Prillieuxina aporosae G.N. Gokul, J. Thomas & N. Mathew, 2021

Gokul, Gopinathan Nair, Thomas, Jacob & Mathew, Nisha, 2021, Prillieuxina aporosae sp. nov. (Asterinales, Asterinaceae) from southern Western Ghats, India, Phytotaxa 487 (2), pp. 177-180 : 179-180

Prillieuxina aporosae G.N. Gokul, J. Thomas & N. Mathew sp. nov. ( Figs 1 , 2 ) MycoBank No.: MB 838019

Type:— INDIA. Kerala: Pathanamthitta, Konni forest division, near Adavi ecotourism point, on the leaves of Aporosa cardiosperma (Gaertn.) Merr. (Euphorbiaceae) , 2 October 2017, Gokul & al. MTCHT 229 (holotype); CATH 18000 (isotype).

Colonies hypophyllous, dense, black, up to 1.5 cm in diameter, confluent. Hyphae substraight to flexuous, branching irregular at acute to wide angles, loosely reticulate, cells 8.5–18 × 1.5–2.5 µm. Appressoria absent. Thyriothecia grouped, connate, lateral or below the surface mycelium, orbicular, dehiscing stellately at the center, margin crenate to fimbriate, scutellum brown to dark brown, 74–210 µm in diameter, fringed hyphae flexuous. Asci globose. Ascospores brown, conglobate, oblong to ellipsoid, slightly pointed at the ends, uniseptate, constricted at the septum, 11–17 × 5–8 µm, wall smooth.

Etymology:—Named after the host genus, Aporosa .

Notes: — Asterina aporosae Hansf. and Meliolaster aporusae Hosag. are the only known asterinacious fungal parasites on the host genus Aporosa ( Hosagoudar 2012) . Based on size of spores, the present collection is comparable with that of Prillieuxina ardisiae (Hansf.) Arx , which is recorded on Ardisia solanacea Roxb. (Myrsinaceae) . However, by considering the host specificity, the large size of thyriothecia which are grouped and many are connate, pointed ends of the ascospores, narrower hyphae and loose reticulation of the hyphae, the specimen can be treated as a new species. It is the first report of Prillieuxina as a phylloplane biotroph associated with the host family Euphorbiaceae .

Figures

FIGURE 1. Prillieuxina aporosae.A. Mature thyriothecium. B. Surface mycelium and ascoma initials. C. Mature ascospores. Illustration by G.N. Gokul.

FIGURE 2. Prillieuxina aporosae. A. Abaxial side of infected leaves. B. Surface mycelium and mature, open thyriothecia. C. Ascoma initials and mature ascospore. D. Ascoma initial and germinating ascospore. Photographs by G.N. Gokul.