Laboulbenia buccalis 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 : 97-99

Laboulbenia buccalis W. Rossi & M. Leonardi sp. nov. ( Figures 1f and 2a )

MycoBank MB 826854

Etymology:—From Latin bucca (= mouth), because the thalli of this species, with very few exceptions, are found on the mouthparts of the host insects.

Dioecious. Female thallus with cells III and IV of the receptacle and perithecium grayish brown; the perithecial tip is dark brown, while the rest of the fungus is paler, with cell I and appendages almost hyaline. Receptacle short, with the basal cell (cell I) longer than maximum width. Suprabasal cell (cell II) about as long as the basal, separated from cell III by a short, almost horizontal septum and from cell VI by a much longer, oblique or concave septum. Cell III quadrangular, about as long or slightly shorter than cell II but wider than the latter. Cell IV smaller than cell III, with the outer margin usually convex. Cell V shield-shaped, separated from cell IV by an oblique septum reaching cell III in its upper, inner angle. Insertion cell thick, distinctly shorter than the upper side of cells IV and V. Outer appendage simple and elongate. Inner appendage consisting of a small basal cell that gives rise on either side to an elongate, simple branch similar, but shorter than the outer and hardly exceeding the perithecial apex; these branches of the inner appendage do not develop simultaneously and are usually of different length, especially in younger thalli. Stalk-cell of the perithecium (cell VI) oblique, distinctly broader than long. Perithecium free for about 2/3 of its length, subelliptical, with a slight hunch on the ventral side at the septum between the 2 nd and the 3 rd layer of wall cells, above which it tapers rather abruptly to the darker tip; apex distinctly turned outwards, consisting of large, rounded and unequal lips, the dorsal being distinctly taller. Length from foot to tip of perithecium 133–157 μm; perithecium 73–90 × 30–47 μm; longest appendage 130 μm.

Male thallus paired with the female and similar to the latter, but never developing the perithecium. Inner appendage consisting of a small basal cell that gives rise on either side to an elongate cell bearing apically a single antheridium with a short, curved and abruptly tapering neck; sometimes also the inner appendage develops a short branchlet, especially in older specimens, which however do not replace the antheridia. Length from foot to tip of antheridia 87–99 μm; longest appendage 157 μm.

Type: — SIERRA LEONE, Occra Hills, 31.XII.1988, W. Rossi , on mouthparts of a worker of Amitermes evuncifer Silvestri (Isoptera, Termitidae , Amitermitinae) (FI4076).

Additional material examined: —Same dada of the type (paratype FI4075); same data of the type, on the mouthparts and on the anterior right tibia of a soldier (paratype FI4077); same data of the type, on the mouthparts of a nymph with wing pads (paratype FI4078). Very many thalli have been examined.

Comments: —The species of Laboulbenia occurring on termites described to date are five (excluding L. antemnalis described above). These are L. hagenii Thaxt. , L. felicis-caprae W. Rossi , L. geminata Buchli ex W. Rossi et Blackwell , L. brignolii W. Rossi et Blackwell , and L. ghanaensis W. Rossi et Blackwell ( Rossi & Blackwell 1986) . All these parasites were found in the African continent and none of them was recorded a second time. The female thalli of L. buccalis share with L. felicis-caprae and L. ghanaensis a simple outer appendage, but obviously lack any antheridium on the inner appendage. Antheridia are two in L. felicis-caprae and one only in L. ghanaensis . L. buccalis differs from the other two species also in the shape of the perithecial tip, which is more slender, with the apex distinctly oblique directed outwards in the new species.

Figures

FIGURE 1.a: Camptomycesafricanus. b:Corethromyces golaensis. c: Corethromycessp.d:maturethallus ofDiaphoromyces minutissimus from the type slide. e: immature thallus of D. minutissimus from the type slide. f: paired male (left) and female (right) thalli of Laboulbenia buccalis from the paratype slide WR4078. Scale bars = 50 μm.

FIGURE 2. a: mouthparts of Amitermes evuncifer bearing thalli of Laboulbenia buccalis. b: paired thalli of Laboulbenia antemnalis: the female thallus (left) is immature; the male thallus bears a terminal antheridium (arrow) in which a spermatium is being formed; the tip bent sidewise is an artifact (paratype WR4281b). c: mature female thallus of L. antemnalis (paratype WR4281a). d: L. penetrans. Scale bars: a, c, d = 50 μm; b = 25 μm.