Morphological and phylogenetic study describes two new Bunodophoron lichen species from New Caledonia

A taxonomic study combining morphology, secondary chemistry and phylogenetic analysis confirmed four species of the lichen genus Bunodophoron in New Caledonia and formally described two new species, Bunodophoron flagellare and Bunodophoron imbricatum. The research also reassessed the identity of previously reported regional records, finding that four names could not be confirmed from the examined material.

The study focused on New Caledonian material collected mainly on Grande Terre in 2022 and 2025, supplemented by herbarium specimens from New Caledonia, Argentina, Australia, Chile, Malaysia and New Zealand. Most recent collections were deposited at the University of Oslo and the Swedish Museum of Natural History, with duplicates at the Herbier de Nouvelle-Calédonie. The researchers examined specimens by dissecting and compound microscopy, measured thallus, fruiting-body and spore features, and used thin-layer chromatography to identify secondary metabolites.

For the molecular analysis, the authors generated 50 sequences from three protein-coding markers: 16 for β-tubulin, 10 for RNA polymerase II largest subunit, or RPB1, and 24 for the DNA replication licensing factor MCM7. They also generated 12 internal transcribed spacer, or ITS, sequences for New Caledonian material. These sequences were combined with published data and analyzed separately by marker and in a concatenated three-locus maximum-likelihood analysis. The protein-coding matrix contained 2,025 aligned positions from 48 specimens, while the ITS matrix contained 552 base pairs.

The maximum-likelihood tree divided the sampled Bunodophoron taxa into two strongly supported principal clades. One contained taxa associated with stictic-acid-related compounds and had 100% ultrafast bootstrap support. The other predominantly included samples with protocetraric acid and had 99% support. The separately analyzed ITS tree had limited sampling but did not conflict topologically with the concatenated protein-coding tree.

Four species-level lineages were identified among the New Caledonian material. Two were the newly described species, while the remaining material was provisionally assigned to Bunodophoron cf. formosanum and Bunodophoron cf. insigne. The new species were recovered in different major clades: B. flagellare was placed in the stictic-acid group, whereas B. imbricatum was placed in the group predominantly containing taxa with protocetraric acid.

Bunodophoron flagellare is a medium-to-large, epiphytic fruticose species with sparingly branched, whitish, slender to whiplash-like lower branches. Its ascomata are terminal, and its mazaedia are conspicuously sooted and exposed on the lower side near the branch apex. Ascospores measured 5.0–9.7 μm in diameter, excluding ornamentation. The species produces sphaerophorin, stictic acid, constictic acid and an unidentified accessory compound. It is currently known only from New Caledonia and may be endemic to the archipelago.

Bunodophoron imbricatum forms compact patches of imbricate, mostly decumbent and sparingly divided branches with a brownish-ochre upper surface. Its ascospores measured 4.7–12.6 μm in diameter, excluding ornamentation. Detected compounds included ascomatic acid, trace 7-O-methylnorascomatic acid, isousnic acid, sphaerophorin and protocetraric acid, although protocetraric acid was absent from one examined specimen. The species is also currently known only from New Caledonia. Both newly described taxa were recorded in mountain rainforests or high-elevation maquis and appear to favor semi-open habitats with comparatively high light availability; they were sometimes found together.

The molecular results changed the interpretation of earlier New Caledonian identifications. New Caledonian material resembling B. kinabaluense formed a separate, strongly supported lineage from specimens collected near that species’ type locality in Borneo. The authors therefore concluded that previous regional reports of B. kinabaluense most likely referred to B. flagellare or to B. formosanum sensu lato. The New Caledonian population identified as B. cf. formosanum was sister to an Australian specimen assigned to that species, but its status remains tentative because no material from Taiwan, the type locality, had been sequenced and B. formosanum shows substantial morphological variation.

New Caledonian samples assigned to B. cf. insigne formed a strongly supported clade with South American material identified as the same species, but genetic divergence and a relatively long branch raised the possibility that the New Caledonian specimens represent a separate, undescribed taxon. The study could not confirm earlier reports of B. australe, B. imshaugii, B. kinabaluense and B. ramuliferum in the archipelago. These were descriptive taxonomic and phylogenetic findings based on the sampled specimens; incomplete locality sampling, uncertain identifications and limited ITS data leave the status and diversity of some lineages unresolved.

Subject of Research: Taxonomic and phylogenetic assessment of the lichen genus Bunodophoron in New Caledonia

Article Title: Taxonomy and phylogeny of the lichen genus Bunodophoron ( Sphaerophoraceae , Lecanorales ) in New Caledonia, with the description of two new species

Article References: Borg, N. H., Wedin, M., Timdal, E., Prieto, M., & Simon, A. (2026). Taxonomy and phylogeny of the lichen genus Bunodophoron (Sphaerophoraceae, Lecanorales) in New Caledonia, with the description of two new species. MycoKeys, 140, 79-101. https://doi.org/10.3897/mycokeys.140.197771

Image Credits: AI Generated

DOI: 10.3897/mycokeys.140.197771

Keywords: Bunodophoron, New Caledonia, lichen taxonomy, phylogenetics, species discovery, morphology, lichen chemistry, molecular analysis, mycology, Taxonomy, phylogeny, lichen