Early Cretaceous Flora Research Articles

New record of Brachyoxylon wood from the Lower Cretaceous of Qingyuan, southeastern China and its palaeoclimatic implications

Early Cretaceous was a key period for the evolution of terrestrial ecosystems. In southeastern China, the late Early Cretaceous (Aptian–Albian) floras are relatively well known and characterized by diverse Cheirolepidiaceae, but the early Early Cretaceous floras in southeastern China are poorly known mainly because of the lack of plant fossils. Here we report petrified woods from a new early Early Cretaceous locality in Qingyuan, southern Zhejiang Province, southeastern China. The new fossil woods collected from the Xishantou Formation (earliest Berriasian, earliest Early Cretaceous) are assigned to Brachyoxylon zhejiangense Tian, Zhu, and Wang based on the anatomy of the secondary xylem. The new material of Brachyoxylon zhejiangense from Qingyuan lacks distinct growth rings or resin canals and has mixed type pitting on the radial walls of the tracheids, araucarioid cross-field pitting, and uniseriate rays. It is the earliest record of Brachyoxylon in southeastern China. Brachyoxylon zhejiangense has been regarded as the wood of the extinct conifer family Cheirolepidiceae and grew in arid to semi-arid environments. Evidence also suggests Cheirolepidiaceae played an important role in the vegetation of southeastern China throughout the Early Cretaceous.

Pseudofrenelopsis dinisii, a new species of the extinct conifer family Cheirolepidiaceae from the probable lower Hauterivian (Cretaceous) of western Portugal

The Cheirolepidiaceae are an extinct family of conifers that was highly diverse during the Mesozoic, particularly at lower latitudes. Cheirolepidiaceous remains assigned to the genera Frenelopsis and Pseudofrenelopsis are very common in the Early Cretaceous floras of Portugal. A new species Pseudofrenelopsis dinisii is described from the Lower Cretaceous sediments (probably lower Hauterivian) of the Santa Susana Formation, at the Vale Cortiço site in the Lusitanian Basin of western Portugal. The new taxon is described based on morphology of the vegetative shoots and cuticular features. Pseudofrenelopsis dinisii consists of leafy shoots with spirally arranged leaves with an attenuate apex that enclose the stem, while leaves of the Brachyphyllum type occur on terminal shoots. The leaf margins bear well-developed trichomes; the stomatal apparatus is deeply sunken and strengthened by papillae, and the cuticle is moderately thick. Like other frenelopsids, P. dinisii displays these and other typically xeromorphic features, but although many other frenelopsids are associated with independent evidence for arid or saline conditions, the palynoflora from the bed with P. dinisii is rich in spores and shows no evidence of marine influence. Pseudofrenelopsis dinisii may represent the non-arid and non-saline end of the wide spectrum of environments occupied by Cheirolepidiaceae; its xeromorphic features may be adaptations to occasional periods of strong water stress. Comparisons with other sequences suggest a trend in the ecological preferences of both Pseudofrenelopsis and Frenelopsis from alluvial and upper deltaic environments before the Albian to saline coastal environments in the Albian and Cenomanian.

Albian ferns of the Partizansk Coal Basin (Primorsky Krai, Russian Far East)

A taxonomic study of Albian ferns from the Partizansk Coal Basin of Primorsky Krai was carried out. The Albian Age was an important stratigraphic milestone, when the Early Cretaceous flora changed to the Late Cretaceous flora. It was revealed that typical Mesozoic Onychiopsis predominated in taphocenoses, and representatives of young and evolutionarily advanced taxa Asplenium, Birisia appeared. The taxonomic composition of ferns in the Albian taphocenoses was almost constant from north to south. The vegetation of the Partizansk Basin occupied the coastal plain during Albian time, which was confirmed by the remains of marine and freshwater mollusks, phytofossils, as well as fish.

