Rhabditidoides aegus n. sp., an associate of stag beetles and sap flow in Japan

Abstract

Rhabditidoides aegus n. sp. from a stag beetle, Aegus subnitidus subnitidus, from Nagoya, Japan, and obtained from the sap flow of an oak tree, Quercus serrata, from Ibaraki, Japan, is described and illustrated. In addition to its distinguishing generic characteristics, e.g., the arrangement of male genital papillae, ⟨v1, v2, v3d, CO, v4, (ph, ad, v5, v6), pd, v7⟩, the new species is characterised by a relatively stout body for both male and female, small stomatal flaps, a secretory pore-like opening, a pair of deirids, three pairs of postdeirids, and a pair of small subventral vulval papillae located just anterior to the female vulva. The new species is morphologically similar to R. humicolus, the species sharing two typological characters: a stomatal flap and vulval papillae. However, the new species is distinguished from R. humicolus by its relatively small vulval papillae, narrower gubernaculum, and the arrangement of genital papillae in which pd and v7 are clearly separate. In addition to the typological characters, the new species is distinguishable from all other species in the genus by its distribution range as it is the first Rhabditidoides species from East Asia.