Paisia pantoporata E. M. FRIIS, M. M. MENDES et K. R. PEDERSEN 2018

Paisia pantoporata E.M.FRIIS, M.M.MENDES et K.R.PEDERSEN, 2018

Text-fig. 33a–c

D e s c r i p t i o n a n d r e m a r k s. Paisia pantoporata is based on about 60 specimens of fossil flowers and isolated floral parts recovered from the Catefica mesofossil flora (for a full description and discussion see Friis et al. 2018a). Flowers are small, about 1 mm long and 1.2 mm in diameter, actinomorphic and pentamerous with a perianth consisting of a single whorl of five tepals, an androecium consisting of a single whorl of stamens, and a gynoecium of five free carpels (Text-fig. 33a, c). The organs of the three whorls are arranged on the same radius with the incurved margins of each tepal embracing a stamen (Text-fig. 33c). Stamens have a short, stout filament that merges above into the anther. Anthers are tetrasporangiate with two pairs of pollen sacs borne laterally and separated by a massive connective.

Pollen grains are small, spheroidal, about 11–14 µm in diameter and pantoporate with six to eight pores. The pollen wall is tectate-punctate with spiny supratectal ornamentation (Text-fig. 33b). The carpels are follicular, narrowly elliptical to obovate with a ventral slit that extends for the full length of the carpel. Each carpel has one dorsal and two ventral bundles and contains about 20–30 seeds borne in two rows along the full length of the ventral suture.

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. Pantoporate pollen occurs scattered among all major groups of angiosperms. However, the characters of the pollen combined with the pentamerous organisation indicate that Paisia pantoporata is most likely an extinct lineage of basal eudicots, probably most closely related to extant Ranunculales.

Flowers of Paisia pantoporata have so far been recovered only from the Catefica locality. Pollen of Paisia pantoporata is also encountered in the palynological strew preparations from Catefica, where it occurs in clumps of several grains. Pantoporate pollen grains of the kind produced by Paisia pantoporata have not been reported from other palynofloras. Pantoporate pollen grains are not uncommon in Early Cretaceous palynofloras (for references see Ibrahim et al. 2015, Friis et al. 2018a), but grains similar to pollen of Paisia pantoporata have not been reported from other mesofossil floras or dispersed palynofloras.