Rossodus manitouensis (Conodonta), a New Early Ordovician Index Fossil

Rossodus is established as the name for a genus of conodonts whose apparatus comprises blade-like coniform elements that have a symmetry transition and oistodontiform elements. The cusps of these elements consist of dense white matter; their shallow basal cavities are enclosed by hyaline material. Morphologic similarity of some of the elements to elements in the apparatuses of Juanognathus Serpagli and Utahconus Miller suggest affinity with those genera, but the presence of an oistodontiform element in Rossodus distinguishes it from the others. The type species, R. manitouensis n. sp., occurs within a limited stratigraphic interval in the Lower Ordovician over a wide region that includes parts of several continents, making the species valuable for regional and intercontinental correlation.