Euconnus sayo Hoshina, 2020: 70.
Euconnus (Euconnus) sayo Hoshina; here placed in Euconnus s. str.
Remarks. This species is known to occur on Shikoku, and it is also a member of the E. fustiger group. Known from only a single male with the body length 1.80 mm, which is clearly larger than that of E. fustiger, but similar to that of E. raucus. This species may in fact be identical with E. raucus, E. yoshidai, or any similarly large-bodied member of the same group. Although its aedeagus illustrated in the original description seems to be intact, and at least the lateral elongate sclerotized structures are similar to those in E. fustiger, it is not possible for me to decide whether this is a distinct species or one of other, poorly described ones.
Hoshina (2020) did not place this species in any subgenus. As all other members of E. fustiger group, E. sayo belongs in Euconnus s. str.