Diagnosis: Sedentary stalked solitary cells which rarely produce colonies of 2–4 cells. Elongated vase-shaped cell with a prominent neck, surrounded by a delicate sheath visible through electron microscopy. Dimensions: body length – 2–3 μm, width – 1 μm, length of the Selleckchem VX770 collar equal to the body, flagellum 1,5-2 times longer than the body, stalk is up to 7 μm. Profiles of the mitochondrial cristae of oval shape. Observed habitat: Gotland Deep and Landsort Deep (central Baltic Sea, IOW station 284, 58°35′N, 18°14′E) suboxic to anoxic water body
(depths see Table 1), facultative anaerobic, brackish (8–16 ‰); Type material: iconotypes: Figure 6B and insertion down left; fixed and embedded specimens (hapantotypes) are deposited at the Oberösterreichische Landesmuseum in Linz, Austria (inventory number 2012/120); live strains (paratypes) are held as clonal cultures (strains IOW73-75) in the laboratory of the Leibniz Institut for Baltic Sea Research in Rostock-Warnemünde; Etymology: minima, due to the small cell
size. Table 1 Isolated strains, with the corresponding isolation depths and physico-chemical data (Gotland (G) and Landsort Deeps (L), central Baltic Sea) and GenBank accession numbers for Selleckchem SP600125 partial gene sequences generated in this study Species Codosiga balthica Codosiga Angiogenesis inhibitor minima Detected via Clone library (G 1) DGGE (G 2, L 3) Isolation (G 4) Isolation (G, L 4) Strain IOW94 IOW73 IOW74 IOW75 Station 271 (G) 271 (G) 271 (G) 284 (L) Depth [m] 206 150 208 260 O2 [μM] 0.85 1.57 0.48 4.23 H2S [μM] 0.13 0.25 1.77 n.det. 18S rRNA JQ034424 JQ034422 n.sub. n.sub. 28S rRNA JQ034425 JQ034423 n.det. n.det. (1Stock et al. 2009 [20]; 2Weber 2008 [37]; 3Anderson et al. [38] (in revision); 4this study; n.det., not detected; n.sub.,
not submitted to GenBank). Remarks. The species described here could easily be separated from C. gracilis based on their size (2–4.5 μm length for IOW73 and IOW94 vs. 4–8 μm for C. gracilis), the shorter flagellum (max. 8 μm vs. 8–20 μm for C. gracilis), the flagellar root microtubules (organised in one row vs. 2–3 rows for C. gracilis[28, 30, 31]) and the shape of mitochondrial cristae. C. balthica differs from C. minima by possessing intracellular bacteria and based on 18S and partial cAMP 28S rRNA gene sequences. No 18S rRNA sequence of Codosiga cultures exists (as discussed in [6]), but the clustering of the 28S rRNA tree supports the separation of both our strains from their nearest neighbour, C. gracilis (Figure 4). Both species descriptions are deposited in ZooBank under urn:lsid:zoobank.org:act:8EA52C91-58CE-4FF9-9007-AC9DED267DD6 (C. minima) and urn:lsid:zoobank.org:act:DF26A642-BD7A-4819-BE8C-40B01A1E7971 (C. balthica). Discussion Putative anaerobic choanoflagellate species have been occasionally detected using microscopical methods [32, 33]. For example, Diaphanoeca sp. and Acanthocorbis sp.