New occurrences of Physarales (Amoebozoa, Myxomycetes) for the state of Minas Gerais, Southeastern Brazil

ABSTRACT

(New occurrences of Physarales (Amoebozoa, Myxomycetes) for the state of Minas Gerais, Southeastern Brazil). Myxomycetes are organisms widely distributed around the globe, found in both hemispheres, and are of great importance for ecological processes such as nutrient cycling. The state of Minas Gerais has records of only 44 species of Myxomycetes, but there are still gaps regarding the distribution of these organisms. In this context, this paper presents the record of two new occurrences of Physarales for the state of Minas Gerais. The collections were made in the municipality of Belo Horizonte, during the X Brazilian Congress of Mycology. After analysis, two species were identified: Physarum bogoriense Racib and Physarum echinosporum Lister. Both represent new occurrences for state of Minas Gerais, increasing the number of species cited for the state from 44 to 46.

Keywords:
Mycetozoa; Physarum; Taxonomy

RESUMO

(Novas ocorrências de Physarales (Amoebozoa, Myxomycetes) para o Estado de Minas Gerais, Sudeste do Brasil). Os mixomicetos são organismos amplamente distribuidos pelo globo, sendo encontrados em ambos os hemisférios, e de grande importância para processos ecológicos, como a ciclagem de nutrientes. O estado de Minas Gerais possui o registro de apenas 44 espécies de mixomicetos, porém ainda existem lacunas quanto à distribuição desses organismos. Neste contexto, este trabalho apresenta o registro de duas novas ocorrências de Pysarales para o estado de Minas Gerais. As coletas foram realizadas no município de Belo Horizonte, durante o X Congresso Brasileiro de Micologia. Após as análises duas espécies foram identificadas: Physarum bogoriense Racib. e Physarum echinosporum Lister. Ambas representam novas ocorrências para o Estado de Minas Gerais, elevando o número de espécies citadas para o Estado de 44 para 46.

Palavras-chave:
Mycetozoa; Physarum; Taxonomia

Introduction

Myxomycetes species are found in both hemispheres, being present in the most diverse environments, from tropical and temperate forests to deserts and frozen zones, where they play an important role, contributing to the decomposition of organic matter and nutrient cycling (Keller et al. 2022). The geographic distribution of its 1050 species (Lado 2005-2024) is mainly influenced by temperature, humidity, and substrate availability conditions (Keller et al 2022, Wrigley de Basanta et al 2013).

Approximately 1/3 of the myxomycete species are known to occur in Brazil, belonging to the six orders of the class, with the largest number being Physarales (111) and Trichiales (52); the Northeast region is the most explored, with emphasis on the state of Pernambuco (BFG 2024).

In the revision carried out by Maimoni-Rodella (2002) for the Southeastern Brazilian region, the occurrence of 10 families, 31 genera and 136 species of myxomycetes was recorded, with the states of São Paulo and Rio de Janeiro having the largest number of species. The author commented that she had not found inventories for the states of Espírito Santo and Minas Gerais, with only old and sparse records of four and eight species, respectively. The myxobiota of the state of Minas Gerais remained little explored in the following two decades and only one article was published, where the occurrence of Diachea leucopodia (Bull.) Rostaf. was recorded on plants of Fragaria x ananassa Duch., the strawberry plant, in the municipality of Estiva, in the south of the state (Ribeiro & Brioso 2019).

According to the Flora e Funga do Brasil project (BFG 2024), only 15 species are confirmed for the state, belonging to five of its six orders, being the Physarales represented by Diachea leucopodia (Bull.) Rostaf. and Didymium iridis (Ditmar) Fr. (Didymiaceae), Fuligo septica (L.) F.H.Wigg., Physarum bivalve Pers. and P. cinereum (Batsch) Pers. (Physaraceae). However, at the 10th Congress of the Brazilian Society of Mycology, Cavalcanti & Agra (2024) presented an updated list for the state, mentioning 44 species, distributed among nine families, highlighting the Trichiaceae, with 12 species, Physaraceae and Stemonitaceae, with eight species each, followed by Didymiaceae (5 spp.), Cribrariaceae (5 spp.), Echinosteliaceae (2 spp.), Liceaceae (2 spp.) and Reticulariaceae (2 spp.).

Contributing to reducing the large gap in knowledge of the distribution of myxomycetes in the state of Minas Gerais, the present work reports the occurrence of two species of Physarales, found in an urban area in the city of Belo Horizonte, capital of the state.

