Ruesticyrtiidae (Radiolaria) are reported from the Köseyahya stratigraphic section in the Köseyahya Nappe exposed near Elbistan town, western part of Eastern Taurides. The lowermost part of this section is composed of alternating sandstone and marl; overlying beds are represented by alternating clayey/cherty limestone, marl and mudstone. Radiolaria from clayey/cherty limestone beds are very well-preserved, diverse and abundant. The overlying strata in the section consist of ammonoid-bearing nodular limestones with tuff interlayers and subsequently “Hallstatt limestones” with abundant ammonoids. A medium- to thick-bedded, clastic and chert free limestone sequence is situated at the top of the section. A middle Carnian age is assigned to strata from the basal part of the Köseyahya stratigraphic section based on characteristic radiolarian fauna and index form, Tetraporobrachia haeckeli. On the basis of abundant and diverse specimens from the family Ruesticyrtiidae, a new genus, Elbistanium n. gen. and three new species are described: Elbistanium gracilum n. gen., n. sp., E. productum n. gen., n. sp. and Xiphotheca munda n. sp. Furthermore, emendation of Xiphotheca karpenissionensis De Wever is proposed.