Assessment Notes

Justification

Ixechinus minor is a fungus of the Boletaceae family known from Madagascar. It has only been documented once, in 1939, and very little information on the species is available. The type specimen was found in a Taipa forest, a threatened ecosystem in Madagascar with high rates of deforestation. However, the potential host species, Uapaca bojeri, has been assessed as Least Concern. While it is possible that this species is rare and subjected to habitat loss, targeted search efforts and research on its habitat and ecology are needed to determine whether this is a truly uncommon, or if it has been overlooked. It is thus plausible that I. minor could fall into any category from Critically Endangered to Least Concern and so it is assessed as Data Deficient (DD).

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Taxonomic notes

Ixechinus minor, originally as 'minus', is the only species currently accepted as part of the Ixechinus genus, of the family Boletaceae. Wolfe (1982) considered Fistulinella minor a homotypic synonym of Ixechinus minor, but it is not included in Index Fungorum (2022) as it is treated as a nomen invalidum in that taxonomic backbone.

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Geographic range

This species is only known from the Ambatofinandrahana district in Madagascar.

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Population and Trends

Ixechinus minor has only been documented in 1938 in Madagascar, from one specimen (Heim 1939). There have been no further records or information on search efforts since, so it is not possible to calculate an estimate of the population size or current trend.

Population Trend: unknown

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Habitat and Ecology

The specimen used for the original description (Heim 1939) was found in a Tapia forest, a forest type characteristic of Madagascar, under the endemic tree Uapaca bojeri. It was described as ectomycorrhizal (Horak 1968).

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Threats

Even though Tapia (Uapaca bojeri) has been assessed as Least Concern (Rabarijaona, 2019), Madagascar’s Tapia forests are subjected to deforestation due to human influence (through charcoal production, timber collection, grazing and fire). It has suffered an estimated loss of 70% to 90% of its area since 1750 and was therefore classified as Endangered in the IUCN Red List of Ecosystems (Keith et al. 2013). This habitat reduction may in turn lead to a reduction in population size and constitute a threat to Ixechinus minor, especially if it is exclusive to this habitat.

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Conservation Actions

Search efforts are needed to understand the ecology and current distribution and population size of this species. Moreover, the synonymy of Fistulinella and Ixechinus has been discussed in the past (Guzmán 1974, Wolfe 1982). Given that Ixechinus minor remains as the only species in the genus, while other species now have other currently accepted names, further research should be done to understand the phylogeny of the species and whether this truly is a monotypic genus.

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Source and Citation

Gonçalves, S.C. & P. Cunha, S. 2023. Ixechinus minor. The IUCN Red List of Threatened Species 2023: e.T238744511A238802886. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T238744511A238802886.en .Accessed on 3 January 2024

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• Country occurrence