Material and methods

The specimens were collected in February 2024 in the city of Belo Horizonte, capital of the state of Minas Gerais, Southeastern Brazil (Figure 1). Dead trunks, soil litter, trunks of living trees that are part of a forest of the campus of the Universidade Federal de Minas Gerais were explored during the mini course “Myxomycetes: collection methodology, herborization and identification”, taught by two authors of the present work (Laise de Holanda Cavalcanti and Jorge Renato Pinheiro Velloso) as part of the program of the X Brazilian Congress of Mycology. The specimens were collected and stored in cardboard boxes (6 x 3 x 8 cm) containing data on coordinates, date of collection, location, and collector(s). The macromorphological and micromorphological analyzes to identify the species were carried out in the Institute of Biological Sciences practical classes laboratory (block A2), as part of the mini-course activities. The collected materials were registered at the Bruno Edgar Irgang Herbarium (HBEI), at the Universidade Federal do Pampa (UNIPAMPA), São Gabriel city campus, Rio Grande do Sul state, Southern Brazil. The color codes presented for the structures followed the work of Kornerup & Wanscher (1978).

Figure 1:
Specimen collection location. The QRCode directs you to the scientific dissemination page Myxomycetes of Brazil, on Instagram.

Results and Discussion

After analysis, two species were identified: Physarum bogoriense Racib. and Physarum echinosporum Lister. Full descriptions, images and notes on the species are provided below.

Physarum bogoriense Racib., Hedwigia 37: 52 (1898)

Figure 2 a-c

Sporangia gregarious, sessile, globose and plasmodiocarps elongate, yellowish grey (3B2) to pale yellowish (3A2), 0.3-0.5 mm wide and up to 3 mm long; hypothallus inconspicuous; peridium triple, the outer wall cartilaginous, attached to the median strongly impregnated with white calcium, the inner wall membranous, colorless, iridescent; dehiscence apical, giving rise to angular fragments formed by the first two layers and more or less triangular reflexed lobes on the sides, exposing the median layer completely impregnated with calcium; capillitium abundant, with numerous, white, rounded calcium nodules, connected by hyaline filaments; spores in mass dark brown (6F2); spores violet brown (11E4) by transmitted light, globose, warty to nearly smooth, 8-9.5 µm in diameter.

Physarum bogoriense was described by Raciborsky (1898) based on a specimen collected from dead leaves in Buitenzorg, Java, the main island of Indonesia (Martin & Alexopoulos 1969; Farr 1976). Subsequent collections showed its wide worldwide distribution, occurring in countries of Africa, Asia, Oceania, Europe, North America, Central and South America. In the review of published works on the Neotropical myxobiota, Lado & Wrigley de Basanta (2008) included P. bogoriense among the few species that could be considered pantropical, with records to 20 countries, 11 of which are in South America. In Brazil, there are no records for the Northern region, but it has a known distribution in six of the nine states in the Northeast, two of the three states in the Southern part of Brazil (RS, SC) and only one state in the Central-West (GO) and one in the Southeast (SP), behaving as a cortico-, leaf- and succulent-growing species in areas of Atlantic Forest, Caatinga, Cerrado and Pampa biomes (Cavalcanti 1985, Gottsberger 1968, Cavalcanti et al. 2006, Ferreira & Cavalcanti 2011, BFG 2024). In São Paulo, it is cited to three municipalities, which have a humid subtropical climate: Itanhaém, coastal state, on living leaves; Pirassununga, at Middle East of the State, in a Cerrado area, on dead branches of unidentified bushes and live leaves of Melinis minutiflora Beauv. (Poaceae); Botucatu, Middle-South of the state, on a bark of an unidentified living tree, bark of Araucaria angustifolia (Bertol.) O.Kuntze and grasses (Cavalcanti 1974, 1978, 1985, Hochgesand & Gottsberger 1996). The sporophores collected in Belo Horizonte, on remains of Syzygium samarangense (Blume) Merr. & LM Perry, in litter above the soil in an urban area, is the first record of the species for the state of Minas Gerais.

Figure 2:
Physarum bogoriense Racib and Physarum echinosporum Lister. a-c. Physarum bogoriense. a. Plasmodiocarps. b-c. Spores and capillitium, showing calcium nodules. d-f. Physarum echinosporum. d. Sporophore. e. Spores. f. Spores and calcium nodules. Scale: a. 2 mm, b-c. 20 µm. d. 0,5 mm. f-g. 20 µm..

Physarum echinosporum Lister, J. Bot., Lond. 37: 147 (1899)

Figure 2 d-f

Plasmodiocarp white (1A1), 0.8-1 mm total height, curved to form C-shaped structures, strongly laterally compressed; peridium double, the outer layer strongly calcareous, with a porcelain-like appearance, the inner layer membranous; dehiscence through an apical fissure; capillitium with white (1A1), small, angular calcium nodules, connected by smooth, hyaline filaments; spores in mass dark brown (6F2); spores reddish-brown (9E6) by transmitted light, globose, wall with well-developed spines that sometimes come together and form wrinkles, 12-13 µm in diameter.

