Arberophyllum spetsbergensis ( Vasilevskaya, 1972 ) Doweld, 2000

Pott, Christian, 2014, The Upper Triassic flora of Svalbard, Acta Palaeontologica Polonica 59 (3), pp. 709-740 : 730-732

Arberophyllum spetsbergensis ( Vasilevskaya, 1972) Doweld, 2000

Fig. 9E–G, O.

1972 Glossophyllum (?) spetsbergense ; Vasilevskaya 1972: 52, pls. 5: 3b; 9: 1b; 14: 3b; 16: 6–8; 17: 1–3a.

1983 Desmiophyllum sp. 1 ; Vasilevskaya 1983: 143, pl. 6: 5.

1983 Desmiophyllum sp. 2 ; Vasilevskaya 1983: 143, pl. 6: 6.

2000 Arberophyllum spetsbergense ( Vasilevskaya 1972) ; Doweld 2000: 93.

Material.— Spitsbergen: Fleur de Lyshamna ( NRM S 080073, S 080087, S 080107– S 080109); Hyrnefjellet ( VSEGEI 10979- 28, 10979-72–10979-74, 10979-95–10979-97); Wimanfjellet ( VSEGEI 10979-08, 10979-29); Teistberget ( VSEGEI 10979- 66, 10979-75). Barentsøya: Schweinfurthberget ( VSEGEI 10979-61). Edgeøya: Kapp Lee ( NRM S 080205, S 080239; VSEGEI 10979-24, 10979-25, 10979-53, 10979-71, 102-29- 12). Hopen: Kollerfjellet (? VSEGEI 21/12163, 22/12163). Carnian (Upper Triassic).

Description.— Arberophyllum spetsbergensis leaves are common in Svalbard; their most characteristic features are the tongue- or strap-shaped lamina and the parallel veins (Fig. 9 E – G, O). Leaves are consistently 100–115 mm long and 16–19 mm wide in the middle (= broadest) portion of the lamina (Fig. 9 F). The leaves lack a petiole and a central rachis. The lamina tapers towards the base, which is typically 3–5 mm wide. The apex of the leaves is acutely rounded. Tapering is relatively abrupt and margins in the middle portions of the leaf are almost parallel. Veins are distinct but not very prominent. They are parallel and bifurcate close to the base of the leaf to support the whole lamina. Vein density is 12–15 veins/cm in the broadest part of the lamina. No anastomoses are visible and each vein is assumed to persist until the apex of the leaf.

Remarks.— Separation of Arberophyllum and Desmiophyllum foliage is almost impossible given the weak characters differentiating these very variable but similar appearing foliage types. If epidermal details are available, the leaves may

Fig. 9. Cycadophytes and ginkgophytes from the Carnian (Upper Triassic) strata of Svalbard. A –D. Nilssoniopteris angustior (Stur ex Krasser, 1909) → Pott, Krings, and Kerp, 2007. A. NRM S 080078-02, from Fleur de Lyshamna. B. NRM S 080221-02, from Kapp Lee. C. NRM S 080235, from Kapp Lee.

D. NRM S 080236-02, from Kapp Lee. E – G. Arberophyllum spetsbergensis ( Vasilevskaya, 1972) Doweld, 2000 . E. VSEGEI 10979-95, from Hyrnefjellet. F. VSEGEI 10979-74, from Hyrnefjellet; note the contracted leaf base (arrowhead). G. VSEGEI 10979-72, from Hyrnefjellet. H – N. Arberophyllum substrictum sp. nov. H. NRM S 080079, from Fleur de Lyshamna, holotype. I. NRM S 080255, from Bertilryggen. J. NRM S 080239-03, from Kapp Lee.

K. VSEGEI 10979-94, from Agardhbukta. L. VSEGEI 10979-66, from Teistberget. M. VSEGEI 10979-77, from Wimanfjellet. N. NRM S080059, from Midterhukfjellet. O. Arberophyllum spetsbergensis ( Vasilevskaya, 1972) Doweld, 2000 , VSEGEI 10979-73, from Hyrnefjellet. Scale bars 10 mm.

be distinguished by the shape of the stomata that are elongate in Desmiophyllum and more circular in Arberophyllum Florin 1936 ; Kräusel 1943; Pott et al. 2007d). However, this character, given by Florin (1936), appears to be very inconsistent even in Florin’s (1936) material, hence unreliable. For macro-morphological differentiation, the number of veins in the middle (= broadest) portion of the leaves may indicate if a leaf is better placed in Arberophyllum (less than 20 veins/cm) or in Desmiophyllum (more than 20 veins/ cm). Following this strategy, all the Svalbard leaves may be assigned with confidence to Arberophyllum . This is also supported by the circular stomata of some of the specimens identified as Glossophyllum sp. by Vasilevskaya (1972) that are here regarded to belong to A. substrictum (see below). One specimen from Hyrnefjellet indicates that the leaves of A. spetsbergensis were arranged in dense clusters on short shoots (Fig. 9E, G), which may have been shed as whole units (cf. Pott et al. 2007d).

Leaves of Arberophyllum spetsbergensis are similar to A. substrictum (see below) and A. florinii , the last of which is very common in the Carnian Lunz flora and probably the best-known Arberophyllum species in general ( Pott et al. 2007d; Pott and Krings 2010). However, A. spetsbergensis leaves are distinguished from both by their shorter and broad- er lamina, with more prominently tapered bases and apices, and by their clustered arrangement on short shoots in contrast to the supposed convolute (or alternate) arrangement of the leaves in A. substrictum and A. florinii (see below; cf. Kräusel 1943; Pott et al. 2007d; Pott and Krings 2010). One leaf from Fleur de Lyshamna fits the description of A. spetsbergensis very closely, but reaches 169 mm in length, which is more than 50% longer than other specimens. Arberophyllum spetsbergensis is relatively common at various localities in Spitsbergen, Edgeøya, and Barentsøya.

Geographic and stratigraphic range.— Svalbard; Carnian.