Laboulbeniomycetes (Fungi, Ascomycota) of Denmark Author Santamaria, Sergi Unitat de Botànica, Departament de Biologia Animal, de Biologia Vegetal i d’Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès (Barcelona), Spain. sergi.santamaria@uab.cat Author Pedersen, Jan Natural History Museum of Denmark (Zoological Museum), University of Copenhagen, Universitetsparken 15, 2100 København Ø, Denmark. japedersen@snm.ku.dk text European Journal of Taxonomy 2021 2021-11-26 781 1 425 http://dx.doi.org/10.5852/ejt.2021.781.1583 journal article 10.5852/ejt.2021.781.1583 2118-9773 5828924 Monoicomyces reboleirae Santam. sp. nov. MB#840608 Fig. 90 Diagnosis Cell VI darkened and constricted below. Primary appendage and cell III pale yellow. Perithecium asymmetric, bearing a conspicuous horn-like outgrowth near the base of the tip which is distinctly bent. Etymology Named after Sofia Reboleira, Portuguese student of millipedes and their fungi, who has actively collaborated in this project. Type material Holotype DENMARK – Lolland, Falster, Møn (LFM) • Gedser ; 54°33.588′ N , 11°58.187′ E ; PF95; on Gnypeta carbonaria (Mannerheim, 1830) (Col. Staphylinidae Aleocharinae ); 29 Sep. 1895 ; F. de Tengnagel Dry0149 ; F. de Tengnagel det.; ZMUC C-F-124216 . Description Thallus amber-coloured, with a blackened foot. Basal cell of receptacle (I) obconical, about 1.5 times as long as broad. Suprabasal cell of receptacle (II) small, triangular to trapezoidal, slightly broader than long. Cell III pale yellowish, cylindrical, 1.5 times as long as broad, sometimes slightly constricted at middle height. Primary septum distinctly constricted ( Fig. 90D, a ). Each thallus includes two secondary receptacles arising from cell II, including respective antheridia and perithecia or their initials. Primary appendage unbranched, entirely pale, consisting of up to six cells gradually longer and slenderer from below upwards, not exceeding in length the perithecial apex. Antheridia pale yellowish, consisting of four superposed tiers of paired cells ( Fig. 90E ). Each of the four cells of the 2 nd and 3 rd tiers bear one phialide. The 4 th tier bears two short secondary appendages, arising side by side but immediately diverging. Perithecial stalk cell (VI) about 1.5 times as long as broad, strongly narrower and darker on its lower half, abruptly inflated upwards, then constricted below the perithecial base. Perithecium more deeply pigmented than surroundings, asymmetric in side view, with an inflated venter. A horn-like outgrowth (remains of the trichogyne base) is found on the base of w 3 wall cell tier, on the same side where the perithecium is much convex, pointing upwards and darker than the perithecial venter ( Fig. 89C , arrow). Perithecial neck short, poorly distinguished, below a rounded, stout, laterally bent apex. Length from foot to tip of perithecium 121–151 µm. Perithecium (including basal cells) 67–79 × 31– 43 µm. Antheridium (including pedicellar cell, without secondary appendages) 36–44 × 11–14 µm. Maximum length of primary appendage (when undamaged) from primary septum above cell III 86 µm. Length of preapical outgrowth 10–12 µm. Fig. 90. Monoicomyces reboleirae Santam. sp. nov. A . A pair of mature thalli. B . Mature thallus. C . Perithecium in detail with arrow pointing to outgrowth. D . Basal area of a thallus in detail showing the primary appendage at left with labelled primary septum (a), the lower receptacle with cells I, II, and III, and the antheridium including labelled stalk (II’) and four tiers of cells (t1–4). E . Base of a thallus in detail, with labelled cells I, II, III and VI. Scale bars: A–B = 50 µm; C–E = 20 µm. Photographs from slide ZMUC C-F-124216 (holotype). Thalli were found very concealed in the last retracted segments of the abdomen of the host. Nothing is known about the collecting circumstances of the host. Remarks This is a well-distinguished species that grows on the last abdominal segment of its host. Thalli are very small and difficult to be detected. It may be compared with M. denticulatus Thaxt. which also has a horned perithecium, but differs by the darkened secondary receptacles lacking secondary appendages. Monoicomyces denticulatus was described from Java and Sumatra on Stenomastax Cameron, 1933 and Atheta (as Homalota ) (Col. Staphylinidae Aleocharinae ) by Thaxter (1915) .