Parastrombidinopsis costalis, Song & Li & Huang & Al-Rasheid & Liu & Hu & Miao, 2018

Song, Wen, Li, Jiamei, Huang, Yaoyao, Al-Rasheid, Khaled A. S., Liu, Weiwei, Hu, Xiaozhong & Miao, Miao, 2018, Morphology of Three Aloricate Choreotrich ciliates, Including Description of a New Species Parastrombidinopsis costalis sp. n. (Ciliophora, Choreotrichia), and phylogeny of the genus Parastrombidinopsis, Acta Protozoologica 57 (3), pp. 153-167 : 163-164

Parastrombidinopsis costalis sp. n.: comparison between populations and related species ( Tables 2, 3)

The two populations correspond well with each oth- er in terms of cell shape, longitudinal ridge and unevenly spaced somatic kineties, except the Sanya population is smaller than Zhuhai population in cell size (25–45 × 13–26 μm vs 50–73 × 23–42 μm after protargol staining), as well as other size related characters such as number of collar membranelles (16–19 vs 19–21) and number of somatic kineties (6–8 vs 8). We think the cell size difference can be considered as populationdependant, and the two populations are conspecific.

The genus Parastrombidinopsis was established by Kim et al. (2005). Prior to the present work, two species have been assigned to the genus: P. shimi Kim et al. 2005 and P. minima Tsai et al. 2008 . Parastrombidinopsis costalis sp. n. can be separated from the other congeners and all the poorly described choreotrich species by its unique longitudinal ridge on dorsal side.

Besides, the new species differs from the type species Parastrombidinopsis shimi by its: 1) smaller cell size (30–70 × 15–40 μm vs. 100–170 × 40–60 μm in vivo); 2) fewer collar membranelles (16–21 vs. 36–48); and 3) fewer somatic kineties (6–8 vs. 36–50).

In addition, the new species differs from P. minima in the arrangement of the AZM (the proximal end locat- ed below the distal end vs. distributed on same horizontal level) and fewer somatic kineties (6–8 vs. 11–15).