Tritaenia Maegdefrau et Rudolf, Mesozoic ‘ Sciadopitys-like’ leaves in mass accumulations

The Late Jurassic to Early Cretaceous genus Tritaenia Maegdefrau et Rudolf 1969 is problematic because of: (1) missing authentic material of its type species, T. linkii ( Roemer 1839) Maegdefrau et Rudolf; and (2) Watson and Harrison's (1998) synonymization of T. linkii with Pseudotorellia heterophylla Watson. This paper: (1) rectifies the status of T. linkii on the basis of newly recovered specimens carrying the original author's authentication; and (2) gives the basis for rejecting Watson and Harrison's claim that T. linkii and T. crassa (Seward) Bose et Manum 1991 represent linear leaves of the heterophyllous taxon Pseudotorellia heterophylla. The three species of Tritaenia known to date ( T. crassa, T. linkii, T. scotica) are reviewed, and the genus is compared with other Mesozoic so-called ‘ Sciadopitys-like’ hypostomatic leaves with a median stomatal zone, many of which occur in mass accumulations such as T. linkii. Deciduousness is indicated for T. linkii and T. crassa by their occurrence in mass accumulations and the possession of well-developed abscission scars. Known mass accumulations of fossil foliage are reviewed and their implications for palaeoenvironmental interpretations discussed.