Abstract

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 on dried basidiomata with the aid of light microscope and scanning electron microscope. Calvatia nodulata is recognized by its pyriform to turbinate basidiomata, exoperidium granulose to pilose and not persistent, subgleba becoming hollow at maturity, nodulose capillitium, and punctate basidiospores (3–5 μm). Detailed description, taxonomic comments, and illustrations with photographs and drawings are provided.

1. 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 (Kreisel [911]). 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].

In Brazil, several mycologists have contributed to the knowledge of this group (Hennings [15], Silveira [16], Rick [17], Baseia [18], Wartchow and Silva [19], Baseia and Calonge [20], Cortez et al. [21], Cortez and Alves [22], and Alves and Cortez [23]). However, there were no records for the genus Calvatia in “brejos.” These areas harbor many endemic species (Joppa et al. [24]), but their biota have not been properly analyzed. Therefore, the aim of this work is to expand the knowledge about the genus Calvatia, describing a new taxon from “brejos” of Northeast Brazil.

2. Materials and Methods

Fieldwork was carried out during the rainy season of 2009 and 2012 in three localities: (1) Área de Proteção Ambiental da Serra de Ibiapaba/CE (03°39′80.6′′S 40°57′62.5′′W), (2) Parque Botânico do Ceará/CE (03°42′50.35′′S 38°38′28.12′′W), and (3) Reserva Ecológica Estadual Mata do Pau-Ferro/PB (06°57′89.9′′S 35°44′95.6′′W). All of them are located in 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.

2.1. Taxonomy

Calvatia nodulata Alfredo & Baseia sp. nov. (Figures 25)Mycobank no.: MB804770.

Diagnosis. Basidiomata 24–55 mm wide, pyriform to turbinate. Exoperidium granulose to pilose, not persistent. Subgleba occupying half of the basidiomata, disappearing at maturity leaving a hollow cavity. Basidiospores 3–5 μm in diam., punctate. Capillitium 2–4 μm in diam., with spaced nodules.

Type: Brazil, Paraiba: Areia, Reserva Ecológica Estadual Mata do Pau-Ferro on decaying leaves, 17.06.2012, D. S. Alfredo n° 97 (Holotype, UFRN-Fungos 1842).

Etymology: In reference to the capillitium, which present a nodulose surface.

Basidiomata 24–55 mm wide × 29–56 mm high, pyriform to turbinate. Exoperidium granulose to pilose, not persistent, brown (N90Y90 M70) in base becoming olive brown (N70Y80 M40) in apex, with sand incrusted. Endoperidium papery, surface smooth to wrinkly, plicate, light brown (N50Y99 M20) to brown (N50Y99 M50). Gleba initially cottony becoming powdery olive brown (N60Y80 M20) at maturity. Subgleba occupying half of the basidioma, initially cottony and in someone disappearing at maturity, leaving a hollow cavity, tapered at the base attached to the substrate. Rhizomorphs scarce, <0.5 mm thick, whitish.

Basidiospores 3.1–4.7 μm × 2.9–4.6 μm ( × ; Qm = 1.05; ), subovoid to ampulliformis, punctate, pedicels 0.5–3.7 μm length, hyaline to pale in 5% KOH, light brown in Melzer’s reagent (weak reaction). Capillitium lycoperdon-type, 2–4 μm diam., hyphae with straight walls < 1.5 μm thick, often ornamented with spaced nodules (0.5–1.5 μm high), occasionally branched and septate, rare circular pits, pale yellow in 5% KOH, without reaction in Melzer’s reagent. Paracapillitium absent. Exoperidium composed of subglobose, claviform, pyriform, obpyriform to elliptic hyphae, 7.5–26.5 μm × 12.7–40.5 μm, walls < 1,5 μm thick, pale yellow in 5% KOH. Endoperidium 3–5.7 μm diam., hyphae straight, walls < 1.5 μm thick, brittle, interwoven, light brown in 5% KOH. Subgleba hyphae 1.5–4.5 μm diam., branched, sinuous walls, pale yellow in 5% KOH. Rhizomorphs with two types of hyphae: one thinner outer 1.5–4.5 μm diam., aseptate, hyaline in 5% KOH, dextrinoid in Melzer’s reagent; one thicker inner 10–27.5 μm diam., septate, hyaline in 5% KOH and light brown in Melzer’s reagent (weak reaction).

Distribution and habitat—known to date from Brazil, growing solitary or two basidiomata on decaying leaves.