First evidence of ranunculids in Early Cretaceous tropics

Early Cretaceous floras containing angiosperms were described from several geographic areas, nearly from the Arctic to the Antarctic, and are crucial to understand their evolution and radiation. However, most of these records come from northern mid-latitudes whereas those of lower paleolatitude areas, such as the Crato Fossil Lagerstätte in NE Brazil, are less studied. Here, we describe from this region of northern Gondwanan origin, two fossil-species of eudicots belonging to a new extinct genus Santaniella gen. nov. Together with several vegetative axes and leaves, anatomically well-preserved fruits with seeds and persistent perianth-like organs allowed us to reconstruct its potential affinities with ranunculids, and presumably Ranunculaceae. Previous records putatively assigned to Ranunculales are all from mid-latitudes, and their first unequivocal occurrence in a low-latitude area supports further the hypothesis of a widespread radiation of the earliest diverging eudicot lineage by this early age.

Cenomanian diatoms (Bacillariophyta) from the Teshio-Nakagawa area, Hokkaido, northern Japan

Diatoms are one of the most important eukaryotic primary producers in the lower ecosystem; understanding their evolutionary history is therefore also important. Throughout most of the Cenozoic hydrosphere, diatoms have flourished. However, as a result of progressive diagenesis and dissolution of the opaline silica that forms their frustules, their early evolution during the Cretaceous is unclear, so the fossil record is incomplete. Largely because of this poor fossil record, little is known about the mid-Cretaceous interval (Cenomanian to Turonian). This study presents a new fossil record of Cenomanian opaline diatoms in carbonate concretions hosting ammonites from Hokkaido in the northwestern Pacific Ocean. Primitive floral assemblages composed of dominantly cylindrical or discoid forms are associated with a few hemiaulid diatoms, one of the predominant taxa since the Campanian age. The Cenomanian diatoms are similar to late Early Cretaceous (Albian) flora reported mainly from the Southern Hemisphere, but given their association with a few taxa typical of the Late Cretaceous, they are somewhat transitional.

First cockroaches (Insecta: Blattaria: Blattulidae) from the Lower Cretaceous Sinuiju Formation, Democratic People's Republic of Korea: Associated fossil plant assemblages and paleoclimatic inferences

Several cockroach specimens were recovered from the Sinuiju Formation in Paektho-dong, Sinuiju City, North Phyongan Province, Democratic People's Republic of Korea (DPRK). These specimens belong to Habroblattula drepanoides Wang, Liang et Ren, 2007. Fossil plant assemblages also recovered from the Sinuiju Formation are typical of Early Cretaceous floras from warm to temperature regions.

A new species of conifer wood Brachyoxylon from the Cretaceous of Eastern China and its paleoclimate significance

ABSTRACT A new species of conifer wood, Brachyoxylon zhoui sp. nov., is described from the Lower Cretaceous Guantou Formation of Zhejiang Province, eastern China. The new species is characterised by a mixed type of radial tracheary pitting, araucarioid cross-field pitting, high uniseriate rays, and the occurrence of traumatic resin canals. The new finding represents the second species of Brachyoxylon from the Guantou Formation and it contributes to the further understanding of the forest composition of the Early Cretaceous flora in eastern China.The quantitative analysis of growth ring anatomy indicates that the forest composition was evergreen with a Leaf Retention Time (LRT) of 3–15 years. It is deduced that the Zhejiang Province was dominated by a subtropical to tropical and relatively semiarid climate during the Early Cretaceous.

