Sergipea 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 : 174-175

Sergipea sp.

Text-fig. 12a–d

D e s c r i p t i o n a n d r e m a r k s. The specimen comprises a cluster of pollen grains, apparently borne in several spherical sporangia ( Text-fig. 12a ). The pollen grains are irregular elliptical in outline, about 20 µm long, 12.5 µm broad, and inaperturate. Each grain shows three sectors separated by rims of thickened and psilate exine with two narrower (proximal?) sectors and one broader (distal?) sector. The two narrower sectors have pointed ends ( Text-fig. 12b ), while the brader sector has more rounded ends (Textfig. 12d). All three sectors between the psilate exine rims are covered by irregular verrucate sculptural elements ( Text-fig. 12b–d ). A fine groove extending close to the margin of the exine rim is seen on both sides of the grains. The function of this groove is uncertain.

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. Sergipea pollen grains are closely similar to certain pollen taxa that are included in the Early to mid-Cretaceous, mainly low palaeolatitude, elater-bearing complex (e.g. Galeacornea STOVER). Pollen grains of the elater-bearing complex are generally thought to be related to the Gnetales ( Dino et al. 1999) . Neumann et al. (2003) also placed species of Sergipea in the Gnetales . While a relationship of Sergipea to extant Gnetales , or to the BEG complex more broadly, seems probable, more detailed comparisons and studies of Sergipea pollen are needed for the secure systematic placement of this unusual pollen type.

The presence of Sergipea at Torres Vedras is the first and only record of the genus from Portugal. It was previously reported in Europe from the stratotype of the Barremian at Angles, southern France, where it occurs in the middle part of the late Barremian section ( Renéville and Raynaud 1981). The genus has also been recorded from a single Early Cretaceous palynological assemblage of early Albian age from the USA (Albian Glenrose Formation, Texas, Tanrikulu et al. 2018). Otherwise, Sergipea has only been reported from Early Cretaceous strata in the Southern Hemisphere, where several species have been recorded from Aptian and Albian strata, particularly from Brazil ( Regali et al. 1974, Neumann et al. 2003).

Figures

Text-fig. 12. Scanning electron microscope (SEM) images of pollen of Sergipea sp. from a group of probable fragmentary pollen sacs; Torres Vedras locality, Portugal. a) Cluster of probable fragmentary pollen sacs that yielded the pollen in this Text-figure; b, c) Pollen grains showing the robust longitudinal ribs separated by prominent areas of granular exine; note the groove along the margins of the longitudinal ribs (arrowheads); d) Pollen grain showing the granular exine flanked by two robust ribs; note the groove along the margins of the longitudinal ribs (arrowheads). Specimen, TV44-S148012 (a–d). Scale bars 150 Μm (a), 12 Μm (c), 6 Μm (b, d).