Fossil Flowers Research Articles

First indisputable fossil Ilex (Aquifoliales: Aquifoliaceae) flower found in Baltic amber.

The genus Ilex (holly) in the monotypic family Aquifoliaceae contains more than 600 species distributed worldwide. Pollen fossils and macrofossils of fruits of Ilex are known from the late Cretaceous (90Ma) and verified leaves from the upper Miocene (10Ma), but until now only a few more or less incomplete flower fossils have been suggested as referable to this genus. This paper reviews the fossil flowers earlier attributed to Ilex and presents a complete and indisputable staminate Ilex flower from Baltic amber (34-38Ma) examined in detail with synchrotron X-ray tomography. This finding may challenge the hypothesis of late Neogene dispersal of the genus from a center of origin in subtropical East Asia.

Flower Buds Confirmed in the Early Cretaceous of China.

The Yixian Formation (Lower Cretaceous) in China is famous worldwide for its fossils of early angiosperms, but there has been only one record of flower buds (Archaebuda lingyuanensis) hitherto, in which only the surface of the flower bud was documented while no internal details were known. Such a partial knowledge of flower buds hinders our understanding of the evolution of flowers, and this knowledge lacuna needs to be filled. Our new specimen was collected from an outcrop of the Yixian Formation (Barremian-Aptian, Lower Cretaceous) near Dawangzhangzi, Lingyuan, Liaoning, China. Our observations reveal a new fossil flower bud, Archaebuda cretaceae sp. nov., from the Lower Cretaceous of China. This new record of Archaebuda in the Yixian Formation not only confirms the truthful existence of the expected gynoecium (plus possible androecium) in a flower bud but also underscores the occurrence of typical flowers in the Early Cretaceous. This new information adds first-hand data to flower sexuality, pollination, and evolution.

The earliest large carpenter bee (Xylocopa) and its adhering pollen (Araliaceae, Theaceae)

AbstractThe association of pollinators with their host plants is a critical element of ecosystem functioning and one that is usually determined indirectly in the fossil record from specific morphological traits of flowers or putative pollinating animals. The exceptionally fine preservation at Messel, Germany, offers an excellent source of data on pollen from fossil flowers as well as preserved adhering to insects as direct evidence of their association with specific floral lineages. Here, we report on pollen recovered from the body and legs of a large carpenter bee (Apidae: Xylocopinae: Xylocopini) from the Eocene of Messel. The fossil is the earliest occurrence of the tribe Xylocopini and represents an extinct subgenus and species, described as Xylocopa (Apocolyx) primigenia subgen. et sp. nov. Two eudicot pollen types were recovered from the bee, one of the family Theaceae (Asterids: Ericales) and another of Araliaceae (Euasterids: Apiales). The pollen grains are compared with various extinct and extant pollen types, and data on floral visitors to modern theaceous and araliaceous flowers are explored in relation to understanding the association of the fossil carpenter with these floral types in the paratropical Eocene biota of Messel.

The Cretaceous diversification of angiosperms: perspectives from mesofossils

Abstract The plant fossil record during the Cretaceous documents a major transition in the dominant group of terrestrial autotrophs, as plant communities from the earlier Mesozoic were transformed by the appearance and rapid diversification of angiosperms. This transformation began in the Early Cretaceous, continued through the Late Cretaceous and led ultimately to the dominance of angiosperms in most terrestrial ecosystems today, which had profound consequences for the other organisms inhabiting terrestrial ecosystems and perhaps the planet as a whole. Our understanding of angiosperm diversification has been greatly improved over the past 50 years by integrated studies of fossil assemblages containing angiosperm pollen and leaves, but especially by new information from mesofossil floras that have provided previously unanticipated detail on floral form in Cretaceous angiosperms and have allowed the recognition of key dispersed pollen types in situ . Information from fossil flowers has greatly facilitated meaningful comparisons with living plants and integration with phylogenetic analyses of extant angiosperms based on DNA evidence. The combined insights from these discoveries provide a broadly consistent and coherent picture of angiosperm evolution through the Cretaceous, which comprises more than half of their entire evolutionary history.