Plant fossils from the Wealden facies (Lower Cretaceous, Berriasian) of Tecklenburg, Westphalia, Germany

While the Early Cretaceous flora of the English Wealden has been extensively revised in the last decades, the flora from the German Wealden is still in need of thorough revision. One major account on a flora from Duingen in the eastern Lower Saxony Basin (Niedersächsisches Becken) has been published a couple of years ago, but was covering freshly collected fossil material only. Here, a small flora from the southern margin of the Lower Saxony Basin is reported coming from Brochter-beck, a district of Tecklenburg, at the northern slopes of the Teutoburger Wald mountain range in Westphalia, Germany. The flora shows a slightly different composition compared to those of the 'classical' German Wealden: it is also characterised by remains of several delicate filmy ferns and cupressoid (taxodiaceous) conifers, but it is dominated by the presence of leaves of Nilssonia schaumburgensis, while other cycadophytes such as cycads and bennettites are entirely absent. One leaf reminiscent of a Ginkgo species was found as well. The relatively fine-grained sandstones of the rocks comprising the flora at Brochterbeck reflect a terrestrial deposit of the Wealden facies, which was deposited under deltaic freshwater conditions in brackish–limnic conditions in a humid, subtropical climate.

Preliminary Study of Flora from the Upper Lower Cretaceous Dalazi Formation in Luozigou Basin, Wangqing, Jilin Province, Northeast China

In the middle Cretaceous vegetation changed rapidly for the diversification of angiosperms, there are few extensive analyses of the plant fossils (including leaves, fruits, seeds and woods) from this period in China. New abundant fossil plants collected from the upper Lower Cretaceous Dalazi Formation in the Luozigou Basin, Wangqing, Jilin Province were studied and 25 species belonging to 17 genera were recognized. Up to date totally 39 species belonging to 25 genera were discovered in the Luozigou Basin. The assemblage is composed mainly of conifers (47.5%) and early angiosperms (30%) and indicates that the vegetation was a transitional flora between the Early Cretaceous fern-gymnosperm flora and the Late Cretaceous angiosperm flora. The flora was a Pseudofrenelopsis-angiosperm assemblage in succession of Early Cretaceous flora and the late Early Cretaceous, probable Albian in age. During the late Early Cretaceous, the Luozigou Basin was dominated by hot and arid climate and sometimes probably interrupted by wet climate.

A new species of Platanus from the Cenomanian (Upper Cretaceous) in eastern Heilongjiang, China

The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province, China, have been ambiguous and controversial, mainly due to a lack of biostratigraphically useful fossils and related radiometric dating. A new species of angiospermous fossil plant, Platanus heilongjiangensis sp. nov., from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U–Pb radiometric methods as 96.2 ± 1.7 Ma, indicating that the Upper Houshigou Formation is of Cenomanian age. This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation, but also shows that Platanus flourished in the early Late Cretaceous floras of the region. This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.

Two New Conifers from the Early Cretaceous of the Rajmahal Basin, India: Implications on Palaeoecology and Palaeogeography

The occurrence of a diverse range of conifers and bennettitales is characteristic of the macroflora from the Early Cretaceous of the Rajmahal Basin, India. In the present paper two new conifer taxa assigned to the families Cupressaceae and Podocarpaceae are described from the intertrappean sediments of the Rajmahal Formation in Jharkhand State. The remains are silicified, composed of sterile and fertile shoots, detached leaves and dispersed seeds. The specimens have been placed under the family Cupressaceae, are described as Hirandubia cupressoides gen. et sp. nov., a species that shows close affinity with the extant cupressaceous genera Platycladus Spach and Chamaecyparis Spach, and provides the first comprehensive record of Cupressaceae from the Early Cretaceous of India. Elatocladus-type shoots and detached leaves have also been recovered. In association with the shoot fragments and detached leaves, a new kind of podocarpaceous dispersed seed designated as Podocarpospermum podocarpoides sp. nov., occurs together with a microsporangiate cone Podostrobus rajmahalensis (Rao) Rao and Bose, having in situ bisaccate pollen grains. These remains are all attributed to the family Podocarpaceae and have some similarities to extant Podocarpus L'Herit ex Pers. Based on the occurrence of a diverse range of conifers and bennettitales in the Early Cretaceous flora of Rajmahal Formation interpretation on palaeoecology and palaeogeography has been done.

