Better Retcon Your Angiosperm (Flowering Plant) Origin Story! Herbaceous Angiosperm Found From Callovian Jurassic China

A Whole Plant Herbaceous Angiosperm from the Middle Jurassic of China

Authors:

Han et al

Abstract:

In contrast to woody habit with secondary growth, truthful herbaceous habit lacking secondary growth is restricted to angiosperms among seed plants. Although angiosperms might have occurred as early as in the Triassic and herbaceous habit theoretically may have been well adopted by pioneer angiosperms, pre-Cretaceous herbs are missing hitherto, leaving the origin of herbs and evolution of herbaceous angiosperms mysterious. Here we report Juraherba bodae gen. et sp. nov, a whole plant herbaceous angiosperm, from the Middle Jurassic (greater than 164 Ma) at Daohugou Village, Inner Mongolia, China, a fossil Lagerst?tten that is worldwide famous for various fossil finds. The angiospermous affinity of Juraherba is ensured by its enclosed ovules/seeds. The plant is small but complete, with physically connected hairy root, stem, leaves, and fructifications. The Middle Jurassic age recommends Juraherba as the earliest record of herbaceous seed plants, demanding a refresh look at the evolutionary history of angiosperms.

Turonian/Coniacian Cretaceous Kholokhovchan Flora Shows Angiosperms Penetrating Into Older Ecosystems

Late Cretaceous Kholokhovchan Flora of Northeastern Asia: Composition, age and fossil plant descriptions

Authors:

Herman et al

Abstract:

The Kholokhovchan Flora comes from tuffaceous – terrigenous deposits of the Vetvinskaya Member (Chalbugchan Group) in the Penzhina and Oklan rivers interfluve, Northeastern Russia. The depositional environment of the plant-bearing deposits is interpreted to have been a freshwater lake. The Kholokhovchan Flora hosts 42 fossil plant species belonging to Marchantiopsida, Polypodiopsida, Ginkgoales, Leptostrobales, Bennettitales, Pinales and Magnoliopsida. It is characterised by diverse angiosperms, less diverse conifers and ferns, by the presence of relatively ancient Sphenobaiera, Phoenicopsis and Pterophyllum together with advanced Late Cretaceous Taxodium, Glyptostrobus and angiosperms, among which platanoids are quite diverse. The Kholokhovchan Flora is most similar to Penzhina and Kaivayam floras of the Anadyr-Koryak Subregion and Arman Flora of the Okhotsk-Chukotka volcanogenic belt (Northeastern Russia) and should be dated as Turonian–Coniacian. The Kholokhovchan Flora, that populated volcanic plateaus and intermontane valleys, are characterised by a mixture of ancient “Mesophytic” plants with typical Late Cretaceous “Cenophytic” taxa. This peculiar composition probably reflects a gradual penetration of new angiosperm-dominated plant assemblages into older floras: during the Late Cretaceous, “Cenophytic” assemblages migrated along river valleys and other disturbed habitats into the interior of Asia, eventually occupying volcanogenic uplands, and in places replacing the “Mesophytic” fern-gymnospermous communities that existed there. Two new angiosperm species, as well as four the most characteristic conifers of the Kholokhovchan Flora, are described: Cupressaceae gen. et sp. indet. cf. Widdringtonites sp., Taxodium cf. olrikii, Taxodium sp., Glyptostrobus sp., Ettingshausenia vetviensis sp. nov. and Parvileguminophyllum penzhinense sp. nov.

Diverse Flowering Plant Pollen Found in Albian Cretaceous China

Palynology of the Early Cretaceous Hanxia Section in the Jiuquan Basin, Northwest China: The discovery of diverse early angiosperm pollen and paleoclimatic significance

Authors:

Zhang et al

Abstract:

The Lower Cretaceous deposits of the Jiuquan Basin (Northwestern China) located in central Asia are famous for the abundant and diverse fossil products with distinct characteristics of Jehol Biota. However, few early angiosperm remains have been published in their entirety. This study presents a palynomorph record from the recently reported fossil-bearing Zhonggou Formation of the Hanxia Section in the Jiuquan Basin. Here, we first discovered abundant and diverse angiosperm pollen with 16 taxa, which can be classified into four morphological types: tricolpate, polyaperturate, monosulcate and etrachotomocolpate apertures. The palynomorph assemblages contain a large number of biostratigraphically significant palynomorphs, such as numerically abundant tricolpate and rare polyaperturate angiosperm pollen grains, which indicate an Early Albian age for the Zhonggou Formation of the Hanxia Section. The overall palynomorph assemblage is dominated by the Perinopollenites, followed by the Classopollis; bisaccate pollen indicate Taxodiaceae-dominant vegetation types. As such, a relatively temperate and humid climatic condition is suggested for this area. Furthermore, two palynomorph assemblages can be distinguished in a stratigraphically upward order with an obviously increasing Classopollis content, indicating a gradual aridification trend during the Early Albian. This climatic change may affect the diversification of early angiosperms based on the correlation with the stratigraphic distribution of discovered angiosperm pollen.

