A new species and new records of Cercophora from Argentina

Three species of Cercophora were found during a survey of the biodiversity of microfungi in northwest Argentina. Cercophora argentina possesses a unique combination of morphological characters and is described as a new species, while C. costaricensis and C. solaris are reported as new records for Argentina. Other species of Cercophora known from this region include C. natalita and C. coprogena, which is fully illustrated for the first time and determined herein to be a synonym of C. californica. All other species are described and illustrated.


INTRODUCTION
Cercophora Fuckel is characterized morphologically by large, membranaceous to carbonaceous, ostiolate, papillate ascomata; asci with an apical ring usually with a subapical globule and ascospores with a brown, swollen head and a hyaline pedicel at maturity. Its most common anamorphs are found in the form genera Phialophora (Udagawa and Muroi 1979), Cladorrhinum (von Arx 1981) and Chrysosporium (Ueda 1994). Species in the genus can be coprophlilous (Lundqvist 1972), xylophilous (Hilber and Hilber 1979) or less frequently are found on soil or in aquatic habitats (Ueda 1994, Chaudhary et al. 2007. Cercophora presently comprises 67 taxa, ac-cording to Index Fungorum (www.indexfungorum. org, 7 Feb 2011). Miller and Huhndorf (2005) showed that Cercophora and other sordariaceous genera are paraphyletic or polyphyletic and concluded that the peridium anatomy is a better indicator of phylogenetic relationships than ascospore morphology in some cases. With respect to the southern cone of South America only Cercophora sordarioides (Speg.) N. Lundq. on dung and Cercophora natalitia (Speg.) N. Lundq. on a dead trunk had been reported from Argentina, while Cercophora coprogena (Speg.) N. Lundq. on dung had been reported from Chile (Lundqvist 1972). Three species of Cercophora were found during our biodiversity studies on Argentinian microfungi occurring on bark and decorticated wood of a native gymnosperm, Podocarpus parlatorei Pilg. One of these possesses a unique combination of characters not known in any other species in the genus and thus is described as new. Two additional Cercophora species are reported and illustrated from Argentina for the first time, while type specimens of three other species known from this area are fully illustrated for the first time.

MATERIALS AND METHODS
Collections were made in a Podocarpus parlatorei forest and in a mixed forest from Cumbres de Taficillo, Sierra de San Javier, Departamento Tafí Viejo, Tucumán province, Argentina. The study area belongs to the District Mountain Forest of the phytogeographical region of Las Yungas, a subtropical zone of the Amazonic Domain, Neotropical Region, which encompasses the Andes from Venezuela and Colombia, entering the northwestern part of Argentina as a narrow section through Jujuy in the north to Salta, Tucuman and finally Catamarca provinces in the south (Cabrera andWillink 1973, Hueck 1978). Fallen stems of Podocarpus parlatorei Pilg. and Sambucus nigra L. ssp. peruviana (Kunth) R. Bolli containing ascomata were collected. The material was dried and deposited in the herbaria of Fundació n Miguel Lillo (LIL) and the Illinois Natural History Survey (ILLS).
Observations, digital imaging and measurements of ascomata, asci and ascospores were made on material mounted in distilled water, 5% KOH and phloxine with either an Olympus CX31 microscope and Olympus SP-350 digital camera or a Zeiss Axioskop microscope and a Dage MTI video camera. Material mounted in calcofluor (Romero and Minter 1988) was examined by epifluorescence (EF) microscopy with a Zeiss Axioplan to observe ascospores Submitted 4 Jan 2011; accepted for publication 19 Apr 2011. 1 Corresponding author. E-mail: romero@bg.fcen.uba.ar Mycologia, 103(6), 2011, pp. 1372-1383. DOI: 10.3852/11-005 # 2011 and apical rings in the asci. Drawings were made with a camera lucida.
Attempts were made to culture these species. Ascospores were removed from ascomata with a sterile needle and transferred to Petri plates containing potato dextrose agar (PDA) (Hawksworth et al. 1995). They were incubated under laboratory conditions with approximately 12 h fluorescent light per day at 25 C. No cultures were obtained due to lack of ascospore germination.

