Assessment Notes

Justification

Only known from the Talamanca Mountains of Costa Rica, Cantharellus atrolilacinus is estimated to have a small population size of 10,000-20,000 mature individuals. Ongoing habitat loss and degradation, e.g. due to agriculture, is expected to be causing a population decline. Such a decline is unlikely to be very rapid (i.e. it would not warrant listing under criterion A), and its distribution is large enough that it would not warrant a listing as based on its range size. Overall, therefore, C. atrolilacinus approaches but doesn't fully meet the thresholds for listing as threatened under criterion C2a(ii). Thus it is assessed as Near Threatened under this criterion.

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Geographic range

The type specimen of this species was collected in mid elevation oak dominated forests in Coto Brus Canton, Costa Rica near the Panamanian boarder (Eyssartier et al. 2003). A record of this species from human observation, made in September 2020, was from San Jose, Costa Rica (GBIF 2024), while twenty two further collections have been made from Costa Rica, through the Talamanca Mountains (GBIF 2024). Observations from Japan (in GBIF 2024) are likely of a different taxon and are not included in this assessment.

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Population and Trends

Records of this species have been collected in the Talamanca Mountains, primarily the Las Tablas Protection Zone in southern Costa Rica. Although much of the area is under protection, habitat loss and degradation is ongoing and the species' population is considered to be in decline.

Based on Dahlberg and Mueller (2011) it is estimated that there would be 10 mature individuals per site, and taking into account the amount of suitable habitat within the Talamanca Mountains, it is plausible that there could be 1,000-2,000 suitable sites for the species across its range. This would give a total population size of 10,000-20,000 mature individuals. With the contiguousness of the habitat these may be suspected to fall into a single subpopulation.

Population Trend: Decreasing

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Habitat and Ecology

This species forms ectomycorrhizae with southern montane neotropical oaks, including Quercus corrugata (Eyssartier et al. 2003).

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Threats

While much of the area from where the species has been reported is under some protection, there is ongoing habitat loss and degradation, for instance due to agricultural activities (e.g. pineapple).

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Conservation Actions

This species could potentially exist within threatened habitat, and so protection of this habitat is required for the successful conservation of this species in the wild. Further research into this species' distribution and habitat preferences would be useful.

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Source and Citation

Mueller, G.M. 2025. Cantharellus atrolilacinus. The IUCN Red List of Threatened Species 2025: e.T269710105A269710107. Accessed on 27 November 2025.

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• Country occurrence