The amber from Totolapa (Chiapas, Mexico) is thought to have been secreted by Hymenea sp. during Early to Middle Miocene time, and then reworked during Pleistocene ash flow events. Most of this amber is preserved within pyroclastic sediments. Peripheral layers of amber pieces from Totolapa yield a wealthy microflora including 1) one morpho-species of filamentous bacterium, 2) a sheathed bacterium Melanothrix mexicana gen. sp. nov., 3) five morpho-species of Actinobacteria (actinomycetes), Scopaeopsis verticillata gen. sp. nov., Thermomonosporopsis chiapasensis sp. nov., and three left in open nomenclature, and 4) diverse fungal mycelia. Melanothrix mexicana, Thermomonosporopsis chiapasensis, Actinobacteria gen. A sp. A and fungi were early colonizers of the fluid bark exudates of resin, and they grew either superficially or centripetally, as observed in modern resinicolous biota.Keywords: Amber, prokaryote, fungi, new taxon, Miocene, Mexico. Resumen