Piercipollis 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 : 218

Piercipollis sp. 1

Text-fig. 42a–c

D e s c r i p t i o n a n d r e m a r k s. Piercipollis sp. 1 is based on an isolated anther containing abundant pollen ( Text-fig. 42a ). The pollen grains are small, about 20 µm in diameter, and monocolpate. The colpus is long, apparently extending to the equator, but none of the grains expose the full length of colpus. The exine is semitectate-reticulate and columellate ( Text-fig. 42b ). The reticulum is coarse, homobrochate and with lumina up to about 0.25 µm in diameter that have polygonal to rounded, irregular outlines ( Text-fig. 42c ). The muri are smooth with slightly rounded profiles and are supported by long scattered columellae. The colpus margin is distinctly delimited by the continuing marginal muri and there is no distinction between the reticulum over the main part of the grains and the reticulum close to the colpus margin. The reticulum detaches easily from the foot layer ( Text-fig. 42b, c ).

The pollen grains of Piercipollis sp. 1 differ from those of Piercipollis simplex in their more dense reticulum, and lumina of more irregular shape. However, incomplete information on the extension of the colpus, and also of details of the colpus margin, preclude formal establishment of a new species.

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. Similar grains have not been observed from other mesofossil floras in Portugal.

Figures

Text-fig. 42. Scanning electron microscope (SEM) images of monocolpate pollen of Piercipollis sp. 1 (a–c) from an isolated anther and Piercipollis sp. 2 (d–f) from a coprolite (not shown); Torres Vedras locality, Portugal. a) Narrow elongate anther that yielded the pollen in (b) and (c); b) Distal view of pollen grain showing well-developed reticulum that is only loosely attached to the foot layer; note the smooth foot layer (arrowhead) of a grain from which the reticulum has become detached; c) Reticulum showing the smooth muri and long columellae that are mostly detached from the foot layer; d–f) Pollen grains in distal (d, e), and lateral views (f) showing the very long colpus and the well-developed reticulum only loosely attached to the smooth surface of the foot layer; note the main body of the grains (foot layer) does not fill out the whole space of the reticulum (f). Specimens, TV44-S148218 (a–c), TV142-S170216 (d–f). Scale bars 300 Μm (a), 6 Μm (b, d–f), 3 Μm (c).