MycoBank MB519727
Etymology: Refers to the type country.
Habitat: on fallen branch of Sambucus nigra ssp. peruviana (Kunth) Bolli. This species belongs to the family Caprifoliaceae and is a native shrub or tree in Argentina occurring at 1500-2000 s.l.m, in several provinces including northwestern Catamarca, Jujuy, southwestern Neuquén and Tucumán (Zuloaga and Morrone 1999).
Geographic distribution: Argentina (Tucumán). Cercophora argentina occurs on wood and possesses a non-areolate peridium with Munk pores and ascospores, 61-73 3 5-6.5 mm. Cercophora appalachianensis O. Hilber & R. Hilber and C. californica are two other species of Cercophora that are reported to have Munk pores in the peridial cells. However both are different from C. argentina. Cercophora appalachianensis possesses ascomata covered by long hairs, smaller ascospores, 37-48(-68) 3 3.5-4.5 mm, and shorter ascospore appendages (Hilber et al. 1987), while C. californica, on dung, possesses an areolate ascomatal wall and longer ascospores (75.5-95 mm), although the original description incorrectly describes the ascospores as being 30-35 mm long (Plowright 1878). Molecular studies have shown that many genera in the Sordariales, including Cercophora, are polyphyletic (Miller and Huhndorf 2005). This new species is proposed within the genus based on morphological characters. Cercophora californica appears to be the same as C. coprogena, which is a younger name and therefore a synonym. Both species occur on cow dung with C. californica known only from the type collection from California, USA, and C. coprogena known only from the type collection from Chile. In both species the ascomata are large and obpyriform with a distinctly sulcate neck (FIGS. 21, 35). The neck appears erumpent through a crusty surface on the dung with the entire ascomata eventually becoming erumpent (FIGS. 22,34). In both species the ascomatal wall in surface view is weakly areolate (FIGS. 23, 36). The cells are arranged in a circular pattern around a central darkened area but are not sufficiently distinct to crack into plates along the lines of the thin-walled hyaline cells. Also present is an uneven brown pigmentation in the outer wall cells of both species. Areolate peridia are seen in a number of Cercophora species that do not appear to be closely related based on analyses of DNA sequence data. The most distinct areolate pattern is seen in Cercophora areolata N. Lundq. where the walls are more strongly carbonized and distinct plates are formed that crack along the lines of weakness of the hyaline cells. Less carbonized but still distinct areoles are seen in C. solaris (Cooke & Ellis) R. Hilber & O. Hilber and C. striata (Ellis & Everh.) N. Lundq. The indistinct or weak areolate type of walls seen in C. californica also is seen in C. coprophila (Fr.) N. Lundq. Areolate walls are not unique to the Sordariales; they also are found in widely distant taxa, such as Cephalotheca Fuckel (Cephalothecaceae) and Bertiella macrospora (Sacc.) Sacc. & Traverso (Melanommataceae). The inner layer of the ascomal wall in C. californica has numerous Munk pores (FIG. 26) as seen in the new species, C. argentina, and as illustrated in C. appalachianensis. Munk pores are predominant in species in the Coronophorales (Nannfeldt 1975) but occasionally are seen in species outside this group (Huhndorf et al. 2004). They do not appear to be phylogenetically significant at taxonomic rank beyond species. The wall of C. californica also is composed of thick-walled cells (FIG. 25), similar to those seen in C. albicollis N. Lundq. The wall of C. albicollis has been interpreted as pseudo-bombardioid (Miller 2003) putatively similar to the walls found in C. costaricensis, C. elephantina (Henn.) N. Lundq. and C. scortea (Cain) N. Lundq., but these walls are not all the same. Cercophora albicollis and C. californica lack the gelatinized layer with ramifying hyphae found in the others. Only thick-walled cells are present and these are predominent in the neck region (FIG. 25). These two species probably represent another group of taxa with a distinct wall type, C. californica, differing with a weak areolate surface pattern not seen in C. albicollis.

Anamorph: unknown.
Habitat: on wood of fallen branch. Geographic distribution: Argentina (Tucumán), Costa Rica (Hilber and Hilber 1979), Venezuela (Portuguesa). Our material agrees with the description by Hilber and Hilber (1979), except for the smaller size of the ascospore appendages (material studied by Hilber and Hilber were 35 mm long, while material by Carroll and Munk [1964] were up to 100-200 mm long). However, as pointed out by Lundqvist (1972), measurements of these structures can vary greatly, depending on the amount of pressure placed on the cover slip at the time of slide preparation. The most striking feature of this species is the ascomal peridium, which was termed pseudo-bombardioid by Lundqvist (1972) and Miller (2003) because the ascomal wall is non-stromatic. The pseudo-bombardioid wall has been described in nine species in three genera of Lasiosphaeriaceae, Arnium ontariense (Cain) J.C. Krug & Cain; Cercophora albicollis, C. costaricensis, C. elephantina, C. palmicola Hanlin & Tortolero, C. scortea, Podospora appendiculata (Auersw. ex Niessl) Niessl, P. fimiseda (Ces. & de Not.) Niessl, and P. perplexans (Cain) Cain (Carroll and Munk 1964, Furuya and Udagawa 1972, Lundqvist 1972, Hilber and Hilber 1979, Hanlin and Tortolero 1987, Bell and Mahoney 1997. The morphology of the pseudo-bombardioid wall is slightly homoplasious in the Sordariales and it appears to have arisen independently in two distantly related groups, although relationships among these groups were unsupported at that time according to Miller and Huhndorf (2005). They also pointed out that ''while ascospore morphology cannot be used for delimiting genera, ascomal wall morphology alone or in combination with other characters is still useful at some level for distinguishing taxa''.