Rightcania and Kvacekispermum: Early Cretaceous Seeds From Eastern North America and Portugal Provide Further Evidence of the Early Chloranthoid Diversification

Abundant flowers, fruits, seeds and stamens that are closely related to extant Chloranthaceae have been reported from the Early Cretaceous floras of Portugal. Among these are small berries with endotestal seeds assigned to the extinct genera Canrightia and Canrightiopsis. Here we describe two new genera, each including a single species, based on fossil fruits and seeds from the Early Cretaceous of eastern North America and Portugal. Both genera have pendent, orthotropous, bitegmic and endotestal ovules/seeds, in which the endotesta consists of a layer of cubic to palisade-shaped crystal cells with endoreticulate fibrous infillings, a combination of features that also characterize Canrightia and Canrightiopsis and that among extant angiosperms are known only for members of the Chloranthaceae. Rightcania kvacekii gen. et sp. nov. from the early to middle Albian Puddledock mesofossil flora of Virginia, USA, is the first representative in the Early Cretaceous floras of North America of a chloranthaceous fossil related to Canrightia and Canrightiopsis. It has three- to five-seeded fruits very similar to fruits and seeds of Canrightia, also with a pronounced tegmen that probably functioned as a nutritive tissue for the developing embryo. Fruits and seeds of Rightcania are larger than those of Canrightia, and also differ in details of the seed coat. Kvacekispermum rugosum gen. et sp. nov. is rare in the late Aptian to early Albian Portuguese mesofossil flora from Vale de Água. It differs from Canrightiopsis in the coarsely rugulate outer surface of the endotesta and its larger size, but is closely similar in the general structure of seed coat and nutritive tissue. Together, Rightcania and Kvacekispermum provide further evidence of the early diversity achieved by chloranthoid angiosperms before the end of the Early Cretaceous.

Charophytes from the Lower Cretaceous Xiagou Formation in the Jiuquan Basin (northwestern China) and their palaeogeographical significance

The charophyte flora from the Lower Cretaceous Xiagou Formation in the Jiuquan Basin, Gansu Province (Northwest China) was investigated, and a total of four species were recognized: Aclistochara huihuibaoensis, Mesochara stipitata, Sphaerochara verticillata and Clavator grovesii var. jiuquanensis. A synonymy is here proposed, i.e., Charites xiagouensis is newly combined to S. verticillata, which is dominant in the flora assemblage. The here-described charophyte assemblage has a high biostratigraphic interest suggesting an early Aptian age for the Xiagou Formation. A sedimentological analysis of the facies indicates that the Xiagou charophyte flora thrived in a shallow freshwater lake. As noticed by previous authors, the late Early Cretaceous flora from the Jiuquan Basin shows a reduced diversity comparing with those from the Central Tethyan Archipelago, where clavatoraceans originated and radiated. As previous studies showed, one of the five clavatoraceans with the greatest global biogeographical extension, C. grovesii var. jiuquanensis spread to the Jiuquan Basin in the early Aptian probably dispersed by the aquatic bird Gansus yumenensis.

Evidence of plant–insect interaction in the Early Cretaceous Flora from the Crato Formation, Araripe Basin, Northeast Brazil

The analysis of insect-plant interaction can be provide paleoecological and paleoenvironmental important data for understanding the co-evolution between plants and insects. Since the appearance of the first evidence of leaves damaged by insects, these organisms have evolved together. In the Araripe Basin, the Crato Formation stands out by having abundance and diversity of fossils species of plants and insects. In this work they are documented interaction records in specimens of ferns, gymnosperms and angiosperms, showing a wide variety of types of interactions. Here we analyze 56 fossil specimens from the collections of the Museum of Paleontology and the Laboratory of Paleontology of the Universidade Regional do Cariri. The types of damage identified in this study is insect galls, leaf margin feeding (herbivory), leaf mines, oviposition of insects and skeletonization, which are present in 19 specimens. This analysis in search for evidences of plant–insect interaction contributes with new interaction patterns for the Crato Formation. Although the low sample rate, the new registers for plant-insect association were compared to records from different cretaceous basins. This suggests new possibilities in the studies for ecological relations and coevolutionary plant-insect during the Cretaceous. In addition, a new type of damage is identified in a pteridophyte.

