Laboulbenia tuberculata W. Rossi & M. Leonardi, sp. nov.
Index Fungorum number: IF 559787; Mycobank number: MB 559787; Facesoffungi number: FoF 12926; Fig. 1
Etymology – From Latin tuberculatus, which means “covered with wart-like projections”.
Holotype – FI WR4035.
Basal cell (cell I) of the receptacle slender and elongate, with almost parallel margins, hyaline above the foot, then gradually darkening from below upwards becoming brown in the upper portion, its surface distinctly warty. Suprabasal cell (cell II) with a wavy surface, broadly pentagonal, much shorter and paler than the basal, from which is separated by a thick, blackish septum looking like a prominent ring. Similar septa, but shorter and symmetrically oblique, divide cell II from cell III and cell VI. Cell III about as long as cell II but distinctly narrower, dark brown, its surface covered with large, dark warts, the warty surface extending to cell VI and to the lower, outer portion of cell IV. The latter as long as cell III but slightly broader and somewhat paler. Cell V very small and lens-like. Insertion cell thick, subtended by a paler line. Outer appendage consisting of a basal cell almost twice longer than broad followed by a linear series of hyaline cells gradually longer and slenderer. Inner appendage consisting of a small and flattened basal cell giving rise to a short cell oriented inwards and bearing distally a pair of falcate antheridia. Cell VI rhombic, shorter than the adjacent cell III. Perithecium colored pale brown, darker in the lower portion, adnate to the receptacle for 3/5 of its length, oblong, slightly inflated, its surface slightly undulate, the darker tip abruptly distinguished, ending in rounded and subhyaline
lips, one of which is larger than the others. Length from foot to perithecial apex 160–180 µm; length from foot to tip of longest appendage 420 µm; perithecium 60–63×23–25 µm.
Material examined – Papua New Guinea, Western Province, Yaromdeng tem, Cave near Finim tel, 9 November 1975, leg. Ph. Chapman, on Altagonum sphodrum Darlington (Coleoptera, Carabidae), FI WR4035 (holotype), FI WR4036.
Notes – The large, irregularly arranged dark warts that cover most of the surface of the receptacle make it possible to distinguish at first sight Laboulbenia tuberculata from any other described species. Smaller warts on the surface of the receptacle are found in L. tuberculifera and L. rugosa, but in the latter species the warts are found only on cells III, IV and V, while in the former these are restricted to cell II (Thaxter 1908; Rossi and Leonardi 2020). The surface of the receptacle of Laboulbens scabra is also completely covered with warts, but in this case the warts are small, uniformly distributed and concolorous with the remaining parts of the thallus (Kong et al. 2020).
Figure 1 – Laboulbenia tuberculata (FI WR4035, holotype). a mature thallus. b mature thallus enlarged. c immature thallus with focus on warts. Scale bars: 25 µm