Introduction
The Chamela Biological Station of the Universidad Nacional Autónoma de México is located within the Chamela-Cuixmala Biosphere Reserve in the municipality La Huerta, Jalisco state, Mexico (Fig. 1). The station has a predominance of tropical dry forest, which safeguards one of the best conserved tropical communities, and this has great biological and ecological importance (Noguera et al., 2002). Although Mexico has extensive areas with tropical dry forest, 160 000 km2 approximately (Challenger, 1998), knowledge of mycobiota in this kind of vegetation and particularly in the Chamela Biological Station is scarce, compared to the great diversity of fungal species in the tropical dry forest (Hawksworth, 1993) and the station. There are several studies that include species from the tropical dry forest such as those from Esqueda et al. (1999), Raymundo et al. (2009, 2014, 2017), Salinas-Salgado et al. (2012), Valenzuela et al. (2012), Álvarez et al. (2016), Contreras-Pacheco et al. (2018), and Reyes et al. (2020). However, few studies are known from the Chamela Biological Station: Ramírez-López et al. (2012), Bautista-Hernández et al. (2015), and Raymundo (2021).
Seventeen species of Geastrum Pers. have been registered in this type of ecosystem (Esqueda et al., 1996, 1999, 2000, 2003, 2009; Pérez-Silva et al., 1999; Guzmán, 2003; Calonge and Mata, 2004; Calonge et al., 2004; Herrera et al., 2005; Bautista-Hernández et al., 2015). This genus belongs to the family Geastraceae, order Geastrales, subclass Phallomycetidae, class Agaricomycetes, subphylum Agaricomycotina of the phylum Basidiomycota (Index Fungorum, 2021). Three species, Geastrum fimbriatum Fr., G. saccatum Fr. and G. violaceum Rick, have been cited from the Chamela Biological Station (Pérez-Silva et al., 1999; Bautista-Hernández et al., 2015). This genus is characterized by stelliform basidiomata, exoperidium with three layers, sessile or stalked endoperidium, sulcate, plicate, folded or fibrillose peristome, distinctly or indistinctly delimited. Microscopically, it can present ornamented basidiospores and mycosclereids or protruding hyphae (Sunhede, 1989), and setae (Baseia and Milanez, 2002). During explorations carried out in the station about a decade ago, a great diversity of Geastrum species was observed, and several specimens with particular macro- and micromorphological characteristics uncommon in the genus called our attention. The objective of this study is to describe and illustrate Geastrum chamelense as a new species for the Chamela Biological Station, based on morphological, ecological and molecular data.
Materials and Methods
Field work
Material of the undescribed species was collected in September 2010 and 2011 in the Chamela Biological Station, Jalisco, Mexico, ca. 19°27'2.1"N, 105°01'33"W, 250 m a.s.l. (Fig. 1, coordinates and elevation were obtained with a Garmin Etrex 10 GPS, Kansas City, USA). The local ecosystem belongs to the semideciduous tropical forest, according to Rzedowski (2006), with Brosimum alicastrum Sw. and Celtis monoica Hemsl. as the dominant tree species. The holotype was deposited in the fungal collection in the Herbarium of the Escuela Nacional de Ciencias Biológicas of the Instituto Politécnico Nacional (ENCB) and the isotype in the fungal collection of the National Herbarium of Mexico (MEXU) of the Instituto de Biología of the Universidad Nacional Autónoma de México (UNAM).
Morphological analyses
This taxonomic study was based on collections of basidiomata with different degrees of maturity. Morphological examinations were conducted using protocols outlined by Sunhede (1989). The colour of the sporomata was coded according to Kornerup and Wanscher (1978), which is indicated in parentheses in the description. For the microscopic study, temporary preparations were made in 70% alcohol and 5% potassium hydroxide (KOH) to elaborate descriptions of colour, size, shape of basidiospores, setae, and hyphae. The length and width of thirty basidiospores and setae were measured with a micrometric scale. Using scanning microscopy, gleba and endoperidium preparations were made, observing the detail of the spore and capillitium ornamentation, as well as the surface of the endoperidium. For the morphometric study, an optical microscope (MO; Primo Star, Carl Zeiss, Göttingen, Germany) and a scanning electron microscope (SEM; Hitachi Su 1510, Hitachi, Japan) were used. To prepare the taxonomic key, the abovementioned species known to occur in the study area were incorporated.