Montsechia vidalii: Earliest Known Flowering Planet Discovered in Hautervian Cretaceous Spain

Indiana University paleobotanist David Dilcher and colleagues in Europe have identified a 125 million- to 130 million-year-old freshwater plant as one of earliest flowering plants on Earth.

The finding, reported Aug. 17 in the Proceedings of the National Academy of Sciences, represents a major change in the presumed form of one of the planet's earliest flowers, known as angiosperms.

"This discovery raises significant questions about the early evolutionary history of flowering plants, as well as the role of these plants in the evolution of other plant and animal life," said Dilcher, an emeritus professor in the IU Bloomington College of Arts and Sciences' Department of Geological Sciences.

The aquatic plant, Montsechia vidalii, once grew abundantly in freshwater lakes in what are now mountainous regions in Spain. Fossils of the plant were first discovered more than 100 years ago in the limestone deposits of the Iberian Range in central Spain and in the Montsec Range of the Pyrenees, near the country's border with France.

Also previously proposed as one of the earliest flowers is Archaefructus sinensis, an aquatic plant found in China.

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Upper Maastrichtian Cretaceous Riparian Forest was Surprisingly Modern

A riparian plant community from the upper Maastrichtian of the Pyrenees (Catalonia, NE Spain)

Authors:

Marmi et al

Abstract:

Angiosperms began to colonise riparian habitats very soon in their evolutionary history, probably already in the Aptian, but it is still poorly known when flowering plants finally dominated entirely these kind of communities as they do in the present. A new fossil plant locality (Molí del Baró-1) from the upper Maastrichtian of the Southern Pyrenees is described in which meandering river facies represent one of the first riparian communities formed only by angiosperms. The fossil assemblage consists of abundant leaves, seeds, logs and sporomorphs. Angiosperms remains dominate in all these cases and the leaf sample is mostly composed of a new eudicot willow-like species, Saliciphyllum gaetei sp. nov., the palm Sabalites longirhachis and an helophytic monocot. Pollen remains suggest that the later belonged to Typhaceae. Most of these plant remains were parautochthonous and deposited in a pond formed in the accretional part of a meander loop. The locality of Molí del Baró-1 represents an unique plant fossil assemblage in the uppermost Cretaceous of southern Europe. It clearly differs from those reported in other Maastrichtian localities of the Pyrenees (Fumanya and South Isona) and from the Campanian-Maastrichtian of Austria and Romania. In addition, it reflects a surprisingly modern physiognomy for a Late Cretaceous riverine plant assemblage that was built up with willow-like plants, palms and reeds.

Euanthus paniigen: a Perfect Jurassic Flower Proving Angoisperms Much Older Than Thought

A perfect flower from the Jurassic of China

Authors:

Liu et al

Abstract:

Flower, enclosed ovule and tetrasporangiate anther are three major characters distinguishing angiosperms from other seed plants. Morphologically, typical flowers are characterised by an organisation with gynoecium and androecium surrounded by corolla and calyx. Theoretically, flowers are derived from their counterparts in ancient ancestral gymnosperms. However, as for when, how and from which groups, there is no consensus among botanists yet. Although angiosperm-like pollen and angiosperms have been claimed in the Triassic and Jurassic, typical flowers with the aforesaid three key characters are still missing in the pre-Cretaceous age, making many interpretations of flower evolution tentative. Thus searching for flower in the pre-Cretaceous has been a tantalising task for palaeobotanists for a long time. Here, we report a typical flower, Euanthus paniigen. et sp. nov., from the Middle–Late Jurassic of Liaoning, China. Euanthus has sepals, petals, androecium with tetrasporangiate dithecate anthers and gynoecium with enclosed ovules, organised just like in perfect flowers of extant angiosperms. The discovery of Euanthus implies that typical angiosperm flowers have already been in place in the Jurassic, and provides a new insight unavailable otherwise for the evolution of flowers.

