Abtylopilus australiensis Yan C. Li, J. Li, Halling, Osmundson & Zhu L. Yang sp. nov.

Figs 6, 8 g

Etymology.

australiensis referring to the species being found in Australia.

Type.

AUSTRALIA • Queensland, Tablelands, Mareeba, Barron Gorge National Park, Wright’s Lookout, 18.8401°S, 145.6427°W, ca 367 m, 4 Feb 2006, T. W. Osmundson 1080 (Holotype: BRI AQ 0796293, Isotype: NY 2049854) .

Diagnosis.

Abtylopilus australiensis differs from other species of Abtylopilus in its reddish-brown pileus, reddish to orange-red hymenophore staining dark red initially then blackish when bruised, orange-red, brownish red to blackish stipe, and a trichoderm pileipellis composed of 3–4 μm wide vertically arranged to slightly interwoven hyphae.

Description.

Basidiomata medium to large sized. Pileus 3.4–5.6 cm in diameter, convex to plane; surface subtomentose, dry, reddish brown (7 E 7-7 F 7); context whitish, staining dark red at first, and then becoming black when injured. Hymenophore depressed around apex of stipe; surface cream (4 A 3-4 A 4) to reddish (6 A 3-6 A 4), becoming orange-red (7 A 6-7 A 7) in age, staining dark red initially then blackish when bruised; pores nearly round, 0.3–1 mm wide, pale cream (4 A 2), becoming pale pinkish brown (7 D 5) to nearly black (4 F 6) in age; tubes up to 4 mm long, concolorous with hymenophoral surface. Stipe 4–5.9 × 0.7–1.1 cm, equal, solid, cream (4 A 2) to yellowish (4 A 4) when young, orange-red (7 A 6) to brownish red (7 D 8) at apex and reddish brown (6 D 8-6 E 8) to blackish (4 F 6) downward when mature; surface densely covered with minute-pruinose squamules; context whitish, staining dark red at first, and then becoming black when injured.

Basidia 25–30 × 8–12 μm, clavate to narrowly clavate, thin-walled, 4 - spored, hyaline to yellowish in KOH. Basidiospores [60 / 2 / 1] (8.0) 8.5–10.5 (11) × (3.0) 3.5–4.5 (5) μm [Q = (1.78) 2.11–2.86 (3.17), Q m = 2.47 ± 0.23], subcylindrical or subfusiform and inequilateral in profile view with slight suprahilar depression, oblong to fusiform in ventral view, smooth, yellowish to brownish in KOH, yellow to yellow-brown in Melzer’s reagent. Hymenophoral trama boletoid; hyphae cylindrical, hyaline to yellowish in KOH, yellowish to yellow in Melzer’s reagent. Cheilocystidia 45–56 × 12–13 μm, broadly subfusiform to fusoid-ventricose, thin-walled, yellowish to brownish in KOH, yellow to yellow-brown in Melzer’s reagent; surface without encrustations. Pleurocystidia morphologically similar to cheilocystidia. Pileipellis a trichoderm, composed of 3–4 μm wide vertically arranged to slightly interwoven hyphae, yellowish brown to brown in KOH and yellow-brown to dark brown in Melzer’s reagent; terminal cells 17–27 × 2–3 μm, subfusiform to cystidioid. Pileal trama composed of thin-walled hyphae; hyphae 2.5–4 μm wide, hyaline to yellowish in KOH and yellowish to yellow in Melzer’s reagent. Clamp connections absent in all tissues.

Habitat and distribution.

Gregarious on soil in rainforest; currently known in Australia.

Notes.

Abtylopilus australiensis is characterized by its reddish-brown pileus; white context staining dark red at first and then becoming black when injured; reddish to orange-red hymenophore staining dark red initially and then blackish when bruised; orange-red, brownish red to blackish stipe; smooth basidiospores; and trichoderm pileipellis. Phylogenetically, Ab. australiensis clusters with Ab. scabrosus and forms a sister group with Ab. indonesiensis, and they are morphologically similar to each other. However, Ab. scabrosus differs from Ab. australiensis in its grayish red to brownish red pileus covered with tomentose squamules; gray to grayish pink hymenophore; white to dingy white stipe covered with dark scabrous squamules; and relatively large basidia measuring 28–55 × 16–17 μm (Li and Yang 2021). Abtylopilus indonesiensis differs from Ab. australiensis in its chocolate-brown to black pileus, pinkish hymenophore, pinkish orange stipe that is deep purple to black toward the base, and relatively small basidia measuring 26–40 × 10–11 μm (Li and Yang 2021).