Three new species of Graphidaceae (lichenized Ascomycota) from the semi-arid region of northeast Brazil Author Dantas, Jaciele De Oliveira Departamento de Biociências, Universidade Federal de Sergipe, Av. Vereador Olímpio Grande, s / n, CEP: 49500 - 000, Itabaiana, Sergipe, Brazil Author Alves, Elaine Santos Departamento de Biociências, Universidade Federal de Sergipe, Av. Vereador Olímpio Grande, s / n, CEP: 49500 - 000, Itabaiana, Sergipe, Brazil Author Lücking, Robert Botanischer Garten & Botanisches Museum, Freie Universität Berlin, Germany Author Cáceres, Marcela Eugenia Da Silva Departamento de Biociências, Universidade Federal de Sergipe, Av. Vereador Olímpio Grande, s / n, CEP: 49500 - 000, Itabaiana, Sergipe, Brazil text Phytotaxa 2017 2017-12-12 331 2 289 294 http://dx.doi.org/10.11646/phytotaxa.331.2.13 journal article 10.11646/phytotaxa.331.2.13 1179-3163 13721716 Thelotrema pachysporoides Dantas, Lücking & M. Cáceres , sp. nov. Fig. 1I–L Mycobank No.: MB 822331. Diagnosis: Differing from Thelotrema pachysporum in the small ascospores and from T. fuscosubtile in the ecorticate thallus and smaller, distinctly brown ascospores. Type : BRAZIL . SERGIP E : Fazenda Santa María da Lage ; 10º44’37” S , 38º05’44” W , 390 m ; isolated remnant of Caatinga vegetation, on tree bark; 28 January 2015 , J . Dantas ( ISE 30802 — holotype ) ; ibid., J . Dantas ( ISE 30801 — paratype ) . Etymology: The epithet refers to the similarity with Thelotrema pachysporum . Description: Thallus corticolous, epiperidermal, up to c. 5 cm diam., continuous; surface uneven, white-grey to pale yellowish grey; prothallus absent. Thallus in section 50–100 μm thick, ecorticate or in part with a loose cortex, 5–10 μm thick, with thick photobiont layer 40–80 μm thick, interspersed with clusters of calcium oxalate crystals. Photobiont Trentepohlia ; cells rounded to irregular in outline, in irregular groups, yellowish green, 8–12 × 6–9 μm. Ascomata rounded, erumpent to prominent, 0.25–0.4 mm diam., 0.15–0.2 mm high; disc partially covered by 0.15–0.25 mm wide pore, grey-brown, thickly white-pruinose; proper margin thin, entire, separated from the thalline margin by a narrow split, forming an indistinct, white rim around the disc; thalline margin thick, smooth to uneven, white-grey to pale yellowish grey. Excipulum entire, pale yellow, 10–20 μm wide, paraplectenchymatous, separated from covering thalline layer by a split; laterally covered by algiferous thallus, 40–60 μm thick; columella absent; hypothecium prosoplectenchymatous, 10–20 μm high, hyaline; hymenium 90–100 μm high, hyaline, clear; epihymenium 5–10 μm high, grey-granular, granules not soluble in K. Periphysoids present, 20–30 μm long; asci fusiform, 70–80 × 15–20 μm. Ascospores 8 per ascus, ellipsoid, 7–13-septate, 25–35 × 7–10 μm, 3–4 times long as wide, becoming brown, distoseptate with lens-shaped lumina, I+ weakly violet-blue when immature. Secondary chemistry: No substances detected by TLC. Distribution and ecology: Thus far only known from the state of Sergipe in northeast Brazil , growing on tree bark in an isolated Caatinga remnant. Characterization and taxonomic relationships: Thelotrema pachysporoides belongs in the T. monosporum group, characterized by a whitish, ecorticate thallus and brown ascospores ( Rivas Plata et al . 2010 , 2013 ). It is most similar to T. pachysporum Nyl. (hence the specific epithet), which differs in the larger ascospores (35–75 × 9–13 μm). The Australian Thelotrema fuscosubtile Mangold, Lücking & Lumbsch ( Mangold et al . 2014 ) is partially (loosely) corticate, has ascomata with a thicker thalline margin and very distinct proper margin, and produces slightly larger ascospores (35–50 × 7–10 μm), which remain hyaline for a long time and eventually become pale brown.