Rhachomyces platyprosophi W. Rossi & M. Leonardi, sp. nov.
Index Fungorum number: IF 559511; MycoBank number: MB 559511; Facesoffungi number: FoF 13388; Fig. 1
Etymology – Named after the host insect genus.
Holotype – FI WR3973.
Axis of the receptacle from almost straight to variably curved or sigmoid, consisting of 15–22 brownish cells gradually enlarging upwards and separated by oblique septa. Appendages spreading, nearly opaque except for the gradually paler and curved tip, longer and more numerous in the upper portion of the receptacle, reaching and sometimes exceeding the perithecial apex. Antheridial appendages relatively numerous, chestnut brown colored, consisting of a slender and elongate cell followed by a very slender antheridium with a paler and sigmoid tip. Perithecium long and slender, subsessile, oblong, light brown colored, the tip gradually tapering, hardly distinguished except for the darker color, the apex hyaline and subtruncate. Length from foot to perithecial apex 500–830 µm. Perithecium 190–290 × 50 µm. Antheridial appendages 50–65 µm. Longest sterile appendage 520 µm.
Material examined – Indonesia, Sumatra, Palembang, s. d., s. c. (from the collection of A. Fauvel in the Institut Royal des Sciences Naturelles, Bruxelles), on abdomen and legs of Platyprosopus indicus Motschulski (Staphylinidae, Staphylininae, Platyprosopini) (FI WR3973a, holotype; FI WR3973b and WR3973c isotypes).
Notes – Due to the large dimensions and the oblong perithecium, the new species can be compared with Rhachomyces carbonii W. Rossi & M. Leonardi, recently described on a rove beetle from Sierra Leone, which however bears a slender and much darker receptacle, shorter and slender appendages and has perithecium with spirally twisted wall cells with an abruptly distinguished tip (Rossi and Leonardi 2018).
Figure 1 – Rhachomyces platyprosophi (FI WR3973a, holotype). Scale bar=100 µm