Laboulbenia cobiae W. Rossi & M. Leonardi, sp. nov.
Index Fungorum number: IF 900429; MycoBank number: MB 900429; Facesoffungi number: FoF 14180; Fig. 1
Etymology – Named after the student of the Diopsidae Cobi Feijen (The Netherlands), who supplied us with the insect bearing the new species of fungus.
Thallus sigmoid, hyaline or almost so, with the perithecium light gray and the appendages brown. Adhesive organ (foot) with a hyaline, contrasting spot in the middle. Basal cell of the receptacle (cell I) curved, about three times longer than broad. Cell II slightly to distinctly larger than the previous one. Cell III much smaller, barrel-shaped, almost 1.5 times longer than broad. At the septum separating cell II from cell III the receptacle has an evident indentation. Cell IV+V similar to, but slightly shorter than cell III and completely free from the perithecium. Insertion cell very narrow and thick. Basal cell of the outer appendage quite large and expanding distally, giving rise to 4 branches consisting of elongate cells darker on the outer side and separated by blackish septa; these branches divide repeatedly forming a fan-shaped tuft of branchlets with hamate tip overcome by a disorganized hyaline matter. Inner appendage consisting of a small basal cell which gives rise to two elongate cells, each bearing distally a pair of grayish, elongate and bottle-shaped antheridia. Cell VI very small and oblique. Perithecial basal cells also small, forming a narrowing below the perithecial body. The latter asymmetrical, with the outer (ventral) margin straight or slightly concave and the inner (dorsal) convex, tapering abruptly upward forming a distinct constriction, above which the enlarged tip appears as two bulky, rounded, unequal lobes, the inner of which is larger and bears a digitiform, curved, hyaline outgrowth. Length from foot to tip of perithecial outgrowth 210–240 µm; from foot to tip of appendages 340–375 µm; longest appendages 175 µm; perithecium including basal cells, without outgrowth 95–100×35–40 µm; perithecial outgrowth 14–16 µm; antheridia 26–28 µm.
Material examined – Sri Lanka, Badulla Distr., Girandurakotte Circuit Bungalow 10 mi. NNE Mahiyanganaya, UV trap, 4–7.IX.1980, leg. K.V. Krombein et al., at the apex of the abdomen of a female specimen of Diopsis nr. indica Westwood (Diptera, Diopsidae) (FI WR4128, holotype).
Notes – Our collection (FI WR4128) is distinguishable from any other described species for the large, rounded upper portion of the perithecium subtended by a marked constriction. The perithecial outgrowth is also an uncommon feature in the genus Laboulbenia, although it is frequent in other genera of the Laboulbeniales. Our collection (FI WR4128) can be compared with Laboulbenia gratiellae W. Rossi, which was described Teleopsis spp. from Malaysia and Thailand (Rossi 1987). The two parasites have appendages with a similar structure, although these are more numerous in Laboulbenia gratiellae. Moreover, in the latter species cells III and IV are undivided but separated from cell V, while it is the contrary in our collection. Therefore, we introduce this collection (FI WR4128) as Laboulbenia cobiae sp. nov.
Figure 1 – Laboulbenia cobiae (FI WR4128, holotype). a, b Mature thalli. Scale bars: a, b=50 µm