Rhachomyces cimmeritei W.Rossi & Mishustin, 2024

Mishustin, Ruslan I., Khodosovtsev, Alexander Y. & Rossi, Walter, 2024, New species and new records of Laboulbeniales (Ascomycota) from countries surrounding the Black Sea, Cryptogamie, Mycologie 20 (11), pp. 139-149 : 146-147

Rhachomyces cimmeritei W.Rossi & Mishustin , sp. nov.

( Fig. 4 )

TYPE MATERIAL. — Russian Federation • W Caucasus, Krasnodar Region, Dzykhra Mt., banks of the Mzymta River; 1200 m alt.; 15.V.1994; leg. I. A. Belousov; on Cimmerites ovatus Belousov, 1998 ( Coleoptera , Carabidae ); holotype: FI [ WR1958 ].

ADDITIONAL EXAMINED MATERIAL. — Russian Federation • W Caucasus, Krasnodar Region, Dzykhra Mt., banks of the Mzymta River; 1200 m alt.; 15. V.1994; leg. I. A. Belousov; on Cimmerites ovatus Belousov, 1998 ( Coleoptera , Carabidae ); FI [WR1956, WR1957, WR2017] • Aibga Ridge; c. 1650 m alt.; 1. VI.1995; leg. A. G. Koval & A. I. Roubchenya; on a female specimen of C. convexus Belousov, 1995 ; KHER [L00328] (#i00259 = SZIK K28).

ETYMOLOGY. — Referring to the name of the host insects.

INDEX FUNGORUM. — IF901677.

DESCRIPTION

Axis consisting of 9-14 cells, the lower of which are brown colored, sometimes quite dark, especially the suprabasal, the others variably paler, depending mainly on the age of the fungus. Basal cell (cell I) usually slender and elongate. Suprabasal cell of the receptacle (II) always smaller, shorter and darker than the former, bearing a long, dark, appendage consisting of elongate cells. The following cells of the axis are paler, gradually larger and isodiametric, the third from the foot bearing a long appendage whose lower cells are shorter, paler and divided by black septa, sometimes paired with a second shorter appendage composed entirely of short and paler cells. This latter type of appendage is the only found on the upper portion of the thallus, is originated in groups of two or three from each cell of the axis, and is sometimes replaced by antheridial appendages. The latter are usually very few, sometimes found only above the insertion of the perithecial stalk-cell, composed of three cells, the lower short and brownish, the second also short but subhyaline, separated from the lower by a blackish septum and bearing distally a hyaline elongate antheridium which has a distinctly tapered and not strongly curved upper portion. Perithecium sessile or short stalked, usually erect, symmetrical, about three times longer than broad, with the lower half slightly inflated and the upper portion more or less distinctly tapering to a truncate-conical tip ending in a blunt apex. Length from foot to perithecial apex (235)255-380(490) µm; perithecium 100-165 × 35-50 µm; perithecial stalk up to 50 µm; longest appendages 230 µm.

NOTES

At a first glance Rhachomyces cimmeritei W.Rossi & Mishustin , sp. nov. looks a lot like R. aphaenopsis Thaxt. , but a closer examination reveals several differences, although none of them is particularly striking. However, the differences in the lower part of the receptacle between the two fungi immediately catches the eye: in the new species the lower cells are dark, slender, and gradually broader, the basal cell being distinctly elongate; in R. aphaenopsis these cells do not differ greatly from each other and from the upper cells. With the exception of the lower ones, the cells forming the axis of the fungus are mostly squarish in the new species, while they are generally broader than long in R. aphaenopsis . The blackish and long appendages are very few in R. cimmeritei W.Rossi & Mishustin , sp. nov., sometimes limited to just one originated from the suprabasal cell; the same are usually more numerous and also longer in R. aphaenopsis . As to the perithecium, the upper portion is narrower than the lower in the new species, sometimes distinctly so, while in R. aphaenopsis the perithecium is nearly oblong, with the upper portion equal or slightly narrower than the lower ( Santamaría & Faille 2007).

Figures

FIG. 4. – Rhachomyces cimmeritei W.Rossi & Mishustin, sp. nov.: A, B, from the type slide; C, paratype (slide WR2017). Scale bar: 100 µm.