Pertusaria rayana E. Tripp & J. Watts, 2025

Pertusaria rayana E. Tripp & J. Watts , sp. nov.

TYPE: USA. Colorado. Eagle County. White River National Forest, Holy Cross Wilderness. Northwest-facing slopes just above the middle fork of Homeskate Creek amongst a dense lower subalpine forest of Picea engelmanii and Pinus contorta . Saxicolous and muscicolous on large, shaded vertical rock faces, locally abundant, 9492 ft. elevation, 39.387 005, -106.451006, 16 July 2024, J. Watts & E. Manzitto-Tripp 2235 ( Holotype: COLO!; Isotypes: ASU!, BYU!, KANU!, NY!). Figures 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7 .

Mycobank #: 860003

Description. Thallus crustose, continuous, thin, smooth, shiny where corticate, becoming ecorticate near regions of isidia development, whitish gray. Prothallus absent. Upper cortex thin, 18–48 μm thick, prosoplectenchymatous. Algal layer interrupted and irregular, up to 25–50 μm thick. Medulla prominent, 74–126 μm. Lower surface consisting of single layer of parallel-oriented hyphae, shiny, whitish gray, lacking attachment structures. Isidia pale yellow to grayish white and slightly lighter in color than surrounding thallus, coralloid, solid, unbranched or branched primarily once towards apex giving a forked appearance, occasionally with additional branching, oftentimes very dense and covering majority of surface of thallus on older thalli, but occurring isolated and dispersed on younger thalli, 125–187 μm thick and up to 750 μm long. Apothecia and associated sexual reproductive structures unknown. Photobiont chlorococcoid, cells 9–16 μm in diameter.

Etymology. This new lichen species is named in honor of Amy Ray of the long-time musical duo, Indigo Girls. Together with Emily Saliers, Amy has been an indefatigable advocate for environmental protection and social justice. She (along with Emily and Winona LaDuke) co-founded the non-profit organization Honor the Earth, which works to promote education and raise awareness of environmental issues impacting indigenous communities. For numerous years, Amy has campaigned to help end nuclear waste dumping on Native American reservations and, together with Emily, has long integrated activism into her tours.Amy’s music is rooted in empathy, justice, wit, and equality, especially equal pay for women and other social rights that are inextricably linked to ecological health. Her songs have kept us company over many years spent understanding and describing lichen biodiversity; they have furthermore inspired much of our own scientific activism to help end repressive behaviors by governments and industries that do not serve the interests of our ecosystems nor human livelihood. This new species reminds us of Amy because its yellow isidia are radiant and full of life. It’s UV+ orange reaction further reminds us that it is rather dynamic on the inside, too.

Chemistry. Spot Tests: K+ pale yellow to K-, C+ orange to C-, KC+ orange, P-, UV+ orange (thallus and isidia). Thin Layer Chromatography: thiopaninic acid (major), atranorin (minor), unknown lichexanthone.

Distribution. So far as currently understood, Pertusaria rayana is restricted to the Sawatch and San Juan Mountain ranges of Colorado where it is known only from two locations in two watersheds: Homeskate Creek immediately below Homeskate Reservoir and Vallecito Creek above Vallecito Reservoir. It is likely to be discovered elsewhere in comparable habitats, as future fieldwork to inventory the lichens of the southern Rocky Mountains continues.

Substrate & Habitat. Pertusaria rayana grows directly over rocks or on mosses over rocks. It is thus far known to be restricted to vertical or slightly overhung rock faces in lower subalpine/upper montane forests proximal to creeks, between ~ 8,700 –10,000 ft. elev. It has been collected associated with other sterile crustose lichens that occur in rich, riparian communities including trees draped abundantly with species of Bryoria Brodo & D. Hawksw. and Usnea Dill. ex Adans. Thus , the new species has an affinity to high humidity environments wherein valley fog likely commonly accumulates. The abundant, long isidia of the species likely represent a dual adaptation for asexual reproduction and fog capture as in the “Cloud Lichens” Niebla Rundel & Bowler , and other fruticose genera associated with foggy habitats ( Stanton & Horn 2013).

