Abstract

A diverse assemblage of mosses from the Early Cretaceous Catefica mesofossil flora, Portugal, is described based on fragments of charcoalified and lignitized gametophytes and a single spore capsule. Nine different gametophyte morphologies are recognized and assigned to Sphagnopsida, Polytrichopsida and Bryopsida. None of the fossils can be included in any extant species. Four species have character combinations not known in any extant genera and are accommodated in three new genera as Chlorosphagnum cateficense gen. et sp. nov. (Sphagnales, family incertae sedis), Physcidium tortuosum gen. et sp. nov. and Physcidium simsimiae sp. nov. (Diphysciales, Diphysciaceae), and Canaliculidium fissuratum gen. et sp. nov. (Dicranales, Leucobryaceae). Three other species can be assigned to extant genera and are described here as Polytrichastrum incurvum sp. nov. (Polytrichales, Polytrichaceae), Dicranodontium minutum sp. nov. and Campylopus lusitanicus sp. nov. (both Dicranales, Leucobryaceae). One additional specimen has features suggesting affinity with Leucobryaceae but lacks characters critical for a definite generic placement. A single spore capsule is unassigned but is similar to capsules of members of the Ditrichaceae (Dicranales). All the fossil mosses recognised in the Catefica mesofossil flora are assigned to orders of extant mosses that diverged prior to the diversification of the Bryidae, the most diverse clade of living mosses. Based on extrapolations from their nearest living relatives, the Catefica mosses likely grew in more or less open environments, and in moist or wet sites that were primarily of low pH and low nutrient status.

Key words

Almargem Formation, Bryophyta, Early Cretaceous, fossil mosses, mesofossils, SRXTM, synchrotron radiation X-ray tomographic microscopy

Abstract

Angiosperm mesofossils are described from the Lower Cretaceous Almargem Formation exposed near the village of Catefica, Portugal, and are thought to be of Aptian-early Albian age. The mesofossil assemblage from Catefica is diverse and, in addition to the angiosperms described here, also contains a rich assemblage of non-angiosperm fossils, including leafy axes of bryophytes and lycopsids, lycopsid and salvinialean megaspores, and sporangia, sori and leaf fragments of ferns. There are also twigs, cones, cone scales, seeds and sporangia of several kinds of conifers. Other seed plants include 11 species of chlamydospermous seeds and vegetative axes related to the BEG group (Bennettiales-Erdtmanithecales-Gnetales). In terms of the number of plant fragments identified, angiosperms are most abundant in the Catefica assemblage and account for more than half of all specimens. Angiosperms also dominate in number of species, but because the non-angiosperm fossils have not been studied in detail the total number of species in the flora is not yet established. Sixty-seven species of angiosperms are recognized. Angiosperm diversity is mainly at the level of non-eudicots, including ANA-grade angiosperms, Chloranthaceae and magnoliids. Remains of chloranthoid angiosperms are especially common, both in the number of specimens and in number of species recognized. About 40 % of the specimens, and more than 25 % of the species are chloranthoids. Remains of magnoliid angiosperms (Magnoliales, Laurales, Canellales, Piperales) are also prominent among the angiosperms. Eudicots are subordinate: only 3–4 % of all angiosperm specimens can be assigned confidently to eudicot angiosperms. Five new genera and six new species of angiosperms are established (Canrightia foveolata sp. nov., Elasmostemon paisii gen. et sp. nov., Endressistemon cateficensis gen. et sp. nov., Ibericarpus cuneiformis gen. et sp. nov., Proencistemon portugallicus gen. et sp. nov., Valvidistemon globiferus gen. et sp. nov.). Several other new taxa are also described, but not formally named.

Key words

Almargem Formation, angiosperms, Early Cretaceous, fossil flowers, mesofossils, pollen, SRXTM, synchrotron radiation X-ray tomographic microscopy

Abstract

A distinctive feature of the major eudicot diversification that occurred through the Late Cretaceous is the unequivocal presence of Cornales and diverse Ericales. Here we describe well-preserved fossil flowers from the Mira locality in western Portugal, of Campanian-Maastrichtian age, that we assign to a new extinct genus of Ericales with two new species; Miranthus elegans gen. et sp. nov. and Miranthus kvacekii sp. nov. The fossil flowers are pedicellate, structurally bisexual, actinomorphic, pentamerous and isomerous, with five narrowly triangular persistent calyx lobes, a five-lobed corolla, five antepetalous stamens, five staminodes alternating with the petals and a semi-inferior, unilocular ovary. The ovary consists of five carpels and has a raised nectariferous ring with stomata-like openings above the insertion of the perianth, and a long five-angled style. A key feature, which confirms a relationship with Primulaceae s. l., is the free, central dome-shaped placenta that bears numerous, densely spaced ovules. The ovary matures into a capsule containing many, minute, reticulate seeds. Flowers of Miranthus are especially similar to those of extant Samolus, a genus of about twelve species that is sister group to other genera of subfamily Theophrastoideae and that has a disjunct distribution mainly in the Southern Hemisphere. Miranthus also appears to have grown in environments influenced by marine conditions, an ecological preference also seen in Samolus. Miranthus expands the diversity of Ericales known from the Late Cretaceous, and together with previously described fossils provides further evidence that the diversification of Ericales was already underway by the Campanian-Maastrichtian stages of the Late Cretaceous.

