Taxonomy and phylogeny of three euplotid ciliates isolated from northeast of China: Euplotes heilongjiangensis n. sp., E. daqingensis n. sp., and E. cf. daidaleos (Alveolata, Ciliophora, Euplotida)
摘要
Ciliates are single-celled organism that play key roles in environmental, evolutionary and ecological systems. Recent faunistic studies on euplotid ciliates biodiversity in northeast of China have revealed many new taxa and little-known species, suggesting higher species diversity than previously thought. As a part of on-going faunistic study of free-living euplotid ciliates in northeast of China, two new Euplotes species and a population of E. cf. daidaleos were investigated based on detailed data. The small subunit ribosomal RNA gene sequences were determined for both species, and phylogenetic analyses based on molecular data support the validity of both species.
ResultsThe living morphology, infraciliature, silverline system, and molecular data of three euplotid species isolated from northeast of China were investigated, including two new species Euplotes heilongjiangensis and Euplotes daqingensis, and a population of Euplotes cf. daidaleos. Euplotes heilongjiangensis is characterized by a combination of features including small size (35–45 × 20–30 μm), nine frontoventral cirri arrangement in affinis-type, one marginal cirrus and two caudal cirri, seven dorsal kinetids with 7–11 dikinetids in the mid-dorsal kinety, and a double-eurystomus type silverline system. Euplotes daqingensis can be recognized by its tiny size (40–50 × 25–35 μm), five conspicuous ridges on dorsal side, nine frontoventral cirri, one marginal and two caudal cirri, eight dorsal kineties, ca. 10 basal bodies in the mid-dorsal kinety and a double-eurystomus type silverline system. The present population of E. cf. daidaleos closely resembles original population, but differs from that in the type of silverline system. The small subunit ribosomal RNA gene sequences were determined for both species. Phylogenetic analyses based on molecular data documented the systematic positions of two new taxa and support the validity of two organism as distinct species.
ConclusionAs a new addition, two new Euplotes species have been published and added to the genus based on their live morphology, infraciliature and silverline system. Furthermore, the genetic data were also added and a reliable identification for environmental monitoring and resource investigations were provided.