Laboulbenia penetrans 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 : 101

Laboulbenia penetrans W. Rossi & M. Leonardi sp. nov. ( Figure 2d )

MycoBank MB 826857

Etymology:—From the Latin verb penetro = to penetrate, because the fungus penetrates with an haustorium into the host insect.

Original description:—Receptacle pale grayish yellow, consisting of a cup shaped, basal cell (cell I) slightly longer than broad, and a much longer suprabasal cell (cell II) with nearly parallel margins, with the surface distinctly rugose in mature thalli. Cell III+IV+V elongate, outer margin distinctly convex in mature thalli, free from the perithecium. Basal cell of the appendage small, distinctly shorter than broad, with a grayish lower half and a hyaline upper half, giving rise externally to a short, simple branch and on the inner side to an almost rounded cell bearing two pairs of antheridia, one sessile, the other on top of an elongate cell. Antheridia grayish, bottle-shaped, sometimes replaced by short branchlets in older thalli. Stalk-cell of the perithecium (cell VI) relatively small, broader than long. Perithecium dark brownish gray, broadly pear-shaped, evenly tapering to a paler tip and ending with three subhyaline and elongated lips, of which two are longer and slightly divergent, the third shorter and larger. The thallus penetrates inside the integument of the host insect with a short and stocky haustorium consisting a subsphaerical base beneath cell I producing laterally a large but short hypha. Length to tip of perithecium 410–500 μm; perithecium 125 × 50–55 μm; longest appendage 70 μm.

Type: — SIERRA LEONE, Western Area, Regent, 27.I.2013, W. Rossi , between mid coxae of Stereocerellus singularis (Becker) ( Diptera , Chloropidae ) (FI4072). Three mature and 3 immature thalli have been observed.

Comments:— Laboulbenia penetrans is clearly allied to L. dahlii (Thaxt.) Thaxt. , described in 1901 (as Ceraiomyces dahlii ) on a “small flower fly” from Ralum, “New Pomerania” (now New Britain in the Bismarck Archipelago of Papua New Guinea). However, the latter parasite has a spherical cell I, slenderer and darker stalk cell of the appendages, much larger and much darker basal cell of the same, the perithecium slender and elongate with the tip distinctly curving outwards. Also L. curtonoti W. Rossi & Kirk-Spriggs , parasitic on the African fly Curtonotum balachowskyi Tsacas , bears a penetrating haustorium, but it is different in almost any other characteristics ( Rossi & Kirk-Spriggs 2011).

It is worth mentioning that the following finding (unpublished) of Laboulbenia dahlii by the German dipterologist Michael von Tschirnhaus shed some light on the identity of the “small flower fly” mentioned by Thaxter: INDONESIA, Moluccas (Maluku) Islands, island Palau Jamdena, east coast near the village Tumbur, 7°50’41”S, 131°23’11”E, on Talipariti tiliaceum (L.) Fryxell ( Malvaceae ) (common name: Sea Hibiscus), 15.III.1989, J. Dürbaum, on the head of a few specimens of Eutropha noctilux (Walker) ( Chloropidae ). Because the latter insect is widely distributed and is also present in the Bismark Archipelago, it is possible that the host of the type of Laboulbenia dahlii was Eutropha noctilux .

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.