An enigmatic organism from the ‘Exshaw’ Formation (Devonian-Carboniferous), Alberta, Canada



Libodiscus ascitus gen. et. sp. nov. (incertae sedis) consists of a flask-like body (mean length of 15 mm; mean maximum width of 9 mm) bearing a flange of plates or flattened tentacles. At one end a pair of arm-like extensions connects with a disc with concentric markings. The flask has transverse structures with prominent relief. Some of these are more or less regularly arranged, but in other specimens they are much more irregular. On what appears to be the inner wall of the flask there are closely spaced striations. Libodiscus is known only from Devonian-Carboniferous transitional strata (‘Exshaw’ Formation) at Crowsnest Pass, southwest Alberta, Canada. Its affinities are speculative and no secure relationship can be demonstrated with metazoans, plants or other problematica such as chitinozoans. The disc is, however, similar to a number of discoidal fossils that previously have been assigned to chondrophorine medusoid hydrozoans. □ Libodiscus ascitus, Exshaw, Devonian, Carboniferous, problematica.