Mesozoic Sciadopitys-like leaves with observations on four species from the jurassic of andøya, Northern Norway, and Emendation of Sciadopityoides sveshnikova

Abstract

Sveshnikova's rejection (1981) of the genus Sciadopitytes (Goeppert et Menge) Florin for Sciadopitys-like leaves is critically discussed. Her institution of the genus Sciadopityoides to replace Sciadopitytes is accepted, although three of the 14 Mesozoic species she referred to the new genus are considered to be invalidly published ( S. hallei Florin, S. scanica Florin, and S. scoticaFlorin). The remaining 11 Mesozoic species of Sciadopitys-like leaves are reviewed and new observations are presented for four of these, three of which are known only from Upper Jurassic sediments of Andøya, northern Norway. Formerly neglected characters are recognized which allow for an emended diagnosis of Sciadopityoides and for two species to be transferred from thatgenus to Sciadopitys (S. lagerheimii Johansson and S. macrophylla Florin). Three species of Sciadopityoides are considered to form a more closely related nucleus within the genus: the type species S. uralensis (Dorofeev et Sveshnikova) Sveshnikova, S. cramer (Halle) Sveshnikova, and S. variabilis (Bose) Sveshnikova. The remaining species appear to form a more heterogeneous group but are difficult to compare because of inadequate information. Because of its present heterogeneous content, Sciadopityoides remains a form-genus. Species diversity of Sciadopitys-like leaves appears to be highest in the Upper Jurassic to Lower Cretaceous. None has so far been recorded in sediments older than the Upper Jurassic, and records are restricted to north of 40° N latitude.