scholarly journals Early Angiosperm Diversification: The Diversity of Pollen Associated with Angiosperm Reproductive Structures in Early Cretaceous Floras from Portugal

1999 ◽  
Vol 86 (2) ◽  
pp. 259 ◽  
Author(s):  
Else Marie Friis ◽  
Kaj Raunsgaard Pedersen ◽  
Peter R. Crane
Keyword(s):  
Early Cretaceous ◽  
Reproductive Structures ◽  
Early Angiosperm ◽  
Angiosperm Diversification

scholarly journals Angiosperm diversification in the Early Cretaceous of Primorye, Far East of Russia

2021 ◽  
Vol 77 (2) ◽  
pp. 231-255
Author(s):  
Lina Golovneva ◽  
Eugenia Bugdaeva ◽  
Elena Volynets ◽  
Yuewu Sun ◽  
Anastasia Zolina
Keyword(s):  
New Species ◽  
Early Cretaceous ◽  
Far East ◽  
New Combination ◽  
Far East Of Russia ◽  
Primorye Region ◽  
Early Angiosperm ◽  
Angiosperm Diversification ◽  
Icp Ms ◽  
Lipovtsy Formation

The Partizansk and Razdolnaya coal basins of Primorye, Far East of Russia, contain diverse early angiosperm fossils (pollen, leaves, and fruits). In this paper, we revise the previous data on early angiosperms of this region and summarize the results of our latest research. Age of the plant-bearing deposits was clarified using isotopic U-Th-Pb LA-ICP-MS and U-Pb ID-TIMS methods. Age of the upper part of the Lipovtsy Formation is 118 ± 1.4 Ma, which corresponds to the late Aptian. The early Albian age (109 ± 1 Ma) is assigned to the upper part of the Frentsevka Formation. The diversification of angiosperms in the Early Cretaceous of Primorye region and their systematic affinity are analyzed. Early representatives of Laurales, Ranunculales, Platanaceae, and probable Cercidiphyllaceae are revealed. New combination Pandanites ahnertii (Krysht.) Golovn., comb. nov. is created, and new species Araliaephyllum vittenburgii Golovn. et Volynets, sp. nov. is described. Reconstructions of herbaceous angiosperms from autochthonous locality Bolshoy Kuvshin are proposed.

scholarly journals Paleobiology of early angiosperms: evidence from sedimentological associations in the Early Cretaceous Potomac Group of the eastern U.S.A.

1992 ◽  
Vol 6 ◽  
pp. 128-128 ◽  
Author(s):  
Leo J. Hickey ◽  
David W. Taylor
Keyword(s):  
Early Cretaceous ◽  
Flood Plain ◽  
Perennial Herb ◽  
Silty Clay ◽  
Stratigraphic Sequence ◽  
Phylogenetic Studies ◽  
Early Angiosperm ◽  
Angiosperm Diversification ◽  
Distal Direction ◽  
Important Evidence

Lately, we proposed a hypothesis that the ancestral angiosperm was a diminutive, rhizomatous to scrambling perennial herb with small simple flowers. Our phylogenetic studies suggest that arborescent to shrubby magnolialians with large, multiparted, complex flowers are derived, rather ancestral as commonly thought. We suggest that the early angiosperm, due to its rhizomatous habit, would have been able to survive in more ephemeral habitats. A test of this idea would be to examine the sedimentological context of early angiosperms.Despite a number of reports of early angiosperm megafossils from Barremian to middle Albian (mid- to late Early Cretaceous) age sediments, only the Potomac Group of the eastern U.S.A. has provided a stratigraphic sequence of early angiosperm diversification. Furthermore, study of this sequence has also linked observations on floristic assemblages to the lithofacies in which they occur, leading Doyle and Hickey to report an ecological expansion of early angiosperms from relatively near-channel environments to a much broader range of flood plain sites during the Barremian/Aptin to latest Albian/early Cenomanian interval represented by Potomac Group deposition. From this those authors inferred that the early angiosperms were “riparian weeds” that grew on moderately unstable, near-channel sites subject to periodic flooding and episodes of alluviation.We recently expanded on these inferences by examining the sedimentology of Dutch Gap, an early angiosperm site at the earliest level of the Potomac Group (Barremain/Aptian-Pollen Zone I) near Richmond, VA. Sediments here appear to represent the meander belt of a fluvial setting. A series of multi-storied channel units at the site are filled with arkosic, medium to coarse, sub-angular sand with pebble- to boulder-size clasts of gneiss, claystone and mudstone concentrated at channel bases, reactivation surfaces, and on lateral accretion surfaces. These channels are cut into inferred levee and splay deposits that consist of thin interbeds of sand and silt alternating with dark grey, micaceous mudstone to claystone. This sequence fines in an inferred distal direction from the channels and the mudstone/claystone interbeds thicken at the expense of the coarser units until they coalesce into relatively thick, dark grey clay beds with only thin silty laminae. These beds are thought to represent floodbasin deposits.The megafossil plants recovered from our studies at Dutch Gap exhibit a clear pattern of association with each other and with these lithofacies. Angiosperms (Celastrophyllum, Rogersia, and an unnamed new form) together with ferns are found in relatively silty interbeds that lie in what appear to be distal levee settings, while the backswamp was dominated by the bennittitalean Dioonites buchianus. Conifers of diverse kinds are dominant only in pinkish, silty clay clasts that are inferred to have been transported from drier flood-plain environments.This study provides added evidence of an association between early angiosperms and moderately unstable, channel-margin sites and, in addition, calls attention to the potential that detailed sedimentological investigations have of providing important evidence on early angiosperm paleoecology.

