Clavatipollenites-

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 : 357

Stamens with monocolpate Clavatipollenites- type pollen sp. 2

Text-fig. 11a–e

Description and remarks. The material comprises a single stamen that has in situ Clavatipollenitestype pollen. The anther is tetrasporangiate, elongate and narrow, about 1.3 mm long and 0.3 mm broad ( Text-fig. 11a ). Pollen is monocolpate and almost circular in equatorial outline, about 24–26 µm in diameter. The aperture is short, about 14 µm long, and has an irregular, indistinctly delimited margin.The colpus membrane is covered by irregular verrucae that grade into the reticulum in the non-apertural regions of the grains ( Text-fig. 11b, c ). The exine is semitectatereticulate with a homobrochate reticulum ( Text-fig. 11b, c ). Lumina are irregular and up to about 3 µm in diameter. Muri are narrow, 0.5 µm wide, ornamented with minute verrucae arranged in a single longitudinal row, or sometimes in two rows. The verrucae are sometimes laterally expanded and form poorly defined transverse ridges. Columellae are long, about 1.5 µm, and widely spaced ( Text-fig. 11e ). Orbicules are tiny, spherical with finely verrucate to spiny surface ornamentation ( Text-fig. 11d ).

Affinity and other occurrences. The pollen grains in this specimen are larger than any of the other Clavatipollenites - type pollen observed in the Catefica mesofossil flora. They are also larger than the pollen grains in situ within anthers of Proencistemon ( Tab. 1 ). See also comments on “Stamens with monocolpate Clavatipollenitestype pollen sp. 1” above.

Figures

Text-fig. 11. Scanning electron microscope (SEM) images of isolated “Stamen fragment with Clavatipollenites-type pollen sp. 2”; Catefica locality, Portugal. a) Fragment of tetrasporangiate stamen with pollen in situ; b) Detail from stamen fragment showing distal and proximal surfaces of in situ pollen grains; c) Pollen grain in distal view showing short colpus with irregular margin and aperture membrane covered by irregular verrucae; d) Detail of pollen wall showing tiny spherical orbicules; e) Detail of pollen wall showing the semitectate-reticulate tectum and long, scattered columellae supporting the narrow muri with finely verrucate supratectal ornamentation. Specimen, Catefica 50-S170389 (a–e). Scale bars = 600 Μm (a), 20 Μm (b), 6 Μm (c), 3 Μm (d), 1.5 Μm (e).