New Classification of the Dictyostelids

Traditional morphology-based taxonomy of dictyostelids is rejected by molecular phylogeny. A new classification is presented based on monophyletic entities with consistent and strong molecular phylogenetic support and that are, as far as possible, morphologically recognizable. All newly named clades are diagnosed with small subunit ribosomal RNA (18S rRNA) sequence signatures plus morphological synapomorphies where possible. The two major molecular clades are given the rank of order, as Acytosteliales ord. nov. and Dictyosteliales. The two major clades within each of these orders are recognized and given the rank of family as, respectively, Acytosteliaceae and Cavenderiaceae fam. nov. in Acytosteliales, and Dictyosteliaceae and Raperosteliaceae fam. nov. in Dictyosteliales. Twelve genera are recognized: Cavenderia gen. nov. in Cavenderiaceae, Acytostelium, Rostrostelium gen. nov. and Heterostelium gen. nov. in Acytosteliaceae, Tieghemostelium gen. nov., Hagiwaraea gen. nov., Raperostelium gen. nov. and Speleostelium gen. nov. in Raperosteliaceae, and Dictyostelium and Polysphondylium in Dictyosteliaceae. The polycephalum complex is treated as Coremiostelium gen. nov. (not assigned to family) and the polycarpum complex as Synstelium gen. nov. (not assigned to order and family). Coenonia, which may not be a dictyostelid, is treated as a genus incertae sedis. Eighty-eight new combinations are made at species and variety level, and Dictyostelium ammophilum is validated

Derecho procesal del siglo XXI. Visión innovadora

Dieciocho ensayos escritos por destacados académicos de América Latina y Europa, que se dan cita en esta obra para responder al desafío de pensar el Derecho procesal del siglo XXI desde una visión innovadora. Los ejes de los debates académicos responden a las siguientes preguntas de investigación: ¿cómo prevenir la corrupción en el proceso judicial?, ¿cómo puede contribuir el Derecho procesal a garantizar los derechos humanos?, ¿cuáles son los aportes de la psicología en el estudio del Derecho probatorio?, ¿qué interacciones existen entre las tradiciones jurídicas del civil law y el common law?, ¿cómo contribuyen las reformas procedimentales en los ámbitos civil, penal, laboral y administrativo al fortalecimiento de la Administración de Justicia? Se trata pues, de la undécima entrega del Grupo de Investigación en Derecho Procesal (Universidad de Medellín), ampliamente reconocido por el juicioso trabajo que realizan sus investigadores a la hora de coordinar esta ya tradicional serie de libros de investigación en Derecho procesal. Como lo menciona Eduardo Oteiza, en el prólogo de esta obra, “basta con recordar el éxito de las anteriores diez ediciones para despertar la curiosidad por enriquecerse con cada una de las colaboraciones, sin perder de vista que se trata de un nuevo hito de uno de los proyectos más importantes de investigación en Derecho procesal de América Latina”

Taxonomía y biología de los primeros registros de acrásidos en la República Argentina

Se aislaron y estudiaron miembros del Phylum Acrasiomycota y taxones afines de muestras de suelo y varios sustratos extraídos del Parque Nacional Iguazú, Misiones, Argentina, durante cuatro campañas entre 1995 y 2003. Los acrásidos (s. lat. Orden Acrasiales) comprende un grupo reducido de organismos que comparten entre sí la naturaleza ameboidea de sus individuos, que generalmente se agregan entre sí. Son aerobios, consumidores de bacterias y partículas de tamaño bacilar; viven en el suelo, heces, cortezas, y otros sustratos. Un taxón afín al grupo tiene importancia médica. Se describen los caracteres taxonómicos de Acrasis rosea (Acrasiaceae), Copromyxa protea (Copromyxaceae), Guttulinopsis nivea (Guttulinaceae), y Sappinia pedata (Sappiniaceae) y sus ciclos de vida, aislados de suelos y distintos sustratos. Estos taxones son nuevos registros para la República Argentina. Otras especies amebianas, relacionadas, tanto morfológica como ecológicamente, son descriptas con fines comparativos. También se analiza la sistemática del orden, como las características morfológicas, ultraestructurales, biológicas y ecológicas

Four New Species of Dictyostelids from Soil Systems in Northern Thailand

Dictyostelid cellular slime molds (dictyostelids) are ubiquitous microorganisms found in the uppermost layers of most soils. Reports on the species diversity of dictyostelids in Southeast Asia, particularly Thailand, are few in number. A survey for dictyostelids performed in northern Thailand in 2008 recovered 15 distinctive forms, including several common species and a number of forms morphologically different from anything already described. Five of the latter were formally described as new to science in a previous paper. An additional five isolates appeared to be morphologically distinct, and this was supported by DNA sequence data and phylogenetic analysis. These isolates representing four species are described herein as species new to science. Detailed descriptions and illustrations of these new species are provided

Additional new species suggest high dictyostelid diversity on Madagascar

© 2020 The Author(s). Published with license by Taylor & Francis Group, LLC. Dictyostelids are a monophyletic group of sorocarp-forming social amoebae in the major eukaryotic division Amoebozoa. Members of this taxon, which is made up of almost 200 described species, are common in terrestrial soils globally. Still, the alpha diversity is not well known in many areas, and new species are frequently recovered. The highest species richness is found in the tropics. Here, five new species are described from soil samples collected in Madagascar. These species—Cavenderia basinodulosa, C. canoespora, Heterostelium radiatum, H. versatile, and Raperostelium stabile—are described based on both morphological characteristics and molecular data, with sequence data from the rDNA small subunit (SSU). The five new species are morphologically disparate, ranging from relatively small, robust taxa such as R. stabile to taxa with variable morphologies such as the larger H. radiatum and H. versatile and the yellow-tinted and irregularly branched species C. canoespora and C. basinulosa. These new species, together with earlier work where 13 other species were described from the island, suggest that there is a range of genetically diverse and highly morphologically variable dictyostelid taxa occurring on Madagascar, suggesting biogeographic patterns even within these very small organisms

Distribution and ecology of dictyostelids in Madagascar

Samples for isolation of dictyostelid cellular slime molds were obtained from 20 collecting sites at 18 localities in south central and southeastern Madagascar during May 2009. At least thirty species of dictyostelids representing seven genera were recovered from 52 samples of soil/humus. This total included 17 species described as new to science, 13 species already known from various localities throughout the world, and four isolates that remain unidentified. Fourteen of the new species isolated from these samples are members of the whorl-branched, light-spored genus Heterostelium (formerly Polysphondylium). The overall level of species richness of dictyostelids in Madagascar is greater than what is known for all of mainland Africa sampled to date. Levels of biodiversity in Madagascar were higher for mesic than for xeric vegetation types, and each of the newly described species of Heterostelium appeared to have a limited distribution among the localities sampled