Referring to the submerged sediment sample where the fungus was isolated.

Spain, Catalonia, Montsant Natural Park, Siurana’s Swamp, from sediments, Feb. 2018, E. Carvalho & J. Gené (holotypeCBS H-24785, cultures ex-type CBS 148242 = FMR 17140).

Subgenus Penicillium, sectionRobsamsonia, series Urticicola.

Mycelium superficial and immersed composed of septate, smooth-walled, hyaline hyphae, 2–2.5 μm wide. Conidiophores mostly terverticillate, in minor proportion biverticillate and quarterverticillate; stipes smooth-walled, 29–142 × 1.5–2.5 μm; metulae divergent, mostly 2, occasionally 3 per stipe/branch, 5.5–7.5 × 1.5–4 μm; phialides 2–5 per metula, ampulliform, 4–5.5 × 1.5–2.5 μm; conidia smooth-walled, ellipsoidal, 3–3.5 × 2–2.5 μm.

Colonies on CYA, 34–37 mm diam., elevated, with some radially furrow, floccose, light yellow (4A5) and yellowish white (4A2) towards periphery, margins entire, sporulation sparse, conidial masses grayish green (28C4); reverse golden brown (5D7) and orange (5A6) at periphery; soluble pigment absent. On MEA, 28–29 mm diam., slightly elevated, floccose, white (1A1) to light yellow (4A5) at periphery, margins entire, sporulation sparse, conidial masses grayish green (27C3); reverse light yellow (4A5); soluble pigment absent. On YES, 33–36 mm diam., slightly elevated at center, radially sulcate, velvety, light brown (6D4) and white (1A1) towards periphery, margins slightly lobate, sporulation sparse, conidial masses grayish green (28C3); reverse grayish orange (5B5); soluble pigment absent. On OA, 18–20 mm diam., elevated at center, fasciculate, yellowish white (4A2) and pale gray towards periphery, margins low and entire, sporulation abundant, conidial masses grayish green (28B3); reverse grayish yellow (4C5); soluble pigment absent. On DG18, 11–13 mm diam., elevated, floccose, white (1A1) at center, pale yellow (4A3) and grayish yellow (4C3) towards periphery, margins entire, sporulation abundant, conidial masses grayish green (27C3); reverse light yellow (4A5) and yellowish white (2A2) at periphery; soluble pigment absent. On CREA, 15–19 mm diam., flattened, floccose, white (1A1) and pale yellow (3A3), margins low and irregular, sporulation sparse, conidial masses grayish green (28B3–C3); reverse white (1A1) and pale yellow (3A3); soluble pigment absent, acid production strong.

5 °C no growth, 15 °C 20–21, 20 °C 25–26, 30 °C 28–30, 35 °C 17–16, 37 °C 9–11, 40 °C no growth.

Spain.

Species in sectionRobsamsonia were characterized by restricted to moderately fast growth rate on CYA at 25 °C (15–32 mm diam in 7 d) and lack or slow of growth on CYA at 30 °C (up to 19 mm diam) (Houbraken et al. 2016; Houbraken et al. 2020). However, the novel species showed faster growth rates on CYA at both temperatures (i.e., 34–37 mm and 28–30 mm diam., respectively). Penicilliumsubmersum shares morphological features with the other two species (P.griseofulvum and P.dipodomycola) of the series Urticicola where it is classified (Fig. 2), which consisted in having bi-, ter, or quarterverticillate, divergent, smooth-walled conidiophores and short phialides (up to 7 µm) (Houbraken et al. 2020). However, P.submersum shows the shortest phialides within the group (4–5.5 vs. 5–7 µm). In addition, our species has strong acid production on CREA, in contrast to the lack of acid production of P.griseofulvum and P.dipodomycola in the same medium (Houbraken et al. 2016, 2020); and colony reverse on CYA and YES in P.submersum is golden brown to orange and grayish orange, respectively, while in P.griseofulvum and P.dipodomycola it is beige brown to dark brown in both culture media (Houbraken et al. 2020). Furthermore, P.griseofulvum differs from P.submersum in its gray colony color, especially on CYA, which is in shades of yellow in our species.