Laboulbenia robusta W. Rossi & M. Leonardi, sp. nov.
Index Fungorum number: IF 900433; MycoBank number: MB 900433; Facesoffungi number: FoF 14184; Fig. 79
Etymology – From Latin robustus=strong, robust.
Thallus slightly sigmoid, colored dirty yellow, with the perithecium becoming darker with age. Basal cell of the receptacle (cell I) regularly expanding distally, almost three times as long as maximum width. Cell II much larger, separated by cell III by a very short, transverse septum and by cell VI by a much longer, oblique and concave septum. Cell III relatively small, almost twice longer than broad, tapering below. Cell IV similar in size to cell III. Cell V relatively large, wedge-shaped, with the inner margin partially free between the perithecium and the very oblique and thick insertion cell. Basal cell of outer appendage quite large, about twice longer than broad, giving rise to two branches which divide dichotomously forming four long, slender, straight, subequal branchlets formed by elongated cells. Inner appendage consisting of a basal cell distinctly smaller than the basal cell of the outer appendage, producing by repeated dichotomous divisions a large and sometimes dense tuft of short branchlets, each bearing apically a hyaline, bottle-shaped antheridium. Cell VI irregularly quadrangular, about as long or slightly longer than maximum width. Perithecium less than half free, its ventral margin evenly convex, forming a slight external prominence between the second and third wall-cells tiers, above which it is abruptly contracted in a blackened and subconical tip which ends in a rounded apex, the lips with hyaline edges turned obliquely outwards. Length from foot to perithecial apex 395–530 µm; longest appendages 470 µm; perithecium 150–195×60–85 µm.
Material examined – Australia, Joondalup Lake, 25 km N to Perth, 1.XII.1990, leg. W. Rossi, on Pseudoceneus iridescens (Castelnau) (Coleoptera, Carabidae, Pterostichinae) (FI WR1588, holotype).
Notes – The distinctive characters of our collection (FI WR1588) are the branching pattern and length of the outer appendage, the dense tuft of antheridia on the inner appendage and the absence of sterile branches on the same and the very oblique insertion cell distinctly free from the perithecium. Our collection bears a superficial resemblance with Laboulbenia anchonoderi Thaxt., which occurs on Anchonoderus sp. (Carabidae, Lebiinae) from Central and South America (Thaxter 1908). The latter fungus is paler and slenderer, with cells III and VI more elongated, the perithecium free for about two thirds, and the inner appendage bearing elongate, sterile branches (Fig. 79). Therefore, we introduce our collection as Laboulbenia robusta sp. nov.
Figure 1 – Laboulbenia robusta (FI WR1588, holotype). a, b Mature thalli. Scale bars: a, b=100 µm