Paramecium bursaria—A Complex of Five Cryptic Species: Mitochondrial DNA COI Haplotype Variation and Biogeographic Distribution

Magdalena Greczek-Stachura,Sebastian Tarcz,Maria Rautian

doi:10.3390/d13110589

Abstract

Ciliates are a diverse protistan group and many consist of cryptic species complexes whose members may be restricted to particular biogeographic locations. Mitochondrial genes, characterized by a high resolution for closely related species, were applied to identify new species and to distinguish closely related morphospecies. In the current study, we analyzed 132 sequences of COI mtDNA fragments obtained from P. bursaria species collected worldwide. The results allowed, for the first time, to generate a network of COI haplotypes and demonstrate the relationships between P. bursaria strains, as well as to confirm the existence of five reproductively isolated haplogroups. The P. bursaria haplogroups identified in the present study correspond to previously reported syngens (R1, R2, R3, R4, and R5), thus we decided to propose the following binominal names for each of them: P. primabursaria, P. bibursaria, P. tribursaria, P. tetrabursaria, and P. pentabursaria, respectively. The phylogeographic distribution of P. bursaria species showed that P. primabursaria and P. bibursaria were strictly Eurasian, except for two South Australian P. bibursaria strains. P. tribursaria was found mainly in Eastern Asia, in two stands in Europe and in North America. In turn, P. tetrabursaria was restricted to the USA territory, whereas P. pentabursaria was found in two European localities.

Highlights

When describing successive members of the P. bursaria complex, specific names should be created by adding a numerical prefix, as for the P. aurelia complex [28]
Within the studied P. bursaria complex, we identified 63 COI haplotypes, which were divided into individual cryptic species as follows: 9 haplotypes belonging to P. primabursaria, 18 haplotypes to P. bibursaria, 31 haplotypes to P. tribursaria, 3 haplotypes to P. tetrabursaria, and 2 haplotypes to P
Sequence analysis of the gene encoding the COI mtDNA fragment from P. bursaria strains revealed that the mean genetic distance within the P. bursaria complex was 0.966 and the p-distance was greater than those observed for species from the P. aurelia and

Summary

Introduction

Many of them consist of cryptic species complexes. The possibilities of solving the above problems have increased significantly in recent decades, mainly due to the dynamic development of molecular biology techniques [5,6,7,8,9]. The main result of the application of molecular tools was the identification of a high genetic variation within individual species [10,11,12], which led to the description of many new species in recent years [7,13,14,15,16,17,18,19]

Methods

Results

Discussion

Conclusion