Corethromyces golaensis 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 : 94-96

Corethromyces golaensis W. Rossi & M. Leonardi sp. nov. ( Figure 1b )

MycoBank MB 826831

Etymology: —From the Gola Rainforest National Park, where this new species, with other two new species described in this same paper, was found.

Original description: —Basal cell of the receptacle (cell I) irregularly trapezoidal, distinctly longer than maximum width, tinged with light brown. Suprabasal cell (cell II) irregularly quadrangular, slightly longer than broad and slightly darker than the basal cell. Stalk-cell of the appendage (cell III) chestnut brown, quadrangular, distinctly longer than broad. Primary axis of the appendage relatively short, consisting of large cell colored dark brown on the outer side, which gives rise internally and distally to long, slender and hyaline branchlets repeatedly divided dichotomously. Stalk-cell of the perithecium (cell VI) variably curved, hyaline, elongate, distinctly tapering to the base, broader distally than the secondary stalk-cell (cell VII) which is distinctly broader than long. Perithecium, including basal cells, about three times longer than broad, distinctly asymmetrical, subsigmoid, its lower portion slightly inflated, the posterior side more convex, the upper portion bent outwards, and the tip rather abruptly distinguished, light brown, tapering to a rounded apex. Length from foot to tip of perithecium 280–335 μm; length from foot to tip of longest appendages 390 μm; perithecium including basal cells 140–185 × 45–50 μm.

Type: — SIERRA LEONE, Eastern Province, Gola Rainforest National Park near Lalehun, 4–5.II.2012, W. Rossi , on Afrobium sp. ( Staphylinidae , Paederinae , Paederini, Cryptobiina ) (FI3686).

Additional material examined: — Northern Province, banks of the river Seli near Bumbuna, 12.V.1991, W. Rossi , on Afrobium sp. (paratype FI1650).

Comments: —The description is based on the thalli found on the elytra of the host insect collected in the Gola Rainforest N.P. These thalli are broadly similar in the general habitus and especially in the shape of the perithecium to Corethromyces buccalis Thaxt. , described on Rugilus ceylanensis (Kraatz) from Sumatra; the most striking difference among these parasites is a large and opaque outgrowth of the receptacle beside the very short appendage of C. buccalis ( Thaxter 1931, Plate XXXIII, figs 16–17). The single thallus obtained from the insect collected near Bumbuna is similar to the “typical” form, although somewhat stockier.

The thalli removed from the legs of the same insect are quite different: cells II, III and the lower cell of the appendage are blackish and opaque, the branchlets of the appendage are shorter on average and the perithecium is yellowish, symmetrical, oblong, with the basal cells and the tip reddish brown ( Figure 1c ). These thalli seem to be more similar to Coretromyces purpurascens Thaxt. than to any other described species. However, C. purpurascens , which is also parasitic on Cryptobiina, has a more elongate perithecium with concolorous basal cells and the receptacle wholly opaque with the exception of the basal cell ( Rossi 2016).

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.