DNA extraction, amplification, and sequencing
The DNA was obtained from herbarium specimens (Table 1). The CTAB protocol of Martínez-González et al. (2017) was used to extract genomic DNA. The DNA was quantified with a Nanodrop 2000c (Thermo ScientificTM, Wilmington, USA). We prepared dilutions from each sample at 20 ng/µl to amplify the next four regions (Table 2): mitochondrial ATPase subunit 6 (atp6), nuclear large subunit ribosomal DNA (LSU), Internal Transcribed Spacer (ITS) and the largest subunit of RNA polymerase II gene (rpb1). The reaction mixture for PCRs was performed on a final volume of 15 µl containing 1× buffer, 0.8 mM dNTPs mix, 20 pmol of each primer, 2 units of GoTaq DNA (Promega, USA) and 100 ng of template DNA. The PCR products were verified by agarose gel electrophoresis. The gels were run for 1 h at 95 V cm⁻³ in 1.5% agarose and 1× TAE buffer (Tris Acetate-EDTA). The gel was stained with GelRed (Biotium, USA) and the bands were visualized in an Infinity 3000 transilluminator (Vilber Lourmat, Eberhardzell, Germany). The amplified products were purified with the ExoSAP Purification kit (Affymetrix, USA), following the manufacturer’s instructions. They were quantified and prepared for the sequence reaction using a BigDye Terminator v. 3.1 (Applied Biosystems, USA). These products were sequenced in both directions with an Applied Biosystem model 3730XL (Applied BioSystems, Foster City, USA), at the Instituto de Biología, UNAM. The sequences obtained were compared with the original chromatograms to detect and correct possible reading errors. The sequences of both strands of each of the genes were analyzed, edited and assembled using the BioEdit v. 7.0.5 (Hall, 1999) to generate a consensus sequence which were compared with those deposited in GenBank (2020), using the tool BLASTN v. 2.2.19 (Zhang et al., 2000).
Species name | Isolate/Voucher/strain | GenBank Accessions | |||
---|---|---|---|---|---|
ITS | nrLSU | rpb1 | atp6 | ||
Schenella pityophila (Malençon & Riousset) Estrada & Lado | Zamora 530 | KF988346 | KF988464 | KF988599 | KF988734 |
Myriostoma coliforme Desv. | Zamora 496 | KF988337 | KF988466 | KF988601 | KF988736 |
Geastrum albonigrum Calonge & M. Mata | MA-Fungi 36140-2 | KF988349 | KF988468 | KF988603 | KF988738 |
Geastrum aff. arenarium | MA-Fungi 68191 | KF988350 | KF988469 | KF988604 | KF988739 |
Geastrum aff. arenarium 2 | Zamora 76 | KF988338 | KF988470 | KF988605 | KF988740 |
Geastrum argentinum Speg. | LPS 48446 | KF988352 | KF988472 | KF988607 | KF988742 |
Geastrum argentinum 2 | MA-Fungi 82605 | KF988353 | KF988473 | KF988608 | KF988743 |
Geastrum berkeleyi Massee | MA-Fungi 74668 | KF988354 | KF988474 | KF988609 | KF988744 |
Geastrum cf. calceum | UFRN-Fungos 723 | KF988340 | KF988477 | KF988612 | KF988747 |
Geastrum campestre Morgan | Zamora 283 | JN943167 | JN939575 | JN991286 | KF988748 |
Geastrum chamelense Bautista-Hernández, Raymundo, Aguirre & R. Valenz. | T. Raymundo 3504 (ENCB) | OL653145 | OL653165 | OL67687 | OL676806 |
Geastrum corollinum (Batsch) Hollós | MA-Fungi 5746 | KF988359 | KF988481 | KF988616 | KF988751 |
Geastrum corollinum 2 | Sunhede 7744 | KF988360 | KF988482 | KF988617 | KF988752 |
Geastrum coronatum Pers. | Zamora 266 | KF988361 | KF988483 | KF988618 | KF988753 |
Geastrum elegans Vittad. | Zamora 189 | KF988366 | KF988488 | KF988623 | KF988758 |
