Odontotrematales Lu€cking ordo nov.
MycoBank number: MB 832006;Index Fungorum number: IF 832006; Facesoffungi number: FoF 13852;
type: Odontotremataceae D. Hawksw. & Sherwood; saprotrophic fungi on wood or rarely parasitic, ascomata rounded, immersed-erumpent to sessile, chroodiscoid to biatorine, often carbonized, excipulum proso- to paraplectenchymatous, usually with distinct periphysoids, hymenium jelly I þ blue, paraphyses unbranched, asci cylindrical, with apically thickened, I– or weakly I þ bluish tholus with small and narrow ocular chamber, ascospores oblong-ellipsoid to cylindrical or fusiform-subsigmoid]. In the phylogenies provided by Baloch et al. (2010; 2013) and Kraichak et al. (2018), the family Odontotremataceae does not form a clade with Ostropales s.str. but falls outside or is sister to the Graphidales-Gyalectales clade; the species of Odontotrema s.lat. which are not related to the type of the genus but fall into Stictidaceae were recently reclassified in the genus Sphaeropezia (Baloch et al., 2013). Therefore, if the Ostropalean assemblage is split into several orders, Odontotremataceae must be recognized at ordinal level, not because of the temporal banding approach, but for topological reasons. Yang et al. (2019) provided a broader analysis of Odontotremataceae, including the genera Odontotrema (with Coccomycetella nested within), Claviradulomyces, Karstenia, and Parakarstenia; the latter expands the morphological and ecological variation of the family in having non-carbonized apothecia, lacking periphysoids, producing rather long ascospores, and being parasitic on bamboo.
In such a revised constellation of the ostropalean assemblage, there would be three basal orders with one family each (Thelenellales, Ostropales s.str., Odontotrematales), together forming a paraphyletic backbone, and two orders with five and two families, respectively (Gyalectales, Graphidales; see below regarding family-level classification within Graphidales). Thelenellales are lichenized and produce perithecioid ascomata; Ostropales s.str. are largely nonlichenized or facultatively lichenized, with apothecioid, typically erumpent ascomata; Odontotrematales are non-lichenized; Gyalectales are lichenized, their ascomata being apothecioid to perithecioid, with largely thin-walled asci; and Graphidales are predominantly lichenized, with apothecioid to often lirellate ascomata and thick-walled asci with a ring-shaped structure protruding into the lumen. This ordinal subdivision would thus go along with a solid level of information content and diagnostic resolution and is accepted here.
Families
Odontotremataceae