# Septotrapelia

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***Septotrapelia*** is a [genus](/source/Genus) of [lichen](/source/Lichen)-forming [fungi](/source/Fungi) in the family [Ectolechiaceae](/source/Ectolechiaceae). It comprises four species.[2] Species in this genus form tiny, scale-like crusts on rocks and are distinguished by their chocolate-brown fruiting discs with pale margins and unusually large [ascospores](/source/Ascospore) divided into three segments. These small, bluish-grey lichens grow primarily on [volcanic boulders](/source/Volcanic_rock) and weathered stone in [tropical](/source/Tropical) and [subtropical](/source/Subtropical) regions, from [Costa Rica](/source/Costa_Rica) and the [Galápagos](/source/Gal%C3%A1pagos) to Thailand and South Korea. The genus was established in 2007 after DNA studies showed that certain species with this distinctive spore structure did not fit into existing lichen groups.

## Taxonomy

*Septotrapelia* was introduced in 2006 by [André Aptroot](/source/Andr%C3%A9_Aptroot) and José Luis Chaves as part of a study describing several new [squamulose lichen](/source/Squamulose_lichen)-forming fungal [genera](/source/Genera); unlike the [ramalinaceous](/source/Ramalinaceae) novelties in that paper, *Septotrapelia* was placed in the Pilocarpaceae (this family has been since synonymized with [Ectolechiaceae](/source/Ectolechiaceae)). The [type species](/source/Type_species), *S. glauca*, was described from specimens collected from [volcanic boulders](/source/Volcanic_rock) in pasture near [Tenorio Volcano National Park](/source/Tenorio_Volcano_National_Park), [Guanacaste](/source/Guanacaste_Province), Costa Rica (about 700 m elevation); the [holotype](/source/Holotype) is housed at the [Instituto Nacional de Biodiversidad](/source/Instituto_Nacional_de_Biodiversidad) (INB).[3]

Aptroot and Chaves separated the genus from superficially similar *[Trapelia](/source/Trapelia)* and *[Trapeliopsis](/source/Trapeliopsis)* on combined : a dull bluish, squamulose thallus; apothecia; and large, , 3-septate [ascospores](/source/Ascospore). They noted that no existing pilocarpaceous genus combined a squamulose thallus with 3-septate spores, and that the spore size exceeded that known in the family—features that, together with the apothecial anatomy, supported recognition at generic rank. The authors also included a [new combination](/source/New_combination) for the widespread [paleotropical](/source/Paleotropical) crustose species *Septotrapelia triseptata* , based on *Lecidea triseptata* (type: [Java](/source/Java)).[3] The 2006 generic name, however, was not [validly published](/source/Validly_published_name) under the prevalent [nomenclatural rules](/source/International_Code_of_Nomenclature_for_algae,_fungi,_and_plants): *[Index Fungorum](/source/Index_Fungorum)* records it as [*nom. inval.*](/source/Nomen_invalidum), citing Art. 38.5(a), indicating that the protologue lacked a compliant [description](/source/Species_description)/ or reference to one. The name was validated the following year by Aptroot and co-authors, who published the genus and type species in *[Fungal Diversity](/source/Fungal_Diversity)* (2007), where they also treated the combination *S. triseptata*.[4]

## Description

*Septotrapelia* comprises small, bluish-grey, [squamulose](/source/Squamulose_lichen) (scale-forming) lichens. The [thallus](/source/Thallus) is dull, (with a fine powdering) and forms convex, elongate about 0.2–0.4 mm wide and up to 2 mm long that may overlap into a mat; thinner thalli are packed with algal cells, whereas thicker ones develop a white [medulla](/source/Medulla_(lichenology)) beneath the . The upper is irregularly and crystal-laden; no is developed.[3]

Apothecia are (with a pale, thallus-coloured margin), initially round then often lobed, 0.5–2.0 mm in diameter, with a dark chocolate-brown, dull that may carry sparse white . The is prominent and can stand above the disc. The is sharply delimited, with an outer [hyaline](/source/Hyaline) layer over a [mottled](/source/Mottle) dark-brown inner portion; the is similarly dark brown. The [hymenium](/source/Hymenium) is non-inspersed, and the is brown with tiny crystals. The supporting threads between spore sacs ([paraphyses](/source/Paraphyses)) have internal walls and fuse together where they meet. The spore sacs ([asci](/source/Ascus)) have a distinctive cap structure () characteristic of the family Ectolechiaceae that [stains](/source/Staining) blue with iodine after alkali treatment (IKI+ after KOH). Spores are colourless, club-shaped (), and divided by three [cross-walls](/source/Septum) (3-septate), typically (23–)30–35 × (6–)8–10 [μm](/source/%CE%9Cm) in size, with a strong constriction at the middle wall and a thin jelly-like outer coating.[3]