scholarly journals Fossil evidence for low gas exchange capacities for Early Cretaceous angiosperm leaves

Paleobiology ◽  
2011 ◽  
Vol 37 (2) ◽  
pp. 195-213 ◽  
Author(s):  
Taylor S. Feild ◽  
Garland R. Upchurch ◽  
David S. Chatelet ◽  
Timothy J. Brodribb ◽  
Kunsiri C. Grubbs ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Early Cretaceous ◽  
Leaf Gas Exchange ◽  
Exchange Capacity ◽  
Basal Angiosperm ◽  
Photosynthetic Gas Exchange ◽  
Angiosperm Evolution ◽  
Early Angiosperm ◽  
Fossil Evidence ◽  
Functional Analyses

The photosynthetic gas exchange capacities of early angiosperms remain enigmatic. Nevertheless, many hypotheses about the causes of early angiosperm success and how angiosperms influenced Mesozoic ecosystem function hinge on understanding the maximum capacity for early angiosperm metabolism. We applied structure-functional analyses of leaf veins and stomatal pore geometry to determine the hydraulic and diffusive gas exchange capacities of Early Cretaceous fossil leaves. All of the late Aptian—early Albian angiosperms measured possessed low vein density and low maximal stomatal pore area, indicating low leaf gas exchange capacities in comparison to modern ecologically dominant angiosperms. Gas exchange capacities for Early Cretaceous angiosperms were equivalent or lower than ferns and gymnosperms. Fossil leaf taxa from Aptian to Paleocene sediments previously identified as putative stem-lineages to Austrobaileyales and Chloranthales had the same gas exchange capacities and possibly leaf water relations of their living relatives. Our results provide fossil evidence for the hypothesis that high leaf gas exchange capacity is a derived feature of later angiosperm evolution. In addition, the leaf gas exchange functions of austrobaileyoid and chloranthoid fossils support the hypothesis that comparative research on the biology of living basal angiosperm lineages reveals genuine signals of Early Cretaceous angiosperm ecophysiology.

Phylogenies and angiosperm diversification

Paleobiology ◽  
1993 ◽  
Vol 19 (2) ◽  
pp. 141-167 ◽  
Author(s):  
James A. Doyle ◽  
Michael J. Donoghue
Keyword(s):  
Early Cretaceous ◽  
Phylogenetic Trees ◽  
Sister Group ◽  
Late Triassic ◽  
Tectonic Activity ◽  
Crown Group ◽  
Extrinsic Factors ◽  
Angiosperm Diversification ◽  
Stem Lineage ◽  
Cladistic Analyses

