Clathropteris sp.

Pott, Christian, 2014, The Upper Triassic flora of Svalbard, Acta Palaeontologica Polonica 59 (3), pp. 709-740 : 718-720

Clathropteris sp. cf. Clathropteris obovata Ôishi, 1932

Fig. 4C–E.

1972 Clathropteris sp. ; Vasilevskaya 1972: 38, pls. 4: 1–3, 10: 1b. 1972 Dipteridaceae indet.; Vasilevskaya 1972: 41, pl. 5: 6.

Material.— Spitsbergen: Hyrnefjellet ( VSEGEI 10979-26– 10979-28, 10979-34); Carnian (Upper Triassic).

Description.— All specimens constitute middle and apical portions of sterile pinnae. The preserved parts are up to 58 mm long and 28 mm wide. Pinnae appear to have had a very thin lamina, the margin is lobate (Fig. 4 C) with the rounded lobes becoming more acute (hook-like) and more arched towards the pinna apex (Fig. 4D– E). A central midvein (less than 1 mm wide) gives off lateral veins at regular intervals of 12–14 mm at an acute angle of 60°, each extending into the tip of a lobe. Lateral veins near the pinna apex are arranged at gradually more acute angles down to 40°. The lateral veins bear almost perpendicularly arranged, very thin subsidiary veins that are barely visible in some cases. These

Fig. 4. Dipteridaceous and matoniaceous ferns from the Carnian (Upper Triassic) strata of Svalbard. A. Dictyophyllum exile ( Brauns, 1862) Nathorst , → 1878, NRM S 080220, from Kapp Lee, two different pinnae on the same specimen ( A 1, A 2). B. Dictyophyllum sp. , VSEGEI 10979-29, from Wimanfjellet. C – E. Clathropteris sp. cf. Clathropteris obovata Ôishi, 1932 . C. VSEGEI 10979-26, from Hyrnefjellet. D. VSEGEI 10979-27, from Hyrnefjellet; note the shape of the lobes (arrowheads). E. VSEGEI 10979-28, from Hyrnefjellet; note the shape of the lobes (arrowhead). F. Clathropteris sp. VSEGEI 10979-12, from Wimanfjellet. G. cf. Cladophlebis sp. , NRM S 080258-02, from Bertilryggen ( G 1), with close-up of distal portion ( G 2). H. Phlebopteris sp. cf. Phlebopteris muensteri (Schenk, 1867) Hirmer and Hörhammer, 1936 . VSEGEI 10979-31, from Wimanfjellet ( H 1), enlargement ( H 2), arrowheads indicate sori. I. cf. Sphenopteris sp. , NRM S 080263, from Edlundfjellet. Scale bars 10 mm.

connect the lateral veins and form the reticulate venation typical of Clathropteris species.

Remarks.— Schweitzer et al. (2009) stated that the discrimination between Clathropteris obovata and C. meniscoides

Brongniart, 1825) Brongniart, 1828 is difficult and based mainly on more distinct veins in C. meniscoides . This character is, thus, only utilitarian in a limited sense. However, following the figures of Schweitzer et al. (2009), foliage of C. obovata appears smoother (due to its less distinct veins) and less robust; in addition, the arrangement of the veins seems slightly different: veins of C. obovata appear to emerge at more acute angles from the midvein than those of C. meniscoides ; and the mesh pattern looks much more regular checkered” in C. meniscoides than in C. obovata . Considering these character tendencies and the excellent figures given by Schweitzer et al. (2009), the Svalbard material more strongly resembles C. obovata than C. meniscoides . However, even if the fossils match quite closely, I retain some reservation due to the fragmentary nature of the material and the very round and regularly shaped marginal lobes of at least two specimens (i.e., VSEGEI 2047-08 and 2047-28). The latter was identified as “Dipeteridaceae indet.” by Vasilevskaya

1972). All other specimens from Hyrnefjellet were assigned to Clathropteris sp. by Vasilevskaya (1972). Clathroperis foliage in Svalbard has only been reported from Hyrnefjellet in southern Spitsbergen (but see below).

Geographic and stratigraphic range.— Europe, Asia; Nori- an–Middle Jurassic.