[PDF] Reassessing the temporal evolution of orchids with new fossils and a Bayesian relaxed clock, with implications for the diversification of the rare South American genus Hoffmannseggella (Orchidaceae: Epidendroideae) | Semantic Scholar (2024)

It is suggested that general floral trait similarity between Pachites species reflects common ancestry, whereas differences in floral morphology, rewards and scent chemistry likely reflect adaptations for different pollination strategies, which evolved during the long time since divergence.

The fit of the phylogenetic Barkeria tree to a stasis model of evolution as well as the lack of phylogenetic signal under a Brownian motion model suggest strong niche conservatism of its species, however, factors other than climate influenced speciation in the allopatric sister species.

The Vanilloideae (vanilloids) is one of five subfamilies of Orchidaceae and is composed of fourteen genera and approximately 245 species, and almost all these protein genes show accelerated base substitution rates compared to the photosynthetic vanilloids.

Dated phylogenies of 12 plant clades from the Cape Floristic Region (CFR) in southern Africa are used to test hypotheses of Neogene climatic and geomorphic evolution and reveal that Early Miocene land surfaces of the CFR were wetter than at present and were dominated by quartzitic substrata.

The broad phylogenetic distribution of NDH loss and the subtle phenotypes of mutants suggest that the NDH complex is of limited biological significance in contemporary plants.

This study examines a genus level analyses by integrating ITS and matK data to all fossil data available on orchids in a molecular Bayesian relaxed clock employed in BEAST and assessed divergence times for the genus Cymbidium with a focus on evolutionary plasticity of photosynthetic characters.

The results indicate that ancestral Orchidinae were hymenopteran-pollinated, food-deceptive plants and that these traits have been dominant throughout the evolutionary history of the subtribe in the Mediterranean.

The studied species were found to be in an endangered status based on their area of occupancy, however, considering their extent of occurrence, they are in a status of less concern.

The research reveals the relevance of the differentiation of Paphiopedilum in Southeast Asia and geological history and explains that the significant evolutionary hotspots of these orchids in the Sundaland and Wallacea might be attributed to repeated migration and isolation events between the south-eastern Asia mainland and the Sunda Super Islands.

Molecular clock analysis based on the whole plastome sequences suggested that Orchidaceae diverged from its sister family 99.2 mya, and the estimated divergence times of five subfamilies are as follows.

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This work focuses primarily on the periodic and anomalous components of variability over the early portion of this era, as constrained by the latest generation of deep-sea isotope records.

RbcL fails to provide strong support for the interrelationships of the subfamilies of the Orchidaceae, and the cladograms presented here should serve as a standard to which future morphological and molecular studies can be compared.

The date estimates suggest that the most recent common ancestor of Begonia could have diversified from the end of the Cretaceous to the beginning of the Neogene, probably during a period of global cooling from the mid Eocene to early Oligocene.

The distinctive, raised tetra- to cyclocytic stomatal subsidiary cells of Earina and characteristic papilla-like absorbing glands and "ringed" guard cells of Dendrobium support the placement of the fossils into these genera, and demonstrate expansion of epiphytic orchids into Zealandia by the mid-Cenozoic and an important role for southern continents in the diversification of Orchidaceae.

An exquisitely preserved orchid pollinarium attached to the mesoscutellum of an extinct stingless bee recovered from Miocene amber in the Dominican Republic, that is 15–20 million years old, constitutes both the first unambiguous fossil of Orchidaceae and an unprecedented direct fossil observation of a plant–pollinator interaction.

These results provide independent evidence that climate cooling following the Middle Miocene Climatic Optimum led to important vegetational shifts in eastern Brazil, causing an increase in the dominance of open versus closed habitats.

This paper examines the validity of the assumption of rate autocorrelation among lineages in relaxed molecular clock models developed to accommodate rate heterogeneity in molecular evolutionary rates.

The observed incongruent relationships among the three major lineages of Heliosperma are better explained by hom*oploid hybridization than by gene duplication/losses because species branching events exceed gene coalescence times under biologically reasonable population sizes and generation times, making lineage sorting an unlikely explanation.

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