Araucariacites sp.

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2019, The Early Cretaceous Mesofossil Flora Of Torres Vedras (Ne Of Forte Da Forca), Portugal: A Palaeofloristic Analysis Of An Early Angiosperm Community, Fossil Imprint 75 (2), pp. 153-257 : 167-169

Araucariacites sp.

Text-fig. 9

D e s c r i p t i o n a n d r e m a r k s. The material comprises several fragments of pollen sacs, as well as isolated pollen clumps, containing Araucariacites pollen annulus; g) Cicatricosisporites sp. 2 spore in proximal view from a clump of spores. Specimens, TV43-S174551 (a), TV44-S174558 (b, c), TV43-S174600 (d, e), TV43-S174601 (f), TV43-S174552 (g). Scale bars 300 Μm (d), 20 Μm (a–c, e–g).

( Text-fig. 9a, d ). Pollen grains are alete, circular in outline, about 65 µm in diameter and typically flattened and folded ( Text-fig. 9d ). The exine surface is finely papillate to microechinate ( Text-fig. 9b ). Abundant small rounded orbicules cover the inner surface of the pollen sacs and are densely distributed over the surface of the pollen (Textfig. 9d). Orbicules are doughnut-shaped, about 2 µm in diameter, with irregular ridges radiating from a small central depression ( Text-fig. 9c ).

A f f i n i t y a n d o t h e r o c c u r r e n c e s. Araucariacites was established by Cookson (1947) based on pollen from Cainozoic strata of the Kerguelen Archipelago. The type species, Araucariacites australis COOKSON , has been used very widely for pollen grains from most regions of the world that range in age from Triassic to Neogene ( Raine et al. 2011). Cookson (1947) compared pollen of Araucariacites australis with pollen of extant Araucaria JUSS. and Agathis SALISB. (Araucariaceae) , but no vegetative remains or cones of Araucariaceae have been encountered in any of the Cretaceous mesofossil floras from Portugal and closely similar pollen is also produced by other conifers, for example by extant Cunninghamia lanceolata HOOK. (Cupressaceae) ( Bykowska and Klimko 2016). However, Araucariacites pollen has been found in situ in an araucarian cone from the Early Cretaceous of Spain ( Kvaček et al. 2018).

Araucariacites pollen grains similar to those from Torres Vedras occur at most of the Early Cretaceous mesofossil localities in Portugal that we have studied, and similar pollen assigned to Araucariacites australis is also common in some of the Torres Vedras palynological preparations studied by Konradsen (1996).

Figures

Text-fig. 9. Scanning electron microscope (SEM) images of inaperturate Araucariacites sp. pollen from two fragmentary pollen sacs; Torres Vedras locality, Portugal. a) Fragmentary pollen sac; b) Granular inner surface of pollen sac (a); c) Orbicule showing finely striate surface; d) Group of pollen grains from pollen sac in (a) showing granular exine surface and numerous orbicules; note that the scale bar (12 Μm) is two times larger than that used for most other pollen grains illustrated in this paper (6 Μm). Specimens, TV44-S148025 (a, b, d), TV44-S148146 (c). Scale bars 150 Μm (a), 12 Μm (d), 3 Μm (b, c).