minima within Craspedida based on partial 28S rRNA sequences excluding the fast evolving divergent D2 region using MrBayes. Posterior probability and bootstrap values above 0.5 and 50 are shown. Scale bar represents 0.1 mutations per position. Values above 0.99 and 99 are presented as bold face branches. Scale bar represents 0.1 mutations per

position. Amoebidium parasiticum (Ichthyosporea) was used as outgroup representative. Cultivation and morphology Choanoflagellate cultures were maintained under oxic conditions. The culture development in both strains was similar during the first 4–6 days after inoculation to fresh medium, though strain IOW94 proliferated one to two days slower under the same conditions, and tends to aggregate to clumps of bacteria. On days 2 to 3, strains demonstrated solitary cells on a stalk of different lengths (Figures 5, 6). On days 3 to Selleckchem I-BET151 4, the development of two-cell colonies appeared (Figure 6A). Such colony types were common for IOW73, and are also typical for Codosiga

gracilis de Saedeleer, 1927 (basionym Monosiga gracilis Kent, 1880), but with larger cell dimensions. Strain IOW94 normally produced 2–4 cell colonies, though occasionally largely colonies were formed. Figure 5 Codosiga balthica n. sp. strain IOW94. Light (A) and transmission ZD1839 manufacturer electron (B-G) micrographs. A. Single cell on the stalk (st), living material under phase contrast. Arrowheads selleck chemicals show the whiskers. B. Longitudinal section through the cell covered with delicate sheath (arrowheads); insert: enlarged mitochondria of class 1 (m1) with tubular/saccular cristae. C. Cytoplasm at cell posterior filled with endobiotic bacteria. D–E. structure of large flagellated bacteria with flagellar at cross section (D) and longitudinal section (E). F. mitochondria class 1 (m1) with tubular/saccular cristae. G. mitochondria class 2 (m2) structure with tubular cristae and lipid globule association with bfb. Scale bars: A – 3 μm, B – 1 μm, C-F – 200 nm, G – 400 nm. Figure 6 Codosiga minima n. Myosin sp. strain IOW73. Light (A) and transmission electron (B-G) micrographs. A. Single cell and two-cell colony

with a stalk (st), living material under phase contrast. B. Longitudinal section of the cell, arrowheads show a delicate sheath around the cell body and proximal part of collar microvilli (mv). Insert upper right: transversal section through the collar with food vacuole (fv) with bacterium at outer side of the collar. Insert down left: two mitochondrial profiles with tube-like cristae (arrows). C. Longitudinal section of feeding cell in the colony: pseudopodium (ps) arises from the neck. D. Longitudinal section of flagellar kinetosome (kn) with one row of radiating microtubules (arrows). Scale bars in A = 4 μm, B (+ upper insert), C = 2 μm, B (down insert), D = 500 nm. Strain IOW94 was present as sedentary stalked solitary cells and as colonies.