Piedraiaceae Viégas ex Cif., Bat. & S. Camposa, Publicações Inst. Micol. Recife 45(1-6): 7 (1956).
MycoBank number: MB 82066; Index Fungorum number: IF 82066; Facesoffungi number: FoF 06972, 2 species.
Pathogenic on human hair. Sexual morph: Ascostroma with pseodoparenchymatic tissue, vary in size and shape. but usually flat, elongated and with a rough surface, dark in colour, multi-loculate in section, containing numerous cavities, irregularly distributed throughout. Each locule becomes erumpent as the asci mature, and can be visible as a small dimple, and contains a single ascus. Pseudostiolate locules, without pseudoparaphyses, with paraphysoids. Asci 8-spored, bitunicate, subglobose to broadly ellipsoidal. Ascospores overlapping, fusiform, curved, more or less straight to falcate, tapering towards both ends, hyaline, rarely light yellowish or greenish, aseptate, thin- walled, with tapering gelatinous appendages or without appendages. Germination by several germ tubes (Ciferri et al. 1956, von Arx & Müller 1975, Eriksson 1981, Liu 2011). Asexual morph: Undetermined.
Type – Piedraia Fonseca & Leão.
Notes – Piedraiaceae was described by Ciferri et al. (1956) under Myriangiales. Piedraiaceae consists of only one genus Piedraia recorded in tropical regions with two species, P. hortae the type species and P. quintanilhae. Piedraia hortae (sexual morph) is a superficial keratinolytic parasite on human hair, known as “black piedra”. The asexual morph of P. hortae is undetermined. Phylogenetic analyses indicated that Piedraia hortae is closely related to Mycosphaerella (Lindemuth et al. 2001, Selbmann et al. 2005). Multi-gene analysis of Dothideomycetes (Schoch et al. 2006) included Paedraiaceae under Capnodiales. Crous et al. (2009c) provided sequence data of four strains of Piedraia hortae (CBS 276.32, CBS 374.71, CBS 375.71, and CBS 480.64) and P. quintanilhae (CBS 327.63). They found that Piedraiaceae clustered within Teratosphaeriaceae with high bootstrap support (>95 % MLBS). Thus, Crous et al. (2009c) treated Piedraia under Teratosphaeriaceae. This result is the same as in Chomnunti et al. (2014) and this study (Fig. 3). However, Teratosphaeriaceae mostly contains plant pathogens. Thus, Piedraiaceae is retained until more evidence is available to resolve its taxonomic placement.