Nilssoniopteris angustior (Stur ex Krasser, 1909 ) Pott, Krings, and Kerp, 2007c

Pott, Christian, 2014, The Upper Triassic flora of Svalbard, Acta Palaeontologica Polonica 59 (3), pp. 709-740 : 728-730

Nilssoniopteris angustior (Stur ex Krasser, 1909) Pott, Krings, and Kerp, 2007c .

Fig. 9A–D.

1885 Taeniopteris angustior nom. nud.; Stur 1885: 97.

1909 Macrotaeniopteris angustior ; Krasser 1909: 39.

1972 Taeniopteris sp. ; Vasilevskaya 1972: 51, pls. 15: 3b; 16: 1–2a, 3–5.

1983 Taeniopteris sp. ; Vasilevskaya 1983: 143, pl. 6: 2–4.

2007 Nilssoniopteris angustior (Stur ex Krasser, 1909) ; Pott et al. 2007c: 1306, pls. 3: 1–7; 4: 1–9.

Fig. 8. Cycadophytes from the Carnian (Upper Triassic) strata of Svalbard. A–E. Pterophyllum brevipenne Kurr ex Schenk, 1864 . A. NRM S080283, → from Fleur de Lyshamna. B. VSEGEI 10979-56, from Wimanfjellet. C. VSEGEI 10979-57, from Wimanfjellet. D. VSEGEI 10979-55, from Wimanfjellet.

E. NRM S080078-01, from Fleur de Lyshamna. F–I. Pterophyllum sp. cf. Pterophyllum firmifolium Ye ex Wu, Ye, and Li, 1980 . F. NRM S080273, from Nørdstefjellet. G. VSEGEI 10979-59, from Teistberget. H. VSEGEI 10979-66, from Teistberget. I. VSEGEI 10979-03, from Teistberget. J, K. Pterophyllum sp. J . NRM S151683, from Sassenfjorden. K. NRM S151682, from Sassenfjorden. Scale bars 10 mm.

Material.— Spitsbergen:FleurdeLyshamna(NRMS080078); Trehøgdene (NRM S151680). Edgeøya: Kapp Lee (NRM S080191–S080197, S080205, S080221, S080234–S080236; VSEGEI 10979-24, 10979-25, 10979-52, 10979-65, 10979- 71). Hopen: Kollerfjellet (?VSEGEI 18/12163–20/12163). Carnian (Upper Triassic).

Description.— Several incomplete specimens of Nilssoniopteris foliage, found at Kapp Lee, are 144.2 mm long and 69.5 mm wide. The narrow and lanceolate leaves are apparently entire-margined and characterised by a prominent rachis up to 3.2 mm wide. The lamina is laterally inserted on the rachis and tapers slightly towards the base; apices are bluntly rounded (Fig. 9B). A petiole is not preserved in the specimens. Numerous parallel, densely arranged veins depart from the rachis at 80–90° (Fig. 9A, C, D), enter the lamina and bifurcate one or two times close to the rachis. Vein density is 15–19 veins/cm. In the distal portion of the leaves, veins are slightly curved towards the apex. The lamina is not subdivided into segments, but local growth aberrations of the leaf margin resemble weak lobations or the lamina is locally lacerated, as in extant Musa leaves (Fig. 9A, D). Epidermal details remain unknown because no organic material could be isolated from any fossil.

Remarks.— Pott et al. (2007c) described Nilssoniopteris angustior in detail from the Carnian flora of Lunz in Lower Austria and demonstrated the bennettitalean nature of these leaves that were originally described as marattialean ferns. Although epidermal details are unavailable from the Svalbard specimens, the fossils match exactly with the leaves described from Lunz, hence, assignment to N. angustior is justified. Epidermal details have been published in detail by Pott et al. (2007c) from specimens from Lunz. Nilssoniopteris angustior is found mainly at Kapp Lee on Edgeøya, but also occurs at Fleur de Lyshamna on Spitsbergen. Vasilevskaya (1972, 1983) described leaves with some reservation as Taeniopteris sp. from Trehøgdene and Kollerfjellet of Hopen that are slender, but fit comfortably in the range from the specimens from Lunz assigned to N. angustior ( Pott et al. 2007c) . The Lunz material, originally described as Taeniopteris ( Stur 1885) and Macrotaeniopteris ( Krasser 1909) was unknown to Vasilevskaya since it was not figured until 2007.

Geographic and stratigraphic range.— Europe; Carnian.