Astrochapsa is a genus of lichen-forming fungi in the subfamily Graphidoideae of the family Graphidaceae. It comprises approximately 28–30 species.
Taxonomy
The genus was circumscribed in 2012 by Sittiporn Parnmen, Robert Lücking, and H. Thorsten Lumbsch during a generic-level reclassification of thelotremoid graphid lichens based on DNA evidence. Phylogenetic analyses showed that several species then placed in the genus Chapsa formed a coherent, separate lineage. To reflect this evolutionary split, the authors erected Astrochapsa and designated Astrochapsa astroidea as the type species. The genus was segregated from Chapsa sensu stricto based on a combination of morphological, anatomical, and chemical characters.
Description
Astrochapsa species form a crustose thallus on bark that is usually well-developed with a dense outer cortex. Their fruiting bodies (apothecia) are round to irregular in shape, with an exposed inner disc and a rim that is often lobed and tends to curve backward (recurved). The rim tissue (excipulum) is typically brown. Under microscopic examination, the ascospores are colorless (occasionally pale brown), elongated (spindle-shaped to cylindrical), with one or more cross-walls. The septa between spore cells are slightly thickened and the cell cavities appear angular—a condition described as "subdistoseptate." The spore walls do not turn blue with iodine (non-amyloid, I–). Chemically, many species lack detectable lichen substances, though stictic acid derivatives are frequent in some.
Habitat and Distribution
Astrochapsa species are bark-dwelling (corticolous) crustose lichens found in warm, humid forests. They occur primarily on trunks and branches of living trees in lowland to montane tropical settings. Geographically, the genus is chiefly tropical and subtropical, with records from the Neotropics (including the Caribbean), tropical Africa, and parts of Asia–Pacific, indicating a pantropical distribution.
Species
As of October 2025, Species Fungorum (in the Catalogue of Life) accepts 29 species of Astrochapsa, including:
- Astrochapsa albella
- Astrochapsa alstrupii
- Astrochapsa amazonica
- Astrochapsa astroidea (type species)
- Astrochapsa calathiformis
- Astrochapsa columnaris
- Astrochapsa elongata
- Astrochapsa fusca
- Astrochapsa graphidioides
- Astrochapsa kalbii
- Astrochapsa lassae
- Astrochapsa lobata
- Astrochapsa magnifica
- Astrochapsa martinicensis
- Astrochapsa mastersonii
- Astrochapsa megaphlyctidioides
- Astrochapsa meridensis
- Astrochapsa mirabilis
- Astrochapsa platycarpella
- Astrochapsa pseudophlyctis
- Astrochapsa pulvereodiscus
- Astrochapsa recurva
- Astrochapsa sipmanii
- Astrochapsa stellata
- Astrochapsa submuralis
- Astrochapsa verruculosa
- Astrochapsa waasii
- Astrochapsa wolseleyana
- Astrochapsa zahlbruckneri
