Clavatipollenites (Walker and Walker, 1984) COUPER

Friis, Else Marie, Crane, Peter R., Pedersen, Kaj Raunsgaard, Mendes, Mário Miguel & Kvaček, Jiří, 2022, The Early Cretaceous Mesofossil Flora Of Catefica, Portugal: Angiosperms, Fossil Imprint 78 (2), pp. 341-424 : 364-366

Stamens with Asteropollis- or Clavatipollenites - type pollen sp. 2

Text-fig. 16d–f

Description and remarks. The material comprises a single, well-preserved, tetrasporangiate stamen with in situ Asteropollis- or Clavatipollenites - type pollen. The filament is very short and the anther was probably almost sessile ( Text-fig. 16d ). The stamen is obovate in outline, about 1.4 mm long and 0.5 mm broad, with a dome shape apical extension of the connective. The aperture is not exposed in any of the grains, which creates uncertainty about their generic assignment, but they were probably monoaperturate. The pollen grains are circular in equatorial view, about 22 µm in diameter ( Text-fig. 16e ). The exine is semitectate-reticulate with a homobrochate reticulum ( Text-fig. 16e, f ). Lumina are irregular and up to about 1.8 µm in diameter. Muri are narrow, about 0.5 µm wide and ornamented with minute verrucae arranged in two rows. Columellae are short and widely spaced. Orbicules were not observed.

Affinity and other occurrences. The specimen is very similar to the “Stamen with Asteropollistype pollen sp. 2” also from Catefica (see above), but both the stamen and the in situ pollen are larger. As only the proximal side of the grains is exposed, it is unknown whether the supposed single aperture is branched as in “Stamen with Asteropollis- type pollen sp. 2” or monocolpate/trichotomocolpate as in other chloranthoid stamens from Catefica. The stamen is currently the largest of the chloranthoid stamens from Catefica that we have encountered and clearly belongs to a separate species.

Figures

Text-fig. 16. Scanning electron microscope (SEM) images of “Stamen fragments with in situ Clavatipollenites- or Asteropollis-type pollen” (sp. 1: a–c; sp. 2: d–f; sp. 3: g–i); Catefica locality, Portugal. a) Stamen fragment showing pollen sacs; b) Distal view of pollen grain from (a) showing semitectate-reticulate tectum; c) Detail of pollen wall showing the semitectate-reticulate tectum and long, scattered, columellae supporting muri with fine pits and rounded supratectal ornamentation; note orbiculae with a finely spiny surface (arrows); d) Stamen showing very short filament, lateral pollen sacs and short apical extension of the narrow connective; e) Folded pollen grain from (d) showing semitectate-reticulate tectum; f) Detail of pollen wall from (d) showing the semitectatereticulate tectum and muri with fine rounded ornamentation; g) Stamen fragment; h, i) Detail of pollen grains from (g) showing the semitectate-reticulate tectum with smooth muri, long scattered columellae and tiny scattered orbicules (arrow). Specimens, Catefica 50-S170395 (a–c), Catefica 49-S172561 (d–f), Catefica 50-S170390 (g–i). Scale bars = 600 Μm (a, d, g), 6 Μm (b, e, h), 1.5 Μm (c, f, i).