Rhachomyces carbonii W. Rossi & M. Leonardi, 2018

Rossi, Walter & Leonardi, Marco, 2018, New species and new records of Laboulbeniales (Ascomycota) from Sierra Leone, Phytotaxa 358 (2), pp. 91-116 : 102

Rhachomyces carbonii W. Rossi & M. Leonardi sp. nov. ( Figure 3d )

MycoBank MB 826858

Etymology:—Named after Graziano Carboni, for his invaluable help during the collecting journeys in Sierra Leone of the first author.

Original description:—Axis of the receptacle usually falcate, consisting of 19–30 cells gradually enlarging from the foot to the base of the perithecium. These cells are black on the anterior side and gradually paler on the ventral; because the width of blackish area remains almost constant along the axis, the lower and more slender cells are entirely black, while the upper, larger cells are almost hyaline on the dorsal side. Appendages one-sided, slender and stiff, gradually longer and more numerous from below upwards, the shorter ones almost entirely blackish brown, the longest with a distinctly curved and paler tip. Antheridial appendages paired to the sterile appendages in the upper portion of the axis, dark brown colored, consisting of a short lower cell and terminated by a long and slender antheridium. Perithecium born on a very short and almost hyaline stalk, light brown, oblong, slightly asymmetrical, the anterior side straight to slightly concave, the posterior convex, the wall cells slightly spiral, the tip rather abruptly differentiated and much darker, the apex rounded and almost hyaline. Length from foot to perithecial apex 560–800 μm; perithecium (including basal cells) 175–200 × 35–45 μm; antheridia 30–39 μm. longest appendages 205 μm;

Type: — SIERRA LEONE, Southern Province, Gola Rainforest National Park near Nemahugoima, 31.I–3.II.2012, W. Rossi , on an undescribed species of Tracypum ( Staphylinidae , Paederinae , Paederini, Cryptobiina ) (FI3685). Seven mature and 4 immature thalli were examined.

Comments: —Among the described species of Rhachomyces , the one most similar to R. carbonii is R. abusculus Thaxt. , parasitic on an unidentified rove-beetle “allied to Lathrobium ” from Liberia ( Thaxter 1896). The two species have a similar habitus, but R. abusculus has shorter appendages with a different apex, cells of the receptacle much less pigmented and not strongly different in size, the perithecium spindle-shaped regularly tapering to the apex without any abrupt constriction.

Figures

FIGURE 3. a: Laboulbenia insolita. b: upper portion of the perithecium of L. insolita. c: Laboulbenia kingsleyae from the type slide. d: Rhachomyces carbonii. e: Amphimyces cerylonis. f: Corethromyces rostellatus. g: Dimeromyces muticus. Scale bars: a, c, d, e, f, g = 50 μm; b = 25 μm.