Laboulbenia insolita 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 : 99

Laboulbenia insolita W. Rossi & M. Leonardi sp. nov. ( Figures 3a and 3b )

MycoBank MB 826855

Etymology:—From Latin insolitus = strange, because of the unusual perithecial appendage.

Original description:—Thallus grayish brown, with darker perithecium; apical appendage very dark brown, somewhat paler at the distal ends; surface of the receptacle and of perithecium distinctly rugose. Basal cell of the receptacle (cell I) irregularly cylindrical, about three times as long as maximum width. Suprabasal cell (cell II), slightly shorter than the basal and gradually narrowed from below upwards. Cell III cup-shaped, slightly shorter than maximum width. Cell IV slightly larger than cell III, irregularly pentagonal, with the outer margin distinctly convex. Cell V relatively large, situated above cell IV, between the perithecium and the narrow and thick insertion cell. Outer appendage consisting of a large basal cell bulging outwards and bearing distally two cells, both giving rise to two simple branchlets with the lower cells much shorter than the distal ones and the tips slightly extending beyond the perithecial apex. Inner appendage consisting of a basal cell slightly smaller than the outer, bearing distally a single cell which gives rise to a couple of branchlets identical with those of the outer appendage. Cell VI very small, from slightly to distinctly broader than long. Perithecium obovoid, with the wall cells arranged spirally and with an invaginated tip flanked by a peculiar outgrowth resembling the handle of an anatomical walking stick. Length from foot to tip of perithecial outgrowth 260–320 μm; length from foot to tip of longest appendages 425 μm; perithecium, without outgrowth 108–132 × 60–75 μm; length of the same with outgrowth 120–155 μm; length of the horizontal portion of the outgrowth 38–47 μm.

Type: — SIERRA LEONE, Western Area, Regent, Jan 1977, W. Rossi , on the mesosternum of Abacetus (Triaenabacetus) cf. pubescens Dejean ( Coleoptera , Carabidae ) (FI4071). Six mature thalli have been observed.

Comments: —The peculiar shape of the perithecial outgrowth easily distinguish the new species from all the many others in the same genus. This outgrowth is vaguely similar to the one of Laboulbenia ceratophora Thaxt. , which however adheres to the perithecial tip without a distinct “stalk” as in L. insolita ( Thaxter 1908, Plate LX, Figs. 32–35). Moreover, in L. ceratophora the perithecium is slender and it is joined to the insertion cell. This latter fungus is parasitic on various Carabidae in Indonesia and New Guinea.

Figures

FIGURE 3. a: Laboulbenia insolita. b: upper portion of the perithecium of L. insolita. c: Laboulbenia kingsleyae from the type slide. d: Rhachomyces carbonii. e: Amphimyces cerylonis. f: Corethromyces rostellatus. g: Dimeromyces muticus. Scale bars: a, c, d, e, f, g = 50 μm; b = 25 μm.