Laboulbenia antemnalis 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 : 96-97

Laboulbenia antemnalis W. Rossi & M. Leonardi sp. nov. ( Figures 2b and 2c )

MycoBank MB 826834

Etymology:—From Latin antemna because most of the thalli of this fungus were found on the antennae of the host insects.

Dioecious. Female thallus with the basal cell of the receptacle (cell I) hyaline, almost twice longer than maximum width, slightly enlarging from below upwards. Suprabasal cell (cell II) pale reddish brown, distinctly longer and slightly broader than the basal, separated from the stalk cell of the appendage by a short, horizontal septum and from the stalk cell of the perithecium (cell VI) by a much longer, very oblique and concave septum. Undivided stalk cell of the appendage (III+IV+V) concolorous with cell II, about 2.5 times longer than broad, almost wholly free and divergent from the perithecium. Appendage very long (when unbroken), consisting of a linear series of elongate cells gradually paler and slenderer. Cell VI russet, almost flattened, slightly concave. Basal cells of the perithecium small, concolorous with cell VI, their surface punctuate. Perithecium reddish brown, slightly paler than the cells below, free except for its base on the inner side, about twice longer than maximum width, with the inner margin more convex than the outer, tapering more or less evenly to the tip, which is not abruptly distinguished, distinctly bent outwards and blackened on the inner side only; apex flattened, consisting of large, hyaline, subequal lips. Length from foot to tip of perithecium 120–135 μm. Longest appendage 150 μm. Perithecium 49–63 × 23–28 μm.

Male thallus consisting of a linear series of cells gradually longer and slenderer. In very early stages the terminal cell acts as a phialide, which soon elongates and gets broken. Total length 45–55 μm.

Type: — SIERRA LEONE, Northern Province, near Bendugu, 21.XI.1984, W. Rossi , on Macrotermes bellicosus (Smeathman) (Isoptera, Termitidae , Macrotermitinae ) (FI4270).

Additional material examined: —Same data of the type (paratypes FI4271, FI4281a, FI4281b, FI4281c).

Comments: —Among the very many species of Laboulbenia described to date, very few have a female thallus lacking an inner appendage paired with a rudimentary thallus consisting of a linear series of five cells. These fungi are considered dioecious, although sometimes there is no evidence of a functional antheridium on the rudimentary thallus, and are all found on ground beetles ( Coleoptera , Carabidae ). The only species among these latter parasites sharing with L. antemnalis a female thallus bearing an undivided stalk-cell of the appendage (cell III+IV+V) is L. endogea Picard , occurring on several species of endogean Scartinae in Sardinia ( Rossi & Santamaria 2008). However, L. antemnalis and L. endogea differ in every other feature and there is nothing suggesting that the two are related.

Interestingly, the species more similar to L. amntemnalis was described in a different genus: Apatomyces laboulbenioides Thaxt. occurring on Tachys ceylonicus (Nietner) ( Carabidae ) from the Philippines. The latter parasite shares with the former the undivided stalk-cell of the appendage, the presence of a tiny male thallus adherent to the foot of the female, and also the lack of an insertion cell; the most obvious difference between the two species is the ramified appendage of A. laboulbenioides ( Thaxter 1931) . It is almost superfluous to add that a review of the taxonomic position of A. laboulbenioides , which is the type species of the monotypic genus Apatomyces Thaxt. , seems more than appropriate.

Figures

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.