Redescription of a calanoid copepod, Bestiolina similis (Sewell, 1914) from the Ryukyu Islands, Japan based on the new morphological and molecular evidences

Abstract

A species of Bestiolina, which superficailly resembles to B. sinica (Shen & Lee, 1966) was collected from the Ryukyu Islands, Japan, and was compared with B. similis (Sewell, 1914) from the Pulicat lake, southwestern India ca. 470 km from the type locality. The species has morphological characteristics as follows: 1) absence of the spinules on the posterolateral corners of the last pedigerous somite; 2) presence of number of spinules on the posterior surface of the second and third exopodal segments of leg 2; 3) presence of number of spinules on the posterior surface of the second exopodal segment of leg 3; and 4) presence of number of spinules on the posterior surface of second exopodal segment of leg 4. These features are identical with B. similis. The sequences of Mitochondrial gene cytochrome oxidase subunit I (mtCOI) have the differences ranging from 0.2 to 1.3% between the specimens from the Pulicat lake, India and those from Ryukyu Islands, Japan, while the discrepancies in mtCOI sequences were from 11.9 to 13.3% between the species and Bestiolina coreana from Korea. Their geographical distributions were also discussed.om the type locality. The species has morphological characteristics as follows: 1) absence of the spinules on the posterolateral corners of the last pedigerous somite; 2) presence of number of spinules on the posterior surface of the second and third exopodal segments of leg 2; 3) presence of number of spinules on the posterior surface of the second exopodal segment of leg 3; and 4) presence of number of spinules on the posterior surface of second exopodal segment of leg 4. These features are identical with B. similis. The sequences of Mitochondrial gene cytochrome oxidase subunit I (mtCOI) have the differences ranging from 0.2 to 1.3% between the specimens from the Pulicat lake, India and those from Ryukyu Islands, Japan, while the discrepancies in mtCOI sequences were from 11.9 to 13.3% between the specie