Physarum echinosporum has a wide geographic distribution and occurs at different altitudinal levels, with records in lowland tropical forest in Colombia (18 msl), up to 4,665 msl, in the Atacama Desert, in Chile (Lado et al. 2007, Rojas et al. 2012). In reviewing articles published to the Neotropics, Lado & Wrigley de Basanta (2008) refer to its occurrence in four countries in Central America (Panama, Jamaica, Leeward and Windward Islands) and four in South America (Brazil, Chile, Ecuador, Uruguay), and Rojas et al. (2018) added Colombia, Costa Rica and Guatemala.

Despite its worldwide distribution, some authors, such as Ing & Hnatiuk (1981), Lado et al. (2007) and Kryvomaz et al. (2020), consider P. echinosporum as a rare or occasional species, with a greater occurrence in tropical forests. In fact, consulting GBIF data covering a period of 119 years (1900-2021), there are only two records in Oceania, five in two European countries, 22 in Asia (India and the Philippines) and 36 in Africa (Cameroon, Madagascar, Morocco and Kenya); for North America, there are 12 records in the United States, obtained in cold and dry regions, such as Alaska and North Dakota, and 35 in Mexico, with more numbers in Central America (55) and South America (41).

Physarum echinosporum occupies diverse microhabitats, behaving as lignicolous, corticicolous, foliicolous (ground and aerial litter) or on succulent plants in dense rainforest, humid and dry forest, restinga, mangrove, caatinga, prairies and deserts (Bezerra et al. 2007, Lado et al. 2007, Rojas et al. 2010, 2012, Costa et al. 2011, 2014). There are records associated with cultivated fruit trees, such as Carica papaya L., Cocos nucifera L. and Mangifera indica L. (Ing & Hnatiuk 1981) and with residential gardens and squares, in Brazil and other countries, such as Australia, Norway and Jamaica, sporulating in lawns, soil leaf and bark of Larix sp. (Farr 1957, Cavalcanti 1976,2002, Davison et al. 2017, NBIC 2024).

In Brazil, P. echinosporum has a restricted distribution, with reports only in the Northeast and Southeast regions, in different ecosystems and microhabitats. It was referred to as corticicolous by Bezerra et al. (2007) in a restinga area, in the state of Rio Grande do Norte, by Barbosa et al. (2016) in dense rainforest in the state of Pernambuco and by Cavalcanti et al. (2014) in mangrove on the coast of Pernambuco, on Conocarpus erectus L. Costa et al. (2011, 2014) comment on its occurrence as foliicolous in the aerial leaf litter of high-altitudinal forest, in the state of Paraíba and Ferreira & Cavalcanti (2011) recorded its presence growing in succulent plants in hyperxerophilous arboreal-subshrub caatinga, in the backlands of Pernambuco. In addition to the three Northeastern states, P. echinosporum has records in São Paulo, in the municipality of Botucatu, where it was found in a rabbit breeding site (Hochgesand & Gottsberger 1996). It was cited for Rio de Janeiro by Maimoni-Rodella (2002), without indication of location and microhabitat. The material collected in the present work, on twigs of Spondias mombin L., constitutes the first record of the species to the state of Minas Gerais.

Acknowledgements

The authors would like to thank the X Brazilian Congress of Mycology, for the space provided; to Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, Conselho Nacional de Desenvolvimento Científico e Tecnológico and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, for the financing granted.

Data Availability Statement:

The dataset for this article is available in the SciELO Dataverse of Hoehnea, at the following link: https://doi.org/10.1590/2236-8906e482024.

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• How to cite:
  Velloso, J.R.P., Cavalcanti, L. H., Ribeiro, M.S., Reck, M.A., Nery, A.S., Rodrigues, C.S., Passos, M.R., Bizarria Jr, R., Moreira, F.B., Toschi, L.A. & Putzke, J. 2026. New occurrences of Physarales (Amoebozoa, Myxomycetes) for the State of Minas Gerais, Southeastern Brazil. Hoehnea 53: e482024, 2026. https://doi.org/10.1590/2236-8906e482024.

Edited by

• Associate Editor:
  Iracema Helena Schoenlein-Crusius

Data availability

Data citations

NBIC - The Norwegian Biodiversity Information Centre, Hoem S (2024). Norwegian Species Observation Service. Version 1.260. The Norwegian Biodiversity Information Centre (NBIC). Occurrence dataset https://doi.org/10.15468/zjbzel accessed via GBIF.org on 2024-04-23. https://www.gbif.org/occurrence/3097844410

Publication Dates

• Publication in this collection
  16 Mar 2026
• Date of issue
  2026

History

• Received
  23 May 2024
• Accepted
  05 Jan 2025