Laboulbenia stigmatophora A. Weir, M. McHugh & W. Rossi, sp. nov.

Index Fungorum number: IF 900435;  MycoBank number: MB 900435; Facesoffungi number: FoF 14186; Fig. 1

Etymology – From Greek: adjective, meaning “bearer of dots”.

Thallus erect to slightly sigmoid, total length from foot to tip of perithecium 220–325 µm. Receptacle deeply punctate throughout. Cell I distinct, hyaline to deep brown with dark punctations merging on outer margin to form a dark brown edge that continues for the length of the receptacle, Cell I tapering towards the foot and forming a distinct stalk to the thallus, 2–3 times longer than broad, 43–73×18–30 µm. Remaining receptacle cells not well distinguished, heavily punctate with brown becoming confluent along the outer margin, a small punctate, but paler region remaining immediately below the insertion cell. Insertion cell usually small, free from, and located towards the base of, the perithecium. Appendages typically light brown to hyaline. Outer appendage basal and suprabasal cells relatively large, basal 15–20 × 15–18 µm, suprabasal 18–23 × 15–18 µm. The latter giving way to usually 2–4 very long (to 370 µm) flexuous, septate, and drawn out branches. Inner appendage basal cell hyaline, rectangular, 8–13×8–10 µm, smaller than outer appendage basal cell. Inner appendage suprabasal cell relatively small, giving way to shorter branchlets that typically form a tuft and on which the antheridia may arise. Antheridia not observed. Perithecium 113–145×53–65 µm, straight, inflated, broadest just below the neck with two crest-like protrusions emerging from the outer margin just below the abruptly tapered apical region. Apex distinctly angled inwards. Basal region of venter smokey-grey, midand upper portion usually pale yellow (but occasionally smokey-grey to chocolate brown), the neck blackened with paler, hyaline, obtuse lip cells.

Material examined – Indonesia, Sulawesi Utara Province, Dumoga-Bone National Park, Plot A, lowland forest, Fi el. ca. 200 m, Flight Interception Trap, 30.X – 06.XI.1985, P.M. Hammond, on the posterior margin of the left elytron of Loxandrus sp. (BM(NH) Code No. 4.165) (Coleoptera, Carabidae, Pterostichini) (K(M) 43517, holotype; AW 299 in SYR, isotype. Sulawesi Utara Province, Dumoga-Bone National Park, Plot A, lowland forest, el. ca. 200 m, Flight Interception Trap, 01–08.V.1982, P.M. Hammond, on the outer margin of the left elytron of Loxandrus sp. (BM(NH) Code No. 4.165), AW 245 in SYR, paratype. Same locality, Edward’s Camp, 03–11.IV.1985, P.M. Hammond, on the outer margin of the left elytron of Loxandrus sp. (BM(NH) Code No. 4.165), AW 289 in SYR, paratype.

Notes – Eight, mature thalli have been examined on different samples of Loxandrus sp. and all of them were on or around the outer margin of the left elytron. There are four species of Laboulbenia known from the species of Loxandrus in Central and South America viz. Laboulbenia decoromanorum Balazuc, L. flagellata Peyr., L. loxandri Thaxt., and L. polyphaga Thaxt. However, our collections (K(M) 43517, AW 299 in SYR, AW 245 in SYR, AW 289 in SYR) differ from above species by their overall thallus morphology and in the shape, coloration, and punctation of portions of the thallus. Further, our collections are morphologically somewhat similar to Laboulbenia helluodis Thaxt. and L. similis. However, our collections differ from L. helluodis in the overall shape of the receptacle, and in the formation of a dense tuft of branches in the appendage The differences with L. similis are described above in the notes for that species (Fig. 1). Interestingly, even though, our collections are morphologically allied with L. similis, their hosts are not closely related and, are often found together in the same habitat, lending support to the idea of a host shift (Rossi 2011). Returning to the characteristics of L. stigmatophora, the heavily punctate receptacle, the distinctive perithecium, and the extremely long, flexuous, appendage branchlets easily serve to distinguish this new species from all other known species of Laboulbenia. These collections are distinguished as an unidentified species and we introduce this collection as Laboulbenia stigmatophora sp. nov.

Figure 1 – Laboulbenia stigmatophora (K(M) 43517, holotype). a, b Mature thalli. Scale bars: a, b=50 µm