Fossilized gut remains have been observed in four of the about twenty trilobite species present in the Letná Formation: Birmanites ingens, Dalmanitina socialis, Deanaspis goldfussi and Selenopeltis buchi. These four trilobites belong to the Dalmanitina-Deanaspis Association, characterizing rather proximal and shallow environments of the Letná Formation. Most of the non-trilobite arthropods discovered in this formation, including forms with non-mineralized exoskeletons, are also found associated with D. goldfussi and/or D. socialis. This suggests that the development of conditions conducive to soft-tissue fossilization was not uncommon in the environment represented by the Dalmanitina-Deanaspis Association.Fatka et al., 2013, p.98