Geastrum elegans 2 | UPS F-560810 | KF988367 | KF988489 | KF988624 | KF988759 |
Geastrum entomophilum Fazolino, Calonge & Baseia | MA-Fungi 70785 | KF988368 | KF988490 | KF988625 | KF988760 |
Geastrum fimbriatum Fr. | Zamora 234 | KF988369 | KF988491 | KF988626 | KF988761 |
Geastrum fimbriatum 2 | Sunhede 7739 | KF988370 | KF988492 | KF988627 | KF988762 |
Geastrum flexuosum (L.S. Domínguez & Castellano) Jeppson & E. Larss. | UPS F-119844 | KF988371 | KF988493 | KF988628 | KF988763 |
Geastrum floriforme Vittad. | MA-Fungi 69173 | KF988372 | KF988494 | KF988629 | KF988764 |
Geastrum floriforme 2 | Zamora 453 | KF988373 | KF988495 | KF988630 | KF988765 |
Geastrum fornicatum (Huds.) Hook. | Zamora 255 | KF988374 | KF988496 | KF988631 | KF988766 |
Geastrum fornicatum 2 | MA-Fungi 30749 | KF988375 | KF988497 | KF988632 | KF988767 |
Geastrum fuscoglebum (Zeller) Jeppson & E. Larss. | Trappe 1071 | KF988376 | KF988498 | KF988633 | KF988768 |
Geastrum fuscoglebum 2 | Trappe 9500 | KF988377 | KF988499 | KF988634 | KF988769 |
Geastrum glaucescens Speg. | MA-Fungi 83762 | KF988378 | KF988500 | KF988635 | KF988770 |
Geastrum glaucescens 2 | MA-Fungi 83763 | KF988379 | KF988501 | KF988636 | KF988771 |
Geastrum hariotii Lloyd | MA-Fungi 80070 | ------- | KF988503 | KF988638 | KF988773 |
Geastrum aff. hariotii | MA-Fungi 78296 | KF988382 | KF988505 | KF988640 | KF988775 |
Geastrum hieronymi Henn. | MA-Fungi 83766 | KF988384 | KF988508 | KF988643 | KF988776 |
Geastrum hieronymi 2 | MA-Fungi 83767 | KF988344 | KF988509 | KF988644 | KF988777 |
Geastrum kotlabae V.J. Staněk | MA-Fungi 39563 | KF988385 | KF988510 | KF988645 | KF988778 |
Geastrum kotlabae 2 | Zamora 440 | KF988386 | KF988511 | KF988646 | KF988779 |
Geastrum aff. kotlabae | MA-Fungi 33300 | KF988387 | KF988512 | KF988647 | ------- |
Geastrum lageniforme Vittad. | Zamora 207 | KF988388 | KF988513 | KF988648 | KF988780 |
Geastrum aff. lageniforme | MA-Fungi 79056 | ------- | KF988515 | KF988650 | KF988782 |
Geastrum michelianum (Sacc.) W.G. Sm. | Sunhede 7738 | KF988397 | KF988524 | KF988659 | KF988791 |
Geastrum michelianum 2 | Zamora 227 | KF988398 | KF988525 | KF988660 | KF988792 |
Geastrum minimum Schwein. | Zamora 191 | KF988400 | KF988528 | KF988663 | KF988795 |
Geastrum morganii Lloyd | Lebeuf HRL0177 | KF988406 | KF988534 | KF988669 | ------- |
Geastrum aff. morganii | Zamora 367 | KF988407 | KF988535 | KF988670 | KF988801 |
Geastrum ovalisporum Calonge & Mor.-Arr. | MA-Fungi 47184 | KF988411 | KF988539 | KF988674 | KF988805 |
Geastrum parvistriatum J.C. Zamora & Calonge | MA-Fungi 69583 | JN943160 | JN939560 | JN991291 | KF988806 |
Geastrum parvistriatum 2 | Zamora 272 | JN943162 | JN939572 | JN991283 | KF988807 |
Geastrum pectinatum Pers. | Zamora 252 | KF988412 | KF988540 | KF988675 | KF988808 |
Geastrum pleosporum Duoanla-Meli | MA-Fungi 56971 | KF988416 | KF988544 | KF988679 | KF988811 |
Geastrum pouzarii V.J. Staněk | MA-Fungi 2944 | KF988417 | KF988545 | KF988680 | KF988812 |
Geastrum pouzarii 2 | Sunhede 7494 | KF988418 | KF988546 | KF988681 | KF988813 |
Geastrum pseudolimbatum Hollós | Zamora 231 | KF988419 | KF988547 | KF988682 | KF988814 |
Geastrum quadrifidum DC. ex Pers. | Zamora 170 | KF988421 | KF988549 | KF988684 | KF988816 |
Geastrum rufescens Pers. | Zamora 253 | KF988424 | KF988552 | KF988687 | KF988819 |
