A radiolarian dated sponge microsclere assemblage from the Miocene Dos Bocas Formation of Ecuador

An assemblage of siliceous sponge microscleres, previously unknown in the fossil record, are described from the Miocene Dos Bocas Formation of coastal Ecuador. The fauna includes several species previously known only from Holocene faunas, and a new taxa Conciliaspongia rarus Gen. et sp. nov. The microsclere assemblage is interpreted as being deposited in close proximity to a shallow (< 25 m) reef area, representing a transition between the localized San Pedro Member and the basin-wide facies of the Dos Bocas Formation. Radiolaria occurring in association with the microsclere assemblage indicate a mid-Early Miocene age (Stichocorys delmontensis zone), and illustrate their biostratigraphic usefulness in enigmatic/exotic facies.