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 Microsomyces psammoechi Thaxt. MB#275376 Fig. 16A–F Memoirs of the American Academy of Arts and Sciences 16: 185 ( Thaxter 1931 ) . – Type : “ On the superior surface of the abdomen of Psammoechus orbicollis Gr. No. 2199, Type , Kamerun , West Africa ”; FH . Diagnostic features Lower receptacle consisting of a thick-walled basal cell. The corticating cells ( Fig. 16D , cc) bear one to several long-stalked perithecia. Primary appendage consisting of 1–2 elongated cells terminated by a spinose antheridium ( Fig. 16D , an, sx). [Detailed description: Majewski 1988 ] Distribution and hosts On Psammoechus Boudier, 1834 (Col. Silvanidae ). This is a rare species on a common host. Only known from Sumatra, Cameroon ( Thaxter 1931 ), Japan ( Majewski 1988 ), and recently found in Europe from Bulgaria ( Rossi et al. 2019a ). Fig. 16. Microsomyces psammoechi Thaxt. A . General habitus with several thalli corticating on host integument. B . Three sporelings with labelled receptacle cells (I, II, and III), the primary septum (a), and a primary antheridium (an). C . Ascospore. D . Young thallus showing cell I, one corticated cell (cc), and the primary antheridium (an) with spinose remaining of ascospore apex (sx). E–F . Haustoria penetrating the host body (arrows). Scale bars: A, D–F = 50 µm; B = 20 µm; C = 25 µm. Photographs from slides ZMUC C-F-124046 (A, C–F), ZMUC C-F-123679 (B). Collections examined from Denmark On Psammoecus bipunctatus (Fabricius, 1792) (Col. Silvanidae ) DENMARK – Bornholm (B) • Svartingedalen ved Baggeå ; 55°11.740′ N , 14 45.260′ E ; VB81; 23 Jun. 2018 ; JP 1155 ; JP det.; ZMUC C-F-123679 , C-F-123680 . – Nordøstsjaelland (NEZ) • Strødam ; 55°58.056′ N , 12°16.273′ E ; UC20; 4 Oct. 2014 ; JP 33 ; JP det.; ZMUC C-F-122508 . – Nordvestsjaelland (NWZ) • Sonnerup Skov ; 55°56.643′ N , 11°34.213′ E ; PH60; 17 May 2019 ; JP 1466 ; JP det.; ZMUC C-F-124046 . – Sydsjaelland (SZ) • Denderup Sø i Denderup Vaenge ; 55°15.075′ N , 11°57.366′ E ; PG82; 9 Jun. 2019 ; JP 1476 ; JP det.; ZMUC C-F-124056 • Østerskov ved Langebaek ; 54°59.421′ N , 12°6.435′ E ; UA19; 19 Aug. 2019 ; JP 1498 ; JP det.; ZMUC C-F-124085 . Remarks First record from Denmark and second from Europe. Probably rare in Denmark and considering the large number of specimens of the widespread and very common host that were examined without finding any infections, it might even be very rare. This species, like its congener, should be considered a true parasite because of the highly developed and branched haustorium which deeply penetrates into the host body ( Fig. 16E–F , arrows).