Specimens examined—Calvatia nodulata (Paratypes): Brazil, Ceará: Viçosa do Ceará, 03.03.2005, R. S. Araújo n° 108 (UFRN-Fungos 995); Tianguá, Serra de Ibiapaba, 19.04.2012, D. S. Alfredo n° 76 (UFRN-Fungos 1843); Caucaia, Parque Botânico do Ceará, 29.03.2009, R. S. Chikowski & T. L. D. Silva n° 18 (UFRN-Fungos 2119); Paraiba: Areia, Reserva Ecológica Estadual Mata do Pau-Ferro, 15.07.2013, J. O. Sousa & D. S. Alfredo n° 167 (UFRN-Fungos 2120).

Additional material examined—Calvatia rugosa: Brazil Rio Grande do Norte: Serra Negra do Norte, Estação Ecológica do Seridó, 18.02.2007, M. M. B. Barbosa s.n. (UFRN-Fungos 924); Calvatia sp.: ibid., 18.02.2007, B. D. B. Silva, E. P. Fazolino & J. J. S. Oliveira s.n. (UFRN-Fungos 399); Vascellum pratense: Natal, Parque Estadual Dunas do Natal, 08.08.2004, I. G. Baseia & M. M. B. Barbosa s.n. (UFRN-Fungos 300); Calvatia cyathiformis: João Câmara, Cauaçu, 04.2012, T. S. Accioly s.n. (UFRN-Fungos 1769, UFRN-Fungos 1770).

Notes. Calvatia nodulata is mainly characterized by its exoperidium not persistent, subgleba occupying half of the basidiomata and in some disappearing at maturity, leaving a hollow cavity, punctate basidiospores, and capillitium hyphae with spaced nodules (Figures 25). Initially, Calvatia nodulata can be confused with a representative of the genus Vascellum Smarda due to the diaphragm-like subgleba hollow (Figure 2(b)) separating the base of the gleba. However, Vascellum species show a well-developed apical pore or dehiscence irregular star-shaped (Ponce de Leon [30] and Homrich [31]). In Calvatia nodulata, dehiscence occurs by disintegration of peridium, fully exposing the gleba (Figures 2(a)-2(b)).

The dehiscence and other features, such as septate capillitium, branched and ornamented (Figures 3(a), 3(c), and 4(b)) and punctate basidiospores (Figures 3(b), 3(d), and 4(c)), make these materials closely related to Calvatia species.

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) and 5), exoperidium granulose to pilose (Figure 2(c)), composed of subglobose to elliptical cells (Figures 2(d) and 4(a)) and nodulose capillitium hyphae (Figures 3(a), 3(c) and 4(b)). These characteristics are absent in C. rosacea, which exhibits an exoperidium furfuraceum and pink, endoperidium hyphae dextrinoid in Melzer’s reagent, subgleba chambered, septate and smooth surface capillitium hyphae. Even Kreisel (page 293, Figure 6), although not calling attention to these characteristics, provides illustrations of exoperidium cells, making it clear that the cell arrangements in both species are distinct. Basidiospores of Calvatia nodulata and C. rosacea under LM are finely verrucose (Figure 3(b)), have small warts connected by grooves (Figure 3(d)) at the base, and are similar in these taxa.

Other species, such as C. pallida A. H. Sm. and C. depressa (Bon.) Zeller & A. H. Sm., have only two similar characteristics to those of C. nodulata, such as size and basidiospores ornamentation (Zeller and Smith [6]). Calvatia rugosa (Berk. & M. A. Curtis) D. A. Reid, reported from Brazil, shows a basidiospore ornamentation similar to our species (Cortez et al. [21]). Calvatia nodulata is easily distinguished from Calvatia guzmanii C. R. Alves & Cortez because C. guzmanii is characterized by a distinctly spinose exoperidium, smooth endoperidium, persistent subgleba, and smooth capillitium with abundant pores (Alves and Cortez [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]).

Calvatia ochrogleba Zeller shows subgleba with bluish tints of the tissues, gleba not falling out easily with cavities, globose, and large basidiospores (5–6.2 μm) (Zeller [35]); these features distinguish C. nodulata mainly because it has different color subgleba and smaller size basidiospores (3–5 μm).

Given the arguments, these distinct characteristics found in Calvatia nodulata make a good support for establishing a new species.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Acknowledgments

The first and second authors would like to thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil) for providing the Master’s scholarship. The authors are grateful for the financial support of the Programa de Pesquisa em Biodiversidade (PPBio Semi-arid). The authors also acknowledge the UFRN Herbarium for loaning the specimens and Renata dos Santos Chikowski for collecting some of the material used in this work and the field notes. The authors are grateful to Dr. Tine Grebenc (Slovenian Forestry Institute) for a critical review of the paper. The paper was corrected by an anonymous English native speaker.