Named in honor of Josep Guarro for his contributions to our knowledge of microfungi.

Spain, Catalonia, Alt Camp, Alcover, Brugent River, sediments, Mar. 2019, D. Torres & J. Gené (holotypeCBS H-24782, cultures ex-type CBS 148238 = FMR 17747).

Subgenus Aspergilloides, sectionGracilenta, series Estinogena.

Mycelium superficial and immersed, composed of septate, smooth-walled, hyaline hyphae, 2.5–3.5 μm wide. Conidiophores predominantly symmetrically biverticillate, occasionally with subterminal branches; stipes smooth- to rough-walled, 88–215 × 3–4 μm; metulae appressed, 2–4 per stipe, vesiculate, 5–10 × 2–4.5 μm (vesicle up to 5.5 μm wide); phialides 3–6 per metula, ampulliform, 6–9 × 1.5–3 μm; conidia smooth-walled, globose, 2–2.5 × 2–2.5 μm.

Colonies on CYA, 38–40 mm diam., slightly raised at center, radially sulcate, velvety, brownish gray (6C2) and white (1A1) towards periphery, margins fimbriate, sporulation moderate, conidial masses greenish gray (28C2); reverse dark brown (6F6) and light brown (6D6) at periphery, becoming entirely brown after 14 d; soluble pigment absent. On MEA, 41–43 mm diam., slightly raised, granular, yellowish green (29B7) and white (1A1) towards periphery, margins slightly fimbriate, sporulation moderate, conidial masses grayish green (28D2); reverse yellowish brown (5E6) at center to grayish yellow at periphery; soluble pigment absent. On YES, 49–51 mm diam., raised at center, radially sulcate, velvety, brownish gray (5C2) and white (1A1) at periphery, margins entire, sporulation sparse, conidial masses greenish gray (28D2); reverse dark green (30F5) and yellowish brown (5D5) towards periphery; soluble pigment absent. On OA, 24–26 mm diam., elevated at center, velvety, white (1A1) at center and dull green (25E3) towards periphery, margins regular, sporulation moderate, conidial masses dull green (25D4); reverse brown (6E4) and yellowish gray (4B2) at periphery; soluble pigment absent. On DG18, 22–25 mm diam., flattened, granular, grayish green (30C3) at center, and dull green (29D49) towards periphery, margins fimbriate, sporulation moderate, conidial masses greenish gray (27D2); reverse grayish green (30E5) and white (1A1) at periphery, soluble pigment absent. On CREA, 22–25 mm diam., flattened, floccose, yellowish green (29B7) and white (1A1) at periphery, margins irregular, sporulation moderate, conidial masses grayish green (27B3–D3); reverse dark gray (1F1); soluble pigment absent, no acid production.

5 °C no growth, 15 °C 17–19, 20 °C 26–28, 30 °C 34–36, 35 °C 4–5, 37 °C no growth, 40 °C no growth.

Spain.

Penicilliumguarroi is the second species included in sectionGracilenta series Estinogena (Fig. 7). This species shows morphological attributes of the series based on its type P.estinogenum, namely that both have symmetrically appressed biverticillate conidiophores with rough-walled stipes (Houbraken et al. 2020). However, P.guarroi mainly differs from P.estinogenum by producing strictly smooth-walled globose conidia, which are ellipsoidal to ovate and with smooth to finely roughened walls in the latter (Abe 1956; Houbraken et al. 2020). In addition to their phylogenetic distance, other members of sectionGracilenta (i.e., series Gracilenta and Macrosclerotiorum) can be differentiated morphologically by the production of monoverticillate conidiophores and the lack of growth at 37 °C, with the exception of P.apimei and P.aquaticum, which are able to grow at this temperature (Barbosa et al. 2018; Houbraken et al. 2020). Penicilliumguarroi was unable to grow at 37 °C, but it shows a maximum temperature for growth at 35 °C (4–5 mm), like other members in the section (i.e., P.macrosclerotiorum, P.angustiporcatum, P.gracilentum and P.estinogenum).