Naviculisporaceae Y. Marin & Stchigel, in Marin-Felix, Miller, Cano-Lira, Guarro, García, Stadler, Huhndorf & Stchigel, Microorganisms 8 (9, no. 1430): 12 (2020)

Index Fungorum number: IF 835496; MycoBank number: MB 835496Facesoffungi number: FoF14637

Etymology – Named after Naviculispora, the type genus of this family.

Type genus – Naviculispora Stchigel, Y. Marín, Cano & Guarro.

Sexual morph Ascomata ostiolate, less frequently non-ostiolate, immersed or superficial, scattered or aggregated, brown to dark brown or black, globose to subglobose, pyriform or ovate, glabrous or covered with flexuous or stiff hairs; neck short or long, dark brown to blackish, conical or cylindrical, papillate, rarely glabrous, mostly with elongate tuberculated projections at the base or covered with small black papillae. Ascomatal wall membranaceous, pseudoparenchymatous, semi-translucent, yellowish to light brown or olivaceous brown, textura angularis or irregularly-shaped cells, or blackish brown, opaque, areolate, cracking in polyhedral plates when crushed. Paraphyses absent or present. Asci unitunicate, 8- to 256-spored, cylindrical or clavate, evanescent, long- or short-stipitate, without apical ring, or apical ring indistinct or distinct, small, subapical globulus or chamber absent or present. Ascospores biseriate or irregularly arranged into the asci, mostly two-celled. One-celled ascospores at first hyaline, becoming ochraceous to brown or blackish brown when mature, ellipsoidal, with somewhat pointed ends, smooth-walled, provided at each end with a germ pore and a lash-like gelatinous cauda. Two-celled ascospores at first one-celled and hyaline, clavate, cylindrical or spatuliform, sometimes vermiform, becoming transversely septate and two-celled; upper cell olivaceous or brown to dark brown, navicular, conical, ellipsoidal, ellipsoidal-fusiform, limoniform, pyriform or obclavate, smooth-walled, septate, with an apical or subapical germ pore, sometimes with one or more transverse septa; lower cell hyaline or pale brown, rarely dark brown, hemispherical, cylindrical, cylindrical-obclavate, or cylindrical-conical, thick- or thin-walled, sometimes with the same length or longer than the upper cell, collapsing or not with age, rarely with 3-5 septa; several secondary appendages sometimes present, small, at the base; apical gelatinous cauda absent or present, lash-like, fibrillate or lamellate. Asexual morph absent or present. Conidiphores reduced to conidiogenous cells or sympodially proliferating. Conidiogenous cells phialidic. Conidia holoblastic, sometimes sessile, hyaline to subhyaline, ellipsoidal to subspherical, obovoid or clavate.

Notes – The family shows a high morphological variability: Arnium caballinum, A. japonense, and A. mendax produce one-celled ascospores [9,39], while in the rest of the species of the family, these are two-celled. Taxa with both kinds of ascospores are also observed in the family Lasiosphaeriaceae s.str. as well as in Podosporaceae and Schizotheciaceae. The ascomata are mostly ostiolate, except in Z. marina, Z. pilifera, and Z. submersa, in which they are non-ostiolate. In our phylogenetic study, these three species with non-ostiolate ascomata grouped in a well-supported clade (100 bs/1 pp) together with T. mangenotii, which produces ostiolate ascomata, suggesting that these could represent a new genus. Further molecular and phenotypic studies are needed to confirm this hypothesis. The ascomatal wall is mostly membranaceous, except in the new genus Areotheca (introduced below), which is characterized by an areolate ascomatal wall. Among the Sordariales, this type of ascomatal wall is only seen in two species of Cladorrhinum, i.e., Cl. coprophilum and Cl. tomentosum. It is also found in a few other Cercophora species, i.e., C. caerulea, C. septentrionalis, and C. sylvatica, but their walls are not as carbonaceous as in Areotheca, in which the fully developed carbonaceous wall breaks into polyhedral plates when crushed. Within the Naviculisporaceae, reference strains of C. ambigua and C. areolata formed a well-supported clade (100 bs/1 pp; Figure 2). Both species are characterized by a well-developed carbonaceous, areolate ascomatal wall that cracks into polyhedral plates when crushed (cephalothecoid). The new genus Areotheca is proposed here to accommodate these two species.