Two sexannulate leech species, 𝑂𝑟𝑜𝑏𝑑𝑒𝑙𝑙𝑎 𝑖𝑚𝑝𝑒𝑟𝑓𝑒𝑐𝑡𝑎 sp. nov. and 𝑂. 𝑘𝑖𝑟𝑖𝑠ℎ𝑖𝑚𝑎𝑦𝑎𝑚𝑒𝑛𝑠𝑖𝑠 sp. nov., from Kyushu, Japan, are described. This study provides the first occurrence record of sexannulate species of 𝑂𝑟𝑜𝑏𝑑𝑒𝑙𝑎 Oka, 1895, in Kyushu. Phylogenetic analysis using nuclear 18S rRNA, 28S rRNA, histone H3, mitochondrial cytochrome c oxidase subunit I, tRNACys, tRNAMet, 12S rRNA, tRNAVal, 16S rRNA, tRNALeu, and NADH dehydrogenase subunit 1 markers showed that the two new species formed a monophyletic lineage with five quadrannulate congeners that are distributed across the western part of Honshu, Shikoku, and Kyushu.
Takafumi Nakano (Fri,) studied this question.