The Preferred Habitat of the Earliest Angiosperms

Leaf energy balance modelling as a tool to infer habitat preference in the early angiosperms

Authors:

Lee et al

Abstract:

Despite more than a century of research, some key aspects of habitat preference and ecology of the earliest angiosperms remain poorly constrained. Proposed growth ecology has varied from opportunistic weedy species growing in full sun to slow-growing species limited to the shaded understorey of gymnosperm forests. Evidence suggests that the earliest angiosperms possessed low transpiration rates: gas exchange rates for extant basal angiosperms are low, as are the reconstructed gas exchange rates for the oldest known angiosperm leaf fossils. Leaves with low transpirational capacity are vulnerable to overheating in full sun, favouring the hypothesis that early angiosperms were limited to the shaded understorey. Here, modelled leaf temperatures are used to examine the thermal tolerance of some of the earliest angiosperms. Our results indicate that small leaf size could have mitigated the low transpirational cooling capacity of many early angiosperms, enabling many species to survive in full sun. We propose that during the earliest phases of the angiosperm leaf record, angiosperms may not have been limited to the understorey, and that some species were able to compete with ferns and gymnosperms in both shaded and sunny habitats, especially in the absence of competition from more rapidly growing and transpiring advanced lineages of angiosperms.

Molecular Clock Suggests Angiosperms Diverged in the Middle to Late Jurassic

Resolution of deep angiosperm phylogeny using conserved nuclear genes and estimates of early divergence times

Authors:

Zeng et al

Abstract:

Angiosperms are the most successful plants and support human livelihood and ecosystems. Angiosperm phylogeny is the foundation of studies of gene function and phenotypic evolution, divergence time estimation and biogeography. The relationship of the five divergent groups of the Mesangiospermae (~99.95% of extant angiosperms) remains uncertain, with multiple hypotheses reported in the literature. Here transcriptome data sets are obtained from 26 species lacking sequenced genomes, representing each of the five groups: eudicots, monocots, magnoliids, Chloranthaceae and Ceratophyllaceae. Phylogenetic analyses using 59 carefully selected low-copy nuclear genes resulted in highly supported relationships: sisterhood of eudicots and a clade containing Chloranthaceae and Ceratophyllaceae, with magnoliids being the next sister group, followed by monocots. Our topology allows a re-examination of the evolutionary patterns of 110 morphological characters. The molecular clock estimates of Mesangiospermae diversification during the late to middle Jurassic correspond well to the origins of some insects, which may have been a factor facilitating early angiosperm radiation.

Cenomanian Cretaceous Paleobotany Fossils From Italy

Cretaceous conifers and angiosperms from the Bonarelli Level; Reassessment of Massalongo's plant fossil collections of “Monte Colle”, Lessini Mountains, northern Italy

Authors:

Gomez et al

Abstract:

The lost plant fossil and fish locality of “Monte Colle”, near the village of Bolca, Verona province, northern Italy has been considered to be of Eocene age since the middle of the nineteenth century. However, upon re-examination of the plant fossils, especially the specimens of Aularthrophyton Massalongo, which closely resemble the fossil conifer Frenelopsis Schenk, led us to suspect that a Cretaceous age was more probable. Fieldwork to re-evaluate the local stratigraphy, and the identification of the radiolarians Crucella cachensis Pessagno and Patellula helios (Squinabol) within the matrix of surviving hand specimens, all definitively show that the fossil bed actually belongs to the uppermost Cenomanian Bonarelli Level. With this revised age, we properly describe the gross morphology of the surviving plant specimens and reinterpret their identifications and affinities. Frenelopsis petraepurae comb. nov., Geinitzia sp., and a single angiosperm leaf type are described and the consequences for nomenclature outlined. Comparisons with coeval Cretaceous plant taxa are also discussed.

Did the Breakup of Pangea Drive the Evolution of Angiosperms During the Cretaceous?

Tectonic-driven climate change and the diversification of angiosperms

Authors

Chaboureau et al

Abstract:

In 1879, Charles Darwin characterized the sudden and unexplained rise of angiosperms during the Cretaceous as an “abominable mystery.” The diversification of this clade marked the beginning of a rapid transition among Mesozoic ecosystems and floras formerly dominated by ferns, conifers, and cycads. Although the role of environmental factors has been suggested [Coiffard C, Gómez B (2012) Geol Acta 10(2):181–188], Cretaceous global climate change has barely been considered as a contributor to angiosperm radiation, and focus was put on biotic factors to explain this transition. Here we use a fully coupled climate model driven by Mesozoic paleogeographic maps to quantify and discuss the impact of continental drift on angiosperm expansion and diversification. We show that the decrease of desertic belts between the Triassic and the Cretaceous and the subsequent onset of long-lasting humid conditions during the Late Cretaceous were driven by the breakup of Pangea and were contemporaneous with the first rise of angiosperm diversification. Positioning angiosperm-bearing fossil sites on our paleobioclimatic maps shows a strong match between the location of fossil-rich outcrops and temperate humid zones, indicating that climate change from arid to temperate dominance may have set the stage for the ecological expansion of flowering plants.