Geastrum rufescens 2 | Zamora 274 | KF988425 | KF988553 | KF988688 | KF988820 |
Geastrum schmidelii Vittad. | Zamora 279 | KF988434 | KF988564 | KF988699 | KF988831 |
Geastrum schmidelii 2 | UPS F-560805 | KF988435 | KF988565 | KF988700 | KF988832 |
Geastrum setiferum Baseia | MA-Fungi 83781 | ------- | KF988571 | KF988706 | KF988837 |
Geastrum smardae V.J. Staněk | Lebeuf HRL 0160 | KF988440 | KF988573 | KF988708 | KF988839 |
Geastrum smithii Lloyd | MA-Fungi 83783 | KF988442 | KF988575 | KF988710 | KF988841 |
Geastrum cf. stipitatum | Zamora 528 | KF988345 | KF988576 | KF988711 | ------- |
Geastrum striatum DC. | Zamora 257 | JN943164 | JN939557 | JN991288 | KF988842 |
Geastrum striatum 2 | MA-Fungi 86672 | KF988443 | KF988577 | KF988712 | KF988843 |
Geastrum violaceum Rick | BAFC 51671 | KF988450 | KF988585 | KF988720 | KF988851 |
Geastrum violaceum 2 | MA-Fungi 82487 | KF988451 | KF988586 | KF988721 | KF988852 |
Loci/Segment | Primer | Sequence 5ʼ- 3ʼ | T(°C) | Reference |
---|---|---|---|---|
ITS5 | GGAAGTAAAAGTCGTAACAAGG | 57 | White et al., 1990 | |
ITS | ||||
ITS4 | TCCTCCGCTTATTGATATGC | 57 | White et al., 1990 | |
LSU | LROR | ACCCGCTGAACTTAAGC | 54 | White et al., 1990 |
LR3 | GGTCCGTGTTTCAAGAC | 60 | White et al., 1990 | |
Afrpb1 | GARTGYCCDGGDCAYTTYGG | 52 | Wu et al., 2014 | |
rpb1 | ||||
Acrpb1 | CCNGCDATNTCRTTRTCCATRTA | 52 | Wu et al., 2014 | |
atp6-5 | ATYGCTTTAGAAAGTTYMTTTGC | 56 | Giachini, 2004 | |
ATP6 | ||||
atp6-6 | GGDATRAARWAWGARAARAARTG | 55 | Giachini, 2004 |
Phylogenetic analyses
To explore the phylogenetic relationships of the new species, an alignment was made based on the taxonomic sampling employed by Zamora et al. (2014). Each gene region was independently aligned using the online version of MAFFT v. 7 (Katoh et al., 2002, 2017; Katoh and Standley, 2013). Alignments were reviewed in PhyDE v. 10.0 (Müller et al., 2005), followed by minor manual adjustments to ensure character homology between taxa. The matrices were formed for ITS by 64 taxa (667 characters), for LSU by 63 taxa (875 characters), atp6 by 64 taxa (451 characters), while that of rpb1 consisted of 64 taxa (684 characters). The aligned matrices were concatenated into a single matrix (64 taxa, 2677 characters). Eight partitioning schemes were established: one for the ITS, one for the LSU, three to represent the codon positions of the gene region atp6 and three for the rpb1 gene region, which were established using the option to minimize the stop codon with Mesquite v. 3.70 (Maddison and Maddison, 2021). The best evolutionary model for alignment was sought using PartitionFinder v. 2 (Lanfear et al., 2014, 2016; Frandsen et al., 2015). Phylogeny was performed with Bayesian inference using MrBayes v. 3.2.6 x64 (Huelsenbeck and Ronquist, 2001). The information block for the matrix included two simultaneous runs, four Montecarlo chains, temperature set to 0.2 and sampling 10 million generations (standard deviation ≤0.1) with trees sampled every 1000 generations. The convergence of the chains was displayed in Tracer v. 1 (Suchard et al., 2018). The highest credibility phylogram of the clades recovered with TreeAnnotator v. 1.8 (Bouckaert et al., 2014) was chosen with a 25% burn-in. Trees were visualized and optimized in FigTree v. 1.4.4 (Suchard et al., 2018).