Approaches to patterns of diversification based on counting taxa at a given rank can be misleading, even when all taxa are monophyletic. Such “rank-based” approaches are unable to reflect a hierarchy of evolutionary events because taxa of the same rank cannot be nested within one another. Phylogenetic trees specify an order of origination of characters and clades and can therefore be used in some cases to test hypotheses on causal relationships between characters and changes in diversity. “Tree-thinking” also clarifies discussions of the age of groups, by distinguishing between splitting of the stem-lineage from its sister group and splitting of the crown-group into extant clades.Cladistic evidence that Pentoxylon, Bennettitales, and Gnetales are the sister group of angiosperms implies that the angiosperm line (angiophytes) existed by the Late Triassic. The presence of primitive members of five basic angiosperm clades indicates that the crown-group (angiosperms) had begun to diversify by the mid-Early Cretaceous (Barremian-Aptian), but not necessarily much earlier. The greatest unresolved issue raised by cladistic analyses concerns the fact that the angiosperm tree can be rooted in two almost equally parsimonious positions. Trees rooted near Magnoliales (among “woody magnoliids”) suggest that the angiosperm radiation may have been triggered by the origin of intrinsic traits, e.g., a fast-growing, rhizomatous habit in the paleoherb and eudicot subgroup. However, trees rooted among paleoherbs, which are favored by rRNA data, imply that these traits are basic for angiosperms as a whole. This could mean that the crown-group originated not long before its radiation, or, if it did originate earlier, that its radiation was delayed due to extrinsic factors. Such factors could be a trend from environmental homogeneity and stability in the Jurassic to renewed tectonic activity and disturbance in the Early Cretaceous. Potentially relevant pre-Cretaceous fossils cannot be placed with confidence, but may be located along the stem-lineage (stem angiophytes); their generally paleoherb-like features favor the paleoherb rooting. The history of angiophytes may parallel that of Gnetales: some diversification of the stem-lineage in the Late Triassic, near disappearance in the Jurassic, and vigorous radiation of the crown-group in the Early Cretaceous.

scholarly journals Diversity in obscurity: fossil flowers and the early history of angiosperms

2010 ◽  
Vol 365 (1539) ◽  
pp. 369-382 ◽  
Author(s):  
Else Marie Friis ◽  
Kaj Raunsgaard Pedersen ◽  
Peter R. Crane
Keyword(s):  
Early Cretaceous ◽  
Phylogenetic Diversity ◽  
Rapid Development ◽  
Distinct Pattern ◽  
Fossil Plants ◽  
Early Angiosperm ◽  
Early Diversification ◽  
History Of ◽  
Fossil Flowers ◽  
Ecological Dominance

In the second half of the nineteenth century, pioneering discoveries of rich assemblages of fossil plants from the Cretaceous resulted in considerable interest in the first appearance of angiosperms in the geological record. Darwin's famous comment, which labelled the ‘rapid development’ of angiosperms an ‘abominable mystery’, dates from this time. Darwin and his contemporaries were puzzled by the relatively late, seemingly sudden and geographically widespread appearance of modern-looking angiosperms in Late Cretaceous floras. Today, the early diversification of angiosperms seems much less ‘rapid’. Angiosperms were clearly present in the Early Cretaceous, 20–30 Myr before they attained the level of ecological dominance reflected in some mid-Cretaceous floras, and angiosperm leaves and pollen show a distinct pattern of steadily increasing diversity and complexity through this interval. Early angiosperm fossil flowers show a similar orderly diversification and also provide detailed insights into the changing reproductive biology and phylogenetic diversity of angiosperms from the Early Cretaceous. In addition, newly discovered fossil flowers indicate considerable, previously unrecognized, cryptic diversity among the earliest angiosperms known from the fossil record. Lineages that today have an herbaceous or shrubby habit were well represented. Monocotyledons, which have previously been difficult to recognize among assemblages of early fossil angiosperms, were also diverse and prominent in many Early Cretaceous ecosystems.

scholarly journals Some Conifers from The Early Cretaceous (Late Aptian – Early Albian) of Catefica, Lusitanian Basin, Western Portugal

2018 ◽  
Vol 74 (3-4) ◽  
pp. 317-326 ◽  
Author(s):  
Mário Miguel Mendes ◽  
Mário Pedro Dinis ◽  
Jiří Kvaček
Keyword(s):  
Early Cretaceous ◽  
Early Angiosperm ◽  
Lusitanian Basin

