Isolation and characterization of microsatellite markers for exploring introgressive hybridization between the Oratosquilla oratoria complex.

The Japanese mantis shrimp Oratosquilla oratoria is one of the most dominant stomatopod species found in coastal waters of the northwestern Pacific. We previously reported cryptic speciation and hybridization in this taxon by integrating mitochondrial and nuclear evidence. The present study aims at developing potential useful microsatellite markers for the O. oratoria complex through transcriptome sequencing, with a view to reveal the occurrence of hybridization. Of the 100 tested microsatellites, 55 were experimentally validated. 24 of these microsatellites were transferable across different species of the O. oratoria complex and showed polymorphic among individuals. The average number of alleles, observed and expected heterozygosity per locus was 6.125, 0.446 and 0.577 for the temperate species, and 6.083, 0.444 and 0.578 for the subtropical and tropical species. We also explore genetic differentiation and hybridization between O. oratoria cryptic species using these 24 microsatellite loci. The pairwise FST values and phylogenetic tree indicated a strong genetic differentiation between the two cryptic species. In addition, Bayesian analysis provided evidence for the presence of hybridization between the O. oratoria complex. These markers provide valuable genomic resources for exploring introgressive hybridization and expanding understanding of evolution in the O. oratoria complex.