Curvularia colbranii 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 colbranii Y.P. Tan & R.G. Shivas sp. nov. Fig. 3 A–D

Type.

Australia, Queensland, Brisbane, from leaf spot on Crinum zeylanicum , 11 Oct. 1976, R.C. Colbran (holotype BRIP 13066, includes ex-type culture).

Description.

Colonies on PDA approx. 5 cm diam. after 7 d at 25 °C, surface funiculose, margin fimbriate, olivaceous black, aerial mycelium white. Hyphae subhyaline, smooth, septate, up to 3 µm in width. Conidiophores erect, flexuous, geniculate, uniformly pale brown to brown, smooth, septate, up to 145 µm long, 4-6 µm wide, basal cell sometimes swollen, up to 8 µm diam. Conidiogenous cells integrated, terminal or intercalary, with sympodial proliferation, pale brown to brown, smooth, mono- or polytretic, with darkened scars. Conidia fusiform to subcylindrical with rounded apex and obconical at the base, brown, end cells pale, (54-) 83-92 (-110) × (13-) 14-16 (-17) µm, brown to dark brown, 6-9-distoseptate; hila slightly protuberant, thickened and darkened, 1-2 µm wide.

Etymology.

Named after Dr Robert (Bob) Chester Colbran (1926-2010), an Australian nematologist and Director of the Plant Pathology Branch, Queensland Department of Primary Industries, in recognition of his significant contributions to Australian plant pathology.

Notes.

Curvularia colbranii is sister to C. boeremae , C. lamingtonensis (see this paper), C. neoindica and C. portulacae , although separated by a considerable genetic distance (Fig. 1). Curvularia colbranii has fusiform to subcylindrical conidia that are distinct from the ellipsoidal to oval conidia of C. boeremae (42-55 × 17-25 µm, this study) and C. neoindica (27-65 × 17-27 µm, Manamgoda et al. 2014) and longer than those of C. lamingtonensis (45-76 × 11-14 µm, this study). Curvularia colbranii has conidia that are 6-9-distoseptate, while C. portulacae has conidia reported as 3-15 celled ( Rader 1948).

Only one other species, C. trifolii , has been reported on Crinum sp. ( Shaw 1984), but this record has not been verified by phylogenetic analyses. Curvularia colbranii is morphologically distinct from C. trifolii , which has curved conidia.