Morphology, ontogenesis and molecular phylogeny of a new saline soil ciliate, Uroleptoides salina nov. spec. (Ciliophora, Hypotrichia)

Abstract

The morphology, morphogenesis and molecular phylogeny of a new saline soil hypotrich ciliate, Uroleptoides salina nov. spec., discovered from China, was investigated. The new species is characterized as follows: body 150–215 × 40–50 μm in vivo, slender and highly flexible; usually four ellipsoidal macronuclear nodules; contractile vacuole absent; cortical granules absent; endosymbiotic algae present; amphisiellid median cirral row consists of 14–25 cirri and terminates about 47% down length of body; usually three buccal cirri and 3–13 cirri left of anterior portion of amphisiellid median cirral row; 3–5 transverse cirri. Morphogenesis during binary fission is characterized by: (1) the parental adoral zone of membranelles is retained completely, parental paroral contributes to the formation of the undulating membranes anlage for the proter; (2) the oral primordium of the opisthe is formed apokinetally; and (3) the amphisiellid median cirral row is formed from two anlagen. Phylogenetic analyses based on SSU rDNA sequence data show that Uroleptoides salina nov. spec. has a close relationship with its morphologically similar species, U. longiseries, U. magnigranulosus, Orthamphisiella breviseries, and Parabistichella variabilis.