Curvularia paraverruculosa Iturrieta-Gonzalez , Gene & Dania Garcia, 2020

Iturrieta-Gonzalez, Isabel, Gene, Josepa, Wiederhold, Nathan & Garcia, Dania, 2020, Three new Curvularia species from clinical and environmental sources, MycoKeys 68, pp. 1-21 : 1

Curvularia paraverruculosa Iturrieta-Gonzalez, Gene & Dania Garcia sp. nov. Fig. 2

Etymology.

Name refers to the phylogenetic closeness to Curvularia verruculosa .

Type.

Mexico, Michoacán, Villa Jiménez, from soil, Sept 2016, E. Rosas de Paz. (holotype CBS H-24293, culture ex-type FMR 17656, CBS 146220).

Description

(PDA at 25 °C). Mycelium composed of branched, septate, subhyaline to pale brown, thin- and smooth-walled hyphae, 2-4 μm wide. Conidiophores semi- to macronematous, mononematous, septate, straight or flexuous, geniculate at upper part, unbranched or slightly branched, smooth-walled, yellowish-brown to brown, 19-85(-145) × 3-6 μm (av. ( ± SD) 49.6 ( ± 43.8) × 4.6 ( ± 0.69)). Conidiogenous cells terminal or intercalary, polytretic, proliferating sympodially, yellowish-brown, with darkened scars, subcylindrical, 4-6 μm wide. Conidia 3(-4)-septate, mostly curved at the third cell from base which is usually larger than the others, sometimes apically bifurcate, verruculose to verrucose, apical and basal cells subhyaline to pale brown, middle cells brown, 11-37 × 8-12 μm (av. ( ± SD) 24 ( ± 18.38) × 9.58 ( ± 1.66)); hila slightly protuberant, thickened and darkened. Sexual morph not observed.

Culture characteristics

(7 d at 25 °C). Colonies on PDA reaching 45 mm diam., dark green (30F8), final edge whitish, velvety, flat, margin regular and fimbriate; reverse dark green (30F8). On PCA and OA, reaching 58-60 mm diam., dark green (30F8), final edge whitish, slightly floccose, flat, margin regular and fimbriate; reverse dark green (30F8). Sporulation was abundant on the three media.

Cardinal temperature for growth.

Optimum 30 °C, maximum 37 °C, minimum 15 °C.

Distribution.

Mexico.

Notes.

Curvularia paraverruculosa is allocated phylogenetically to a strongly-supported clade (100/1) with C. verruculosa and C. americana (Fig. 1 ). All three species commonly have 3-septate conidia, but these can be distinguished by their size and ornamentation. Although conidia in C. verruculosa , the closest phylogenetic species and C. paraverruculosa are entirely verruculose, they are larger in the former (20-40 × 12-17 μm) ( Sivanesan 1987). Furthermore, C. paraverruculosa also produces apically bifurcate conidia (Fig. 2 ), which have not been described in C. verruculosa . The conidia of C. americana are smaller (13-28 × 7-15 μm) and smooth-walled with a slightly verruculose basal cell ( Madrid et al. 2014). In addition, microconidiation, described in C. americana , has not been observed in C. paraverruculosa .

Figures

Figure 1. Phylogenetic tree of the Curvularia species most related to the new taxa based on Maximum Likelihood analysis obtained by RAxML, using the combined analysis of ITS, gapdh and tef 1 and rooted with Bipolaris maydis CBS 136.29 and Bipolaris saccharicola CBS 155.26. Bootstrap values (bs) greater than 70 % and Bayesian posterior probabilities (pp) greater than 0.95 are given at the nodes (bs / pp). Bold branches indicate bs / pp of 100 / 1. The novel species are highlighted in bold. Ex-type isolates are marked with a superscript T.

Figure 2. Curvularia paraverruculosa sp. nov. (ex-type FMR 17656). A-C Colonies on PDA, PCA and OA, respectively, at 25 ° C after 7 d D-H conidiophores and conidia. Scale bars: 10 μm.