A taxonomic study has been performed for the thirty-two retrieve bryozoan species from the measured
Serravallian Maradah Formation section at Z138, Jabal Zaltan, northeastern Sirt Basin, Libya. Among this
unique assemblage only two new species Calpensia spinosa and Thalamoporella zaltaniensis have been
established. The Cubitostrea shells provide the most attachments of the encrusting bryozoans.
The reported species are of Mediterranean/Atlantic distributional affinity. However the new species are
considered as an endemic species. The limestones and marls are rich in erect flexible and encrusting forms
which indicate inter-subtidal (10-50m) environments with moderate rate of sedimentation and relatively
strong wave actions. Highly agitated environment is specially recognized from the investigated
assemblages in the lower part of Ar Rahlah Member of Maradah Formation as suggested on taphonomical
basis.