Clavatipollenites sp. 1

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. 1

Text-fig. 22a–g

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 small tetrasporangiate stamens with pollen in situ ( Text-fig. 22a, b ). The anthers are up to about 0.52 mm long. Pollen grains in situ within the stamens were described by Friis et al. (1999) as type J.1. The grains are monoaperturate and almost circular in equatorial outline, about 14–16 µm in diameter, semitectatereticulate with a homobrochate reticulum ( Text-fig. 22c–f ). Lumina are irregular and up to about 1.2 µm in diameter. Muri are ornamented with tiny verrucae arranged in two rows. Columellae are of medium size and widely spaced ( Text-fig. 22g ). The aperture is broad, rounded and covered by irregular verrucae that grade into the reticulum in the non-apertural regions of the grains ( Text-fig. 22c–e ) .

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. In their general shape, form of the pollen wall, and the indistinctly delimitated aperture, these pollen grains are similar to various dispersed pollen assigned to the genus Clavatipollenites . Pollen grains of Clavatipollenites are usually compared to pollen of extant Ascarina . However, the pollen described here differs from that of extant Ascarina in having a very broad and rounded colpus. Similar pollen to the fossil grains described here also occur in several stamens recovered from the Catefica mesofossil flora.

Figures

Text-fig. 22. Scanning electron microscope (SEM) images of fragmentary stamens (a, b) with in situ pollen of Clavatipollenites sp. 1 (c–g); Torres Vedras locality, Portugal. a, b) Fragmentary tetrasporangiate stamens; c–e) Distal view of pollen grains showing large, rounded aperture and the irregular verrucate aperture membrane; f) Proximal view of pollen grains showing dense reticulum; g) Section through the fractured pollen wall showing foot layer, columellae and muri with faint supratectal ornamentation. Specimens, TV44-S105013 (a, c, d), TV44-S105019 (b, e–g). Scale bars 300 Μm (a, b), 6 Μm (c–f), 3 Μm (g).