# Transdrakea

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Transdrakea
> Markdown URL: https://mediated.wiki/source/Transdrakea.md
> Source: https://en.wikipedia.org/wiki/Transdrakea
> Source revision: 1246496324
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

***Transdrakea*** is a small [genus](/source/Genus) of [lichen](/source/Lichen)-forming [fungi](/source/Fungi) in the family [Teloschistaceae](/source/Teloschistaceae).[1] It comprises two species of [crustose lichens](/source/Crustose_lichen) that [grow on rocks](/source/Saxicolous_lichen). The genus is characterised by its poorly developed [thallus](/source/Thallus), apothecia (fruiting bodies), and small with thin [septa](/source/Septum). Chemically, *Transdrakea* species contain [anthraquinones](/source/Anthraquinone), particularly [parietin](/source/Parietin).

## Taxonomy

The genus was [circumscribed](/source/Circumscription_(taxonomy)) in 2023 by the lichenologists Ulrik Søchting and Ulf Arup. The genus name alludes to its distribution on both sides of the [Drake Passage](/source/Drake_Passage), which separates South America from Antarctica.[2] *Transdrakea* is closely related to the genus *[Gondwania](/source/Gondwania)*, with both genera belonging to a [clade](/source/Clade) of predominantly Southern Hemisphere taxa within the subfamily Xanthorioideae of the family [Teloschistaceae](/source/Teloschistaceae). [Molecular phylogenetic](/source/Molecular_phylogenetic) analyses place *Transdrakea* as [sister](/source/Sister_group) to *Gondwania*, with both genera forming a well-supported clade distinct from other related genera such as *[Austroplaca](/source/Austroplaca)* and *[Cerothallia](/source/Cerothallia)*.[2]

## Description

*Transdrakea lichens* are characterised by their [crustose](/source/Crustose_lichen) growth form, meaning they grow closely adhered to their , typically rocks. The [thallus](/source/Thallus), which is the main body of the lichen, is poorly developed and often inconspicuous. The most prominent features of *Transdrakea* are its reproductive structures, the [apothecia](/source/Apothecia). These are small, -shaped fruiting bodies that contain the fungal spores. In *Transdrakea*, the apothecia are , which means they have two distinct margins: an inner composed of fungal tissue, and an outer that contains algal cells. The apothecia are typically yellow to orange in colour and can be up to 0.4 mm in diameter.[2]

Under a microscope, the internal structure of the apothecia reveals several features. The [hymenium](/source/Hymenium), the spore-producing layer, is relatively thin at 50–60 [μm](/source/%CE%9Cm) high. The [paraphyses](/source/Paraphyses), sterile filaments between the spore-producing cells, are simple or slightly branched at the tips and only slightly enlarged at their apices. The , which are the reproductive spores produced in sacs called [asci](/source/Ascus), are a key diagnostic feature of *Transdrakea*. They are relatively small, typically measuring around 10–11 μm long by 4–5 μm wide. A distinctive characteristic is their very thin [septum](/source/Septum), the internal wall that divides the spore into two cells, which is usually only about 1.5 μm thick.[2]

Chemically, *Transdrakea* lichens contain [anthraquinone](/source/Anthraquinone) pigments, with [parietin](/source/Parietin) being the dominant compound. This places them in what lichenologists refer to as A, a classification based on the proportions of different anthraquinones present in the lichen.[2]

## Species

Two species are recognised in *Transdrakea*:[2]

- *[Transdrakea alacalufes](/source/Transdrakea_alacalufes)* – The [type species](/source/Type_species) of the genus, found in [Patagonia](/source/Patagonia) and the [Falkland Islands](/source/Falkland_Islands).
- *[Transdrakea schofieldii](/source/Transdrakea_schofieldii)* – Originally described as *Caloplaca schofieldii*,[3] this species occurs in Antarctica, southern Chile, and the Falkland Islands.

The two *Transdrakea* species can be distinguished by their growth patterns and geographical distributions. *T. alacalufes* typically has numerous, dispersed apothecia, while *T. schofieldii* tends to have apothecia aggregated in rock crevices.[2]

## References

1. Søchting, Ulrik; Sancho, Leo Garcia; Arup, Ulf (2023). "The lichen genera *Gondwania* and *Transdrakea* gen. nov. (Teloschistaceae) – speciation in three southern continents". *Plant and Fungal Systematics*. **68** (2): 304–319. [doi:10.35535/pfsyst-2023-0015](https://doi.org/10.35535/pfsyst-2023-0015)

1. Dodge, C.W. (1968). "Lichenological notes on the flora of the Antarctic continent and the subantarctic islands. VII.-VIII". *Nova Hedwigia*. **15**: 285–332.

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