Thelephora pacifica Villarr., 2024

Villarruel-Ordaz, J. L., Maldonado-Bonilla, L. D., Sánchez-Espinoza, A. C., Garibay-Orijel, R. & Álvarez-Manjarrez, J., 2024, Thelephora pacifica (Basidiomycota: Thelephorales), a new species of the tropical forests in the Mexican Pacific coast, Phytotaxa 634 (3), pp. 204-214 : 207-210

Thelephora pacifica Villarr. -Ord., Alvarez-Manjarrez, Maldonado & Sánchez, sp. nov.

( FIGURE 2 )

TYPE: — MÉXICO. Oaxaca: San Gabriel Mixtepec municipality, Rancho El Sagrado , September 27th, 2019, Villarruel-Ordaz 1883, photo VO 2019-125, (Holotype: MEXU-HO 30494 )

MycoBank: 850299

GenBank number: OR548196 (ITS), OR602208 (LSU)

Etymology. Regarding distribution in Pacific tropical forests of Mexico.

Diagnosis. Basidiomata flabellate, fleshy to slightly leathery, grayish brown with olive-yellow tones towards the margin of the lobules, pileus fibrillose surface and hymenophore is irregular to papillate. Subglobose warty spores. It develops in subtropical oak forests in transition to semideciduous tropical forest.

Thelephora pacifica bears a resemblance to T. ganbajun in terms of basidiomata morphology, differing primarily in the pileus surface coloration—grayish to black in T. ganbajun , while T. pacifica displays grayish-brown tones with olive colors along the margin. Furthermore, T. pacifica boasts larger spores ((4.3–) 4.7–6.8 (–7.3) × (3.6–) 4.0– 5.5 (–6.0) µm) compared to T. ganbajun . Additionally, T. pacifica shares similarities with T. pseudoganbajun , but it distinguishes by having smaller basidia (19.5–30 × 4.7–6.3 µm).

Description. Basidiomata 23–42 mm height, 21–54 mm wide, petaloid to flabellate, tenacious fleshy to leathery consistency; surface marked with concentric lines, regularly longitudinally plicate, occasionally, it may have a pseudostipe slightly fibrillose to tomentose at base; grayish brown (5D3,2) with slightly pale olive-yellow (4C3) margin, and shades darkening to dark grayish brown (5F2–6F3) toward base; hymenophore smooth to papillate, warty or folded, grayish brown (8D2–9D3), darkening to grayish brown to purplish brown (8F3–10F4) towards base and margin on both sides of basidiome yellowish white (2, 3, 4A2) with olive yellow tones (3B2, 3C3); occasionally a cylindrical, irregular stipe with a pubescent surface, dark grayish brown (5F2) to almost black, from 15 to 23 mm length and up to 3 mm in width.

Basidia 19.5–30 µm long and 4.7–6.3 µm wide medially, tetrasporic, cylindrical to sub-cylindrical, slightly curved or contoured, hyaline, thin-walled, 2–3 µm sterigmata, clamped at the base; no cystidia observed. Basidiospores (4.3–) 4.7–6.8 (–7.3) × (3.6–) 4.0–5.5 (–6.0) µm (ornamentation excluded), Lm = 5.7 µm, Am = 4.8 µm, Qm = 1.18, globose to subglobose in polar view and broadly ellipsoid in lateral view, tuberculate to nodular, thick-walled, warty ornamentation 0.3 to 0.5 µm thick, translucent yellowish in KOH (5%). Hyphal system monomitic, 3–4 µm in diameter, highly branched hyphae with presence of fibulae, with cyanescent reaction in KOH (5%) in some portions of the context.

Habit and habitat. Growing gregariously in a gradient of subtropical oak forest with sub-perennial tropical forest from 650 to 800 meters above sea level.

Additional specimens examined. MÉXICO, Oaxaca: San Gabriel Mixtepec municipality, Camino a la Finca Aurora , cerro de la Olla , August 2nd, 2019, Villarruel-Ordaz 1802, photo VO 2019-44 ( FCME 28004 ; NCBI: OR548194 (ITS)) ; Rancho El Sagrado , September 20th, 2019, Villarruel-Ordaz 1859, photo VO 2019-101 ( LCB-UMAR 0605 ; NCBI: OR548195 (ITS); OR602206 (LSU)) ; September 27th, 2019, Villarruel-Ordaz 1883, photo VO 2019-125 ( MEXU-HO 30494 ; NCBI: OR548196 (ITS); OR602208 (LSU)) ; October 1st, 2023, Villarruel-Ordaz 1959, photo VO 2023-1 ( LCB-UMAR 0607 ) ; Jalisco: San Sebastián del Oeste municipality, Sánchez Jácome s.n. ( IBUG; NCBI: OR548193 (ITS)) .

Note. Thelephora pacifica exhibits morphological similarities to T. ganbajun sensu Zang (1987:85) , as originally described in China. The original description T. ganbajun indicated echinulate spores measuring 7–12 × 6–8 µm. However, Li et al. (2020) reevaluated the type specimen and determined that the spores were tuberculate and considerably smaller (4.5–6 × 4.2–5 µm). In order to have a better understanding of the morphological characters of T. ganbajun, Li et al. (2020) provided a revised description based on their own collected specimen. They reported spores are 4.5–5.5 × 4–5 µm (including ornamentation) consistent with the type specimen. Our specimens present a larger spore size than that reported by Li et al. (2020). Additionally, there are distinctions in the coloration of the surface of the pileus and hymenophore, with T. ganbajun presenting grayish to almost black tones, while T. pacifica displays a grayish brown coloration with olive yellow tones towards the margin. Furthermore, Yang et al. (2023) present a more detailed description of T. ganbajun based on the type specimen ( TABLE 1 ). Our specimens differ from the description of T. ganbajun sensu Yang et al. (2023) primarily in their larger spore size ( TABLE 1 ).

T. pacifica shares morphological similarities with T. pseudoganbajun Yang & Yuan (2023: 11) , particularly in the shape and ornamentation of the spores. However, they differ in the size of the basidia, with those of T. pseudoganbajun being larger 45–65 × 6–10 µm, and showing a blue-greenish reaction to KOH (3%) in the context.

T. pacifica is also very similar to Thelephora vialis , as reported from the State of Jalisco, Mexico by Sánchez-Jácome & Guzmán-Dávalos (1997), representing a new record for Mexico.The macroscopic characteristics documented by these authors align closely with those of T. pacifica . However, a significant discrepancy is observed in spore characteristics. Although the size of spores can overlap in both species, there is a discernible difference in the thickness of the ornamentation. In our specimens, the ornamentation can be up to 0.5 µm thick, whereas the specimens reported for Jalisco had ornamentation as thick as 0.8 µm.

Liu et al. (2021) emphasized the diagnostic significance of basidia in the infrageneric identification of Thelephora . They reported that T. vialis exhibits basida sizes from 26.4–64.0 × 5.6–10.4 µm, a range that contrasts significantly with the observations in our specimens, indicating a substantial difference ( TABLE 1 ).

Figures

FIGURE 2. Morphological characteristics of Thelephora pacifica. A. Basidiome in its natural environment; B. Hymenophore displaying distinctive folds and warts; C–D. Macroscopic features of basidiome; E. Tuberculate spores; F. Context hyphae with fibulae; G. Basidia and basidioles; H. Tuberculate spores. Images E–G were captured using a light microscope, while H shows spores observed under a scanning electron microscope (12.9 mm × 7.5 K).