Caloplaca nigra
Caloplaca nigra is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae.[1] Found on rocks predominantly in the Galápagos Islands, it is characterised by its dark reproductive structures (apothecia).
| Caloplaca nigra | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Teloschistales |
| Family: | Teloschistaceae |
| Genus: | Caloplaca |
| Species: | C. nigra |
| Binomial name | |
| Caloplaca nigra Bungartz & Søchting (2020) | |
Taxonomy
The species Caloplaca nigra was formally described and catalogued by lichenologists Frank Bungartz and Ulrik Søchting. The species epithet nigra derives from the Latin for "black", alluding to the colour of its apothecial discs. The type specimen is from the Galápagos Islands, specifically from San Cristóbal Island's hills south of Punta Pit at the island's northeast coast.[2]
Description
The lichen has a brownish-olive, distinctly areolate thallus. These areoles, in some instances, appear as though outlined by a whitish border, especially around their periphery. The apothecia, ranging from sparse to abundant, are more or less aspicilioid (more of less immersed in the thallus) at the onset. Their margins are hard to distinguish from the thallus, later becoming more adnate and lecanorine. Apothecial discs are flat to slightly convex and black. Microscopic examinations of Caloplaca nigra reveal a brownish-olive epihymenium and a hymenium that is clear and free from any dispersion. Asci are broadly clavate and resemble the Teloschistes-type. The ascospores, numbering eight per ascus, are polaribilocular and range from ellipsoid to broadly ellipsoid, measuring approximately 10.0–11.3 by 5.8–7.8 μm.[2]
Chemical spot tests conducted on the thallus and apothecia have shown consistent non-reactivity. Secondary metabolites have not been identified in the species.[2]
The Galápagos also has another species, C. floridana, which shares the trait of black apothecia with Caloplaca nigra. However, C. floridana is corticolous, growing on tree bark, and displays distinct thallus characteristics and chemical reactions that differentiate it from Caloplaca nigra. Although DNA extraction for Caloplaca nigra proved challenging, its unique attributes underscore its classification as a separate species.[2]
Habitat and distribution
Endemic to the Galápagos Islands, Caloplaca nigra has been observed growing on rocks in environments ranging from sun-drenched coastal regions to the lower transition zones. These habitats are typically exposed to significant sunlight, wind, and rainfall.[2]
See also
References
- "Caloplaca nigra Bungartz & Søchting". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 24 August 2023.
- Bungartz, Frank; Søchting, Ulrik; Arup, Ulf (2020). "Teloschistaceae (lichenized Ascomycota) from the Galapagos Islands: a phylogenetic revision based on morphological, anatomical, chemical, and molecular data". Plant and Fungal Systematics. 65 (2): 515–576. doi:10.35535/pfsyst-2020-0030.