Pseudosperma calciphilum Sanna, Mua, Porcu, Casula, Rinaldi, Mifsud & Garrido-Benavent 2024, sp. nov.
Creators: name: Sanna, Massimo
name: Mua, Alberto
name: Porcu, Giuseppe
name: Casula, Marco
name: Rinaldi, Andrea C.
name: Mifsud, Stephen
name: Garrido-Benavent, Isaac
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Inocybaceae
Pseudosperma
Pseudosperma calciphilum

description: Pseudosperma calciphilum Sanna, Mua, Porcu, Casula, Rinaldi, Mifsud & Garrido-Benavent, sp. nov. (Figures 2-3) MycoBank MB 850154
Etymology:—The species epithet “calciphilum ” refers to the apparently strict growth of this species on calcareous soils.
Diagnosis:— Pseudosperma calciphilum is macroscopically characterized by its medium to large basidiomata composed of yellow-amber, brown-ochre to brown pileus, with an obtuse umbo and with fibrillose-rimose margin surfaces that frequently show white velar remnants; lamellae at first white with a slight yellowish hue, then grayish-white and finally light brownish-olive with a white lamellar edge. Stipes enlarged at the base but not bulbous, with a pruinose-fibrillose surface, slightly scaled in the upper half. Context white and smell with mixed components: herbaceous-sourish, oily-honey, and slightly spermatic. Microscopically, it is characterized by the presence of ellipsoid to subphaseoliform spores with size (9–)10.76– 12.55 –14.34(–17.62) × (5.91–)6.7– 7.39 –8.09(–9.91) µm, Q= 1.29– 2.17, Qm= 1.70, thin-walled cylindric-claviform to claviform cheilocystidia, some septate at the base and with size 26– 48.4 –71 × 10– 16 –23 µm, Q= 2.4–3.5, Qm= 3, and long catenate hairs with cheilocystidioid terminal elements mixed with caulocystidioid-like elements in the upper part of the stipes, with size 45– 78 –110 × 11– 16.9 –21 µm. Its nrITS region has more than 3% genetic distance from the nrITS type sequences of P. umbrinellum (GenBank nrITS accession number HM209796), P. melleum (NR_171959) and P. conviviale (MT095091).
Holotype:— ITALY: Cagliari, Parco Colle San Michele, urban park with planted Quercus ilex subsp. ilex, on calcareous soil, 39º14’33.12” N, 9º06’30.94” E, 55 m above sea level, 6 December 2021, leg. A. Mua & M. Sanna (CAG! B/5.8.1). GenBank accession numbers: ON799406 (nrITS), OQ341419 (nrLSU) and OQ348110 (rpb2).
Description:— Pileus small to moderately large, 25–55 (80) mm in diameter, initially conical-convex, then convex up to flat-convex with a low, obtuse umbo; margin initially rounded, then straight, sometimes cracked; surface colour amber yellow (pl. XVI, 21’, b – code Ridgway 1912), brown-ochre (pl. XV, 17’ O–Y, i – code Ridgway 1912), brown (pl. XV, 17’O–Y, m – code Ridgway 1912), slightly darker at the center, smooth, fibrillose-rimose, splitting longitudinally near the edge, exposing the white flesh underneath; white velipellis present over the disc and the margin, here with a cortiniform appearance. Lamellae crowded, adnate-emarginated, L= (40–)50–90(–110), 1=1(–3), at first white with a slight yellowish hue, then grayish-white, pale grey and finally light brownish-olive (pl. XXX, 19’’, k - code Ridgway 1912); lamellar edge white, fimbriate in places. Stipes 25–60 × 6–16 mm, cylindrical, enlarged towards the base but not bulbous, full; surface white, pruinose-fibrillose, with scales in the upper half; colour initially white with a yellowish tinge, then becoming beige-chamois (pl. XXX, 19’’, b - code Ridgway 1912), paler near the apex. Context firm, white, slightly yellow at the upper part. Smell with mixed components: herbaceous-sourish, oily-honey, and slightly spermatic. Basidiospores (9–)10.76– 12.55 –14.34(–17.62) × (5.91–)6.7– 7.39 –8.09(–9.91) µm, Q= 1.29–2.17, Qm= 1.70 (n= 186), smooth, brown, ellipsoidal, also subphaseoliform in dorsiventral profile, ovoid in front profile, apex rounded, hilar appendices slightly pronounced, guttulate. Basidia 30.5– 37 –44 × 10– 12.5 –15 µm, claviform, tetrasporic, occasionally bisporic; sterigmata 3–5.5 µm long. Cheilocystidia 26– 48.4 –71 × 10– 16 –23 µm, Q= 2.4–3.5, Qm= 3, thin-walled, cylindrical-claviform, claviform, even pyriform, some subutriform, some septate at the base with one septum. Lamellar edge sterile. Pleurocystidia absent. At the upper third of the stipe there are long catenate hairs grouped in tufts and caulocystidioid hairs mixed with caulocystidia-like elements, 45– 78 –110 × 11– 16.9 –21 µm, Q= 3.3–6.5, Qm= 4.7. Pileipellis with cylindrical hyphae arranged in a cutis, sometimes slightly intermingled, 3–5 µm wide, slightly jellified, pigment brownish, encrusting, intracellular yellowish to brown-ochraceous pigment also present. Stipitipellis formed by cylindrical parallel hyphae, occasionally intermingled, 5–10 µm wide, with the presence of intracellular and encrusting brownish-yellowish pigment.
