Calostoma naaxtututs Deloya-Olvera, Virgen-Vasquez, Xoconostle-Cázares & J. Pérez-Moreno, 2023

Deloya-Olvera, Miriam, Xoconostle-Cazares, Beatriz, Vasquez, Sofía Virgen, Pérez-Moreno, Jesús, Martínez-González, César Ramiro, J. Almaraz, Juan, Jimenez, Mario & Sánchez-García, Martín E., 2023, Two new neotropical species of the ectomycorrhizal gasteroid genus Calostoma (Sclerodermatineae, Boletales) used as a food source by the Ayuuk jä’äy ethnic group from Southern Mexico, Phytotaxa 612 (2), pp. 148-158 : 153-154

Calostoma naaxtututs Deloya-Olvera, Virgen-Vasquez, Xoconostle-Cázares & J. Pérez-Moreno , sp. nov.

Index fungorum number: IF556486, Mycobank number: MB 830881, GenBank: MF521438 and MF521440

Etymology:— Refers to the name used by Ayuuk jä’äy people to designate this edible species naax tututs (naax =earth, tututs =egg) literally meaning “egg of the earth” due to egg-like flavour of the fungus.

Gasterocarp in the form of a globose spore-sac with short stipe, formed by longitudinal anastomosed strands, reddish-brown in colour, cartilaginous when fresh and hard when dry, from 5 to 15 mm in height, × 24 mm in diameter. Spore-sac orange to red, 23 to 30 mm in diameter, with a gelatinous exoperidium 3 mm thick, hyaline, when ripe, it opens at the apex on the side of the ostiole. Mesoperidium reddish orange attached to the exoperidium. Endoperidium papyraceous of cream-yellowish colour. Ostiole apical star-shaped with five to six raised edges, which breaks and release the spores. Gleba creamy, whitish-yellowish. Basidiospores extensively ellipsoid (9.3) 9.9–13.8 (14.6) × (7.0) 7.3–10.8 (11.7) μm, Q= 1.08–1.71 μm; Qm = 1.27 μm, ornamented with reticulum (exospore) with a single agglomerated layer with irregular spaces which can be closed by the same reticulum ( Fig. 2b ). Spore-sac formed by a network of intertwined hyphae 1.5–7.8 μ in width ( Figure 2 ).

Holotype: — MEXICO, Oaxaca, Santa Maria Tlahuitoltepec , on Quercus obtusata Bonpl. forest soil, 17°6’27.2”N, 96°3’51.5”W, 2477 m, 19 August 2015, Deloya-Olvera 51 ( MEXU29001 !, holotype designated here).

Paratype:— MEXICO, Oaxaca, Santa Maria Tlahuitoltepec , on Quercus obtusata forest soil, 17°6’27.2”N, 96°3’51.5”W, 2477 m, 19 August 2015, Deloya-Olvera 53 ( MEXU29008 !, paratype designated here) .

Diagnosis: Differing from other Calostoma species by its thick gelatinous exoperidium, persistent, hyaline, 3 mm thick; size of basidiospores (9.3)9.9–13.8(14.6) × (7.0)7.3–10.8(11.7) µm, Q= 1.08–1.71 μm; Qm= 1.27 μm; and stipe size: 0.5–1.5 cm high × 0.3–1.0 cm in diameter.

Notes: Calostoma naaxtutus is different from its closest phylogenetic species C. cinnabarinum due to: i) its greater globose spore-sac; the former species has a 20–30 mm spore-sac in diameter, while in the later species the folllowing measures have been recorded: 10–20 mm; 10–15 mm; 8–10 mm and 8–12 mm by Masse (1888); Castro-Mendoza et al. (1983); Kim et al. (2007) and Baseia et al. (2010), respectively; ii) the ontogeny of the exoperidium, while it has been recorded that in C. cinnabarinum , the gelatinous exoperidium falls when mature ( Coker & Couch, 1928; Castro-Mendoza et al. 1983; Kim et al. 2007), in the case of C. naaxtutus , the exoperidium persists even in mature specimens; iii) the longer spores reported for C. cinnabarinum : 15–18 µm, 14–20 µm, 12–22 µm, 10–20 µm, 12–15 µm and 13.5–16.5 µm, by Masse (1888); Coker & Couch (1928); Castro-Mendoza et al. (1983); Kim et al. (2007) and Guzmán (1973), respectively, while our specimens have spores ranging from 9.9–13.8 µm in length; iv) the shorter stipe, previously reported from 7–10cm, 2–5 cm, 3.5 cm and 1.5–2.0 cm by Desvaux (1809); Masse (1888); Castro Mendoza et al. (1983); and Baseia et al. (2007), respectively, but in our specimens the stipe ranged from 0.5–1.5 cm high; and iv) genetic differences which showed that C. naaxtutus is included in a monophyletic clade (1 Bayesian Posterior Probability and 100% bootstrap proportion for Maximum likelihood), closer but different to that of C. cinnabarinum . Calostoma naaxtutus differs from the other two species of the genus, previously recorded from Mexico, because C. lutescens (Schwein.) Burnap has globose spores, (6–)7.7–10.5 µm in diameter; and C. ravenelii (Berk.) Massee has an exoperidium which is non-gelatinous, and also has longer spores (12–)13.5–16.8(–18) µm ( Guzmán, 1973).

Figures

FIGURE 2. Calostoma naaxtututs (a–b) and C. tooteic (c–f). a. Gasterocarp appearance (Holotype), showing color variation (in the top right corner). b) Scanning electronic microphotography showing the ornamentation pattern of spores; c–d) Gasterocarp appearance (Holotype), showing colour variation in (e). f. Scanning electronic microphotography showing the ornamentation pattern of spores; (g) Gathering of Calostoma ethnotaxa by Ayuuk jä´äy women.