Monoicomyces crassicaulis Santam. sp. nov.

MB#840607

Figs 84, 107B

Diagnosis

Similar to M. fragilis, but differing by an enlarged, inflated cell VI, by a more elongated perithecia, with septa between wall cell tiers marked by elevations, and by a narrow, bent perithecial neck.

Etymology

The species epithet derives from crassus, “fat”, and caulis, “stalk”, referring to the inflated perithecial stalk cell.

Type material

Holotype DENMARK – Nordvestsjaelland (NWZ) • Garbølle; 55°34.107′ N, 11°34.293′ E; PG66; on Oxypoda elongatula Aubé, 1850 (Col. Staphylinidae Aleocharinae); 21 Apr. 2018; JP 1059; JP det.; ZMUC C-F-123576.

Paratypes DENMARK – Østjylland (EJ) • Skallerund i Stenholt Skov; 56°11.410′ N, 9°20.787′ E; NH22; on O. elongatula; 24 Mar. 2019; L. Kjaer-Thomsen & L. Thomas 1401; JP det.; ZMUC C-F-123947 • Vest for Ørnsø ved Silkeborg; 56°9.126′ N, 9°30.588′ E; NH32; on O. elongatula; 24 Nov. 2019; JP 1545; JP det.; ZMUC C-F-124306 . – Nordøstsjaelland (NEZ) • Skodsborg Dam i Jaegersborg Hegn; 55°49.068′ N, 12°33.937′ E; UB48; on O. elongatula; 18 Nov. 2018; JP 1244; JP det.; ZMUC C-F-123772 • Syd for Løjesø i Rude Skov; 55°49.866′ N, 12°28.551′ E; UB49; on O. elongatula; 12 Apr. 2018; JP 1034; JP det.; ZMUC C-F-123546 . – Sydsjaelland (SZ) • Denderup Sø i Denderup Vaenge; 55°15.075′ N, 11°57.366′ E; PG82; on O. elongatula; 9 Apr. 2019; JP 1425; JP det.; ZMUC C-F-123971 • Holmegårds Mose; 55°17.685′ N, 11°47.928′ E; PG73; on O. elongatula; 31 Mar. 2019; JP 1411; JP det.; ZMUC C-F-123957 • Storskov syd for Sparresholm; 55°13.234′ N, 11°57.463′ E; PG82; on O. elongatula; 17 Feb. 2019; JP 1389; JP det.; ZMUC C-F-123932 • Tryggevaelde Å ved Varpelev; 55°21.055′ N, 12°15.877′ E; UB23; on O. elongatula; 6 Jan. 2018; JP 1592; JP det.; ZMUC C-F-124353 . – Vestjylland (WJ) • Sønderkaer syd for Bindeballe; 55°39.107′ N, 9°16.682′ E; NG16; on O. elongatula; 10 Mar. 2002; H. Liljehult 1469; JP det.; ZMUC C-F-124049 • Velling; 56°3.078′ N, 8°18.596′ E; MH51; on O. elongatula; 16 Dec. 2018; JP 1266; JP det.; ZMUC C-F-123794 .

Description

Thallus amber to brown, with darker antheridia, appendages, and foot. Basal cell of receptacle (I) obconical, about 1.5 times as long as broad. Suprabasal cell of receptacle (II) small, trapezoidal, broader than long. Cell III entirely darkened, with the inner side distinctly convex (Fig. 84G–H). Each thallus includes two to several secondary receptacles arising from cell II, with respective perithecia and antheridia.

Primary appendage unbranched, very elongated if unbroken, entirely brown, consisting of a short, inflated basal cell, and several very elongated cells, exceeding in length the perithecial apices. Basal cell of primary appendage between two constricted and darkened septa above and below; the latter is the primary septum (Fig. 84G–H, a).

Secondary receptacles including an externally darkened stalk supporting perithecia and antheridia with secondary appendages. Antheridia consisting of four superposed tiers of paired cells (Fig. 84D–F, tn). Each cell in the first tier is about three times as long as broad and fully dark brown. Brown suffusion occupies the basal area of 2 nd tier, with cells about twice longer than broad. Cells of 3 rd tier hyaline and subtriangular. The 2 nd and 3 rd tiers of cells bear four phialides altogether (Fig. 84E, an). The 4 th tier consists of two subtriangular cells, smaller than cells of the 3 rd tier; bearing two dark, very elongated secondary appendages which exceed in length the perithecial apices, and sometimes two cells representing initials for an additional pair of secondary appendages (Fig. 84D, *).

Perithecial stalk cell (VI) 3–4 times as long as broad, narrower and darkened at the base, distinctly inflated upwards, then abruptly constricted below the perithecial base. Perithecia elongate fusiform, with septa separating the two lower tiers of wall cells marked by slight elevations; broader at w 1 -w 2 level which form a deeply pigmented venter (Fig. 84A). Tiers w 3 and w 4 almost hyaline, the w 3 forming a narrow neck which slightly bents laterally and ends in a blunt apex (Fig. 84A).

Maximum length from foot to tip of perithecium 175–242 µm. Perithecium (including basal cells) 115– 133 × 27–34 µm. Antheridium (including pedicellar cell, without secondary appendages) 54–62 × 12– 16 µm. Length of primary appendage (when undamaged) from primary septum above cell III 209–294 µm.

Thalli were found on various body parts of the hosts. The hosts were sifted from moist moss and leaf litter in a partly shady peat bog, beaten from rush in a sun-exposed swamp along a rivulet, sifted from moist beech leaf litter in a partly dried out forest pond, sifted from wet Sphagnum mosses and leaves around Carex tussocks in a sun-exposed Sphagnum bog, sifted from moist fine crumb and mice-nests in and under Carex paniculata tussocks at the edge of a sun-exposed forest pond, sifted from moist leaf litter and moss in a raised bog, sifted from moist moss and leaf litter in a partly sun-exposed alder swamp, sifted from wet, fresh flood debris along the banks of a river and sifted from moist leaf litter and moss in an open willow/birch/alder swamp.

Remarks

Majewski (1994b) already mentioned that thalli on Oxypoda differ from those on Ocalea although he did not formally describe any new taxa. After studying the abundant material from Danish Oxypoda elongatula, we conclude that a new species should be erected because the differences are stable and remarkable.As mentioned above, in comparison with the closely allied M. fragilis, thalli of M. crassicaulis sp. nov. are larger, with narrower perithecia having a well-distinguished, bent neck, with a simple primary appendage, with both cells III as well as the basal cell of appendage producing a very characteristic figure, in addition to a broadened and distally inflated cell VI.