Paramyrothecium sinense J.M. Liang, G.S. Li & L. Cai

Liang, Junmin, Li, Guangshuo, Zhou, Shiyue, Zhao, Meiqi & Cai, Lei, 2019, Myrothecium-like new species from turfgrasses and associated rhizosphere, MycoKeys 51, pp. 29-53 : 29

Paramyrothecium sinense J.M. Liang, G.S. Li & L. Cai sp. nov. Fig. 6

Type.

China, Beijing, Olympic Park, from rhizosphere soil of Poa sp., 13 Dec 2017, S.Y. Zhou, holotype HMAS 247956, ex-holotype culture CGMCC3.19212 = LC12136.

Description.

Colonies on PDA, CMA and OA approx. 5-6 cm diam. after 7 d at 25 °C. Hyphae white, hyaline, smooth, branched, 1-2 μm wide, reverse on PDA pale luteous. Conidiomata sporodochial, stromatic, cupulate, superficial, scattered or gregarious, oval or irregular in outline, 80-600 μm diam., 50-150 μm deep, with a white setose fringe surrounding an olivaceous green to black agglutinated slimy mass of conidia. Stroma poorly developed, hyaline, of textura angularis. Setae arising from stroma, thin-walled, hyaline, 1-3-septate, straight to flexuous, 45-90 μm long, 1-3 μm wide, tapering to an acutely rounded apex. Conidiophores arising from the basal stroma, consisting of a stipe and a penicillately branched conidiogenous apparatus; stipes unbranched, hyaline, septate, smooth, 20-30 × 2-3 μm; primary branches aseptate, unbranched, smooth, 13-40 × 2-3 μm; secondary branches aseptate, unbranched, smooth, 8-15 × 2-3 μm; terminating in a whorl of 3-6 conidiogenous cells; conidiogenous cell phialidic, cylindrical to subcylindrical, hyaline, smooth, straight to slightly curved, 7-16 × 1-3 μm, with conspicuous collarettes and periclinal thickenings. Conidia aseptate, hyaline, smooth, cylindrical, 6-7 × 2-3 μm (av. 7 ± 0.3 × 2 ± 0.2 μm, n = 40), rounded at both ends.

Distribution.

China.

Etymology.

Named after the country of collection, China.

Additional isolate examined.

China, Beijing, Olympic Park, from rhizosphere soils of Poa sp., 13 Dec 2017, S.Y. Zhou, LC12137, LC12138, LC12139.

Notes.

Lombard et al. (2016) introduced a new genus, Paramyrothecium , based on an epitype of Myrothecium roridum Tode, 1790. Gams (2016) pointed out that Myrotheciella catenuligera , the type species of Myrotheciella was listed as a synonym of P. roridum by Lombard et al. (2016), thus Paramyrothecium is illegitimate and Myrotheciella should be the correct name for Paramyrothecium . However, the original description of Myrotheciella catenuligera suggested that it lacks seta ( Spegazzini 1911), thus is clearly different from the morphological circumscription of P. roridum . Therefore, we do not agree with the treatment of Lombard et al. (2016) of listing Myrotheciella catenuligera as a synonym of P. roridum .

Paramyrothecium sinense formed a highly supported distinct clade closely related to P. humicola . The setae of this species are terminated with obtuse apices, dissimilar to the acute apices in P. humicola . In addition, the conidiophore stipes (20-30 μm long) and primary branches (13-40 μm long) of P. sinense are much longer than those of P. humicola (stipe, 12-22 μm long; primary branches, 7-17 μm long) ( Lombard et al. 2016). Among old un-sequenced taxa in Myrothecium , only M. biforme and M. dimorphum show seta with obtuse apices, but both taxa produce two types of conidia ( Jiang et al. 2014; Watanabe et al. 2003).