A new extinct member of the resin producer group of the Mexican amber: Hymenaeaphyllum mirandae n. gen. n. sp. (Detarioideae-Leguminosae)

One of the most important amber deposits with bioinclusion outcrops in Chiapas, southern Mexico, dated ca. 23–15 Ma (early–middle Miocene). Angiosperms (flowering plants) are the most frequently recorded group, with ca. 16 families based principally on fossil flowers and occasional leaves, including members of Leguminosae. This study reports new bifoliolate-compound leaves preserved in Mexican amber, represented by a pair of leaflets marginally attached to a short petiole. Each leaflet is ovate to oblong with an entire margin and has an acuminate apex with a pinnate primary vein. Their characteristics are comparable with bifoliate compound leaves of extant members of Cercidoideae, Caesalpinioideae, and Detarioideae subfamilies. Their asymmetrical base, brochidodromous secondary veins, and abundant translucid glands allow establishment of a new extinct resin-producing member of the Hymenaea clade (Detarieae, Detarioideae), Hymenaeaphyllum mirandae n. gen. n. sp. Hymenaea clade includes Guibourtia, Hymenaea, and Peltogyne, all with similar foliar architecture and other plant characteristics, including reproductive structures. The connection of Hymenaeaphyllum mirandae with extinct members of resin-producing plants recognized previously is uncertain. The discovery of Hymenaeaphyllum mirandae in the Mexican amber suggests that the Boreotropical Flora extended to low latitudes of North America during the Miocene.

First flower inclusion and fossil evidence of Cryptocarya (Laurales, Lauraceae) from Miocene amber of Zhangpu (China)

Lauraceae have one of the oldest fossil records of angiosperms with the earliest known evidence from the mid-Cretaceous. However, most of these records are based on leaves, especially from the Cenozoic of Asia, which are often challenging to assign to extinct or extant genera or species. In contrast, fossils of reproductive organs are more informative, but remain scarce. We here described the first Cenozoic Lauraceae flower of Asia and confirmed the presence of Cryptocarya in the Miocene Zhangpu flora (Fujian Province, south-eastern China) based on an amber inclusion. We scanned the specimen using synchrotron radiation-based micro-computed tomography (SRμCT) and then compared the fossil with extant flowers of the genus. The present fossil flower is small, bisexual, and polysymmetric, with a whorled and trimerous perianth and androecium along with a hypanthium around the gynoecium. The perianth comprises six undifferentiated tepals, the androecium consists of nine stamens and three innermost staminodes, and the gynoecium of a single carpel with a superior, unilocular (and uniovulate) ovary. Our study also shows that the fossil shares an unusual position of the typical staminal glands and a short androecial tube on the rim of the hypanthium with at least one extant Australian species of Cryptocarya, which have not been reported before. Nowadays, Lauraceae are still present in tropical to subtropical regions, mostly in American and Asian rainforests. The discovery of many Lauraceae leaf fossils in Zhangpu, as well as the amber flower of this study, is consistent with the current reconstruction of the amber source environment as a megathermal seasonal rainforest during the Mid-Miocene.

Angiosperm flowers reached their highest morphological diversity early in their evolutionary history.

Flowers are the complex and highly diverse reproductive structures of angiosperms. Because of their role in sexual reproduction, the evolution of flowers is tightly linked to angiosperm speciation and diversification. Accordingly, the quantification of floral morphological diversity (disparity) among angiosperm subgroups and through time may give important insights into the evolutionary history of angiosperms as a whole. Based on a comprehensive dataset focusing on 30 characters describing floral structure across angiosperms, we used 1201 extant and 121 fossil flowers to measure floral disparity and explore patterns of floral evolution through time and across lineages. We found that angiosperms reached their highest floral disparity in the Early Cretaceous. However, decreasing disparity toward the present likely has not precluded the innovation of other complex traits at other morphological levels, which likely played a key role in the outstanding angiosperm species richness. Angiosperms occupy specific regions of the theoretical morphospace, indicating that only a portion of the possible floral trait combinations is observed in nature. The ANA grade, the magnoliids, and the early-eudicot grade occupy large areas of the morphospace (higher disparity), whereas nested groups occupy narrower regions (lower disparity).

