- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Melonis pompilioides is generally recognized as a reliable deep-water indicator of Neogene sediments of the world. In foraminiferal assemblages of the eastern hemisphere, however, from Neogene sections which apparently are shelf or upper bathyal deposits, a Pleistocene specimen identified by DiGrande (1967) as M. pompilioides should be, on closer inspection, referred to M. soldani (d'Orbigny), a shallow-water homeomorph. Photographs of tests of the two specimens taken with a scanning electron microscope suggest specific differences which are not always clearly defined in illustrations; differences in pore size, sutural relief, and relation of the umbilicus and sutures are discussed. Application of these criteria will allow more precise identification. Evolutionary considerations appear to be negligible.