Piperales

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 : 201-202

Order Piperales ?

Tectate pollen grains from coprolite

Text-fig. 33a–d

R e m a r k s. Several large tectate-punctate and apparently monocolpate pollen grains occur in a coprolite/ pollen clump (specimen S137906 ) together with a wide range of other pollen types. The pollen grains are almost circular in polar view, about 26–30 µm in diameter, and with a short, apparently circular aperture ( Text-fig. 33a, b ). The exine surface is smooth with densely spaced perforations of various sizes ( Text-fig. 33a–c ). One specimen seen from the proximal side has a somewhat rugulate surface (Textfig. 33d), and it is unknown whether this grain belongs to a separate taxon .

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. Pollen resembling these tectate grains have not been observed in other Early Cretaceous floras from Portugal and their systematic affinity is uncertain. Although the grains show certain similarities with other tectate grains from the Torres Vedras locality that are thought to be of piperalean affinity (see above), they differ in several features, especially in the shorter and broader aperture, and they may not be related. These pollen grains are also much larger than the grains associated with Appomattoxia and Appofructus , as well as putatively related grains assigned to Dejaxia and Goczania , and also lack the fine spines on the tectum surface. The pollen grains in the coprolite also differ from the the pollen of Burgeria , mainly in the configuration of the aperture and different exine surface.

In their general morphology, size and apparently thick pollen wall these tectate pollen grains are more similar to grains of Tucanopollis described from the Barremianearly Aptian of Brazil ( Regali 1989), but lack the echinate supratectal ornamentation and the characteristic verrucate colpus membrane of Tucanopollis pollen. The Torres Vedras grains are also similar to dispersed pollen described from the Early Cretaceous of southern England as CfA Barremian- ring, but the Torres Vedras grains are larger and lack the fine spines on the tectum surface (Hughes 1994). The pollen grains from the coprolite are also similar to grains assigned to the extinct genus Crassipollis GÓCZAN et JUHÁSZ in the very thick tectate pollen wall. However, all six species of Crassipollis described by Góczan and Juhász (1984) from the Albian of Hungary, including the type species, are characterized by a long, straight colpus that is sometimes broader at each end. This contrasts with the more rounded aperture seen in specimens from the Torres Vedras coprolite. Pollen grains assigned to Crassipollis from the Barremian of Spain ( Villanueva-Amadoz et al. 2015) are more similar to the Torres Vedras grains in their aperture configuration, but the Spanish grains are smaller.

Figures

Text-fig. 33. Scanning electron microscope (SEM) images of tectate-punctate pollen from probable coprolite (not shown); Torres Vedras locality, Portugal. a–c) Monocolpate pollen grains in distal view (a, b) showing poorly defined aperture and punctate surface of the tectum (c) of the grain in (b); d) Pollen grain showing slightly rugulate surface of tectum; aperture not visible. Specimens, TV44-S137906-06 (a–c), TV44-S137906-08 (d). Scale bars 6 Μm (a, b, d), 3 Μm (c).