Results
Molecular analysis
The ITS, LSU, atp6 and rpb1 sequences obtained from Geastrum chamelense were deposited in GenBank (Table 2). In the Bayesian analysis, the standard deviation between the chains stabilized at 0.002 after 10 million generations, indicating MC3 reached a stationary phase. To confirm that the sample size was sufficient, the parameter file was examined in Tracer v. 1.6 (Suchard et al., 2018): all parameters had an estimated sample size of over 1500. The posterior probabilities (PP) obtained were estimated by generating a strict consensus tree in MrBayes. Bayesian inference analysis recovered a well-supported clade (PP=1) of the new species (Fig. 2).
The topology of the phylogenetic tree is similar to that reported by Zamora et al. (2014). The new species is phylogenetically distant from G. setiferum Baseia, the taxon with which it bears the greatest morphological similarity, sharing the presence of setae in the endoperidium. It forms a well-supported clade with G. hieronymi Henn. and G. cf. calceum.
Key to species of Geastrum found in the Chamela Biological Station, Jalisco, Mexico
1a. Basidiomata with setae on the endoperidial surface .... Geastrum chamelense Bautista-Hernández, Raymundo, Aguirre & R. Valenz.
1b. Basidiomata without setae on the endoperidial surface ........................................ 2
2a. Exoperidium pink to purplish ….………………… Geastrum violaceum Rick
2b. Exoperidium brown grey, brown orange, beige …………………….………….. 3
3a. Basidiomata growing on rotten wood or dead leaves, with white subiculum ………………………………… G. schweinitzii (Berk. & M.A. Curtis) Zeller.
3b. Basidiomata growing on soil, without white subiculum .................................. 4
4a. Basidiomata separating the mycelial layer from the exoperidium easily at maturity ................................................. G. javanicum Lév.
4b. Basidiomata with arachnoid aspect, exoperidium with longitudinal ridges, the mycelial layer not easily separating from the exoperidium ........... G. lageniforme Vittad.
Taxonomy
Family Geastraceae
Geastrum chamelense Bautista-Hernández, Raymundo, Aguirre & R. Valenz., sp. nov. Figs. 3, 4, 5.
TYPE: MEXICO. Jalisco, municipality La Huerta, Reserva de la Biosfera Chamela - Cuixmala, Chamela Biology Station, km 60 Barra de Navidad-Puerto Vallarta highway, Eje Central, 250 m, 19°27'2.1"N, 105°01'33"W, 28.IX.2010. T. Raymundo 3504 (holotype: ENCB!, isotype: MEXU!); Mycobank: MB839090.
Geastrum chamelense is distinguished from other species of the genus Geastrum by its depressed, globose, semifornicate basidiomata, exoperidium 60 mm diameter, splitting into 4-7 rays, setose endoperidium, setae 102-330 × 10.2-15.3 μm, plicate peristome, not delimited; basidiospores 4.2-5 μm, globose, densely warty, dark brown.
Basidioma unexpanded, semihypogeous, depressed globose, light brown (5D6), 30 mm diameter; exoperidium 60 mm diameter, splitting into 4-7 rays, with the tips recurved, semifornicate horizontally, brown grayish (10E3), consistency carnose, in dry specimens not hygroscopic; mycelial layer attached to the litter, dimitic, 2.1-2.8 μm wide, with skeletal hyphae, thick-walled, aseptate, not branched, greenish yellow, light brown (5D6); fibrous layer 3.2-4 μm wide, thick-walled, light yellow; pseudoparenchymatous layer 14.4 -34.8 × 12-24 μm, globose to subglobose, brown yellow; without mycelial cords; endoperidium setose, sessile, subglobose to depressed, 15 × 20-30 mm, concolorous with exoperidium, constituted by interwoven hyphae, thick-walled, greenish yellow, 5.1-6.8 μm wide; setae 102-330 × 10.2-15.3 μm, thick-walled, lumen narrow; peristome plicate, not delimited; mycosclereids absent; gleba chocolate brown to blackish; basidiospores 4.2-5 μm diameter, globose, densely warty, dark brown in KOH 5%; basidia not observed; capillitial hyphae 5.6-7.2 μm diameter, aseptate, brown in KOH 5%, thick-walled, lumen narrow, not branched, surface with small warts and litter.
Habit and habitat: growing gregarious on soil in tropical dry forest.
Distribution: only known from the type locality.
Etymology: the specific epithet chamelense refers to the Chamela Biological Station, where this species has been collected.
