Graptolites of the genus Mediograptus Bouček and Přibyl from the uppermost Llandovery of Cornwallis Island, Arctic Canada

Isolated specimens of three species of Mediograptus are described from latest Llandovery (Telychian) strata of the Cape Phillips Formation, Cornwallis Island. One species is new, Mediograptus? bicercis n. sp., whereas the other two, Mediograptus flittoni and Mediograptus morleyae, have previously been recorded only from the Telychian of Wales. A possible paleolatitudinal control on mediograptid distribution is suggested, with one suite of taxa characterizing higher paleolatitudes (Bohemia), the other, including the species described herein, lower paleolatitudes (Wales, Arctic Canada). The diagnosis for the genus Mediograptus is emended.