The Protostelida: A New Order of the Mycetozoa

Abstract

The order Protostelida of the Mycetozoa is characterized by an amoeboid feeding stage varying from uninucleate cells to multinucleate, reticulate plasmodia. The protoplasts have filose pseudopodia, contractile vacuoles, and nuclei with central nucleoli. Simple sporocarps, each with a slender, non-cellular stalk and 1, or sometimes 2, terminal spores are produced Nutrition is holozoic. Sexuality is unknown. SCHIZOPLASMODIOPSIS pseudoendospora Olive, Martin, and Stoianovitch from Florida is described for the 1st time. Two families are recognized: (I) Cavo-stelidae, with the single amoebo-flagellate genus Cavostelium, and (2) Protostelidae, a non-flagellate group of 4 known genera in 2 series[long dash](a) one with nonapophysate, nondeciduous spores (Schizoplasmodiopsis and Protosteliopsis) and (b) a 2nd with apophysate, deciduous spores (Schizoplasmodium and Protstelium). The order is widely distributed Throughout the world. The possible relationships of the order with other groups of Mycetozoa are discussed.