Reinterpretation of the mid-Cretaceous fossil flower Endobeuthos paleosum as a capitular, unisexual inflorescence of Proteaceae

Reinterpretation of the mid-Cretaceous fossil flower Endobeuthos paleosum as a capitular, unisexual inflorescence of Proteaceae

First buckthorn (Rhamnaceae) fossil flowers from India

AbstractFossil leaves, fruits, and woods assigned to Rhamnaceae have been recorded from India, however, there are no previous reports of rhamnaceous fossil flowers from India. Here, we report the first fossil flowers in appreciable numbers from the early Eocene (Palana Formation) sedimentary sequences of Gurha Lignite Mine, Rajasthan, western India, and show that they are attributable to Rhamnaceae. We examined variation in flower morphology among extant and extinct rhamnaceous species as a basis for interpreting our fossil flowers. The specimens are small star‐like, pentamerous, actinomorphic, gamosepalous flowers with triangular, keeled sepals with acute apices, spathulate, short‐clawed petals alternating with sepals, shallow, five‐lobed nectary disc with prominent pentagonal outer margin, and a centrally placed globose ovary with stigma scar. The flowers co‐occur with ziziphoid leaves and are recognized as a new species Eopaliura indica Patel, Rana & Khan sp. nov. Because of aforesaid characteristics, fossil flowers are easily identifiable as Rhamnaceae and should provide a reliable means of documenting the evolutionary history of this family during the Cenozoic.

Potential pollinators and paleoecological aspects of Eocene Ludwigia (Onagraceae) from Eckfeld, Germany

Paleogene flower-insect interactions and paleo-pollination processes are, in general, poorly understood and fossil evidence for such floral and faunal interactions are rarely reported. To shed light on angiosperm flower-insect interactions, we investigated several hundred fossil flowers and insects from the middle Eocene Fossil Lagerstätte of Eckfeld, Germany. During our work, we discovered a unique fossil Ludwigia flower (bud) with in situ pollen. The ecological preferences (climate, biome, habitat, etc.) of extant Ludwigia and the paleoecological configurations of the fossil plant assemblage support the taxonomic affiliation of the flower bud and an Eocene presence of Ludwigia in the vicinity of the former Lake Eckfeld. Today’s Ludwigia are mostly pollinated by Hymenoptera (bees). Therefore, we screened all currently known hymenopteran fossils from Eckfeld but found no Ludwigia pollen adhering to any of the specimens. On the contrary, we discovered Ludwigia pollen adhering to two different groups of Coleoptera (beetles). Our study suggests that during the Eocene of Europe, Ludwigia flowers were visited and probably pollinated by beetles and over time there was a shift in primary flower visitors/pollinators, from beetles to bees, sometime during the late Paleogene to Neogene.

Parrotiaflower blooming in Miocene rainforest

AbstractParrotiaC. A. Meyer (Hamamelidaceae) is a relictual genus with only two extant species disjunctly distributed in the subtropical forests of East China and temperate forests of North Iran. Fossil records suggest thatParrotiawas widespread in Europe and Asia during the Miocene, but its fossils are predominantly based on pollen and leaves. In this paper we describe the first fossil flower ofParrotiabased on an exceptionally well‐preserved amber inclusion from the middle Miocene of Zhangpu, Southeast China. The fossil flower was investigated with light microscope and microcomputed tomography techniques.Parrotia zhiyaniisp. nov. is a small apetalous staminate flower subtended by a pair of prominent bracts. The androecium consists of 12 stamens, and each stamen consists of a short, slender filament and a prominent, elongated anther. The anthers with short simple trichomes on the outer surface and a prominent apical connective extension are opened by longitudinal slits. Unlike its living relatives, the newParrotiafrom Zhangpu grew in a Miocene seasonal tropical rainforest.

