Two new species of with cirrotype-9, sp. nov. and sp. nov. (Ciliophora, Spirotrichea, Euplotida), from the coasts of Patagonia: implications from their distant, early and late branching in the phylogenetic tree.

Two new species have been isolated from cold shallow sandy sediments of the extreme Southern Chilean coasts: sp. nov., from a low-salinity site at Puerto Natales on the Pacific coast, and sp. nov., from a marine site at Punta Arenas on the Atlantic coast. has a medium body size (53×36 µm ), a dorsal surface marked by six prominent ridges, a double dargyrome, six dorsal and two ventrolateral kineties, a buccal field extending to about 3/4 of the body length, an adoral zone composed of 28-32 membranelles, and nine fronto-ventral, five transverse and two or three caudal cirri. The bulky, hook-, horseshoe- or 3-shaped macronucleus is associated with one sub-spherical micronucleus. The central body region hosts taxonomically unidentified endosymbiotic eubacteria. has a small body size (39×27 µm ), a smooth dorsal surface marked by three deep grooves, a double dargyrome, four dorsal and two ventrolateral kineties, a buccal field extending to about 2/3 of the body length, an adoral zone composed of 23-25 adoral membranelles, and nine fronto-ventral, five transverse and three caudal cirri. The macronucleus is hook- or C-shaped and associated with one spherical micronucleus. Endosymbiotic bacteria belonging to the genus reside preferentially in the anterior cell region. Both species lack the fronto-ventral cirrus numbered 'V/2', whereby their cirrotype-9 conforms to the so-called 'pattern I', which is the basic distinctive trait of the genus Borror and Hill, 1995. Phylogenetic analyses of small subunit rRNA gene sequences, however, classify into its own early branching clade and into a late branching clade. This indicates a polyphyletic nature and taxonomic inconsistency of the genus , which was erected to include species with cirrotype-9 pattern I.