Sulzbacheromyces leucodontium Coca, Gómez-Gómez, Guzmán-Guillermo & Dal Forno, 2023

Coca, Luis Fernando, Gómez, Salomé Gómez, Guillermo, Jorge Guzmán, Trujillo, Edwin Trujillo, Clavijo, Laura, Zuluaga, Alejandro, Forno, Manuela Dal & Lumbsch, H. Thorsten, 2023, Sulzbacheromyces leucodontium (Basidiomycota, Lepidostromataceae), a new species of basidiolichen widely distributed in the Neotropics, Phytotaxa 597 (2), pp. 153-164 : 157-160

Sulzbacheromyces leucodontium Coca, Gómez-Gómez, Guzmán-Guillermo & Dal Forno sp. nov.

( Figs. 2 and 3 )

MycoBank No.: MB 000000

Type:— COLOMBIA. Caqueta: San José de Fragua, Parque Nacional Natural Alto Fragua Indi Wasi, terricolous in an open and humid area, 600 m elev., 1˚15’54.1” N, 76˚07’50.5” W, 27 October 2017, Coca et al. 9262 ( FAUC: holotype; JBB, F: isotypes) .

Diagnosis:—Thallus crustose forming a thin granulose film, terricolous in clay; basidiomata erect and unbranched, cylindrical to slightly fusiform, apically acute, and white. It differs from other species of Sulzbacheromyces with white basidiomata due to the absence of a prothallus, unbranched basidiomata, and the absence of clamp connections in the context hyphae.

Description:— Thallus crustose, terricolous in orange clay soil, forming a thin granulose film covering the substrate surface, presenting a moss green coloration, (25−)50−110 µm thick, homoiomerous, and compact. Photobiont trebouxioid, frequently grouped occasionally in a continuous layer, with spherical to ellipsoid cells 24–38 µm, with 6 to 26 chloroplast 5–8 µm, surrounded by hyphae. Basidiomata dispersed, fusiform to clavarioid, frequently with an inflated base, white to ivory white, (6)10–20 (25) mm high, 0.6–0.9 mm diam. at the base and 0.4–0.8 mm diam., unbranched at the apex, with solid context.

Context hyphae septate, 2–4 µm wide, thin-walled, without ornamentations, irregular, thickened towards the septum, and sparsely branched. Subhymenial hyphae septate, tightly arranged, irregular, and thin walled. Hymenial hyphae developed along the basidiomata. Basidia clavate, thin-walled, hyaline, 12 × 5 µm, bearing two small sterigmata, 4–5 µm. Basidioles 25–33 µm high, smooth-walled, and bearing oil droplets. Basidiospores ellipsoid and hyaline, thin-walled, 3 × 6 µm. Clamp connections not observed in any part.

Etymology:—The epithet refers to the unique white basidiomata within Sulzbacheromyces and its shape that is reminiscent of the elongated ivory tusks of elephants.

Distribution and ecology:— Sulzbacheromyces leucodontium is a terricolous species found on orange clay soil. It has been found in Colombia in the departments of Caquetá and Putumayo, in a tropical rainforest from the Andean-Amazon Piedmont. In Brazil, it has been reported a single time on soil from the Amazonian Rainforest from an extractive reserve and conservation area, where locals use the forest resources, such as rubber, sustainably. It has also been found in Mexico in the municipalities of Naranjal and Los Reyes near Pico de Orizaba.

Ranging from Mexico to western Brazil, this species has the broadest geographical distribution of the genus in the Americas observed to date. The two other Colombian species, S. chocoensis and S. tutunendo , are so far restricted to their type localities, while the Brazilian species, S. caatingae , has so far only been found in Northeastern Brazil, although in three different biomes ( Sulzbacher et al. 2016). This pattern of one species from the genus with a broad distribution and several more species of the genus having narrower distributions has also been observed in Asia, where Sulzbacheromyces sinensis is found in several countries ( Japan, China, South Korea, Taiwan, Philippines) and S. bicolor , S. yunnanensis and S. fossicola are more restricted. Unfortunately, we are yet to see what the evolutionary and distributional patterns are in Africa, since so far, only one species in the genus has been reported for the Democratic Republic of Congo, namely S. miomboensis . The monotypic Ertzia akagerae (Eb. Fischer, Ertz, Killmann & Sérusiaux) Hodkinson & Lücking in Hodkinson et al. (2014:175) is the only other species reported from the order Lepidotromatales in the African Continent, more specifically, in Rwanda. This emphasizes a lot more studies are needed in this part of the world, not only in basidiolichens, but in lichenology overall, since large parts of this continent remain underexplored ( Fryday et al. 2022).

Remarks:— Sulzbacheromyces leucodontium is the only Neotropical Sulzbacheromyces species with persistently large white basidiomata. S. chocoensis may have white basidiomata at the base, but from the third middle upwards, they are usually reddish orange. In the Paleotropics, two species with pale basidiomata are recognized, S. bicolor and S. fossicola . However, S. bicolor is distinguished by having basidiomata with yellow apices, a thallus with a white prothallus, and hyphae with clamp connections. S. fossicola differs by having a chlorococcoid photobiont and white basidiomata that branch at the base of the sporome. In addition, the two species are only distantly related to our new species and have not been reported from the Neotropics.

