The morphology and SSU rRNA gene sequence analysis of a poorly-known brackish water ciliate, Pinacocoleps tesselatus (Kahl, 1930) (Ciliophora, Colepidae) from Hangzhou Bay, China.

The morphology and infraciliature of a poorly-known colepid ciliate, Pinacocoleps tesselatus (Kahl, 1930) Foissner et al., 2008, collected from brackish-water biotope (salinity 12 per thousand) in Hangzhou Bay, China, were investigated using live observations and silver impregnations. This species is characterized by its length of 60-85 μm in vivo, ovular shape, two anterior and three posterior spines, 21-25 longitudinal and 11 transverse ciliary rows on average, a macro and micro nucleus, and one terminal contractile vacuole. The key to all known seven Pinacocoleps species is updated. Additionally, we characterized the taxon P. tesselatus via small subunit rRNA gene data. Our phylogenetic analyses performed using both maximum-likelihood and Bayesian methods indicate that P. tesselatus falls into the core assemblage of the family Colepidae.