Notes. Pertusaria rayana ( Figure 6 View FIGURE 6 ) is a charismatic and easily recognizable species in Colorado by its pale yellow, dense, long, and coralloid isidia. The isidia of Pertusaria rayana are more yellow than the underlying thallus as a function of uneven pigment distribution, a phenomenon also characteristic for Lepraria saliersiae wherein the margins are far more pigmented than central portions of the thallus. Of isidiate Pertusaria in North America, Pertusaria rayana is readily differentiable by its substrate and chemistry, making it difficult to confuse for any congeneric species. Chemically, the most similar species is P. flavocorallina Coppins & Muhr , however that species lacks atranorin and has a K+ violet pigment at the apices of its isidia ( Gilbert & Coppins 1992). Furthermore, P. flavocaroallina is known from maritime rather than continental habitats. Additional features that help differentiate Pertusaria rayana from other isidiate species in western North America can be found in the key below (Part 2). It is possible the new species could be confused for a few other isidiate crustose lichens in other genera. Namely, some could confuse Pertusaria rayana for Loxosporopsis corallifera Brodo, Henssen & Imshaug , which differs by its UV+ white reaction owing to the presence of divaricatic acid in the thallus, its heavily contorted isidia, and its corticolous habit ( Brodo & Henssen 1995). Lepra corallina (L.) Hafellner, a primarily European species, is similarly saxicolous on vertical rock faces like Pertusaria rayana , but the former produces thamnolic acid and is therefore P+ yellow-orange and UV- ( Tønsberg 1992).

Our phylogenetic analyses strongly support the reciprocal monophyly of our two accessions of Pertusaria rayana (99% BS). The clade containing both accessions of the new species was resolved as sister to P. sommerfeltii (Flörke ex Sommerf.) Fr. , which is a widespread, sexually reproducing species, but without support.

Conservation Assessment. Pertusaria rayana is here assessed as Critically Endangered (CR) under IUCN criterion D because of its highly restricted occurrence in humid, riparian upper montane/lower subalpine forests where only ~10 mature individuals have been observed, making the estimated total population size fewer than 50 individuals. Although future fieldwork will surely result in the discovery of additional populations of this remarkable new species, it nonetheless is likely to be rare to very rare, as the authors have searched numerous other watersheds (with seemingly suitable habitat) for individuals, but without success.

Additional Specimens Examined. USA. Colorado. Eagle County. White River National Forest, Holy Cross Wilderness, middle fork of Homeskate Creek, rich, north-facing slopes amongst subalpine forest dominated by Abies lasiocarpa and Populus tremuloides , saxicolous on shaded rocks, 9796 ft. elev., 39.381 02 -106.45019, E. Manzitto-Tripp 11,300 (COLO!). White River National Forest, Holy Cross Wilderness, middle fork of Homeskate Creek, rich, north-facing slopes amongst subalpine forest dominated by Abies lasiocarpa and Populus tremuloides , 39.388 01 - 106.449 80, 9,441 ft. elev. E. Manzitto-Tripp 11,302 (COLO!). La Plata County. San Juan National Forest, Weminuche Wilderness, Vallecito Creek Trail (529) between the second and first bridges along east banks of Vallecito Creek, spruce bark beetle-damaged montane forest in a large valley with abundant granitic cliffs, canopy of mostly dead Picea engelmannii , Pseudostuga menziesii , and the occasional Abies concolor , understory lush with Rubus spp. , Lonicera involucrata , Prunus americana , and Quercus gambelii , muscicolous over nearly vertical rock ~ 10 m above creek, 37.540 005, -107.523342, 8705 ft. elev., J. Watts & E. Manzitto-Tripp 4103 (COLO!).