Thyrinulaceae X.Y. Zeng, S. Hongsanan & K.D. Hyde, fam. nov.

MycoBank number: MB 557945; Index Fungorum number: IF 557945; Facesoffungi number: FoF 06898, 10 species.

Pathogens on surface of leaves or petioles. Leaf spots epiphyllous or hypophyllous, circular to irregular, single to confluent, brown. Sexual morph: Ascomata superficial, dark brown, hysterothecial, opening by elongated, longitudinal or Y-shaped slits, margin without restricted brown, superficial hyphae. Asci 8-spored, bitunicate, broadly ellipsoid to somewhat obovoid, intermixed among hyphae-like, septate, branched pseudoparaphyses, with ocular chamber. Ascospores cylindrical to ellipsoid, hyaline, 1-septate, constricted at septum, ends obtusely rounded, guttulate, smooth-walled. Asexual morph: Coelomycetous or hyphomycetous. Coelomycetous: Mycelium brown, septate, branched, verrucous. Conidiomata brown, acervular, solitary to gregarious or confluent, immersed to erumpent, depressed globose, unilocular. Ostiole absent, dehiscence by irregular splits of apical wall in the middle part. Conidiomatal wall composed of a single layer of brown cells in the basal part. Conidiophores arising from inner wall layer of basal stroma, brown, branched at the base, septate. Conidiogenous cells brown, holothallic, cylindrical, integrated or discrete, determinate, verrucous. Conidia brown, arthric, formed by disarticulation of the conidial chain, produced in simple unbranched chains with the youngest conidium at the base, surrounding by mucoid sheath, ellipsoidal to globose or subcylindrical, truncate at the base, aseptate, verrucose, guttulate (adapted from Giraldo et al. 2017). Hyphomycetous asexual morph: Conidiophores single or sporodochial, if conidiophores single, micronematous, mononematous, straight to slightly flexuous, brown, septate, smooth; if conidiophores sporodochial, brown, verrucose, thick-walled,  branched, septate. Appressoria when present, numerous, entire, globose to cylindrical, alternate to unilateral, aseptate, brown, penetration peg central on the appressorial cell. Conidiogenous cells holoblastic, monoblastic, integrated, intercalary, cylindrical to elliptical, light brown to brown, smooth, sometimes with indistinct scars. Conidial secession schizolytic. Conidia solitary or in branched or simple acropetal chains, ellipsoidal to cylindrical, aseptate to multiseptate, medium brown to brown, smooth or verruculose, sometimes with rounded ends.

Type: Thyrinula Petr. & Syd.

Notes: This family is introduced to accommodate species that are phylogenetically related to Asterinales sensu lato, a clade that is typified by the type sequence data of Asterina and Lembosia obtained by Guatimosim et al. (2015). However, the genetic distance between the two genera is less than the two Asterina species in their phylogeny, indicating that these two sequences are questionable. There are three genera included in this family based on phylogeny, and they are sister to Parmulariaceae (Parmulariales).