RESUMEN
A new species of Physarum (Myxomycetes), Physarum atacamense is described in this paper, and details are provided on its life cycle as observed in spore-to-spore culture in agar. The new species was collected during studies of the Atacama Desert in Chile. It has been collected directly in the field and isolated in moist chamber cultures prepared with material from an endemic cactus. The combination of characters that make this species unique in the genus are its large fusiform nodes of the capillitium, its long, bicolored stalk and the very dark brown and densely warted angular spores. The morphology of specimens of this myxomycete was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details and life cycle stages are included in this paper. The importance of resistant stages in the life cycle of this myxomycete is stressed, and the close association of this myxomycete with its plant substrates is discussed.
Asunto(s)
Mixomicetos/clasificación , Mixomicetos/ultraestructura , Physarum/clasificación , Physarum/ultraestructura , Chile , Clima Desértico , Esporas Protozoarias/clasificación , Esporas Protozoarias/ultraestructuraRESUMEN
A new species of Didymium (Myxomycetes), D. operculatum, is described in this paper, and details of its life cycle are provided. The new species was recorded during studies of the Atacama Desert in Chile. It has been collected directly in the field and isolated in moist chamber cultures prepared with material from an endemic cactus. The distinguishing characters of this species are its dehiscence by means of an apical operculum combined with a whitish calcareous stalk and the banded reticulate ornamentation of the spores. The morphology of this new myxomycete was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details are included in this paper. Some comments are made on the patterns of distribution of Didymium species in arid lands and adaptive characters enabling this genus to colonize such extreme environments. It is proposed that a longer cycle and the ability to resort to resistant forms many times during their development reflect the response of these myxomycetes to the largely unfavorable conditions of their environment.
Asunto(s)
Mixomicetos/clasificación , Mixomicetos/crecimiento & desarrollo , Biodiversidad , Chile , Clima Desértico , Microscopía Electrónica de Rastreo/métodos , Morfogénesis/fisiología , Micología/métodos , Mixomicetos/citología , Esporas Protozoarias/ultraestructuraRESUMEN
A new stipitate species of myxomycete of the genus Licea is described based on material from arid areas in Argentina and Chile. It was isolated from moist chamber cultures and found fruiting on field collections, usually on the same substrate, Puya sp. (Bromeliaceae). It differs from all described species in the genus in that it has stipitate sporocarps with dehiscence by defined preformed platelets and a smooth inner peridial surface. The new species has polyhedral, yellow spores with a uniform thick spore wall and dense warts except on irregularly dispersed raised bands with fewer warts, visible by SEM, an ornamentation not previously observed in the genus. Life-cycle events are described and illustrated, from germination to sporulation, based on moist chamber and agar cultures. The morphology of the myxomycete specimens was examined with scanning electron microscopy and light microscopy, and both light and SEM micrographs of relevant details are included.
Asunto(s)
Clima Desértico , Mixomicetos/clasificación , Clima , Microscopía Electrónica de Rastreo , Mixomicetos/aislamiento & purificación , Mixomicetos/ultraestructura , América del SurRESUMEN
A new species of Didymium (Myxomycetes), D. infundibuliforme, is described herein, and details are provided on its life cycle as observed in spore to spore culture on agar. The new species was recorded during intensive studies of areas of the Monte Desert in Argentina and the Atacama Desert in Chile. It has been collected directly in the field in both countries on several occasions over 4 y and isolated in moist chamber cultures prepared with material from native plant species. The characters that make this species unique in the genus are its funnel-shape sporocarps with white stalks, the apical circumscissile dehiscence of the sporotheca that causes the base to resemble a calyculus and the ornamentation on the spores. The morphology of specimens of this new myxomycete was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details are included in this paper.
Asunto(s)
Clima Desértico , Estadios del Ciclo de Vida , Mixomicetos/crecimiento & desarrollo , Mixomicetos/ultraestructura , Animales , Argentina , Bromeliaceae/microbiología , Chile , Medios de Cultivo , Microscopía Electrónica de Rastreo , Mixomicetos/clasificación , Mixomicetos/fisiología , Esporas Protozoarias/fisiología , Esporas Protozoarias/ultraestructuraRESUMEN
A new species of myxomycete, Didymium umbilicatum, isolated from the bark of Agavaceae, is described from arid zones of Mexico. This species was obtained from moist chamber cultures of Yucca spp. bark, collected in four different years from two states (Puebla and Querétaro) in central Mexico and found in the field from Hidalgo, Oaxaca and Puebla on the dead remains of Agave sp. The new species has small, flat, white sporocarps or short plasmodiocarps, 0.2-1.3 mm diam, and 0.15-0.4 mm tall. They are sessile on a reduced base or have a short, calcareous pale stalk and warted spores, warts fused in an irregular subreticulum by SEM. It is the sixth species of Didymium recently described from arid areas. The stability of the taxonomic characters of the species was confirmed by spore-to-spore culture on agar. Life cycle events are described from germination to sporulation. The morphology of the myxomycete specimens was examined with scanning electron microscopy and light microscopy, and micrographs of relevant details are included.
Asunto(s)
Mixomicetos/fisiología , Mixomicetos/ultraestructura , Animales , Asparagaceae/parasitología , Estadios del Ciclo de Vida , México , Microscopía Electrónica de Rastreo , Corteza de la Planta/parasitologíaRESUMEN
A new succulenticolous Myxomycete species, Didymium wildpretii, found on decaying remains of various species of cacti, is described from two arid zones of the world. This species was collected from central Mexico, at the southern limit of the Chihuahuan Desert, and from the Canary Islands (Spain). The new species has small, pale yellow sporocarps, 0.1-0.7 mm high, that are sessile or have short, orange-yellow, calcareous stalks and small, uniformly warted spores. The stability of the taxonomic characters of the species was confirmed with both moist chamber cultures and spore-to-spore culture on agar. Life cycle events are described from germination to sporulation. Myxomycete specimens were examined with scanning electron microscopy and light microscopy, and micrographs of relevant morphological details are included.