Esteban M. Crespo

The species of Scleroderma from Argentina, including a new species from the Nothofagus forest

Five ectomycorrhizal species of Scleroderma were identified from herbarium and field-collected specimens from Argentina. A new hypogeous species, Scleroderma patagonicum, was recorded in association with native Nothofagus spp. in Patagonia. The epigeous species S. albidum, S. areolatum, S. bovista and S. citrinum were associated with various exotic tree species. A phylogenetic analysis based on the ITS region of Scleroderma species, including S. patagonicum, illustrates its distinct status within Scleroderma, including its placement among species with reticulate spores. Descriptions with SEM images of the spores and a key to the species are provided.

Tulostoma domingueziae sp. nov. from Polylepis australis woodlands in Córdoba Mountains, central Argentina

The new species, Tulostoma domingueziae, is described and illustrated. It was found in Polylepis australis woodlands in central Argentinean highlands. Tulostoma domingueziae is characterized by the combination of a warty exoperidium, contorted stipe covered by thin scales that break off, mouth slightly projected and the socket with up to six dentate hanging membranes. DNA sequence data demonstrated that T. domingueziae is distinct from Tulostoma species for which sequence data are available.

CHEMOMETRIC APPROACH TO CHAROPHYTE PRESERVATION (TRIASSIC CERRO PUNTUDO FORMATION, ARGENTINA): PALEOLIMNOLOGIC IMPLICATIONS

ABSTRACT A first-time chemometric study of energy-dispersive X-ray (EDX) data of Charophyta gyrogonites is presented. Specimen provenance is a microbialitic carbonate lacustrine succession from the Triassic (Anisian, 243.8 ± 1.9 Ma) of the Cerro Puntudo Formation, San Juan, Argentina. Gyrogonites from three different strata of the succession are studied. Data obtained by EDX include major and minor components, which are analyzed by principal component analysis (PCA). The aim of this study is twofold: first to determine the preservation features of gyrogonites by way of a chemometric approach (i.e., EDX followed by PCA) and then to infer the likely, original chemical composition of the paleolake inhabited by charophytes. EDX spectra show the presence of O, Ca, and minor elements (e.g., Si and Mg), indicating a predominantly calcium carbonate (CaCO3) composition. Principal component analysis supports differences obtained between central and peripheral areas of the gyrogonites, indicating a higher CaCO3 content in their central part. On the other hand, in their outer part, the CaCO3 diminishes and the presence of Si compounds is recorded. No significant differences among gyrogonites from the three different strata are found, implying a similar preservation mode. This suggests a differential diagenetic pattern for the external cells of the gyrogonites than their centers. These results have implications regarding the chemical composition of the paleolake water (Si and Ca availability) and the provenance and catchment areas. Results are encouraging regarding the usefulness of a chemometric approach for studies of fossil remains in lacustrine environments when other techniques of chemical analysis are not available.

Broomeia congregata Berk., 1844 (Agaricales: Broomeiaceae): New distribution record for San Luis, Argentina

Broomeia congregata Berk. is a gasteroid fungus with a predominant African distribution. However, it has been documented twice, in 1912 and 1973, as occurring in Catamarca Province (Argentina, South America). Nearly forty years later, a new finding is reported for San Luis Province, Argentina. The report includes new morphological information based on scanning electron microscopy (SEM). In addition, some phenological, biogeographical and ecological implications concerning B. congregata are discussed.