Key words

Campanian, Ericales, fossil flowers, Maastrichtian, Primulaceae s. l., SRXTM, synchrotron radiation X-ray tomographic microscopy

Abstract

Three new genera, Atlantocarpus, Lambertiflora and Mugideiriflora, are described from the Early Cretaceous of North America and Portugal based on floral structures with multicarpellate and apocarpous gynoecia that have been studied using scanning electron microscopy and synchrotron radiation X-ray tomographic microscopy. Lambertiflora and Mugideiriflora have numerous perianth parts in several series, as well as many stamens and many carpels borne on a short conical receptacle. Atlantocarpus has many carpels arranged spirally on an elongated receptacle. Perianth and stamens are not preserved in Atlantocarpus, but scars of two sizes at the base of the receptacle indicate the presence of several series of tepals and stamens. Phylogenetic assessment of the three new genera indicates close relationships with members of extant Austrobaileyales, which is also favoured by the apparently ascidiate carpels of Atlantocarpus. However, the phylogenetic signal is not strong and the fossils also share many features with magnoliid angiosperms. Fully secure resolution of their relationships is hampered by lack of information of critical floral features in the fossil material, the constellation of likely plesiomorphic characters that they exhibit, and inadequate knowledge of character homologies and character evolution among extant taxa. There is also the broader concern about whether phylogenetic patterns can be reliably inferred for the earliest phases of angiosperm evolution based solely on a depauperate assemblage of extant taxa given extensive extinction over the last 100 million years. The new genera add to growing evidence of diverse extinct angiosperms with multiparted flowers during the Early Cretaceous that have a variety of relationships to extant ANA-grade angiosperms and magnoliids.

Key words

apocarpous, Cretaceous, early angiosperms, fossil flowers, multiparted, Potomac Group, SRXTM, synchrotron radiation X-ray tomographic microscopy

Abstract

An Early Cretaceous mesofossil flora is described from the lower part of the Almargem Formation (late Barremian-early Aptian) from Torres Vedras (NE of Forte da Forca), Portugal. The flora is the oldest mesofossil flora containing angiosperm remains to be described in detail based on well-preserved flower, fruit and seed remains. In addition to angiosperms, the mesofossil flora also includes megaspores, sporangia and tiny leaves of spore-bearing plants. There are also twigs, cone fragments and seeds of conifers and seeds assigned to the BEG group. In total about 100 species have been distinguished. Most abundant in terms of plant fragments identified, are spore-bearing plants and conifers. Although only about 18 % of the specimens can be attributed to angiosperms, angiosperm diversity is unexpected high considering the age of the flora. Angiosperms account for about 62 % of all species recognized. Angiosperm diversity is mainly at the level of ANA-grade angiosperms, eumagnoliids and in a few cases early diverging lineages of monocots. Eudicots are subordinate. Twenty new genera and 28 new species of angiosperms are established Anaspermum operculatum gen. et sp. nov., Appofructus nudus gen. et sp. nov., Appomattoxia minuta sp. nov., Burgeria striata gen. et sp. nov., Canrightia elongata sp. nov., Choffaticarpus compactus gen. et sp. nov., Dejaxia brevicolpites gen. et sp. nov., Dinisia portugallica gen. et sp. nov., Eckhartia brevicolumella gen. et sp. nov., Eckhartia longicolumella sp. nov., Eckhartia intermedia sp. nov., Eckhartianthus lusitanicus gen. et sp. nov., Eckhartiopsis parva gen. et sp. nov., Gastonispermum antiquum sp. nov., Goczania rugosa gen. et sp. nov., Goczania inaequalis sp. nov., Goczania punctata sp. nov., Ibrahimia verminculata gen. et sp. nov., Juhaszia portugallica gen. et sp. nov., Kempia longicolpites gen. et sp. nov., Kvacekispermum costatum sp. nov., Mcdougallia irregularis gen. et sp. nov., Nicholsia brevicolpites gen. et sp. nov., Piercipollis simplex gen. et sp. nov., Reyanthus lusitanicus gen. et sp. nov., Samylinaea punctata gen. et sp. nov., Teebacia hughesii gen. et sp. nov., Vedresia elliptica gen. et sp. nov.). Comparison with results of a palynological study from the same horizon that yielded the mesofossil flora shows a marked underestimation of angiosperm diversity in the palynoflora, a pattern that has also been recognized elsewhere.

Key words

early eudicots, fossil flowers, fossil seeds, fossil megaspores, fossil stamens, mesofossil flora, Sergipea, synchrotron radiation X-ray tomographic microscopy (SRXTM), tricolpate pollen