Inclusions of flowers of Podopterus (Polygonaceae) in the Miocene amber of Simojovel de Allende, Chiapas, Mexico

Background and Aims: The Miocene amber from Chiapas, Mexico, shows high diversity of biological inclusions such as plants, fungi, arthropods, and vertebrates, being one of the most important amber-bearing areas worldwide. The aim of this work is to describe a new record based on four bisexual flowers belonging to the fossil species Podopterus mijangosae, that has been described recently based on its winged fruits only.Methods: The morphological and anatomical characteristics of the four fossil flowers were observed using a binocular stereoscopic microscope. The taxonomic affinity was decided by consulting specialized literature, as well as the review of herbarium material of the genera Podopterus, Fallopia, and Neomillspaughia of Polygonaceae.Key results: The four fossil specimens are bisexual, small, and have actinomorphic flowers, with differentiated perianth, three petals and three sepals per series, stamens are free and with thread-like filaments, anthers are dithecal and basifixed, the ovary is superior, syncarpous, 3-angular, with three free styles, and capitate stigmas. Conclusions: This new report of flowers of Podopterus adds more evidence that the family Polygonaceae was an important component of the tropical forest of Simojovel de Allende, Chiapas, Mexico, during the Miocene.

Winged Fruits of Friisifructus aligeri gen. et sp. nov. from the Late Cretaceous of Western North America

Premise of research. Fossil flowers and fruits with unresolved affinities among extant angiosperms may potentially represent extinct families or orders. The characterization and systematic assessments of such fossils will undoubtedly further our understanding of extinct angiosperm diversity, which is crucial for reconstructing the evolution of angiosperms in deep time. Here, we report two three-dimensionally preserved winged fruits from Campanian (∼82–80 Ma) deposits on Sucia Island, Washington State, that represent a new genus. We explore potential phylogenetic relationships of this genus relative to higher taxa across the angiosperm phylogeny.Methodology. The fossils were studied using microcomputed tomography (μCT) scanning and light microscopy. A three-dimensional reconstruction of one winged fruit was created from the μCT scans. The phyloscan method was used to assess the systematic positions of the winged fruits. Using the reconstruction, the fossil fruits were compared to extant angiosperms and extinct winged fruits to assess potential affinities.Pivotal results. The μCT scans and reconstruction of the winged fruit reveal a pentamerous perianth, five pairs of fin-wings, two whorls of persistent stamens, five semicircular nectary pads, an inferior unilocular ovary, and a style with three stylar branches. Phyloscan analyses recover the winged fruits within the rosid clade, but they cannot be assigned to any extant family or order within the group because of differing floral and fruit morphologies.Conclusions. The winged fruits are assigned to Friisifructus aligeri gen. et sp. nov. This new genus and species add to the diversity of winged fruits from the Cretaceous, which are relatively uncommon. Moreover, the unique morphology of Friisifructus indicates that this genus may belong to an extinct family of rosids.

Integrating Fossil Flowers into the Angiosperm Phylogeny Using Molecular and Morphological Evidence.

Fossils are essential to infer past evolutionary processes. The assignment of fossils to extant clades has traditionally relied on morphological similarity and on apomorphies shared with extant taxa. The use of explicit phylogenetic analyses to establish fossil affinities has so far remained limited. In this study, we built a comprehensive framework to investigate the phylogenetic placement of 24 exceptionally preserved fossil flowers. For this, we assembled a new species-level data set of 30 floral traits for 1201 extant species that were sampled to capture the stem and crown nodes of all angiosperm families. We explored multiple analytical approaches to integrate the fossils into the phylogeny, including different phylogenetic estimation methods, topological-constrained analyses, and combining molecular and morphological data of extant and fossil species. Our results were widely consistent across approaches and showed minor differences in the support of fossils at different phylogenetic positions. The placement of some fossils agrees with previously suggested relationships, but for others, a new placement is inferred. We also identified fossils that are well supported within particular extant families, whereas others showed high phylogenetic uncertainty. Finally, we present recommendations for future analyses combining molecular and morphological evidence, regarding the selection of fossils and appropriate methodologies, and provide some perspectives on how to integrate fossils into the investigation of divergence times and the temporal evolution of morphological traits. [Angiosperms; fossil flowers; phylogenetic uncertainty; RoguePlots.].

