Calvatia nodulata , a New Gasteroid Fungus from Brazilian Semiarid Region

Studies carried out in tropical rain forest enclaves in semiarid region of Brazil revealed a new species of Calvatia. The basidiomata were collected during the rainy season of 2009 and 2012 in two states of Northeast Brazil. Macroscopic and microscopic analyses were based ondried basidiomatawith the aid of lightmicroscope and scanning electronmicroscope.Calvatia nodulata is recognized by its pyriform to turbinate basidiomata, exoperidium granulose to pilose and not persistent, subgleba becoming hollow atmaturity, nodulose capillitium, and punctate basidiospores (3–5 μm). Detailed description, taxonomic comments, and illustrations with photographs and drawings are provided.


Introduction
The genus Calvatia was established by Fries in 1849 and is characterized by globose to pyriform basidiomata, with a subgleba and a dehiscence occurring by irregular fragmentation of the peridium in the upper portion of the basidioma, leaving the gleba exposed (Morgan [1], Coker and Couch [2], and Cunningham [3]).Calvatia species are distributed worldwide but mostly occur in arid, semiarid, and tropical regions (Lange [4]).In this context, the "brejos" are included, the term utilized to refer to tropical rain forest enclaves located in the semiarid Northeast Brazil (Santos et al. [5]).
Several studies have attempted to organize the genus (Lange [4], Zeller and Smith [6], Morales and Kimbrough [7], and Martín [8]), and some authors classify Calvatia as a species complex ).The studies of the molecular phylogeny (Larsson and Jeppson [12], Bates et al. [13]) have not been decisive in the elucidation of the relationship of the monophyly of Calvatia.However, Bates et al. [13] showed one clade of Calvatia s. str.with good support to North American specimens, but these results should not be taken as definitive.In the present paper, we therefore considered the classification based on morphology date in accordance with Calonge and Martín [14].

Materials and Methods
Fieldwork was carried out during the rainy season of 2009 and 2012 in three localities: (1)   tropical rain forest enclaves in Northeast Brazil (Figure 1).Moreover, in order to conduct comparative studies, dried specimens were borrowed from the Herbarium of the Universidade Federal do Rio Grande do Norte (UFRN).Macroscopic and microscopic analyses were based on dried basidiomata.For microscopic observations, sections were mounted in 5% KOH and Melzer's reagent on glass slides (Baseia and Calonge [20], Alfredo et al. [25]).These were examined and photographed under a light microscope (LM) Nikon Eclipse Ni with NIS-Elements support software.Thirty randomly selected basidiospores were measured (including ornamentation) under LM at 1000x magnification (Alfredo and Baseia [26]).The basidiospores surfaces were examined under a Shimadzu SSX-550 scanning electron microscope (SEM) in accordance with Cortez et al. [27].Statistic measures of basidiospores followed Silva et al. [28].Line drawings were prepared and arranged using the camera lucida drawing tool.Color references followed Küppers [29].Air-dried vouchers are deposited in the UFRN Herbarium.Etymology: In reference to the capillitium, which present a nodulose surface.
The dehiscence and other features, such as septate capillitium, branched and ornamented (Figures 3(a  During specimen studies the aforementioned characteristics show a close relationship with Calvatia rosacea Kreisel [9], but a thorough analysis separates these two species: Calvatia nodulata has a developed subgleba, which in some specimens disappears with age, leaving a hollow cavity (Figures 2(b [23]).These characteristics differ from those observed in C. nodulata, especially when compared with microstructures of the exoperidium and capillitium surface.
Rodrigues et al. [32] reported Calvatia cyathiformis f. cyathiformis (Bosc) Morgan also from Brazilian semiarid region, a less closely related species with C. nodulata.Its developed subgleba is similar, but the powdery gleba, septate, smooth and abundant pitted capillitial threads, and echinulate basidiospores are purplish brown at maturity, these sets of morphological features data are discrepant in C. nodulata.Other species, such as Calvatia sporocristata Calonge and Calvatia oblongispora V. L. Suárez, J. E. Wright & Calonge, show elongated basidiospores quite similar to C. nodulata, but the dextrinoid endoperidium hyphae, brittle and smooth surface capillitium hyphae, and ellipsoid to amygdaloid basidiospores with crests-like ornamentation of C. sporocristata (Calonge et al. [33]) differ from the C. nodulata, whereas C. oblongispora is separate by its double exoperidium, various size pores capillitium with smooth surface, and cylindrico-ellipsoid basidiospores with aligned crests ornamentation (Suárez et al. [34]).
Given the arguments, these distinct characteristics found in Calvatia nodulata make a good support for establishing a new species.

Figure 1 :
Figure 1: Map showing localities of fieldwork in tropical rain forest enclaves in Northeast Brazil.