Hypoxylon xmatkuilense P. Reyes, Pinzon, R. Valenz. & Raymundo 2024, sp. nov.

Hypoxylon xmatkuilense P. Reyes, Pinzón, R. Valenz. & Raymundo sp. nov. Fig. 3 Gen Bank. ITS (OR 807999), LSU (OR 807990), RPB 2 (OR 825476), TUB 2 (OR 825467). Diagnosis. It characterized by having stromata effused-flattened, surface vinaceous, perithecia obovoid and dark brown KOH-extractable pigments. Etymology. from the Mayan Xmatkuil “ place where God is asked ” in reference to the place where it was collected for the first time. Holotype. Mexico • Yucatán, east from cemetery, comisaría Xmatkuil; 14 Oct 2021; P. Reyes leg.; UADY 3. Paratypes. Mexico • ibid.; 11 July 2023; P. Reyes leg.; UADY 118 • ibid; P. Reyes leg.; UADY 119. Description. Stromata effused-flattened, 25–100 mm long × 5–20 mm wide × 1 mm thick, surface pruinose, young stromata have a thin layer Dark Vinaceous (82), when mature this layer is lost, leaving remains that appear Brown Vinaceous (84) (Fig. 3 a), subsurface blackish, composed of weakly carbonaceous tissue and inconspicuous brownish black granules; perithecia 1.2–1.5 mm diam, obovoid inconspicuous with umbilicate ostioles (Fig. 3 b); KOH-extractable pigments dark brown (Fig. 3 c); asci not seen; ascospores 10–12 × 4–5 µm, unicellular, ellipsoid, inequilateral, narrowly rounded ends, with straight 2 / 3 spore-length germ slit on the convex side (Fig. 3 d), dark brown, perispore dehiscent in 10 % KOH (Fig. 3 e). Host. Growing on dead wood of Gymnopodium floribundum Rolfe (Polygonaceae) in deciduous forest Notes. It shares the effused-pulvinate to flattened stromata and vinaceous surface with H. lateripigmentum, H. pulicicidum, H. investiens, H. hinnuleum, H. olivaceopigmentum, it differs by having perithecia obovoid, dark brown KOH-extractable pigments and perispore dehiscent (Ju and Rogers 1996; Bills et al. 2012; Kuhnert et al. 2014 a; Sir et al. 2019); Fournier et al. (2024) described H. aeneipigmentatum as a new taxon from Saül, French Guiana, based on ITS sequences, and noted that it belongs H. investiens complex; moreover reported about a basal perithecial nucleus as a new differential character in this group.