Habitat and distribution:—Terrestrial, gregarious under Quercus ilex subsp. ilex and Q. ilex subsp. rotundifolia, in Mediterranean climate, on calcareous soil, in late autumn. At present it is known only from the islands of Sardinia (Italy) and Malta, and Valencia (eastern Iberian Peninsula, Spain). Interestingly, the Maltese locality was dominated by Pinus halepensis and Pistacia lentiscus. However, pollen records indicate that Quercus spp. were present throughout most of the Maltese landscape a few thousand years ago (Gambin et al. 2016).
Collections of Pseudosperma calciphilum examined:— ITALY: Cagliari, Parco Colle San Michele, urban park with planted Quercus ilex subsp. ilex, on calcareous soil, 39°14’33.12”N, 9°06’30.94”E, 55 m above sea level, 6 December 2021, leg. A. Mua and M. Sanna (CAG! B/5.8.1), holotypus; ITALY: Cagliari, Parco Colle San Michele, urban park with planted Q. ilex subsp. ilex, on calcareous (marly) soil, 39°14’33.67”N, 9°06’30.53”E, 55 m above sea level, 6 December 2021, leg. A. Mua and M. Sanna (CAG! 5/3.63), GenBank accession numbers: nrITS ON799411, nrLSU OQ341322, rpb2 OQ348109; ibidem, 1 December 2022, leg. A. Mua and M. Sanna (n° 1569 MS); ibidem, 12 December 2022, 39°14’38.06”N, 9°06’46.50”E, 75 m above sea level, leg. A. Rinaldi (n° ACR-2022-66); SPAIN: Valencia, Quatretonda, Barranc de les Fontetes, Assut Nova, under Q. ilex subsp. rotundifolia, on calcareous (marly) soil, 38°55’53.73”N, 0°24’22.80”W, 200 m above sea level, 8 December 2011, leg. I. Garrido-Benavent, IGB213, VAL_Myco 1671, GenBank accession number: nrITS OQ341418; ibidem, under Q. ilex subsp. rotundifolia and Pinus halepensis, on calcareous (marly) soil, 38°55’54.65”N, 0°24’22.97”W, 192 m above sea level, 4 November 2012, leg. I. Garrido-Benavent, IGB166, VAL_Myco 1672, GenBank accession number: nrITS OQ341420; MALTA: Siġġiewi, Verdala, five fruiting bodies in a maquis composed mainly of Pinus halepensis accompanied by a few Pistacia lentiscus, on calcareous soil, 35°51’38.16”N, 14°23’53.84”E, 180 m above sea level, 15 December 2022, leg. S. Mifsud, SM743, GenBank accession number: nrITS OR603126.
description: Published as part of Sanna, Massimo, Mua, Alberto, Porcu, Giuseppe, Casula, Marco, Rinaldi, Andrea C., Mifsud, Stephen & Garrido-Benavent, Isaac, 2024, Pseudosperma calciphilum (Inocybaceae), a new Mediterranean species from Sardinia (Italy), Malta, and Valencia (Spain), pp. 253-264 in Phytotaxa 633 (3) on pages 259-260, DOI: 10.11646/phytotaxa.633.3.5, http://zenodo.org/record/13879158