| Wegea | |
|---|---|
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Arthoniomycetes |
| Order: | Arthoniales |
| Genus: | Wegea Aptroot &Tibell (1997) |
| Type species | |
| Wegea tylophorelloides Aptroot & Tibell (1997) | |
Wegea is a fungalgenus in the orderArthoniales. It has not been placed into afamily.[1][2] It is amonospecific genus, containing the little-known single speciesWegea tylophorelloides. The species has amorphology similar tocalicioid fungi (a group characterized by their distinctive pin-like or club-shapedfruiting bodies) but does not form a powder spore mass (mazaedium). The genus, established in 1997, is known only from a single collection found growing on dead bark in the lowlandrainforests ofPapua New Guinea.
Wegea was established as a new genus in 1997 byAndré Aptroot andLeif Tibell to accommodate a distinctivecalicioid fungus that could not be placed within any existing taxonomic groups. The genus ismonotypic, containing only the single speciesW. tylophorelloides, which serves as both thetype species and the defining representative of the genus. The genus nameWegea honours the prominent mycologistWalter Gams, recognizing his significant contributions to fungal taxonomy andsystematics. Thespecies epithettylophorelloides reflects themorphological similarities between this fungus and members of the related genusTylophorella, indicating their close evolutionary relationship while acknowledging the distinct differences that warrant separate generic status.[3]
Taxonomically,Wegea is classified within the orderArthoniales, a diverse group ofascomycete fungi that includes both lichenized and non-lichenized species. Within this order,Wegea belongs to the calicioid fungi, a morphologically defined group characterized by their distinctive pin-like or club-shaped fruiting bodies. Despite sharing many structural features with other Arthoniales,Wegea represents one of the non-lichenizedlineages within this predominantly lichen-forming order.[3]
The closest relative toWegea appears to beTylophorella, particularlyT. pyrenaica, based on similarities inascus structure, spore development, and overall morphology. However, several key differences distinguishWegea fromTylophorella: the absence of lichenization, the presence of distinctive pigmentation, shorter-stalked fruiting bodies, and spores that remain 3-septate throughout maturity rather than fragmenting into individual cells.[3]
Thetype specimen ofW. tylophorelloides was collected from theFinisterre Range foothills in Papua New Guinea'sMadang Province, where it was found growing on the bark of a felled tree in lowland rainforest at roughly 230 metres elevation. This specimen, designated as holotype CBS 33330, is preserved in multipleherbaria and serves as the definitive reference for the species.[3]
The fungus produces distinctive fruiting bodies (ascomata) that are short-stalked and measure 0.26–0.34 mm in height. These structures have a widened, subspherical top portion (capitulum) that appears greyish to reddish-brown with an uneven surface. The stalk itself is short, black, and smooth, measuring 0.12–0.14 mm in diameter. The lower portion of the stalk consists of strongly intertwined, translucent thread-like structures (hyphae) that are 5–8 micrometres (μm) in diameter, while the upper part contains irregularly distributed reddish pigment crystals.[3]
A key diagnostic feature ofWegea is its distinctive spore ornamentation. The mature spores are dark brown with an elaborate surface pattern that is clearly visible underlight microscopy. When examined withscanning electron microscopy, the spores reveal an intricate network of irregular ridges and depressions across their surface. The spores are 3-septate (divided by threecross-walls), measuring 12–18 × 4–6 μm, and have a slightly asymmetric, elongated shape.[3]
The internal structure of the fruiting bodies includes strongly thickenedasci (spore-containing sacs) at their tips, with a distinct layered chamber. Unlike many related fungi in the Arthoniales,Wegea lacks certain chemical reactions typical of the group and does not form a lichenized partnership with algae. The fungus also contains a reddish pigment that is not soluble inacetone.[3]
Wegea shares several morphological features with the related genusTylophorella, including the overall structure of its fruiting bodies and spore characteristics. However, it differs in being non-lichenized, having shorter-stalked fruiting bodies, containing distinctive pigmentation, and producing 3-septate spores that remain intact at maturity rather than fragmenting into individual cells as occurs inTylophorella.[3]
Wegea tylophorelloides is known only from itstype locality in Papua New Guinea, where it was discovered in theMadang Province along the foothills of theFinisterre Range. The species inhabits lowlandtropical rainforest environments at relatively low elevations, with the type collection made at about 230 meters above sea level.[3]
The fungus appears to be asaprobic colonizer of dead wood, having been found growing on the bark of a recently felled tree invirgin rainforest. This suggests thatW. tylophorelloides may play a role in the decomposition of woody plant material in these tropical ecosystems. The species was initially discovered during a lichenological expedition in 1992, and subsequent visits to the same locality in 1995 confirmed its presence on additional lichen-coveredsubstrates, though no fruiting bodies were observed during the later collection. The habitat represents acorticolous (bark-dwelling) niche within the tropical rainforest ecosystem, growing in the high humidity and environmental conditions characteristic of lowland New Guinea forests. The specificmicrohabitat requirements and ecological preferences ofW. tylophorelloides remain poorly understood due to the limited number of collections and observations.[3]