Rhagasostoma Koschinsky 1885

Genus Rhagasostoma Koschinsky, 1885 Type species

Rhagasostoma hexagonum Koschinsky, 1885, by subsequent designation (Canu & Bassler 1917: 31). Eocene, Lutetian, Gosaumergel von Götzreuth (= Gerhartsreiter Schichten), graben near Siegsdorf- Gerhartsreit, Traunstein, Bavaria, Germany. A neotype was chosen and figured by Taylor et al. (2018b).

Colony encrusting or erect, vincularian and dichotomously branching. Autozooids subhexagonal; zooidal boundaries raised. Cryptocyst extensive, granular, sometimes peripheral caverns present. Gymnocyst lacking or minutely present. Opesia terminal or subterminal, occupying about one-third of the frontal surface, longitudinally elliptical, with deep opesiular indentations at the proximolateral corners, sometimes with occlusor lamina. Ovicells endozooidal or immersed. Avicularia vicarious and about the same size as autozooids, or interzooidal; opesia roundish or longitudinally elliptical, located centrally, usually with thin articular ridges bearing two short teeth proximally and a short or long, slit-like opesiular indentation between the teeth; sometimes wedge-like structures present. Kenozooids rounded or oval bifoliated and located at edges of colonies with opesia roundish, small.