Enterographa Rotundata

''Enterographa rotundata'' is a species of corticolous (bark-dwelling) crustose lichen in the family Roccellaceae. This species was discovered in Brazil, growing on the smooth bark of trees in the Brazilian Caatinga forest. It has round (lichen structures where spores are produced), a feature that sets it apart from most of its kind.

Taxonomy

''Enterographa rotundata'' was first formally described by lichenologists Marcela Cáceres, Edvaneide Leandro de Lima, and André Aptroot in 2012. Its type specimen was discovered by the second author on the bark of a tree in the Catimbau National Park, in the Pernambuco state of Brazil, at an altitude of approximately . The species name ''rotundata'' is derived from the Latin word , which translates to "round", a fitting descriptor for the species' distinct round .

Description

The ''Enterographa rotundata'' lichen has a crust-like thallus (lichen body), which is often very thin, making it appear almost non-existent. Its colour varies from pale pinkish to pale brownish, and it adheres closely to the surface of the tree bark. Its is from the green algal genus '' Trentepohlia''.

''Enterographa rotundata'' is distinguished by its round or slightly ellipsoidal ascomata, the sexual reproductive structures of lichen, which are dark brown to black in colour. The ascomata are 0.1–0.2 mm wide with a raised, ochraceous white margin approximately 0.05 mm wide. Each ascus, the spore-bearing structure within the ascomata, typically contains eight hyaline . These are narrowly (club-shaped), 50–60 by 3.5–5.0 μm in size, and surrounded by a gelatinous sheath.

One of the notable characteristics of ''Enterographa rotundata'' is its lack of detectable substances, which is relatively unusual for a lichen. It has been observed to have no reactions with the standard chemical spot tests (UV−, C−, P−, and K−); the lack of substances has been confirmed by thin-layer chromatography.

Habitat and distribution

''Enterographa rotundata'' is primarily found on the smooth bark of trees in the Caatinga forest, a unique dry forest biome found only in Brazil. In this environment, it coexists with other lichen species such as '' Dirinaria leopoldii'', ''Lecanora leprosa'', '' L. leproplaca'', '' Pertusaria ventosa'', '' Phaeographis ventosa'', and ''Ramboldia haematites''.

Similar species

''Enterographa rotundata'' is one of very few ''Enterographa'' species with round apothecia. It bears a superficial resemblance to ''Enterographa lecanoracea'' and '' Enterographa mesomela'', both of which, however, have distinguishing features. ''E lecanoracea'' is characterised by larger ascomata, while ''E. mesomela'' has a grey-green thallus and slightly shorter ascospores.

Other species such as '' E. anguinella'', '' E. batistae'', '' E. byssoidea'', and '' E. perez-higaredae'' also have typically round apothecia but differ in their ascomata size, chemistry, and habitat. For instance, ''E. batistae'' has the smallest ascomata, ''E. byssoidea'' is recognised by its apothecium margin, and ''E. perez-higaredae'' is known for the presence of psoromic acid.

The lichen species ''Lecanographa atropunctata'' is also superficially similar but can be differentiated by its thicker dark brown to black and , more septate ascospores, and the presence of schizopeltic acid, a compound not found in ''Enterographa rotundata''.

References

{{Taxonbar, from=Q107656306

Roccellaceae
Lichen species
Lichens described in 2013
Lichens of Northeast Brazil
Taxa named by André Aptroot
Taxa named by Marcela Cáceres