Several mesofossil floras discovered in the Early Cretaceous rocks from the Lusitanian Basin of western Portugal comprise numerous well-preserved conifer remains. Here we report the occurrence of four conifer types in the mesofossil flora from the Catefi ca locality, about 4 km south of Torres Vedras in the Estremadura region on the western Portuguese Basin. The specimens were recovered from rocks belonging to the Almargem Formation, interpreted to be of late Aptian - early Albian age. It includes three Cheirolepidiaceae genera Frenelopsis SCHENK, Pseudofrenelopsis NATH. and Watsoniocladus V.SRINIV., and one conifer twig of Pagiophyllum-type. These conifers, which co-occurred in the same depositional bed with a well-diversified early angiosperm assemblage including flowers, seeds, fruits and dispersed stamens with pollen in situ, provide new insights into Early Cretaceous palaeoecology.

scholarly journals Geminispermum, an Early Cretaceous (early–middle Albian) cupulate unit from the angiosperm-dominated Puddledock flora of eastern North America

2019 ◽  
Vol 59 (2) ◽  
pp. 229-239 ◽  
Author(s):  
Else Marie Friis ◽  
Peter R. Crane ◽  
Kaj Raunsgaard Pedersen
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
New Genus ◽  
Eastern North America ◽  
Seed Plant ◽  
New Genus And Species ◽  
Reproductive Structures ◽  
Short Transverse ◽  
Reproductive Unit ◽  
The One

Abstract A new genus and species, Geminispermum virginiense, is described based on a well-preserved coalified cupulate reproductive unit recovered from the Early Cretaceous (early–middle Albian) Puddledock locality, Virginia, U.S.A. The reproductive unit is bisymmetrical and consists of an axis that bifurcates into two cupule-bearing stalks, each in the axil of a bract. Each cupule stalk bears a single non-valvate cupule recurved towards the center of the reproductive unit. The cupule opens distally by a short transverse slit with a distinct upper margin. Each cupule almost completely encloses a single orthotropous seed that is free from the cupule except at the base. The nucellus is also free from the integument except at the basal point of attachment. Geminispermum combines features of the ovulate structures of Caytoniales, Umkomasiales (= Corystospermales, including Doyleales) and Petriellales, but cannot be included in any of these existing orders as they are currently understood. The recurved, closed, non-valvate cupules are particularly similar to those of Caytonia, Petriellaea and Reymanownaea in external morphology, but differ in being one-seeded. The cupules of Geminispermum differ from the one-seeded cupules of Umkomasiales in being non-valvate and in having only a single cupule per bract. Geminispermum is perhaps most similar to the one- or two-seeded non-valvate cupules of Ktalenia from the Early Cretaceous of Argentina, but Ktalenia is poorly preserved, details of cupule architecture are uncertain, and the cupules appear to be associated with a single strongly dissected bract. Geminispermum is currently the only unequivocal seed plant cupule recovered from the Early Cretaceous Potomac Group and is distinct from all previously described cupulate reproductive structures.

Woody or not woody? Evidence for early angiosperm habit from the Early Cretaceous fossil wood record of Europe

Palaeoworld ◽  
2008 ◽  
Vol 17 (2) ◽  
pp. 142-152 ◽  
Author(s):  
Marc Philippe ◽  
Bernard Gomez ◽  
Vincent Girard ◽  
Clément Coiffard ◽  
Véronique Daviero-Gomez ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Fossil Wood ◽  
Early Angiosperm

High-precision U–Pb zircon age from the Anfiteatro de Ticó Formation: Implications for the timing of the early angiosperm diversification in Patagonia

2013 ◽  
Vol 48 ◽  
pp. 97-105 ◽  
Author(s):  
Valeria S. Perez Loinaze ◽  
Ezequiel I. Vera ◽  
Mauro G. Passalia ◽  
Magdalena Llorens ◽  
Richard Friedman ◽  
...  
Keyword(s):  
High Precision ◽  
Zircon Age ◽  
Early Angiosperm ◽  
Angiosperm Diversification

scholarly journals The Early Cretaceous Mesofossil Flora of Torres Vedras (Ne of Forte Da Forca), Portugal: A Palaeofloristic Analysis of an Early Angiosperm Community

2019 ◽  
Vol 75 (2) ◽  
pp. 153-257 ◽  
Author(s):  
Else Marie Friis ◽  
Peter R. Crane ◽  
Kaj Raunsgaard Pedersen
Keyword(s):  
New Species ◽  
Early Cretaceous ◽  
New Genera ◽  
Early Angiosperm ◽  
Palynological Study

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.

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