Phase-contrast X-ray microtomography links Cretaceous seeds with Gnetales and Bennettitales

  title={Phase-contrast X-ray microtomography links Cretaceous seeds with Gnetales and Bennettitales},
  author={Else Marie Friis and Peter R. Crane and Kaj Raunsgaard Pedersen and Stefan Bengtson and Philip C. J. Donoghue and Guido W. Grimm and Marco Stampanoni},
Over the past 25 years the discovery and study of Cretaceous plant mesofossils has yielded diverse and exquisitely preserved fossil flowers that have revolutionized our knowledge of early angiosperms, but remains of other seed plants in the same mesofossil assemblages have so far received little attention. These fossils, typically only a few millimetres long, have often been charred in natural fires and preserve both three-dimensional morphology and cellular detail. Here we use phase-contrast… 

X-ray Synchrotron Microtomography of a silicified Jurassic Cheirolepidiaceae (Conifer) cone: histology and morphology of Pararaucaria collinsonae sp. nov.

This fossil develops the understanding of the dominant tree element of the Purbeck Fossil Forest, providing the first evidence for ovulate cheirolepidiaceous cones in Europe, and significantly extends the known palaeogeographic range of Pararaucaria, supporting a mid-palaeolatitudinal distribution in both Gondwana and Laurasia during the Late Jurassic.

Paleohistology of the Cretaceous resin-producing conifer Geinitzia reichenbachii using X-ray synchrotron microtomography.

Depositional environmental context combined with histological features of G. reichenbachii suggest that this conifer was adapted to a range of marginal-littoral ecosystems including those open to the sea paleoenvironments and innermost ones influenced by strong continental inputs.

Early Cretaceous mesofossils from Portugal and eastern North America related to the Bennettitales-Erdtmanithecales-Gnetales group.

Four new genera and six new species of fossil seed are described from five Early Cretaceous mesofossil floras from Portugal and eastern North America, suggesting that this newly recognized complex of extinct plants, together with Bennettitales, Erdtmanithecales, and Gnetales (the BEG group), is phylogenetically closely related.

Distinctive quadrangular seed-bearing structures of gnetalean affinity from the Late Jurassic Morrison Formation of Utah, USA

A new kind of seed-bearing structure is described based on three-dimensional casts and partially permineralized small cones from the Upper Jurassic Brushy Basin Member of the Morrison Formation, in

Two early eudicot fossil flowers from the Kamikitaba assemblage (Coniacian, Late Cretaceous) in northeastern Japan

The fossil currently provides the earliest record of the Buxaceae family and documents the presence of Trochodendraceae in eastern Eurasia during the middle part of the Late Cretaceous.

Is the anthophyte hypothesis alive and well? New evidence from the reproductive structures of Bennettitales.

Characters of bennettitalean plants are summarized and new evidence for the structure of cones and seeds is presented that help clarify relationships of Bennettitales to flowering plants, Gnetales, and other potential angiosperm sister groups.

Paleoecological and Phylogenetic Implications of Saxicaulis meckertii gen. et sp. nov.: A Bennettitalean Stem from the Upper Cretaceous of Western North America

This fossil documents greater structural diversity among Cretaceous bennettitaleans than previously known and tentatively documents an additional growth habit (underground stem).

Reconstructing Krassilovia mongolica supports recognition of a new and unusual group of Mesozoic conifers

Paracytic stomata, and other features of this new group, recall features of extant and fossil Gnetales, raising questions about the phylogenetic homogeneity of the conifer clade similar to those raised by phylogenetic analyses of molecular data.



Former diversity of Ephedra (Gnetales): evidence from Early Cretaceous seeds from Portugal and North America.

The fossil seeds document that key reproductive characters and pollen germination processes have remained unchanged within Ephedra for about 120 million years or more and support the previously suggested relationship between Erdtmanithecales and Gnetales.

Anatomically preserved Cycadeoidea (Cycadeoidaceae), with a reevaluation of systematic characters for the seed cones of Bennettitales.

Four anatomically preserved ovulate cycadeoid cones have been recovered from three localities in Upper Cretaceous sediments of Vancouver and Hornby Islands, British Columbia, Canada, revealing details of the reproductive biology shortly before extinction of the clade.

Morphology and affinities of an Early Cretaceous Ephedra (Ephedraceae) from China.

Detailed investigations on Lower Cretaceous Ephedra L. fossils (Gnetopsida) reveal morphological characters similar to those of extant Ephedra rhytidosperma Pachomova, including articulate branches

Applications of X-ray synchrotron microtomography for non-destructive 3D studies of paleontological specimens

ABSTRACT Paleontologists are quite recent newcomers amongthe users of X-ray synchrotron imaging techniques at the Eu-ropean Synchrotron Radiation Facility (ESRF). Studies of theexternal morphological

Pteridosperms are the backbone of seed-plant phylogeny1

These five extant groups were embedded in the derived half of a morphologically diverse spectrum of extinct taxa that strongly influenced tree topology and elucidated patterns of acquisition of morphological character-states, demonstrating that pteridosperms and other more derived “stem-group” Gymnosperms are critical for understanding seed-plant relationships.

Pollen Organs and Seeds with Eucommiidites Pollen

The characteristic Mesozoic pollen genus Eucommiidites is described from pollen organs and seeds recovered in Cretaceous strata of North America and Europe and shows that the pollen grains each have a distinct distal colpus flanked by two lateral colpi in an equatorial position.

Seed ferns and the origin of angiosperms

Analysis of a critically revised morphological data set for seed plants indicates that trees in which Gnetales are nested in conifers, as in molecular analyses, are almost as parsimonious as those inWhich G netales are linked with angiosperms, suggesting that the molecular arrangement should be accepted.

On the Origin of Angiosperms.

Gnetales and Angiosperms.-Last year ARBER and PARKIN announced'4 their "strobilus theory of angiospermous descent;" and now they have applied it to the interpretation of the relationships of