Curvularia petersonii Y.P. Tan & R.G. Shivas

Tan, Yu Pei, Crous, Pedro W. & Shivas, Roger G., 2018, Cryptic species of Curvularia in the culture collection of the Queensland Plant Pathology Herbarium, MycoKeys 35, pp. 1-25 : 1

Curvularia petersonii Y.P. Tan & R.G. Shivas sp. nov. Fig. 4 D–G

Type.

Australia, Northern Territory, Daly Waters, from leaf spot on Dactyloctenium aegyptium , 20 Mar. 1985, R.A. Peterson (holotype BRIP 14642, includes ex-type culture).

Description.

Colonies on PDA approx. 5 cm diam. after 7 d at 25 °C, surface funiculose, olivaceous black, velutinous with some aerial mycelium, margin fimbriate. Hyphae subhyaline, smooth to asperulate, septate, up to 3 µm in width. Conidiophores erect, straight to flexuous, rarely branched, slightly geniculate, uniformly brown, sometimes pale brown at apex, smooth, septate, up to 110 µm long, 4 µm wide. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia obovoid to ellipsoidal, straight to slightly curved, (15-) 17-19 (-21) × (5-) 5.5-6 (-7) µm, brown, end cells pale, 3-distoseptate, hila non-protuberant, thickened and darkened.

Etymology.

Named after Ron A. Peterson, an Australian plant pathologist, in recognition of his contributions to tropical plant pathology.

Notes.

The multilocus phylogenetic analyses placed C. petersonii sister to C. americana and C. verruculosa , although separated by a considerable genetic distance (Fig. 1). Both C. americana and C. verruculosa have been found in Australia ( DAF Biological Collections 2018, Herbarium Catalogue 2018). Curvularia petersonii is distinguished from the ex-type culture of C. americana in two loci (94% in ITS and 92% in gapdh) and from a reference culture of C. verruculosa in three loci (92% in ITS, 92% in gapdh and 98% in tef1α). Curvularia petersonii has smaller conidia than C. americana (13-28 × 7-15 µm, Madrid et al. 2014) and C. verruculosa (20-40 × 12-17 µm, Sivanesan 1987).

Curvularia petersonii is only known from a single specimen on Dactyloctenium aegyptium in the Northern Territory. Many Curvularia species have been associated with Dactyloctenium , including C. clavata , C. dactyloctenicola , C. dactyloctenii , C. eragrostidis , C. lunata , C. neergaardii , C. pallescens and C. verruculosa ( Sivanesan 1987, Manamgoda et al. 2014, Farr and Rossman 2018, Herbarium Catalogue 2018, Marin-Felix et al. 2017b), although these records have not been verified by phylogenetic analyses.