Abrothallus nephromatis Suija & Pérez-Ortega, 2015

Suija, Ave, Ríos, Asunción De Los & Pérez-Ortega, Sergio, 2015, A molecular reappraisal of Abrothallus species growing on lichens of the order Peltigerales, Phytotaxa 195 (3), pp. 201-226 : 213-215

Abrothallus nephromatis Suija & Pérez-Ortega , sp. nov.

Mycobank MB#809371; Fig. 8

Diagnosis:—The new species differs from other Abrothallus species by host selection ( Nephroma ), from A. welwitschii by having smaller ascomata up to 540 μm wide, and smaller ascospores in dimensions of 11.7–(13.9)–16.4 × 4.4– (5)–6.2 × 3.2–5.3 μm, from A. boomii by having 8-spored asci and narrower conidia in dimensions 6.2–(7.7)–14.3 × 2.9–(4.7)–5.6 μm.

Type:— CANADA. British Columbia: Wells Gray Provincial Park, Dawson Falls, elev. ca. 800 m, on Nephroma parile on dead trunk of Betula forest, 22 July 2008, D. Ertz 12514 & P. Diederich (holotype BR-LICH-6515-16).

Mycelium immersed, K/I–. Ascomata superficial on thallus of Nephroma spp. , penetrating through the cracks of lichen thallus, black, especially young ascomata covered with greenish pruina, flat 270–(392)–540 μm wide, ca. 170–200 μm high; the ascomata are surrounded by black necrotic rim. Epihymenial layer of dark brown granules, K+ greenish, N ± violet; hymenium greenish, K+ intensified, 55–72 μm high; exciple ca. 70–75 μm wide in vertical section; hypothecium light brown, hypothecial cells rectangular, covered with brown pigment, 6.5–11 × 4–7 μm (n=10). Asci bitunicate, clavate, 36.5–55 × 9–12.5 μm, with eight ascospores. Ascospores 2-celled, at the beginning hyaline, later brown, overmatured spores dark brown, verruculose, asymmetric, only slightly constricted at septum, 11.7–(13.9 ±1.2)–16.4 × 4.4–(5 ±0.5)–6.2 (upper cell)/3.2–(4. 2 ±0.5)–5.3 (lower cell) μm (n=20), l/w (upper cell) ratio = 2.7–2.8. Interascal filaments unequally dichotomosly branched, ca. 2–2.5 μm wide, the tip not or only slightly widened. Anamorph present, pycnidial. Pycnidia immersed, later erumpent, ca. 200 μm wide; pycnidial wall K+ green, N ± violet. Conidiogenous cells holoblastic, lining the cavity of pycnidia, 6.2–(10.7 ±2.5)–14.3 × 2.9–(3.8 ±0.7)–5.6 (n=13) μm. Conidia simple, hyaline, obpyriform with truncated end, 6.5–(7.7 ±0.7)–8.7 × 3.7–(4.7 ±0.6)–6.1 μm (n=20).

Etymology:—The epithet refers the host genus, Nephroma .

Notes:—The new species is known from Europe ( Norway, Sweden, Italy), Asia (Russian Far East), North-America ( Canada, USA), Greenland, Australia, New Zealand and Africa ( Tanzania, Uganda). Abrothallus nephromatis has been recorded on Nephroma parile , N. helveticum , N. rufum , and N. tropicum .

The darkened rim around the ascomata (and conidiomata) is especially obvious near older ascomata under which the hyphae of the lichen mycobiont and cells of the photobiont are collapsed, which indicates the parasitic nature of this lichenicolous fungus. The damage to the host is not evident near younger ascomata.

Abrothallus nephromatis has been noted earlier as A. welwitschii ( Goward & Thor 1992, Holien & Tønsberg 1994, Ihlen & Wedin 2008, Santesson et al. 2004, Zhurbenko et al. 2012), A. bertianus ( Alstrup & Hawksworth 1990) or A. parmeliarum (C, ex Herb. MSC. no. 3615). The species superficially resembles A. welwitschii having flattened ascomata which rise through cracks in the host thallus, but differs by having slightly smaller ascomata and ascospores, and by its DNA sequence characteristics.

There are at least two additional species growing on Nephroma spp. represented by singleton lineages in the phylogenetic tree ( A. boomii and A. kamchatica ). The sexual morphs of both species show slight but distinct differences from the A. nephromatis ( Table 2), but main differences between all three species lie on the characters of their asexual morphs. Both A. nephromatis and A. boomii have semi-immersed pycnidia with hyaline conidia, but the conidia are generally narrower in A. nephromatis (6.5–(7.7)–8.7 × 3.7–(4.7)–6.1 μm vs 7–(9.2)–10.5 × 5.5–(6.54)–8 μm). On the other hand, pycnidia in A. kamchatica are superficial and conidia are pale brown when mature.

