Dictyostelids living in the soils of the Atlantic Forest, Iguazu region, Misiones, Argentina: description of new species

E M Vadell,J C Cavender

doi:10.3852/mycologia.99.1.112

Abstract

Thirteen new species and varieties of dictyostelid cellular slime molds (csm) were isolated from soils of the Atlantic Subtropical Rain Forest at the Iguazú Falls, Northeastern Misiones Province, Argentina. Seven new species are described herein, one of them is a Polysphondylium, while the rest of the species belong to the genus Dictyostelium. Also, six taxa are new varieties of Dictyostelium and Acytostelium, which will be reported later. Fourteen Northern Hemisphere (Tikal) species have also been isolated from Iguazú soils, some of them new records for Southern South America. This csm community, when compared with others from forests of the Northern Hemisphere, particularly Tikal, Guatemala, give some insight into a possibly different evolutionary history and/or natural selection in the two areas.

Highlights

Dictyostelid cellular slime molds were recovered from soils of the Atlantic Subtropical Rain Forest at Iguazu Falls, NE Misiones (25u 289 S), Argentina during 1995 and 2003 (Vadell 2003, Vadell and Cavender 1995)
D. vermiformum has small worm-like migrating pseudoplasmodia and prostrate lower sorophores
The data obtained from Iguazumake possible a comparison of Neotropical dictyostelids from the Northern and Southern Hemispheres

Summary

INTRODUCTION

Piaggio (1989) reported the distribution of 5 species in Eastern Uruguay. Vadell & Cavender (1995) and Vadell (2003) first reported on the dictyostelid research at Iguazu , Misiones, Argentina. Vadell (2000) reported 7 species from the southernmost subtropical forest near the estuary of the Rio de la Plata, Punta Lara, in the Province of Buenos Aires, Argentina (34u 499 S). A recent survey from the valdivian and Nothofagus forest of Patagonia added six out of nine still undescribed species from the southern colder regions of Argentina, between 40u and 55u S (Cavender et al 2005). The distributions of most of the new taxa of Iguazu , appear to be confined to the Eastern Atlantic Semievergreen Rain Forest of South America. D. vermiformum has small worm-like migrating pseudoplasmodia and prostrate lower sorophores. Brevicaule Vadell et Cavender has stout solitary sorophores and spores with small vesicles. Polysphondylium arachnoideum, the other large species, forms a network of thin terminal segments, almost spider web-like

MATERIALS AND METHODS

Findings

DISCUSSION