Additional material examined: MEXICO. Jalisco, municipality La Huerta, Chamela-Cuixmala Biosphere Reserve, Chamela Biology Station, km 60 Barra de Navidad - Puerto Vallarta highway, Eje Central, 50 m, 19°27'2.1"N, 105°01'33"W, 18.IX.2011, T. Raymundo 4064 (ENCB); loc. cit., R. Valenzuela 14534 (ENCB); loc. cit., 28.IX.2010, E. Aguirre y S. Bautista-Hernández (MEXU 27044).
Geastrum javanicum, Búho, 23.IX.2012, E. Aguirre y S. Bautista-Hernández (MEXU 28929).
Geastrum lageniforme, Eje Central, 27.IX.2013, E. Aguirre y S. Bautista-Hernández (MEXU 28996).
Geastrum schweinitzii, Eje Central, 18.IX.2011, E. Aguirre-Acosta (MEXU 28883). Geastrum violaceum, Tejón, 21.X.2009, E. Aguirre y S. Bautista-Hernández (MEXU 25836).
Discussion
Geastrum chamelense was macroscopically characterized because the basidiomata, when mature, have a grey to greyish brown colour, a globose depressed endoperidium, folded and non-delimited peristoma, and a non-hygroscopic and arcuate exoperidium. Microscopically, it presented densely ornamented spores and setiform hyphae on the surface of the endoperidium, which, under a stereomicroscope, were observed as small erect blackish brown spines.
A similar species is G. setiferum, described from Brazil (Baseia and Milanez, 2002; Trierveiler-Pereira et al., 2011) and Argentina (Castiglia et al., 2013), which presents setae in the endoperidium. However, macro- and micromorphological differences delimit both taxa, such as the peristome, colour of the basidiome, and size of the setae and spores, indicating that this is a new species. Baseia and Milanez (2002) described G. setiferum with a fibrillose to almost sulcate and defined peristoma, while Trierveiler-Pereira et al. (2011) mentioned that it was fibrillose to slightly plicated. However, the specimen from Argentina was reported as conical to mammiform, with the apex truncated, finely plicated, and not delimited (Castiglia et al., 2013), showing a heterogeneity with this characteristic in both Brazilian and Argentinian specimens, in addition to presenting a pseudo-stipe and apophysis (Trierveiler-Pereira et al., 2011; Castiglia et al., 2013). In the Mexican specimens, few folds were observed, and it was sessile, not delimited, and without apophysis. Furthermore, the colour of the endoperidium differed because in the specimens from Brazil and Argentina, the tones ranged from greyish orange to light brown, while in the Mexican ones, it was greyish brown. Although macroscopically they are similar, we considered that the differences between the microscopic characteristics were preponderant for the separation of both species.
Geastrum setiferum has setae of 95-215 × 20-47 µm (Baseia and Milanez, 2002; Trierveiler-Pereira et al., 2011; Castiglia et al., 2013), differing notably in the proposed taxon which has setae that are longer and slender, measuring up to 330 × 12-16 µm. Additionally, the setae were observed with dichotomous terminations, a character that was not addressed by the aforementioned authors. Regarding the size of the spores, those of G. setiferum measure 2.5-4 µm diameter (Baseia and Milanez, 2002; Trierveiler-Pereira et al., 2011), while in G. chamelense, they are 4.2-4.9 µm diameter, including ornamentation in both species. Therefore, our new species has larger spores.
Molecular analysis showed that G. hieronymi is found in the same clade as G. chamelense, sharing an arched exoperidium, fibrillose peristome, endoperidial surface with spines, which are formed by bundles of hyphae (Zamora et al., 2014) or strongly asperate with acute or subpyramidal spicules (Ponce de León, 1968). Although these authors refer to G. hieronymi as having a stalked endoperidial body and prominent apophysis, this character was not observed in the studied specimens. Regarding the microscopic characteristics, the spores of G. hieronymi are much larger, up to 6 (m in diameter and warty (Ponce de León, 1968). Therefore, the differences are notable between both species.
Conclusions
Geastrum chamelense is recognized as a new species based on morphological, ecological and molecular data. Although this species is close to G. setiferum because they share the setiferous elements in the endoperidium, the macro- and micromorphological characters and its position in the phylogenetic hypothesis based on ITS, LSU, rpb1 and atp6 markers were decisive to separate them as different species. Worldwide, Geastrum has 109 valid species (Index Fungorum, 2021); of those, 29 species (26.6%) have been reported in Mexico, including G. chamelense. It is important to continue with taxonomic studies of this genus to contribute with new records and new species for the Mexican mycobiota.