Additional specimens examined: — NORWAY. Nord-Trøndelang: Overhalla, ca. 1 km W of Fess, old spruce forest, boreal rain forest, elev. 50–100 m ( UTM: 32W/33W, PS 4453/UM5553, map 1723 I; 64º29’N 12º00’E), on Nephroma parile on a twig of Picea , 28 July 1993, R. Santesson 33564, det. as Abrothallus welwitschii (UPS) ; Sør- Trøndelang: Dovre, Oppdal, Drivstein, on N. parile , 13 June 1864, Th.M. Fries, det. R. Santesson as A. welwitschii (UPS) ; GREENLAND. Julianehaab, Narsarsuaq, on N. parile on the base of trunk of Betula , 21 September 1953, P. Gelting 21152a, det. R. Santesson as A. welwitschii (UPS) ; Narsarsuaq, Blomsterdalen (61º10’N 45º18’W), on N. parile on twig, 25 July 2005, A. Suija & V. Alstrup, det. A. Suija (TU-65904); CANADA. British Columbia: Wells Gray Provincial Park, Dawson Falls, elev. ca. 800 m, forest, on N. parile on twigs of conifer, 22 July 2008, D. Ertz 12518 & P. Diederich ( BR-LICH 6511-12); Alberta: Chester Lake, elev. 700 m, on thallus of N. parile on twig of Picea glauca , 24 September 1979, T. Goward 79-1368 79-21 (K(M): 166775 (ex herb IMI 260721); RUSSIA. Kamchatka Peninsula, Elizovskiy District, Levaya Schapina River, elev. 335 m (55º08’19”N 159º59’07”E), on N. parile , 5 August 2009, D. Himelbrant & I. Stepanchikova, det. M. Zhurbenko as A. welwitschii (LE-260313); ibid., on N. parile on lignum, 5 August 2009, D. Himelbrant & I. Stepanchikova, det. M. Zhurbenko as A. welwitschii (LE-260303); Ust-Kamchatskiy District, 33 km NE of Kluchi, elev. 500 m (56º33’28”N 161º10’39”E), 24August 2002, D. Himelbrant & E. Kuznetsova, det. M. Zhurbenko as A. welwitschii (LE-261722); USA. Montana: Glacier National Park, Flathead County, John’s lake, Thuja plicata-Tsuga heterophylla habitat, elev. 1379 m ( UTM N.5391 E.290), on N. parile on moss over rock and on dead wood, 7 December 1983, A. DeBolt 264 (C (ex Herb. MSC. no. 3615)); Montana: Kootenai National Forest, Lincoln Co., Seichelles Mountains, Pinkhorn Creek (Camp 32), elev. 840 m (48º50’11”N 115º11’27”W), on Nephroma sp. , 30 July 2006, S. Pérez-Ortega 3159 & T. Spribille ( MA); Montana: Lincoln Co., Western Cabinet Mountains, Ross Creek, in ancient cedar grove, elev. 870 m (48.207789ºN 115.916213ºW), on N. parile on Thuja plicata , 17 April 2001, T. Spribille 10581 & T. Goward (hb. Spribille). AUSTRALIA. Australian Capital Territory: Cribbs Creek, Bimberi Range, 35 km SW of Canberra, dry sclerophyll forest on rocky slope above creek, elev. 1470 m (35º37’S 148º46’E), on N. helveticum on semi-shaded boulder, 19 February 1985, H. Streimann & J.A. Curnow 34991 (B-0139/2008-6); NEW ZEALAND. South island, Nelson, Nelson Lakes National Park, ca. 1 km SSW St. Arnaud, along peninsula Nature Walk, regenerating Nothofagus solandri dominated forest, elev. 615 m (41º48’S 172º50’E), on N. rufum on base of Nothofagus solandri , 15 January 1990, M. Wedin 2689, det. as A. welwitschii ( UPS (L-20360)54842); Nelson, Nelson Lakes National Park, Lake Rotoiti Peninsula, on N. rufum on Leptospermum , 28 February 1980, D. Galloway (BM-000006393); TANZANIA. Kilimanjaro: Mt. Kilimanjaro, W slope, E of Lemosho Glades, in the ericaceous belt, elev. 2800–2900 m (3º1’–2’S 37º11’E), on N. helveticum on various high shrubs, 14 January 1970, R. Santesson 21280b, det. as A. welwitschii (UPS) ; Kilimanjaro: Mt. Kilimanjaro, W slope, E of Lemosho Glades, elev. 2500–2800 m (03º01’–02’S 37º09’–11’E), on Stoebe kilimandscharica in the upper part of the montane forest belt, 14 January 1970, R. Santesson 21232b, det. as A. welwitschii ( UPS (F-156136)450261); KENYA. Kenya colony, Mt. Elgon, in the crater (alpine region), in the Alchemilletum, not far from “Maji ya moto”, elev. 3600 m.s.n, on N. helveticum , 18 May 1948, O. Hedberg 986d ( UPS); UGANDA. Bugisu, N. Bugisu, Mt. Elgon, near Sasa Mountain Hut, elev. 3090 m (01º10’N 34º28’E; Grid XS-63.30), on N. tropicum among bryophytes on branch of low tree, T.D.V. Swinscow, K. Lye & A. Katenda 2U 44/5A, det. R. Santesson as A. welwitschii ( UPS (F-156139)450264).

Figures

FIGURE 8. Abrothallus nephromatis (holotype). a: ascomata surrounded by the black necrotic rim; b: semi-immersed pycnidia; c: crosssection of the ascoma; d: ascus and ascospores; e: detail of the hymenium; f: ascospores. Scale bars: a–b = 500 μm; c = 200 μm; d–e = 25 μm; f = 10 μm