Clavatipollenites sp. 3

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 : 189

Clavatipollenites sp. 3

Text-fig. 23d–j

D e s c r i p t i o n a n d r e m a r k s. The material comprises two fragments of small tetrasporangiate stamens with pollen in situ ( Text-fig. 23d, g ). The grains are monoaperturate and almost spherical, about 18 µm in diameter, semitectate-reticulate with a homobrochate reticulum ( Text-fig. 23e, f, h–j ). Lumina are irregular and up to about 1.7 µm in diameter. Muri are ornamented with tiny verrucae arranged at the top of the muri or in irregular rows ( Text-fig. 23f, j ). Columellae are long and widely spaced ( Text-fig. 23f, j ). The aperture is irregular, rounded to triangular, poorly defined and covered by irregular exine elements that grade into the reticulum ( Text-fig. 23e, f, h ). Orbicules that occur in one of the specimens are small, spherical with a spiny surface and a small central depression ( Text-fig. 23i ).

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. The nature of the reticulum and the supratectal ornamentation resembles that of other grains described here as chloranthoids. The grains are similar to the pollen of Clavatipollenites sp. 1 in their broader and rounded aperture, but the aperture is smaller, the grains are larger, and the reticulum is coarser.

Figures

Text-fig. 23. Scanning electron microscope (SEM) images of Clavatipollenites sp. 2 (a–c) from a fragmentary stamen, and stamen fragments with in situ pollen of Clavatipollenites sp. 3 (d–j); Torres Vedras locality, Portugal. a, b) Distal (a) and proximal (b) view of pollen showing simple, elongate colpus on distal surface and semitectate-reticulate pollen wall; c) Detail of pollen wall showing muri with finely verrucate supratectal ornamentation and long scattered columellae; d) Fragment of tetrasporangiate stamen; e, f) Distal views of pollen from stamen fragment showing poorly defined aperture, coarse reticulum and long scattered columellae; g) Fragment of stamen; h) Distal view of pollen showing poorly defined aperture covered by irregular verrucae; i, j) Pollen wall showing rounded orbicules (i) and fractured pollen wall showing long scattered columellae (j). Specimens, TV43-S136728 (a–c), TV44-S149201 (d–f), TV44-S149220 (g–j). Scale bars 300 Μm (d, g), 6 Μm (a, b, e, f, h), 3 Μm (c), 1.5 Μm (i, j).