New Fossil Evidence Suggests That Angiosperms Flourished in the Middle Jurassic

Angiosperms are a group of plants with the highest rate of evolution, the largest number of species, the widest distribution and the strongest adaptability. Needless to say, angiosperms are the most important group for the humans. The studies on the origin, evolution and systematics of angiosperms have been the major challenges in plant sciences. However, the origin and early history of angiosperms remains poorly understood and controversial among paleobotanists. Some paleobotanists insist that there were no angiosperms in the pre-Cretaceous age. However, this conclusion is facing increasing challenges from fossil evidence, especially Early Jurassic Nanjinganthus, which is based on over two hundred specimens of fossil flowers. Studying more fossil plants is the only reliable way to elucidate the origin and early evolution of angiosperms. Here, we document a new species of angiosperms, Qingganninginfructus formosa gen. et sp. nov, and provide the first detailed three-dimensional morphology of Qingganninginfructus gen. nov from the Middle Jurassic of Northwest China. A Micro-CT examination shows that the best-preserved fossil infructescence has eleven samaroid fruits, each with a single basal ovule. Since these fossils are distinct in morphology and organization from all organs of known gymnosperms and angiosperms (the latter are defined by their enclosed ovules), we interpret Qingganninginfructus as a new genus of angiosperms including a new species, Q. formosa gen. et sp. nov., and an unspecified species from the Middle Jurassic of Northwest China. The discovery of this new genus of angiosperms from the Middle Jurassic, in addition to the existing records, undermines the "no angiosperms until the Cretaceous" stereotype and updates the perspective on the origin and early history of angiosperms.

Description and systematic affinity of flower and seed fossils of Erica sect. Chlorocodon (Ericaceae) from the early Pleistocene of Madeira Island, Portugal

AbstractPalaearctic Erica sect. Chlorocodon, known as the wind‐pollinated besom heaths (WPBH), includes the Macaronesian E. azorica, E. platycodon subsp. platycodon and E. platycodon subsp. maderincola together with the Mediterranean and North African E. scoparia. Despite the broad extant distribution, the mainland fossil record of this section is scarce and poorly preserved and dated, and Macaronesian fossils were so far unknown. Here we discuss the systematic affinities of the first fossils of a WPBH found in Macaronesia, within a 1.3 Ma (Pleistocene, Calabrian stage) Madeira Island fossiliferous deposit. One flower and dissociated seed fossils were found in the same sediment layer, being preserved as coalified compressions with cuticular preservation. Both the flower and seed fossils present unique WPBH characters. The flower fossil is characterised by an exserted, peltate and discoid stigma – an unequivocal adaptation to anemophily, unique within Palaearctic Erica taxa. The seed fossils are of small size, presenting a testa with channelled anticlinal cell‐walls, a characteristic only found in the extant Macaronesian WPBH. Morphological, anatomical, and biometric comparisons of the fossils to extant flowers and seeds suggest that the fossils are related to the Palaearctic E. sect. Chlorocodon, being morphologically close to E. azorica. Here we assign them to E. aff. azorica. These findings suggest a colonisation to Madeira Island prior to 1.3 Ma, corresponding to the oldest and unambiguous WPBH fossils, at least 0.90–1.2 Ma older than the oldest known record. The fossil flower also indicates the presence of anemophilous traits since at least the early Pleistocene. Finally, the presence of a WPBH could suggest the same ecological role in seral communities, important to the establishment of the Madeiran temperate stink‐laurel forest.

First Fossil Mallow Flower from Asia

Premise of research. Malvaceae, or the mallows, are well known from the Cenozoic sediments of Asia and are represented by many fossil leaves, woods, fruits, and pollen. Until now, no fossil flower of Malvaceae has been reported from the Cenozoic sediments of Asia. The present study addresses this lacuna and documents the evidence of mallow fossil flowers from Asia for the first time.Methodology. Fossil flowers similar to modern flowers of Bombax L. (Malvaceae) were recovered from the latest Neogene (Pliocene) sediments of Chotanagpur Plateau, Jharkhand, eastern India. They were revealed by careful removal of the overlying matrix and studied under light microscopy.Pivotal results. The fossil flowers, characterized by irregularly lobed sepals, obovate-elliptic petals, numerous stamens bearing long filaments, and characteristic reniform anthers, are recognized as a new species, Bombax asiatica Hazra, Bera et Khan sp. nov. A morphological principal coordinates analysis and cladistic parsimony analysis based on floral morphological characters support this taxonomic assignment.Conclusions. This fossil evidence provides an important clue about the past diversity and paleobiogeography of the mallow family in the Indian Cenozoic. This finding and earlier reported Malvaceae fossils from the same locality also indicate the presence of tropical climate in Jharkhand, eastern India, during the time of deposition.

