INTEGRATIVE TAXONOMY OF THE COMPLEXES GEASTRUM JAVANICUM LÉV. AND G. VELUTINUM MORGAN (GEASTRALES, BASIDIOMYCOTA) WITH EMPHASIS ON NEOTROPICAL SPECIES
Biodiversity. Earthstar. Geastraceae. Phylogenetics. Systematics.
The genus Geastrum Pers. is the most representative (100-120 spp) of the family Geastraceae and is characterized by its basidiomes with starlike dehiscence, making them known as earthstars. It has distribution in all continents except Antarctica. In the last estimate, 71 species of Geastrum were cataloged in Brazilian territory, which represents about 50% of the known species. This genus presents a great pharmacological and biotechnological potential, besides the important role in the cycle of molecules such as carbon and nitrogen, reinforcing the importance of correctly identifying these organisms. The identification of fungi based only on morphological aspects aggravates taxonomic problems such as the cryptic or semi-cryptic species. The nominal species Geastrum javanicum Lév. and Geastrum velutinum Morgan harbor a species complex, concealing the diversity of the genus, mainly due to the use of these names for species not yet described by science. Thus, comparative studies using molecular (sequencing of ribosomal DNA regions) and morphological data from exsiccata named G. javanicum and G. velutinum were performed to correctly identify the specimens. The analyses were based on methodologies specific for Geastrum and adding new taxonomic characters (size of hyphae of the exoperidium, basidiospores ornamentation size, crystals found in the rhizomorph). 62 exsiccates named G. javanicum and G. velutinum have been analyzed and three new species identified: Geastrum calycicoriaceum, G. tupiense e Geastrum sp. nov. The present work can also contribute to the generation of new Geastrum sequences for the Neotropical region, elucidating the position of these individuals in the systematics of the genus from morphological and phylogenetic studies, promoting a greater evolutionary and systematic understanding of the group.