[Pycnidia](/source/Pycnidia) occur on the lobes as small, pinkish-yellow spherical structures (about 0.4 mm), producing rod-shaped [conidia](/source/Conidia) 5–6 × 1 μm. In standard [spot tests](/source/Spot_test_(lichen)) the thallus is K−, C−, PD− and UV−; [thin-layer chromatography](/source/Thin-layer_chromatography) shows [usnic acid](/source/Usnic_acid) and a [terpene](/source/Terpene), and the chemistry of the medulla is otherwise unremarkable.[3]

## Habitat and distribution

*Septotrapelia* is a [saxicolous](/source/Saxicolous_lichen) (rock-dwelling) genus: the type species (*S. glauca*) grows on volcanic boulders in open pasture near Volcán Tenorio National Park, Guanacaste, Costa Rica, at around 700 m elevation. Aptroot and co-authors also pointed to two further elements likely assignable to the genus: a sterile, sorediate, squamulose crust from the [Galápagos](/source/Gal%C3%A1pagos) (saxicolous), and a [crustose](/source/Crustose_lichen) species they recombined as *S. triseptata*, which is common and often abundant on soil and weathered rock, particularly in tropical Asia.[3]

## Species

- *[Septotrapelia glauca](/source/Septotrapelia_glauca)* – Costa Rica
- *[Septotrapelia multiseptata](/source/Septotrapelia_multiseptata)* [5] – South Korea
- *[Septotrapelia triseptata](/source/Septotrapelia_triseptata)* – tropical Asia
- *[Septotrapelia usnica](/source/Septotrapelia_usnica)* [6] – [Galápagos Islands](/source/Gal%C3%A1pagos_Islands)

## References

1. Lendemer, James C. & Hodkinson, Brendan P. (2013). ["A radical shift in the taxonomy of *Lepraria* s.l.: Molecular and morphological studies shed new light on the evolution of asexuality and lichen growth form diversification"](https://www.tandfonline.com/doi/full/10.3852/12-338). *Mycologia*. **105** (4): 994–1018. [doi:10.3852/12-338](https://doi.org/10.3852/12-338). [PMID 23709574](https://pubmed.ncbi.nlm.nih.gov/23709574). Retrieved 15 October 2025.

1. Hyde, K.D.; Noorabadi, M.T.; Thiyagaraja, V.; He, M.Q.; Johnston, P.R.; Wijesinghe, S.N. et al. (2024). ["The 2024 Outline of Fungi and fungus-like taxa"](https://www.researchgate.net/publication/385939154). *Mycosphere*. **15** (1): 5146–6239 [5253]. [doi:10.5943/mycosphere/15/1/25](https://doi.org/10.5943/mycosphere/15/1/25). [hdl:11577/3540520](https://hdl.handle.net/11577/3540520)

1. Aptroot, A.; Umaña, L.; Chaves, J.L.; Trest, M.T. (2006). ["A first assessment of the Ticolichen biodiversity inventory in Costa Rica: three new squamulose genera (Lecanorales: Ramalinaceae and Pilocarpaceae)"](https://www.researchgate.net/publication/292626025). *Journal of the Hattori Botanical Laboratory*. **100**: 617–624.

1. Aptroot, A.; Saipunkaew, W.; Sipman, H.J.M.; Sparrius, L.B.; Wolseley, P.A. (2007). ["New lichens from Thailand, mainly microlichens from Chiang Mai"](https://www.researchgate.net/publication/228515656). *Fungal Diversity*. **24**: 75–134.

1. Aptroot, A. & Moon, K.H. (2014). "115 New reports of microlichens from Korea, including the description of five new species, show that the microlichen flora is predominantly Eurasian". *Herzogia*. **27** (2): 347–365. [doi:10.13158/heia.27.2.2014.347](https://doi.org/10.13158/heia.27.2.2014.347)

1. Bungartz, Frank; Hillmann, Georg; Kalb, Klaus; Elix, John A. (2013). ["Leprose and leproid lichens of the Galapagos, with a particular focus on *Lepraria* (Stereocaulaceae) and *Septotrapelia* (Pilocarpaceae)"](https://zenodo.org/record/5100473). *Phytotaxa*. **150** (1): 1–18. [doi:10.11646/phytotaxa.150.1.1](https://doi.org/10.11646/phytotaxa.150.1.1)

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Adapted from the Wikipedia article [Septotrapelia](https://en.wikipedia.org/wiki/Septotrapelia) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Septotrapelia?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.