The Late Cretaceous (Coniacian) leaf and cone flora from the Sudetes
Halamski, Adam T.; Kvaček, Jiří
published: Nov 25, 2015
Late Cretaceous (Coniacian, mostly late Coniacian; ammonite- and inoceramid-based stratigraphy) leaf floras from the Nysa Kłodzka Graben in the Sudetes (south-western Poland) are described. Plant remains are preserved in coarse clastic rocks as imprints devoid of cuticles and occur in marginal marine sediments deposited by a palaeocurrent flowing along the shores of the East Sudetic Island, the origin place of the plants. The main fossil plant localities are Idzików (Kieslingswalde) and Nowy Waliszów (Neuwaltersdorf). The leaf flora consists of thirty-three species, described on the basis of about 320 identifiable specimens. Five fern species (belonging to Nathorstia, Monheimia, cf. Anemia, and Sphenopteris) are mostly represented by single specimens. Conifers are represented by Geinitzia reichenbachii (Geinitz) Hollick & Jeffrey and Frenelopsis aff. alata (K. Feistmantel) Knobloch (foliage) and Geinitzia cf. schlotheimii L. Kunzmann, Knoll & Gaipl and Conago sp. (cones). The bulk of the flora consists of twenty-four dicot species, representing the genera Dryophyllum, Juglandiphyllites, Dalbergites, Debeya (all the above Eudicotyledoneae), Cinnamomoides, Laurophyllum, Magnoliphyllum, Ficonium, Ettingshausenia, Amelanchites, Dryandroides, Apocynophyllum, Salicites, and Dicotylophyllum (Dicotyledoneae incertae sedis). Dryophyllum geinitzianum (Goepp.) Halamski & J. Kvaček comb. nov. is sufficiently well preserved to allow a detailed reconstruction: it is a compound trifoliolate leaf composed of folioles with irregularly serrate margins; it belongs to the order Fagales s.l. Two new species are described. Dicotylophyllum montis-nivium sp. nov. is characterised by ovate leaves that are entire-margined in most specimens, whereas in some they possess single large teeth. Dicotylophyllum thaddaeiguniae sp. nov. is elliptic in shape, entire-margined, but has a peculiar rectangular base reminding of that of Credneria senonensis (Knobloch) Němejc & Kvaček. Genera Dalbergites, Cinnamomoides, Magnoliphyllum, and Ficonium are emended. Monocots are represented by Pandanites cf. spinatissimus Petrescu & Duşa ex Popa et al. and Smilacites panartius (Bayer) Halamski & J. Kvaček comb. nov. The most common species in the studied material are Laurophyllum acuminatum (Goepp.) J. Kvaček & Halamski comb. nov. and Dryophyllum geinitzianum (the two representing about half of the material), both presumably dominating a riparian forest. Upland or mesophilous vegetation might be represented by Amelanchites cerasiformis (Vel.)Halamski & J. Kvaček comb. nov., Dicotylophyllum montis-nivium sp. nov., and several small-leaved representatives of Dalbergites and Dicotylophyllum. Frenelopsis grew in salt marshes, whereas Pandanites and Geintizia belong to back swamp vegetation. The studied flora belongs to the subtropical vegetation belt and is most similar to slightly older or younger (Turonian to Santonian) assemblages from the Bohemian Cretaceous Basin. Notable similarities with the flora of the Cenomanian to lower Coniacian Frontier Formation in Wyoming should also be noted.