Biology:Malmidea hechicerae

Short description: Species of lichen

Malmidea hechicerae
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Lecanorales
Family:	Malmideaceae
Genus:	Malmidea
Species:	M. hechicerae
Binomial name
Malmidea hechicerae Kalb (2021)
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Holotype site: Monte Zerpa, Venezuela

Malmidea hechicerae is a species of corticolous (bark-dwelling), crustose lichen in the family Malmideaceae. It is found in Venezuela.

Taxonomy

The lichen was formally described as a new species in 2021 by the German lichenologist Klaus Kalb. The type specimen was collected from Monte Zerpa (Distr. Libertador, Mérida) at an elevation of 2,200 m (7,200 ft), where it was found growing in a cloud forest. The species epithet refers to its type locality, known as La Hechicera.

Description

Malmidea hechicerae is a crustose lichen with a continuous thallus that is 40–60 µm thick. The thallus surface is [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], with the [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] being more or less spherical and measuring 0.1–0.25 mm in diameter. These verrucae have a dull, whitish-grey appearance. The species lacks both soralia and isidia (reproductive propagules). The medulla of the verrucae and thallus is white, reacting K+ (lemon-yellow), occasionally showing a slightly orange-yellow hue, and P+ (orange), best observed in sections under a light microscope.

The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of Malmidea hechicerae is [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] with cells measuring 6–8 µm in diameter. The apothecia are sessile and rounded, ranging from 0.6–1.3 mm in diameter and 0.3–0.4 mm in height. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of the apothecia are more or less flat and vary in colour from beige to brownish or dark brown. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is of the granifera-type, remaining [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]], and is whitish to cream-coloured, bulging, and elevated above the disc. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is hyaline (translucent) to brownish, particularly at the edges, while the medullary excipulum is filled with colourless opaque [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that partly dissolve in potassium hydroxide, producing a greenish-yellow efflux.

The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of the lichen is roughly 20 µm high and light brown, with a centrally located [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] measuring 50–70 µm high that narrows towards the margin and is dark brown, not reacting to K. The [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] is light brown, and the hymenium is hyaline, measuring 70–80 µm in height. The asci are 55–65 µm long and 8–15 µm wide, each containing 6 to 8 [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] that lack septa. These ascospores are broadly ellipsoid, with equally thickened and [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] walls, measuring 13–17 by 7–9 µm, and are surrounded by a [[Glossary of lichen terms#{{biology:{1}}}|{{Biology:{1}}}]] of 1–1.5 µm.

In terms of chemistry, Malmidea hechicerae is characterized by several xantholepinone substances, detectable using thin-layer chromatography. Atranorin is not detected in this species. Malmidea coralliformis similar in appearance to M. hechicerae but has a different set of xantholepinones.

References

Wikidata ☰ Q123983216 entry