The largest amber-preserved flower revisited

Amber exquisitely preserves the delicate organs of fossil flowers for millions of years. However, flower inclusions can be rare and usually do not exceed 10 mm in size. Here we report an exceptionally large flower from late Eocene Baltic amber, measuring 28 mm across, which is about three times as large as most floral inclusions. This fossil was described over 150 years ago as Stewartia kowalewskii (Theaceae) and has never been revised. The analysis of pollen extracted from the anthers of the flower inclusion, however, revealed strong affinities to Asian species of Symplocos (Symplocaceae), prompting the new combination Symplocos kowalewskii comb. nov. et emend. This fossil represents the first record of Symplocaceae from Baltic amber and supports affinities of its flora to evergreen broadleaved and mixed mesophytic forests of present-day East and Southeast Asia. The rarity of such large-sized flower inclusions is likely due to the size of the resin outpouring and its properties, which might affect the embedding of plant organs.

REPORT OF A BICARPELLARY FLOWER FROM THE DECCAN INTERTRAPPEAN SERIES OF MOHGAONKALAN, INDIA.

The present flower from its oblique transverse section appears to be the smaller in size among the flowers reported from the Deccan Intertrappean series. It is 1.00 X 1.22 mm in diameter. Swollen at middle and tapering at its ends indicate its companulate shape. The flower is actinomorphic, hermaphrodite, pentamerous and hypogynous. The perianth lobes are ten in numbers arranged in two whorls of 5+5 each. The outer whorl contains five tepals may be termed as calyx while the inner five may be as corolla. Stamens are five in number, polyandrous giving pentamerous appearance to the flower. Pollen grains are tricolpate and psilate without any external outgrowth. The anther is basifixed. Gynoecium is bicarpellary, syncarpous with superior, bilocular ovary. Each locule contains single ovule in it with axile placentation. Ovary wall is multilayered and smooth. The present flower is totally different from the reported fossil flowers and living genera of modern families. Hence it is kept under separate form genus Mohgaoanthus deccanii gen. et sp. nov.

Review of flowers and inflorescences with in situ pollen from the Miocene Foulden and Hindon Konservat-Lagerstätten, southern New Zealand

Well-preserved flowers of Miocene age containing anthers and in situ pollen are exceptionally rare in the fossil record of the Southern Hemisphere. A review of the 70 or so flowers/inflorescences from the 23 Ma Foulden Maar diatomite and the 15 Ma carbonaceous mudstones of the Hindon Maar Complex reveals a wide range of morphological features including petals, stamens and anthers with in situ pollen. The flowers range in size from 2 to 23 mm and vary in shape from generalist dish-bowl, to tubular or bell-shaped. The association of these flowers with previously described dispersed pollen provides crucial new data on source plants. The range of taxa represented by flowers include Alstroemeriaceae (Luzuriaga), a palm (Arecaceae), Akaniaceae (Akania), Araliaceae (Pseudopanax), cf. Cunoniaceae, Elaeocarpaceae, Euphorbiaceae, Loranthaceae, Meliaceae (‘Dysoxylum’), Monimiaceae (Hedycarya), Onagraceae and Rutaceae and other, as yet unidentified taxa. Some, such as Fuchsia and Hedycarya, represent the only definite fossil flowers for their respective families. Although all these fossil species are extinct, about half of the families have living relatives in New Zealand, while relatives of other locally extinct taxa now occur in eastern Australia and New Caledonia. Some genera also provide links to South America (e.g., Fuchsia). Consistent with evidence from leaves, the flowers indicate a mesothermal rainforest flora that occupied the fertile basaltic soils surrounding the small maar lakes. Overall, the flowers are remarkably similar to their modern-day relatives suggesting that floral size, structure and pollination syndromes have changed little since the Miocene.