Ramalina mahoneyi Quedensley & Véliz, is described from Pico Zunil in Guatemala. Ramalina mahoneyi morphologically appears closely related to R. celastri (Sprengel) Krog and Swinscow, but its apothecial discs are peach-colored and marginal, the thallus is gray-blue and overall much smaller than that of R. celastri.
During field work on Pico Zunil (Fig. 1), located in the Sierra Chuatroj in the western Guatemalan Department of Quetzaltenango, the first author discovered several specimens of an unusual Ramalina. Available taxonomic keys preliminarily identified this as Ramalina celastri (Kashiwadani & Kalb, 1993; Brodo et al., 2001; Kashiwadani & Nash, 2004). However, these specimens of Ramalina differed from R. celastri by having a small, gray-blue thallus, and peach-colored instead of pale gray or pale yellow apothecia. In addition, the apothecia are marginal in these specimens, but in R. celastri they are marginal and laminal. The apothecial discs are always convex at maturity, whereas in R. celastri the apothecial discs are flattened to slightly convex. Based on these differences, R. mahoneyi is described below as a new species.
Ramalina mahoneyi T.S. Quedensley & M. Véliz P., sp. nov. (Fig. 2).
type: GUATEMALA. QUETZALTENANGO: Municipality of Zunil, Sierra Chuatroj, northwestern slopes of Pico Zunil, 14°44′32.0″ N, 91°28′03.1″ W, elev. 2900 m, corticolous near base of trunks of Alnus acuminata Kunth in dense cloud forest, 3 January 2008, T. Sultan Quedensley 4677 (HOLOTYPE: F; ISOTYPES CAS, MSC, NY, US).
Ramalinae celastri (Sprengel) Krog and Swinscow similis sed differt apotheciis percicinis marginalibus et thallo atrocyaneo ubique multo minore.
thallus fruticose, subpendent, branches flattened, 2–4 cm long, with individual lobes 0.7–3.0 mm wide; margins involute; upper surface gray-blue; lower surface grayblue. pseudocyphellae linear, white, present only on the underside of the thallus. photobiont a Trebouxia green alga. apothecia marginal, 0.3–1.2 mm in diameter. DISC convex, without pruina, peach-colored, exciple occluding with age. ASCI elongate-clavate, 8—spored, ASCOSPORES hyaline, 1—septate, broadly fusiform, 4–6 × 12–16 µm. pycnidia not observed. spot tests cortex K-, C-, KC-, P-; medulla K-, C-, KC-, P-. secondary metabolites not detected using thin layer chromatography. Trace amounts of usnic acid in the cortex detected by high-performance liquid chromatography.
This new species appears to be closely related to Ramalina celastri (Sprengel) Krog & Swinscow, a wide-ranging species also in the Neotropics (Krog & Swinscow 1976) and extending to the southwest United States (Brodo et al., 2001). Both species have striate pseudocyphellae and a shrubby growth habit. Ramalina mahoneyi is distinguished by its smaller thallus and apothecia (Fig. 3). Ramalina mahoneyi is only known from the type locality where it is not abundant. Ramalina celastri is found throughout Central America (Nash et al., 2004), but has not yet been reported for Pico Zunil and Guatemala has few records of lichens, including macrolichens, collected in the region.
Ramalina mahoneyi occurs near the base of trunks of Alnus acuminata in a dense cloud forest on the northwestern slopes of Pico Zunil. Associated trees included Alnus acuminata, Cupressus lusitanica, Chiranthodendron pentadactylon, Fucshia paniculata, and Verbesina apleura. Roldana heterogama was a common shrub.
More field work focused on collecting Ramalina in Western Guatemala could help elucidate the distribution of this species. Furthermore, while the genus Ramalina is easily recognized is the field, species diversity within the genus is large and species descriptions can be dubious due to innumerable intergrades across a geographic range (Howe, 1913).
The Latin epithet refers to Dr. Donald Mahoney, horticultural manager at the San Francisco Botanical Garden. Don has had an overwhelming positive influence on the first author's life. Under his guidance the senior author gained a wealth of knowledge about botany and horticulture, especially pertaining to New World cloud forest species.
additional specimens examined: GUATEMALA. QUETZALTENANGO: Municipality of Zunil, Sierra Chuatroj, northwestern slopes of Pico Zunil, 14°44′32.0″ N, 91°28′03.1″ W, elev. 2900 m, corticolous near base of trunks of Alnus acuminata Kunth in dense cloud forest, 7 May 2005, T. Sultan Quedensley 2292 (BYU, NY, TEX, US) and 2 January 2005, T. Sultan Quedensley 2198 (BIGU, F, OMA).
acknowledgments
For field work conducted on Pico Zunil, we thank the Graduate College and Biology Department at the University of Nebraska at Omaha and The New York Botanical Garden for support. Timmy Buxton (Cabrillo College) and David McKenzie (The University of Wyoming) assisted with field work. We would like to thank Robert Lücking at The Field Museum for his assistance with this project and for bringing to light that we had come across an undescribed species. Mallory Tarpinian of the University of Nebraska at Omaha assisted with HPLC analysis. We also thank Dr. Robert Egan of the University of Nebraska at Omaha for his guidance with this paper, Guy Nesom for assistance with the Latin diagnosis, and Robert Harms of the The University of Texas at Austin Plant Resources Center for help with producing the figures. Lastly, we thank Teofil Nakov and James Mauseth of The University of Texas at Austin for assisting with microscope photography.
