Cenozosia excorticata Jung & Werner, 2023

Jung, Patrick, Werner, Lina, Briegel-Williams, Laura, Emrich, Dina & Lakatos, Michael, 2023, Roccellinastrum, Cenozosia and Heterodermia: Ecology and phylogeny of fog lichens and their photobionts from the coastal Atacama Desert, MycoKeys 98, pp. 317-348 : 317

Cenozosia excorticata Jung & Werner sp. nov.

Fig. 5

Type.

Chile. Atacama Desert , Pan de Azucar National Park (25°59'03"S, 70°36'55"W; 764 m a.s.l.) specimen HBG-025792 (Herbarium Hamburgense, Hamburg, Germany).

Diagnosis.

Recognized by its perforated, leprose thallus.

Etymology.

The epithet ' Cenozosia excorticata ' refers to the chondroid, perforated cortex which is loosely wrapped around a whitish medulla that penetrates the cortex during new growth.

Description.

Thallus white to gray-brown with a leprose appearance, forming nest-like structures around 5 cm across but also large examples of more than 12 cm have been observed. Thallus divided into many long branches, up to 9 cm long, 0.3 mm thick, narrow cylindrical-teretiform but terminally kinked with a pale brown to blackened base. Mostly made of primary, fastigiate branches, sometimes dichotomously divided, especially towards the tips. Cortex made of pale, gray, hyaline, coalesced hyphae, forming a strongly perforated and wide sleeve around the white medulla pillowed by a few hyphal strands that crisscross between medulla and cortex sleeve. Medulla white, forming a loose, irregular strand made of crisscrossing hyphae within the cortex sleeve. During new growth the whitish medulla strand penetrates the cortex. Juvenile medulla strands without cortex sleeve are terminally light brown. Apothecia, round, bowl-shaped, gray with a concave, pink disc, mostly emerging lateral, sometimes terminal, up to 0.5 cm in diameter. Spores two celled, divided by a septum. Trebouxioid photobiont arranged in infrequent nests throughout the loose medulla and cortex network.

Secondary metabolites.

Decarboxynorstenosporic acid, decarboxydivaricatic acid, zeorin. UV-, K-, C+ red, central strand only, KC+ yellow, central strand only, P-.

Distribution and ecology.

Epiphytically directly on cacti stems or needles, preferably on Eulychnia sp., in the fog zones together with C. cava and various Ramalina species.

Notes.

Similar to various Niebla species but endemic to the Atacama Desert forming the distinct Cenozosia cluster.

Figures

Figure 5. Cenozosia excorticata sp. nov. A-D photographs of Cenozosia excorticata sp. nov. on cacti needles in the National Park Pan de Azucar and under laboratory conditions E-I different close-ups of thallus sections showing the bright white central strand surrounded by a layer of gray, hyaline coalesced hyphae forming a perforated cortex and chondroid strands that crisscross the medulla. Note that new growth of branches is initiated by the whitish inner strand that breaks through the perforated cortex structures (G, I) J, K apothecia with pink hymenial disc L microscopic cross section through the apothecium with two-celled spores divided by a septum. QR code redirects to 3 D scan of Cenozosia excorticata sp. nov. PW: Lichen.