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- Paisia, an Early Cretaceous eudicot angiosperm flower with pantoporate pollen from PortugalPublication . Friis, Else Marie; MENDES, MÁRIO; Pedersen, Kaj RaunsgaardA new fossil angiosperm, Paisia pantoporata, is described from the Early Cretaceous Catefica mesofossil flora, Portugal, based on coalified floral buds, flowers and isolated floral structures. The flowers are actinomorphic and structurally bisexual with a single whorl of five fleshy tepals, a single whorl of five stamens and a single whorl of five carpels. Tepals, stamens and carpels are opposite, arranged on the same radii and tepals are involute at the base clasping the stamens. Stamens have a massive filament that grades without a joint into the anther. The anthers are dithecate and tetrasporangiate with extensive connective tissue between the tiny pollen sacs. Pollen grains are pantoporate and spiny. The carpels are free, apparently plicate, with many ovules borne in two rows along the ventral margins. Paisia pantoporata is the oldest known flower with pantoporate pollen. Similar pantoporate pollen was also recognised in the associated dispersed palynoflora. Paisia is interpreted as a possibly insect pollinated, herbaceous plant with low pollen production and low dispersal potential of the pollen. The systematic position of Paisia is uncertain and Paisia pantoporata most likely belongs to an extinct lineage. Pantoporate pollen occurs scattered among all major groups of angiosperms and a close match to the fossils has not been identified. The pentamerous floral organisation together with structure of stamen, pollen and carpel suggests a phylogenetic position close to the early diverging eudicot lineages, probably in the Ranunculales.
- New insights into the morphology and taxonomy of the Cretaceous conifer Frenelopsis based on a new species from.the Albian of San Just, Teruel, SpainPublication . Barral, Abel; Gomez, Bernard; Daviero-Gomez, Veronique; Lecuyer, Christophe; Mendes, Mário; Ewin, Timothy A. M.Frenelopsis justae sp. nov. is reported from the middle – lower upper Albian Escucha Formation of San Just, Teruel province, Spain. It shows micro-morphological features hitherto undescribed in the genus Frenelopsis including: (1) individual stomatal apparatus comprised of only three subsidiary cells; (2) clusters of 2–3 stomatal apparatus sharing a single subsidiary cell; (3) stomatal rows that bifurcate; and (4) an internal, cylindrical, cell layer preserved between the adaxial and abaxial cuticles. The morphology in the genus is reinterpreted, the long leaf sheath consisting of the proximal abaxial surface of 2–3 fused leaves lacking visible sutures with short distal free parts. Therefore, the generic diagnosis is emended, and new microscopic features added. We show that the appearance, morphology and structure of the leaf surfaces, free leaf tips, and stomatal apparatus are highly variable and regard them as innovation hot-spots in Frenelopsis species. We emphasize the need to perform thorough quantitative analysis of Frenelopsis morphology, including description of metrics variance, to improve our knowledge of its taxonomy, phenotypical plasticity and evolutionary trends.
- Canrightiopsis, a new Early Cretaceous fossil with Clavatipollenites-type pollen bridge the gap between extinct Canrightia and extant ChloranthaceaePublication . Friis, Else Marie; Grimm, Guido W.; MÁRIO MIGUEL MENDES; Pedersen, Kaj RaunsgaardCanrightiopsis with three species (C. intermedia, C. crassitesta, C. dinisii) is described from the Early Cretaceous of Portugal based on small, one-seeded berries. The fruits are derived from bisexual flowers with three stamens borne on one side of the ovary. There are no traces of a perianth. Pollen is of the Clavatipollenites-type, monocolpate, semitectate, reticulate-columellate with heterobrochate reticulum and muri with beaded supratectal ornamentation. The ovary is unilocular with a single pendant, orthotropous and bitegmic ovule. The seed is endotestal. The endotesta consists of one layer of palisade-shaped crystal cells with fibrous infillings. The fruit wall has resin bodies or cavities from presumed ethereal oil cells sometimes seen as stomata-like structures on the fruit surface. A phylogenetic analysis resolves Canrightiopsis as a close relative of extant Chloranthaceae, particularly close to extant Chloranthus and Sarcandra. All three taxa share the one-sided position of the stamens on the ovary. An evolutionary sequence from fossil Canrightia to fossil Canrightiopsis and extant Chloranthus and Sarcandra is suggested by loss of perianth, reduction in number of ovules and stamens and displacement of stamens to one side of the ovary. Canrightiopsis also shares several critical features with extant Ascarina including monoaperturate pollen and beaded supratectal ornamentation of the pollen wall.
- A new species of the spore genus Costatoperforosporites from Early Cretaceous deposits in Portugal and its taxonomic and palaeoenvironmental significancePublication . MENDES, MÁRIO; Barron, Eduardo; Batten, David J.; Pais, JoaoA new species of spore, Costatoperforosporites friisiae sp. nov., is described from the Early Cretaceous (late Aptian-early Albian) deposits of Catefica in the Lusitanian Basin, western Portugal. Although the morphology of the muri is clearly of the Cicatricosisporites type, the presence of micropores on these sculptural elements and within the intervening grooves is a particularly distinctive feature and more typical of spores that have been attributed previously to Costatoperforosporites. As a result, this genus is emended not only to accommodate Costatoperforosporites friisiae but also to differentiate it more clearly from other, similar, murornate genera. It is considered to represent the family Anemiaceae. So far, Costatoperforosporites friisiae has only been encountered in the Catefica palynoflora. The presence of many other pteridophyte spores, especially of schizaealean derivation, together with abundant cheirolepidiacean remains at this locality, strongly suggests a warm, moist climate and diverse source vegetation.