Atrotorquata spartii Thambugala, Camporesi & K.D.Hyde.
Index Fungorum number: IF550914, Facesoffungi number: FoF00387, Fig. 1
Etymology – In reference to the host genus Spartium
Holotype – MFLU 14–0738
Saprobic on Spartium junceum. Sexual morph Ascomata 400–475 μm high × 280–375 μm diam. (x̄ = 435×337 μm, n = 5), solitary to scattered, or sometimes gregarious, immersed beneath clypeus, dark brown to black, unilocular, globose to subglobose with a central ostiole. Peridium 15–32 μm wide, composed of thick walled, dark brown to black cells of textura angularis. Hamathecium comprising 3–4 μm wide, septate, guttulate, hyaline paraphyses, embedded in a gelatinous matrix. Asci 160–230 × 14–24 μm (x̄ = 196 × 20 μm, n = 10), 8-spored, unitunicate, cylindric-clavate, straight or curved, short pedicellate, with an apical ring bluing in Melzer’s reagent. Ascospores 19–23 × 8.5–9.5 μm (x̄ = 21.2 × 9 μm, n = 15), uniseriate, ellipsoid to fusiform, rounded at both sides, hyaline when immature, becoming brown to yellowish-brown when mature, 1-septate, constricted at the septum, guttulate, smooth-walled or striate, surrounded by a mucilaginous sheath. Asexual morph Undetermined.
Culture characters – Ascospores germinating on PDA within 24 h and germ tubes arising from both end cells. Colonies growing slow on PDA, reaching a diam. of 20 mm after 30 days at 18 °C, circular, dense, initially white becoming pale white, velvety, radiating towards the entire to slightly undulate edge, non-pigmented.
Material examined – ITALY, Province of Rimini [RN], Pennabilli, on dead branches of Spartium junceum L. (Fabaceae), 9 October 2012, E. Camporesi, IT 799–1 (MFLU 14–0738 holotype), ex-type living cultures, MFLUCC 13–0444. ibid., Province of Forlì-Cesena [FC], Fiumicello, Premilcuore, on dead branches of Spartium junceum (Fabaceae), 29 April 2013, E. Camporesi 799–2 (MFLU 14–0821), living cultures, MFLUCC 13–0445.
GenBank accession numbers – LSU: KP325443
Notes – Atrotorquata was introduced by Kohlmeyer and Volkmann-Kohlmeyer (1993) as a monotypic genus in order to accommodate Atrotorquata lineata. This genus is characterized by ascomata immersed under a clypeus, cylindrical asci with a J+, apical ring and brown, two-celled, ascospores, with 5–7 longitudinal striations at each apex, and surrounded by a mucilaginous sheath (Kang et al. 1999a, b). Kang et al. (1999a, b) placed Atrotorquata in Cainiaceae based on morphology. Unfortunately, the LSU sequence data for Atrotorquata lineata are not publicly available, while the available ITS sequence (AF009807) has not been included in any publication. In our LSU phylogenetic tree, Atrotorquata spartii is closely allied to Monographella nivalis (UPSC 3273) and clustered outside of the Cainiaceae. Based on a megablast search of NCBIs GenBank nucleotide database, the closest hit using the ITS sequence for our second
collection MFLU 14–0821/ MFLUCC 13–0445 is Atrotorquata lineata (GenBank AF009807; Identities=405/ 489(83 %). Atrotorquata lineata shares similar morphology with A. spartii in having immersed, subglobose ascomata, cylindrical asci with a J+, apical ring, and uniseriate, brown, 1-septate ascospores, but differs in having a hyaline clypeus, a light brown to hyaline peridium and ellipsoidal, slightly curved ascospores. Based on both morphology and molecular phylogeny, A. spartii is identified as a new species of the genus Atrotorquata. Multi-gene phylogenetic analysis of the type species of Atrotorquata is required in order to confirm the family placement in this genus.
Fig. 1 Atrotorquata spartii (holotype) a, b Appearance of ascomata on host substrate as minute ostiolar dots c Section through ascoma d Ostiole. e Peridium f Pseudoparaphyses g Ascus in Melzer’s reagent showing J+, apical apparatus h–j Immature and mature unitunicate ascospores k–o Ascospores. Scale bars: c=150μm, d, h–j=50μm, e=20μm, f, k–o=10μm.