogenetic relationships among 55 Foraminifera inferred from partial small subunit rDNA sequences, including representatives of all groups shown in Fig. 1, as well as 3 members of the genus Ammodiscus, 7 members of the order Miliolida, and 2 members of the order Spirillinida. Because of the high divergence of the SSU rDNA sequences in the three latter groups, 500 unambiguously aligned positions were kept in phylogenetic analyses for this dataset. The topology shown was obtained with the ML method by using the F84 substitution model. Because the exact position of the root is yet unclear, the tree is drawn with a basal trichotomy. Representatives of the genus Ammodiscus and the orders Miliolida and Spirillinida form a clearly monophyletic group, but their placement as a sister group to Psammosphaera sp. is not supported. Due to the reduced number of analyzed positions, the resolution among the other groups of Foraminifera is weaker than in Fig. 1. The bootstrap support values >80% for NJ and ML analyses are indicated at internal nodes.