Biodiversity studies of myxomycetes in Madagascar

Abstract

The results of the first comprehensive study of myxomycetes from the island of Madagascar, a world biodiversity hotspot, are reported in this paper. The island is of continental origin, the fourth largest in the world, and has been geographically isolated for more than 160 million years, since its separation from Gondwanaland. The isolation, size and topography of Madagascar have triggered the development of a great variety of different habitats and favoured multiple evolutionary pathways, resulting in many animals and plants that exist nowhere else on earth. Fieldwork for the biodiversity survey of the central and southern parts of the island took place in May 2009, to coincide with the end of the rainy season. Tropical moist forest, sclerophyll forest and dry forest were selected for sampling in Ranomafana, Andringitra, Andohahela and L'Isalo National Parks. Some unique vegetation was sampled in the spiny dry forest and succulent scrub with plants from the genera Alluaudia, Euphorbia, Kalanchoe and Pachypodium. The survey produced 124 species from 22 different genera in more than 750 myxomycete collections. In this paper one species, Perichaena madagascariensis, is described as new to science, 21 species are new records for Africa, and 106 are reported for the first time from Madagascar. Some unusual collections included Physarum lakhanpalii that appeared on Ravenala madagascariensis, Fuligo intermedia and Licea nannengae found on Adansonia grandidieri, Perichaena pulcherrima, Physarum dictyosporum, and P. echinosporum on Euphorbia and Licea rufocuprea on bark. The scope, methods and results of this survey are included in this paper, and comments are made on the ecology, distribution and substrate association of the myxomycetes of these areas of Madagascar. Macrographs, micrographs and SEM images of interesting species are included. The results indicate that the island of Madagascar has a unique assemblage of species of myxomycetes, different from neighbouring islands and from similar but distant environments.

Nivicolous Trichiales from the austral Andes: unexpected diversity including two new species

“…Ecology and distribution: Described originally from New Zealand (Martin 1962(Martin , 1963 as T. craterioides G. W. Martin, not T. craterioides Corda, further reported from Argentina (Lado et al 2014) and Madagascar (Wrigley de Basanta et al 2013).…”

First records of Myxomycetes associated with members of the Cactaceae in Australia

“…The occurrence of P. depressa on dead portions of succulent plants has been reported in several studies (Estrada-Torres et al 2009;Lado et al 2011Lado et al , 2019Wrigley de Basanta et al 2013). However, the species has been recorded from a wide range of substrates and does not appear to have a preference for succulent substrates.…”

“…Didymium iridis, like the preceding species, has been reported from surveys of deserts (e.g. Estrada-Torres et al 2009;Wrigley de Basanta et al 2013;Stephenson et al 2019) but most of the substrates on which it occurred were derived from non-succulent plants. The species has been reported from a range of habitats in Australia (White et al 2020;Stephenson 2021).…”

“…Blackwell and Gilbertson (1980) recorded P. leucophaeum from cacti, but specimens of this species were associated with non-succulent substrates in other surveys that included at least some desert areas (e.g. Lado et al 2013;Wrigley de Basanta et al 2013;Stephenson et al 2019). Its distribution within Australia is scattered but widespread (Stephenson 2021).…”

Additional new species suggest high dictyostelid diversity on Madagascar

“…Geographically disconnected areas with high levels of endemicity, such as Madagascar, are hypothesized to have unique protist assemblages, mirroring the patterns seen in macroflora and -fauna. A study of the sister taxon to the dictyostelids-the myxomycetes-suggests this pattern in amoebae (Wrigley de Basanta et al 2013).…”