Figure 1.
Bayesian phylogeny of the SSU rDNA sequences obtained from the collodarians.
Four novel collodarian sequences and two environmental sequences (<3 µm) are shown in bold and light gray text, respectively. Family names are shown to the right of the black bars. Numbers on nodes indicates posterior probabilities of the Bayesian method and bootstrap values of the ML analysis. Scale bar at lower left shows 0.1 substitutions per site for the Bayesian analyses.
Figure 2.
Divergence times among 12 collodarian sequences, based on the estimation of the partitioned Bayesian approach.
Estimated divergence ages (million years ago) are shown at the root of each node. Gray shaded boxes on the nodes indicate 95% credible intervals. Star symbols represent the first appearance dates of Collosphaeridae and Collozoidae, as inferred from the fossil record [20], [21].
Table 1.
Morphological features of collodarian species and family.
Figure 3.
Schematic evolutionary model of Collodaria compared in relation with paleoceanographic environmental changes.
(a) The black line shows the change of paleotemperature calculated from the stable oxygen isotopic (∂18O) values of the benthic foraminifera from the Eocence to recent [50]. The vertical bars indicate the presence of ice sheets and icebergs in each hemisphere, with the solid bar representing permanent presence of ice-sheets and the dash bar representing ephemeral presences [50], [51]. Two key geological events associated with the discussion are enclosed in the boxes [25]–[28], [31]–[34]. (b) Schematic evolutionary model of Collodaria and their divergence times. The estimated divergence time were shown on the nodes. Pictures on the tree represent schematic models of each collodarian cell characteristic. Abbreviations: Colloz, Collozoidae; Colloph, Collophidae; Collosph, Collosphaeridae; Thalla, Thalassicollidae. Each schematic cell structure is shown on the evolutionary tree.
Table 2.
Sample IDs and sampled locations.
Table 3.
Sequences used for phylogenetic analysis.