The Rhaetian flora of Rögla, northern Scania, Sweden

Abstract

Rögla is the northernmost locality yielding Mesozoic plant fossils in Scania, southern Sweden, and is one of the northernmost Rhaetian assemblages in Europe. The assemblage consists of over 500 specimens collected 50-60 years ago, of which 139 yielded identifiable plant remains referable to 15 plant species; another 19 specimens are tentatively assigned to four species because of their fragmentary preservation. The flora includes sphenophytes, ferns, cycads, bennettitaleans, seed ferns of uncertain alliance, conifers and some leaf remains that are tentatively assigned to ginkgophytes based on their epidermal anatomy. The species-level composition of the assemblage is consistent with a Rhaetian age and is similar to well-known floras from nearby Höganäs and Bjuv, except for the absence of cycads belonging to Nilssonia, which are very common in most other Scanian floras. The fossil assemblage is interpreted to derive from multistorey vegetation occupying moist habitats on a coastal plain. Strong affinities are evident with the coeval floras of Jameson Land, Greenland, reinforcing the concept of a distinctive North Atlantic floristic sub-province at the close of the Triassic.

The Upper Triassic flora of Svalbard

“…Dictyophyllum exile is a typical Rhaetian species and it is possible that the specimen under study was collected ex situ on the beach and derives from a Rhaetian layer exposed higher on the cliffs. This taxon is readily confused with D. nathorstii Zeiller, 1903, which is distinguished mostly by its basally adnate pinnae as opposed to the completely free pinnae in D. exile (Schweitzer et al 2009;Pott and McLoughlin 2011). However, this character is not useful if only isolated pinnae are preserved.…”

“…The fragments are identical to material from Scania, southern Sweden, figured by Nathorst (1878a, b) and Pott and McLoughlin (2011). Dictyophyllum exile is a typical Rhaetian species and it is possible that the specimen under study was collected ex situ on the beach and derives from a Rhaetian layer exposed higher on the cliffs.…”

“…Hirmer and Hörhammer 1936;Schweitzer et al 2009;Pott and McLoughlin 2011 Type species: Non designatus (see Farr and Zijlstra 1996).…”

Biota and palaeoenvironment of a high middle-latitude Late Triassic peat-forming ecosystem from Hopen, Svalbard archipelago

“…The floras of Skåne (southern Sweden) and Scoresby Sound (Greenland), preserved at approximately 40-458 N palaeolatitude, were prime representatives of this floristic belt based on their shared occurrence of Dipteridaceae, Czekanowskiales and Ginkgoales. However, these two regions share such a broad range of distinctive taxa and richness in Bennettitales (Harris 1932b;Pott & McLoughlin 2009) that they appear to constitute a distinct North Atlantic subprovince, at least during the Rhaetian (Pott & McLoughlin 2011). The Hopen permineralized flora may represent a slightly higher latitude, specialized ecological expression of that subprovince's flora in the Late Triassic.…”

“…Information on the composition of, and interactions within, Late Triassic terrestrial ecosystems in Europe derives mostly from fossil assemblages located from Italy to Skåne (southern Sweden), which represent low-to lower middle-palaeolatitude lowland biotas (Dobruskina 1994;Kustatscher et al 2010Kustatscher et al , 2012Pott & McLoughlin 2011). Recently, Strullu-Derrien et al (2012) documented evidence of invertebrate interactions with bennettitalean roots in a permineralized peat block derived from the island of Hopen in the Svalbard archipelago, around 2500 km north of Skåne.…”