Early Cretaceous flora from the Pranhita-Godavari Basin (east coast of India): taxonomic, taphonomic and palaeoecological considerations

AbstractThe Early Cretaceous flora from the Gangapur Formation (Pranhita-Godavari Basin, east coast of India) was studied. Its plant diversity and abundance patterns were examined, and its palaeoecology and environment were interpreted, based on the micro- and macrofloras and sedimentological inputs. The flora is rich and diverse, and consists of bryophytes, pteridophytes, pteridosperms, gymnosperms and angiosperms. The microflora shows higher taxonomic diversity and abundance than the macroflora. Overall, the study indicated an abundance of conifers, particularly Podocarpaceae. The taphocoenosis of the flora comprises local to regional elements derived from riverbank, floodplain, backswamp and valley settings. Taken together, the data on the flora and sedimentology suggest that warm and humid environments prevailed.

Paisia, an Early Cretaceous eudicot angiosperm flower with pantoporate pollen from Portugal

A new fossil angiosperm, Paisia pantoporata, is described from the Early Cretaceous Catefica mesofossil flora, Portugal, based on coalified floral buds, flowers and isolated floral structures. The flowers are actinomorphic and structurally bisexual with a single whorl of five fleshy tepals, a single whorl of five stamens and a single whorl of five carpels. Tepals, stamens and carpels are opposite, arranged on the same radii and tepals are involute at the base clasping the stamens. Stamens have a massive filament that grades without a joint into the anther. The anthers are dithecate and tetrasporangiate with extensive connective tissue between the tiny pollen sacs. Pollen grains are pantoporate and spiny. The carpels are free, apparently plicate, with many ovules borne in two rows along the ventral margins. Paisia pantoporata is the oldest known flower with pantoporate pollen. Similar pantoporate pollen was also recognised in the associated dispersed palynoflora. Paisia is interpreted as a possibly insect pollinated, herbaceous plant with low pollen production and low dispersal potential of the pollen. The systematic position of Paisia is uncertain and Paisia pantoporata most likely belongs to an extinct lineage. Pantoporate pollen occurs scattered among all major groups of angiosperms and a close match to the fossils has not been identified. The pentamerous floral organisation together with structure of stamen, pollen and carpel suggests a phylogenetic position close to the early diverging eudicot lineages, probably in the Ranunculales.

Fossil record of Ephedra in the Lower Cretaceous (Aptian), Argentina.

Fossil plants from the Lower Cretaceous (upper Aptian) of the La Cantera Formation, Argentina, are described. The fossils studied represent a leafy shooting system with several orders of articulated and striated axes and attached leaves with unequivocal ephedroid affinity. We also found associated remains of ovulate cones with four whorls of sterile bracts, which contain two female reproductive units (FRU). Ovulate cone characters fit well within the genus Ephedra. Special characters in the ovulate cones including an outer seed envelope with two types of trichomes, allowed us to consider our remains as a new Ephedra species. Abundant dispersed ephedroid pollen obtained from the macrofossil-bearing strata also confirms the abundance of Ephedraceae in the basin. The co-occurrence of abundant fossil of Ephedra (adapted to dry habitats) associated with thermophilic cheirolepideacean conifer pollen (Classopollis) in the unit would suggest marked seasonality at the locality during the Early Cretaceous. Furthermore, the floristic association is linked to dry sensitive rocks in the entire section. The macro- and microflora from San Luis Basin are similar in composition to several Early Cretaceous floras from the Northern Gondwana floristic province, but it may represent one of the southernmost records of an arid biome in South America.

