Spathulosporaceae Kohlm., Mycologia 65(3): 615 (1973)
MycoBank number: MB 81388; Index Fungorum number: IF 81388; Facesoffungi number: FoF 01798; 6 species.
Parasitic on marine algae. Sexual morph: Ascomata subglobose, ovoid, pyriform, subiculate, coriaceous or leathery, dark brown, sterile hairs enclosing ascoma, ostiolate, ostiolar canal surrounded by tube-like projection extending into the ascomatal cavity, papillate or epapillate. Paraphyses lacking. Asci 8-spored, clavate to subglobose, thin-walled, unitunicate, without apical ring, deliquescing early. Ascospores overlapping multi-seriate, hyaline, fusiform, cylindrical or ellipsoidal, aseptate to 3-septate, with apical appendages. Reproductive structures: Antheridial. Spermatia ellipsoidal to fusiform, without appendages. Trichogynes simple or branched, septate, arising from the margin of young ascoma (adaped from Maharachchikumbura et al. 2016b).
Type genus – Spathulospora A.R. Caval. & T.W. Johnson
Notes – Spathulosporaceae is characterized by crustose, dark thalli, peg-like individual penetrating cells, intracellular crusts and stromata, antheridia with spermatia and trichogynes, ostiolate ascomata without paraphyses, deliquescing asci, and 1-celled, appendaged ascospores. The genus was introduced by Cavaliere & Johnson (1965) and currently comprises Spathulospora and Retrostium with six species (Nakagiri & Ito 1997, Index Fungorum 2020, Jones et al. 2019). However, sequence data are available only for S. antarctica and S. adelpha. This family was first placed in Spathulosporales then so as to read and then in Lulworthia (Kohlmeyer 1973, Inderbitzin et al. 2004, Campbell et al. 2005, Jones et al. 2009). However, Maharachchikumbura et al. (2015, 2016b) confirmed the placement of Spathulosporaceae in Spathulosporales by molecular analysis using available sequence data. Spathulospora was introduced by Cavaliere & Johnson (1965) and referred to the Spathulosporomycetes, Spathulosporomycetidae (Locquin 1984), Spathulosporales (Kohlmeyer 1973), Spathulosporaceae (Kohlmeyer 1973). It is a marine genus on the seaweed Ballia spp. (Rhodophyta), and is typified by Spathulospora phycophila. However, two Spathulospora species (S. antarctica, S. adelpha), have shown a relationship to Lulworthiales, but with low support (Inderbitzin et al. 2004, Campbell et al. 2005, Jones et al. 2009, 2019). There are no sequences for the type of this genus, hence, new collections, isolations and sequencing are required to determine its phylogenetic placement.