Trochila urediniophila Gomez-Zap., Haelew. & Aime, 2021

Gomez-Zapata, Paula Andrea, Haelewaters, Danny, Quijada, Luis, Pfister, Donald H. & Aime, M. Catherine, 2021, Notes on Trochila (Ascomycota, Leotiomycetes), with new species and combinations, MycoKeys 78, pp. 21-47 : 21

Trochila urediniophila Gomez-Zap., Haelew. & Aime sp. nov. Fig. 4

Diagnosis.

Differs from Trochila ilicina in ecological strategy (fungicolous symbiont); sizes of asci (102.4-111.2 × 10.5-11.6 µm), ascospores (9.0-9.7 × 6.3-7.1 µm), paraphyses (3.2-3.6 µm wide); and the inamyloidity of its ascus apex.

Type.

Holotype: Reliquiae Farlowiana No. 723; Trinidad and Tobago, Port of Spain, Trinidad, Maraval Valley, ca. 10.5°N, 61.25°W, alt. ± 301 m a.s.l., 1 Apr 1912, leg. R. Thaxter, on uredinia of Cerotelium fici [as Phakopsora nishidana ] ( Pucciniales , Phakopsoraceae ) on the underside of Ficus maxima ( Rosales , Moraceae ) leaves, PUL F27668 (ex-PUR F18316). Ex-holotype sequences: isolate F18316 (3 apothecia, ITS: MT873946, LSU: MT873951).

Etymology.

Referring to the intimate association of the fungus with the uredinia of Cerotelium fici .

Description.

Apothecia protruding from uredinia of Cerotelium fici , gregarious in small groups or rarely solitary, discoid to irregular-ellipsoid when crowded, 0.4-1.0 mm diam., subsessile on a broad base, flat to slightly concave at maturity, dark grayish yellow brown (81.d.gy.yBr) to dark grayish brown (62.d.gy.Br), margin marked and lighter than hymenium, light grayish yellow brown (79.l.gr.yBr) to medium yellow brown (77.m.yBr), receptacle concolor with margin and surface slightly pruinose. Asci †(86.4-)102.4-111.2(-121.8) × (9.1-)10.5-11.6(-13.1) µm, 8-spored, cylindrical, †uniseriate; apex rounded to subconical, inamyloid (IKI, KOH-pretreated or not), base arising from croziers. Ascospores †(7.6-)9.0-9.7(-10.9) × (5.1-)6.3-7.1(-8.1) µm, ovoid to ellipsoid, aseptate, hyaline, smooth-walled, guttulate, containing †one to two pale yellow (89.p.Y) to yellow gray (93.y Gray) oil drops (LBs), 2-5 µm diam., OCI = (40-)55.1-66.9(-81)%. Paraphyses cylindrical to slightly or medium clavate-spathulate, unbranched, smooth, septate, hyaline, †(2.3-)3.2-3.6(-4.1) µm wide, apex up to 6.8 µm wide. Medullary excipulum †17.4-79.4 µm thick, textura intricata strong brown (55.s.Br) to deep brown (56.deepBr). Ectal excipulum of textura globulosa - angularis at base and lower flanks, strong yellow brown (74.s.yBr) to dark brown (59.d.Br), †32.8-93.5 µm thick, cells †(7.3-)9.0-10.8(-15.3) × (6.0-)7.5-8.7(-11.5) µm; at upper flanks and margin cells vertically oriented of textura prismatica, 17-34 µm thick, at margin and upper flank cells protruding like short hairs, hyaline, aseptate, cylindrical, †(9.5-)16-20.6(-29.1) × (3.0-)3.9-4.5(-5.8) µm. Asexual state unknown.

Notes.

Trochila urediniophila is the first known fungicolous member of the genus. The specimen described here was discovered during a survey of hyperparasites of rust fungi at PUR. Apothecia of T. urediniophila were never observed in direct contact with the plant tissue; instead, they grew directly on the uredinia of Cerotelium fici on the underside of Ficus maxima leaves. Trochila ilicina is most similar to T. urediniophila , but T. urediniophila differs from T. ilicina in its distinctly wider ascospores, larger asci, inamyloid ascus apex, and wider apex of the paraphyses. The uredinia of the host fungus, C. fici , become a solidified mass that changes in color from dark orange yellow (72.d.OY) without apothecia of Trochila to brownish black (65.brBlack) where apothecia are present.

A second duplicate of the Reliquiae Farlowiana No. 723 is also deposited at PUR (accession PUR F1098). However, no apothecia were present on this specimen, nor could additional specimens of T. urediniophila be found on any of the other specimens of C. fici housed at PUR. At least eight other duplicates are housed at BPI, CINC, CUP, F, ISC, MICH, and UC ( MyCoPortal 2020). It is unknown whether any of them may host T. urediniophila .

Figures

Figure 4. Morphological features of Trochila urediniophila, holotype collection (PUL F 27668) a 1 - a 4 dried apothecia growing on uredinia of Cerotelium fici a 2, a 3 substrate (uredinia) on which the apothecia grow (arrows) b 1 transverse section of apothecia; arrow pointing out the substrate b 2, b 3 details of excipulum at margin and upper flanks b 4 cells at base c 1 - c 3 asci d 1 paraphyses e 1 - e 3 ascospores e 2, e 3 oil drops (LBs) inside ascospores. Mounted in: Congo Red (c 1, e 2), H 2 O (b 2, c 3, d 1, e 1, e 3), KOH (b 1, b 3, b 4, c 2). Scale bars: 1 mm (a 1 - a 3); 500 µm (a 4); 200 µm (b 1); 50 µm (b 2); 20 µm (b 3, b 4, c 2, c 3, d 1); 2 µm (c 1, e 1 - e 3).