Ref ID : 5753
Frederick C. Page and Richard L. Blanton; The Heterolobosea (Sarcodina: Rhizopoda), a new class uniting the Schizopyrenida and the Acrasidae (Acrasida). Protistologica XXI(1):121-132, 1985
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The Vahlkampfiidae and the Acrasidae are two families of amoebae previously recognised as similar in some respects, though only the Acrasidae form fruiting bodies. An electron-microscopic investigation of the Vahlkampfiidae has shown further similarities: mitochondria with discoid cristae, Golgi system not organised as the usual dictyosomes, and close proximity between rough endoplasmic reticulum and mitochondria. Although the nucleolus divides during mitosis in the Vahlkampfiidae and usually disintegrates in the Acrasidae, both have a closed intranuclear orthomitosis. Other characters support the proposal of a relationship. The family Gruberellidae is erected for a genus which resembles the Vahlkampfiidae in every respect except the fate of the nucleolus during mitosis. The order Schizopyrenida, including the families Vahlkampfiidae and Gruberellidae, and the order Acrasida restricted to the family Acrasidae (Acrasis and Pocheina) are united in a new class Heterolobosea of the subphylum Sarcodina. This first formal recognition of relationship between amoebae which form fruiting bodies and amoebae which do not emphasises the need for further investigation of possible relationships between mycetozoans and other Sarcodina.