Dung Beetles Probably did NOT Feed on Dinosaur Droppings

The evolution of scarab beetles tracks the sequential rise of angiosperms and mammals

Authors:

Ahrens et al

Abstract:

Extant terrestrial biodiversity arguably is driven by the evolutionary success of angiosperm plants, but the evolutionary mechanisms and timescales of angiosperm-dependent radiations remain poorly understood. The Scarabaeoidea is a diverse lineage of predominantly plant- and dung-feeding beetles. Here, we present a phylogenetic analysis of Scarabaeoidea based on four DNA markers for a taxonomically comprehensive set of specimens and link it to recently described fossil evidence. The phylogeny strongly supports multiple origins of coprophagy, phytophagy and anthophagy. The ingroup-based fossil calibration of the tree widely confirmed a Jurassic origin of the Scarabaeoidea crown group. The crown groups of phytophagous lineages began to radiate first (Pleurostict scarabs: 108 Ma; Glaphyridae between 101 Ma), followed by the later diversification of coprophagous lineages (crown-group age Scarabaeinae: 76 Ma; Aphodiinae: 50 Ma). Pollen feeding arose even later, at maximally 62 Ma in the oldest anthophagous lineage. The clear time lag between the origins of herbivores and coprophages suggests an evolutionary path driven by the angiosperms that first favoured the herbivore fauna (mammals and insects) followed by the secondary radiation of the dung feeders. This finding makes it less likely that extant dung beetle lineages initially fed on dinosaur excrements, as often hypothesized.

Seven Angiosperm Pollen Species Recovered From Barremian/Aptian North China & Their Implications

The palynoflora of the Lower Cretaceous strata of the Yingen-Ejinaqi Basin in North China and their implications for the evolution of early angiosperms

Authors:

Zhang et al

Abstract:

A total of 41 spore species and 63 pollen taxa, including seven angiosperms, were identified from 24 samples of the Early Cretaceous succession (latest Barremian to Aptian) at the Wulan Section in the east part of the Yingen-Ejinaqi Basin, Inner Mongolia, China. In a stratigraphically upward order, three types of palynomorph assemblages were identified. Palynological assemblage I (PA I) was dominated by bisaccate pollen, whereas palynological assemblages II (PA II) and III (PA III) were characterised by abundant Classpollis associated with more spores. PA III contained the highest spore content. Angiosperm pollen display an increasing trend in diversity and abundance from PA I to PA III. PA I is most likely correlated to the Chinese Cretaceous palynofloral Transitional Zone and northern Disacciatrileti – Cicatricosisporites Province, whereas the assemblages II and III represent the transitional zone. The composition of these assemblages suggests that the climate was cool and humid within the basin during the latest Barremian, subsequently warmer and drier during the Early Aptian and, finally, became slightly wetter and warmer during the Late Aptian. Early angiosperm pollen occur frequently in this section, including that of Clavatipollenites, Asteropollis and Songipollis. On the stratigraphical order, these angiosperm pollen show a clear and continuous increase regarding the relative abundance and diversity of angiosperm, which most likely reflects the incipient dispersion of angiosperm plants during the latest Barremian to Late Aptian in inner East Asia. Lastly, a comprehensive compilation of published literature indicates that the emergence and evolution of early Asteropollis was not simultaneously worldwide, most likely occurring earlier in Eurasia than in other regions with a dramatic increase in both diversity and abundance prior to the emergence of tricolpate pollen.

Did Cretaceous Mammals Become Less Diverse Because of the Angiosperm Radiation?

Mammal disparity decreases during the Cretaceous angiosperm radiation

Authors:

David M. Grossnickle and P. David Polly

Abstract:

Fossil discoveries over the past 30 years have radically transformed traditional views of Mesozoic mammal evolution. In addition, recent research provides a more detailed account of the Cretaceous diversification of flowering plants. Here, we examine patterns of morphological disparity and functional morphology associated with diet in early mammals. Two analyses were performed: (i) an examination of diversity based on functional dental type rather than higher-level taxonomy, and (ii) a morphometric analysis of jaws, which made use of modern analogues, to assess changes in mammalian morphological and dietary disparity. Results demonstrate a decline in diversity of molar types during the mid-Cretaceous as abundances of triconodonts, symmetrodonts, docodonts and eupantotherians diminished. Multituberculates experience a turnover in functional molar types during the mid-Cretaceous and a shift towards plant-dominated diets during the late Late Cretaceous. Although therians undergo a taxonomic expansion coinciding with the angiosperm radiation, they display small body sizes and a low level of morphological disparity, suggesting an evolutionary shift favouring small insectivores. It is concluded that during the mid-Cretaceous, the period of rapid angiosperm radiation, mammals experienced both a decrease in morphological disparity and a functional shift in dietary morphology that were probably related to changing ecosystems.