Despite belonging to a distinct order, Multiclavula mucida (Pers.) R.H. Petersen (1967:212) , ( Cantharellales ), is the most phenotypically similar species that occurs in the Neotropics to Sulzbacheromyces leucodontium . Nonetheless, the ecology of these species is different, with M. mucida growing primarily in rotten logs versus the terricolous habit of S. leucodontium . Additionally, Multiclavula occurs more frequently in mountain ecosystems, whereas Sulzbacheromyces is restricted to lowland and sub lowland forests.

Specimens examined (Paratypes):— COLOMBIA. Caquetá: Belén de los Andaquíes , Parque Municipal Natural Andakí , 1100 m elev., 1˚36’ N 75˚58’ W, 5 October 2021, Coca et al. 13505 ( JBB) . Belén de los Andaquíes, Entre la vereda Las Verdes y vereda Quisayá , 575 m elev., 1˚36’ N 75˚55’ W, 4 October 2021, Coca et al. 13248 ( JBB) . Putumayo: Puerto Asís, Vereda Las Acacias , 260 m elev., 0˚29’ N 76˚19’ W, 19 August 2021, Coca 13201 ( FAUC, JBB) . MEXICO. Veracruz: Naranjal, UMA environmental station Tequecholapa , ca. 700 m elev. 18°48’ N 96°57’ W, 7 October 2022, Torres-Cantú 3082 ( XALU) . Los Reyes, Zoquiapan , 700 m elev., 18°39’N 97°03’W, ca. 7 October 2022 Guzmán-Guillermo 3008 ( XALU) . BRAZIL. Acre: Sena Madureira, Reserva extrativista Cazumbá-Iracema , Núcleo Cazumbá , disturbed tropical rain forest 150 m elev., 09˚07’ S 68˚57’ W, 10 April 2019, M. Cáceres, A. Aptroot & J.G. Cavalcante ISE 50192 ( ISE, ABL) .

Phylogeny

The alignment used was 615 bp in length, with an estimate of 40 % invariable sites. Sulzbacheromyces is presented as a monophyletic taxon that supports previously proposed phylogenies ( Hodkinson et al., 2014; Coca et al., 2018 Liu et al., 2018, 2019). The inferred genus phylogenetic tree showed two main lineages ( Fig. 4 ), one with Asian species and another with American and African species, however, lacking strong support. This result is not consistent with previous studies ( Coca et al., 2018; Liu et al., 2018). However, the relationships did not receive strong support either in our studies or previous studies.

The Neotropical species remain monophyletic (66ML/0.99PP) consistent with our previous study ( Coca et al. 2018); however, the relationships between the species are poorly supported. Sulzbacheromyces leucodontium collected in Brazil, Colombia and Mexico grouped with other Colombian species but the sister group relationships lack support. We hypothesize this may be due to the lack of undiscovered taxa and the phylogeny being inferred from a single locus (ITS only). Nonetheless, ITS seems to be of extreme importance in helping establish species boundaries in this group, especially because so few morphological characters are present and of taxonomic importance. We further anticipate more species in this genus to be discovered and promote the use of integrative taxonomy to test how much phenotypic plasticity these species present, which will help us better understand patterns of diversity and speciation in the genus. The relatively simple thallus and basidiomata of Sulzbacheromyces give limited morphological information and make species delimitation challenging. Although the Neotropical species S. caatingae , S. chocoensis , S. tutunendo and the new species S. leucodontium show a rather similar overall morphology, they present distinct ecological and geographical distribution patterns. S. caatingae is found in the altitudinal range between 0 and 500 m and is almost restricted to the Caatinga ecosystem, extending to the adjacent Atlantic Rainforest ( Sulzbacher et al. 2016). S. chocoensis and S. tutunendo are sympatric occurring in the tropical rainforest of the Colombian Chocó region. Coca et al. (2018) considered these two species semi-cryptic, as defined by Vondrák et al. (2009).

The new species, S. leucodontium , occurs in the Colombian Andean-Amazonian Piedmont, the Brazilian Amazon and the Madrean-Caribbean transition in Mexico. It is readily distinguished from other neotropical Sulzbacheromyces species by having white basidiomata, and the presence of colonial, trebouxioid algae in the thallus.

Figures

FIGURE 2.Sulzbacheromyces leucodontium. A. Thallus andbasidiomata.B. Detail of the cracked basidiomata.C. Insertion of basidiomata and thallus, note the clustering of the photobiont in small spheres in the thallus. D. Hyphae of the context. E. Basidia and basidioles F. Basidiospores (Coca 13248 JBB). Drawings by: Omar Bernal

FIGURE 3. Field and lab pictures of Sulzbacheromyces leucodontium. A. Specimen in field with thallus and basidiomata (Putumayo, Coca 13201, scale 27 mm). B. Type specimen in field (Caquetá, Coca 9262). C. Specimen in field with thallus and basidiomata (Mexico, Veracruz, Guzmán-Guillermo 3008) D. Detail of the thallus and basidiomata (Putumayo, Coca 13201, scale 9 mm). E. Cross section of the thallus of S. leucodontium on soil (Caquetá, Coca 13248, Scale 52 µm.). F. trebouxioid photobiont (Caquetá, Coca 13248, Scale 25 µm). Photos by: L.F.Coca (A-B, D-F); J.Guzmán Guillermo (C)

FIGURE 4. Best-scoring Maximum Likelihood tree using the ITS barcoding marker for the known Sulzbacheromyces species. Supported branches (bootstrap values ≥70 and posterior probability>0,95) are thickened and bootstrap support values are indicated below branches, Asian species are present in warm color, Neotropical species are present in cool color and African species in green.