pdf: http://www.geologie.ac.at/filestore/download/JB1503_393_A.pdf

Based on Late Jurassic material from Portugal, Lithocodium aggregatum Elliott, originally described as a calcareous alga from the Lower Cretaceous, was reinterpreted as a loftusiid foraminifer by Schmid & Leinfelder (1996). Recently, the necessity of a taxonomic revision of the Late Triassic and Late Jurassic forms has been stressed by Schlagintweit et al. (2010) who redescribed the Lower Cretaceous Lithocodium aggregatum Elliott as a heterotrichale calcareous green alga. Abundant specimens occurring in the Late Jurassic of the Northern Calcareous Alps of Austria show that these in contrast
are ichnological structures (ichnogenus Entobia) produced by excavating sponges that bored their galleries into calcareous substrates (calcimicrobial oncoids and metazoan skeletons). Around the bored chambers and between the branching canals, the originally microbial microstructures are no more discernible and transformed into dense micrite. Thin-walled microcrystalline bodies with or without lateral appendages inside the borings are interpreted as remains (impregnated body wall?) of the sponges. The core zone of all-side bored oncoids may show an irregular “bacinellid” meshwork that is interpreted as the traces of so called pioneering excavating filaments, which are known from modern clionaid sponges. Spicules were never observed inside the empty chambers, but occasional silicification of oncoids point to their former presence. The empty chambers are often colonized by the foraminifer Troglotella incrustans Wernli & Fookes representing a further example of the common association of cryptoendolithic foraminiferans and sponges.