Sagenopteris sp.

Pott, Christian, 2014, The Upper Triassic flora of Svalbard, Acta Palaeontologica Polonica 59 (3), pp. 709-740 : 733

Sagenopteris sp.

Fig. 6C.

1972 Planta indet.; Vasilevskaya 1972: 55, pl. 19: 1, 2.

Material.— Spitsbergen: Hyrnefjellet (VSEGEI 10979-78); Carnian (Upper Triassic).

Description.— A fragmentary, 65.1 mm long, petiolate leaflet comes from Hyrnefjellet. The basally tapering lamina is 30.9 mm wide at its widest preserved part and is characterised by a midvein giving off numerous anastomosing secondary veins at an angle of c. 20°, arching to c. 50° towards the leaf margin (Fig. 6C). Vein density is c. 20 veins/cm at the leaf margin.

Remarks.— Only one specimen of Sagenopteris sp. was found in the Svalbard assemblages. It was originally published as Planta indet. by Vasilevskaya (1972), and indeed, its systematic assignment is somewhat problematic. The leaf also resembles examples described as Gontriglossa species from the Carnian Molteno Formation of southern Africa ( Anderson and Anderson 1989). However, Gontriglossa is a typical Gondwanan taxon and has never been reported from the Northern Hemisphere. The only fossils from the Northern Hemisphere approaching the specimen under study are the petiolate leaflets of Sagenopteris , as described e.g., from the Middle Jurassic of Yorkshire or the Late Cretaceous of Greenland and assigned to the Caytoniales ( Harris 1964; Boyd 1992). Anastomosing veins are also known from Anthrophyopsis foliage from the Rhaetian of e.g., Iran, but differences in the shape of the lamina and the venation are readily recognisable ( Schweitzer and Kirchner 1998). A leaf identified as Glossopteridium from the Rhaetian of Poland by Bochenski (1957) is similar to the leaves of Sagenopteris or Glossopteris . Sagenopteris is known from Rhaeto-Liassic to Late Cretaceous deposits, but has not yet been described from older strata. Specimens of Sagenopteris and Gontriglossa are strikingly identical even in epidermal anatomy right down to stomatal morphology (cf. Harris 1964; Anderson and Anderson 1989). Specimens of both genera have been identified as Glossopteris earlier (e.g., Brongniart 1830; Lindley and Hutton 1833; Thomas 1958), but their heterogeneousness has been shown ( Anderson and Anderson 1989). The reconstructions of the habit of the plants and the arrangement of the leaves highly differ from each other; Anderson and Anderson (1989) gave evidence by impressive fossils, whereas Harris (1964) did not publish photographs of any fossil specimens, but merely gave quite fragmentary line drawings. I assign the Svalbard specimen to Sagenopteris even though it would constitute the oldest representative of the genus, but I refrain from referring it to a formal species due to its fragmentary nature.