Leaves of Podozamites and Pseudotorellia from the Early Cretaceous of Mongolia: stomatal patterns and implications for relationships

Strap-shaped, parallel-veined leaves of Podozamites and Pseudotorellia are among the most common fossils in Late Triassic to Early Cretaceous floras from the Northern Hemisphere. Podozamites is considered to be the leaf of a voltzian conifer, but its cuticle is poorly known, whereas Pseudotorellia, with a thick cuticle and haplocheilic stomata, is commonly considered to be the leaf of a ginkgoalean. Here we describe the leaf morphology, cuticle and stomata of Podozamites and Pseudotorellia based on excellently preserved material from the Early Cretaceous of central Mongolia. Podozamites harrisii sp. nov. has transversely oriented, paracytic (probably syndetocheilic) stomata that are regularly arranged in longitudinal files. Pseudotorellia resinosa sp. nov. and Pseudotorellia palustris sp. nov. have scattered, longitudinally oriented stomata in which the two guard cells are sunken and surrounded by 2–5 specialized lateral subsidiary cells and 1–3 unspecialized polar cells. Association evidence and similarities in cuticular structure suggest that Podozamites harrisii was produced by the same plant as the seed cone Krassilovia. The distinctive stomatal pattern of Podozamites harrisii and Krassilovia is also seen in some species of Swedenborgia and Cycadocarpidium, suggesting these plants may all belong to the same natural group. Cycadocarpidium, Krassilovia and Swedenborgia have previously been treated as conifers, but their transversely oriented, paracytic stomata hint instead at a possible relationship with Bennettitales and Gnetales.

Early Cretaceous flora of India- A review

Earth’s terrestrial ecosystem during the early Cretaceous was marked by the dominance of naked seeded plants and appearance of flowering plants. Tectonic changes and evolutionary processes affected southern floras of the globe during this time. Review of Indian early Cretaceous flora distributed in peri and intra–cratonic basins signify homogenity of composition with regional variations. The flora composed of pteridophytes, pteridospermaleans, pentoxylaleans, bennettitaleans, ginkgoaleans, coniferaleans, taxaleans and taxa of uncertain affinity along with sporadic occurrence of flowering plants represent a unique Indian Early Cretaceous flora. Similitude of basinal floras with marginal differences can be attributed to taphonomic limitations and taxonomic angularity. A perusal of available data brings out an opportunity for novelty in floral composition and variable associations dictated by prevailed environmental conditions. The eastern, western and central regions of India hold distinct litho units encompassing plant mega fossils represented by leaf, wood / axis, seed, fructification and associated marker forms. Remarkable tenacity of certain plant groups, which even found in modern flora and vulnerability of many taxa constitute a blend of extinct and extant. The appearance and extinction of certain taxa can be explained as a cumulative affect of evolutionary and climatic factors. Perpetuation of gondwanic floral elements during the early Cretaceous along with newly evolved floral components testifies evolutionary innovations and changing ecological constraints.

Krassiloviella limbelloides gen. et sp. nov.: Additional Diversity in the Hypnanaean Moss Family Tricostaceae (Valanginian, Vancouver Island, British Columbia)

Premise of research. Despite an increase in interest in the fossil record of bryophytes (i.e., liverworts, hornworts, and mosses), the biology and taxonomy of these organisms remain understudied and, at times, elusive. In the pre-Cenozoic, especially, few taxonomically informative moss fossils are known. From this perspective, the anatomically preserved Apple Bay flora of Vancouver Island holds a wealth of Cretaceous moss diversity that, until very recently, has remained unexplored.Methodology. Fossils are preserved anatomically in carbonate concretions and studied in serial sections prepared using the cellulose acetate peel technique.Pivotal results. Krassiloviella limbelloides gen. et sp. nov., defined by tricostate homocostate leaves and much-branched stems, is a new addition to the pleurocarpous moss family Tricostaceae (superorder Hypnanae).Conclusions. Krassiloviella limbelloides is the second bryophyte described as a result of ongoing studies of the Early Cretaceous Apple Bay flora of Vancouver Isl...