Aspergillus megasporus Visagie, Yilmaz & Seifert

Visagie, Cobus M., Yilmaz, Neriman, Renaud, Justin B., Sumarah, Mark W., Hubka, Vit, Frisvad, Jens C., Chen, Amanda J., Meijer, Martin & Seifert, Keith A., 2017, A survey of xerophilic Aspergillus from indoor environment, including descriptions of two new section Aspergillus species producing eurotium-like sexual states, MycoKeys 19, pp. 1-30 : 7-9

Aspergillus megasporus Visagie, Yilmaz & Seifert sp. nov. Fig. 6

Etymology.

Latin, megasporus, in reference to the large conidia produced by this species.

Typus.

Canada, Nova Scotia, Wolfville, house dust, 29 January 2015, collected by Allison Walker, isolated by Cobus M. Visagie, holotype DAOM 741781, culture ex-type DAOMC 250799 = CBS 141929 = DTO 356-H7 = KAS 6176.

Additional material examined.

Canada, New Brunswick, Little Lepreau, house dust, 29 January 2015, collected by Allison Walker, isolated by Cobus M. Visagie, culture DAOMC 250800 = DTO 356-H1 = KAS 5973. The Netherlands, Dutch chocolate butter, August 2007, collected and isolated by Martin Meijer, culture CBS 141772 = DTO 048-I3.

ITS barcode.

KX540910. Alternative identification markers: BenA = KX450892, CaM = KX450905, RPB2 = KX450897.

Colony diam

7 d (in mm), 25 °C.CYA 3-8; CY20S 30-35; MEA 3-5; MEA20S 24-35; DG18 47-50; YES 15-16; M40Y 45-47; MY50G 35-40; MY10-12 40-44; CY20S, DG18, MEA20S at 37 °C no growth, CREA no growth.

Colony characters.

CYA: Colonies with restricted growth; conidiophores and cleistothecia absent. CY20S: Colonies grow faster than on CYA; sporulation moderately dense, greyish to dark green (30E5-F5); cleistothecia yellow, sparse. MEA: Colonies with restricted growth; conidiophores and cleistothecia absent. MEA20S: Colonies grow faster than on MEA; sporulation moderately dense, greyish to dark green (30E5-F5); cleistothecia yellow, moderately abundant. DG18: Colonies very fluffy with abundant aerial mycelia giving rise to conidiophores; sporulation moderately dense, dull to dark green (28E3-F3); cleistothecia abundant, dark yellow to orange. Homothallic.

Micromorphology on DG18.

Cleistothecia eurotium-like, wall consisting of one layer of flattened cells, yellow to orange, globose, 115-205 μm diam. Asci eight-spored, globose, ellipsoidal to pyriform, 14-19.5 μm diam. Ascospores lenticular, equatorial crest roughened, convex surface smooth, 5-8 × 3.5-6 μm (6.4 ± 0.6 × 4.9 ± 0.5), n = 51. Conidiophores radiate and columnar, uniseriate; stipes smooth, (30 –)60– 1000 × (9 –)13– 20 μm; vesicle globose, (8.5 –)20– 60 μm diam; phialides ampulliform, covering 70-100% of vesicle, (9 –)11– 15 × 5-7 μm; conidia roughened to spiny, ellipsoidal, connectives often visible, 7-12 × 6-8.5 μm (9.5 ± 1.0 × 6.9 ± 0.5), average width/length = 0.72, n = 85.

Extrolites.

Echinulin; neoechinulin A & B; preechinulin; quinolactacin A1 & A2; unknowns C15H20O2, C21H37N, C24H30O6, C29H37O2N3, C21H44O2. In addition, asperflavin, emodin, erythroglaucin, physcion and bisanthron were found in CBS 141772. Some additional extrolites, tentatively identified as tetracyclic compounds, were detected in CBS 141772

Notes.

The concatenated phylogeny of BenA, CaM and RPB2 resolves Aspergillus megasporus in a clade with Aspergillus brunneus , Aspergillus niveoglaucus , Aspergillus neocarnoyi , Aspergillus glaucus and Aspergillus proliferans . None of these species are able to grow on CY20S at 37 °C. Aspergillus niveoglaucus and Aspergillus megasporus can be distinguished from other species by their large conidia, which are up to 11 and 12 μm in the longest axis respectively. Aspergillus megasporus colonies grow faster than Aspergillus niveoglaucus on DG18.