Benthic ciliates from Sepetiba Bay (Rio de Janeiro, Brazil) with description of Pseudokeronopsis sepetibensis n. sp. (Spirotrichea: Urostylida)

During the period from 2001 to 2002, we examined samples of water and sediment from five stations in Sepetiba Bay, located in the south region of Rio de Janeiro state, Brazil. We identified 32 species of ciliate protists representing seven classes: Karyorelictea, Heterotrichea, Spirotrichea, Litostomatea, Phyllopharyngea, Protostomatea and Oligohymenophorea. Among the Spirotrichea, we discovered Pseudokeronopsis sepetibensis n. sp., characterized by a unique combination of three features: 3 contractile vacuoles, an inconspicuous mid-ventral row, and 4 5 frontoterminal cirri. It showed yellow-greenish coloration and elongated body outline (100 140 m x 20 26 m). On average, there were 44 adoral membranelles, 50 left marginal cirri, 48 right marginal cirri and 41 mid-ventral cirri disposed in a straight row past the level of the oral region. Other features include 4 frontoterminal cirri and a constant number of 3 transverse cirri; 8 frontal cirri (4 anterior and 4 posterior arranged as an atypical bicorone).