Santonian Early Campanian Research Articles

Late Mesozoic Tectono-stratigraphic evolution of the Hekimhan Basin and the environs (central eastern Anatolia): implications for the eastern Taurides and Gürün Curl

ABSTRACT The east-west trending Taurides form a curved area in central eastern Anatolia known as the Gürün Curl. In order to understand the origin of the Gürün Curl and Tauride evolution in general, the results of a new field study of this region have been synthesized together with previously published data. We suggest that the geodynamic evolution of the area began with the likely presence of a Tethys Ocean transform fault. This fault separated the Taurides into the Akdere Sector in the west and the Munzur Sector in the east in the Late Cretaceous. During the late Santonian–early Campanian, ophiolites obducted onto the Munzur Sector, while platform sediments continued to accumulate in the Akdere Sector. This was followed by the development of an Andean-type arc-type magmatism (the Baskil Arc) during the early–middle Campanian in the Munzur Sector. Continued closure of the Tethys led to the collision of the Bitlis Massif in the south of the Munzur Sector in the Campanian. This, in turn, resulted in continental subduction and slab roll-back that was controlled by a Subduction Transform Edge Propagator (STEP) Fault that lay on the original transform fault between the Akdere and Munzur sectors. Because the subducted slab was free at its western corner, the western edge rolled back faster than in the east, leading to an asymmetrical extensional regime on the upper plate that created the late Campanian Hekimhan Basin. While these geodynamic events were taking place in the Munzur Sector, the Akdere Sector was in a platform setting. During the Palaeocene, the Late Mesozoic units of the Akdere Sector began to overthrust on the Hekimhan Basin and the ophiolites. Following the Palaeocene, all these tectonostratigraphic units were covered by Eocene sediments around the Gürün Curl of which the modern appearance was completed by the Miocene to Recent movements along the strike-slip faults.

Correlation of the late Santonian-early Campanian of Texas, USA with the Anglo-Paris Basin (United Kingdom) and other regions

Correlation of the late Santonian-early Campanian of Texas, USA with the Anglo-Paris Basin (United Kingdom) and other regions

Novas ocorrências de moluscos das formações Santa Marta e Snow Hill Island (Membro Gamma), Cretáceo Superior, Ilha James Ross, Península Antártica

Although the fossil record from Antarctica is increasing continuously, there is still a great lack of knowledge regarding the past biodiversity of this continent. Here we present the first occurrences of the ammonoid Pseudophyllites? cf. latus in the Santa Marta Formation (Santonian-early Campanian) and the scaphopod Laevidentallium? sp. (Laevidentallidae) in the Gamma Member (late Campanian) of the Snow Hill Island Formation (late Campanian - early Maastrichtian). The presence of Laevidentalliidae in the Gamma Member characterizes the oldest occurrence of this family in Antarctica and it is apparently another taxon that originated in this continent and later migrated to lower latitudes.

Changes in biogeographic distribution patterns of southern mid-to high latitude planktonic foraminifera during the Late Cretaceous hot to cool greenhouse climate transition

The biogeographic distribution of planktonic foraminifera from southern mid-to high latitudes region are discussed to identify links between species distribution patterns and the changes in Late Cretaceous climate. We present relative abundance data for planktonic foraminifera spanning from the hot greenhouse climate of the Turonian to the cooler greenhouse of the Maastrichtian based on study of Ocean Drilling Program (ODP) holes 690C (Maud Rise), 700B (Northeast Georgia Rise), 1138A (Kerguelen Plateau) and 762C (Exmouth Plateau). These drill sites were located between 47° and 65°S paleolatitude in the southern South Atlantic and southern Indian Ocean where there is a good record of changes in vertical gradients and sea surface temperatures (SSTs) and shifts are well expressed due to amplification of global climatic variations in the circum-Antarctic region.The stratigraphic distribution of planktonic foraminiferal marker species that consistently occur at all sites enables construction of a new biozonation scheme that is applicable to the southern mid-to high latitude region. Quantitative data from planktonic foraminifera are used to examine variation in assemblage composition, permitting interpretation of changes in the patterns of surface water stratification. In addition, temporal biogeographic patterns are documented from the stratigraphic record of endemic species of the Southern Ocean and of species displaying poleward or equatorward migration.Results indicate that the broadest latitudinal expansion of the Tethyan tropical climatic belt coincided with the highest paleotemperatures of the Turonian–Santonian. The onset of significant sea surface temperature cooling in the late Santonian–early Campanian led to a progressive increase in the latitudinal temperature gradient and greater biogeographic differentiation among planktonic foraminiferal assemblages. These trends resulted in the establishment of a Transitional Bioprovince with Tethyan and Austral affinities in the southern latitudes that persisted through the Campanian and Maastrichtian and the development of a well-defined Austral Bioprovince that is observed by the early Maastrichtian at paleolatitudes south of 60°S.

Characteristics of Radiolarian Evolution in the Campanian and Maastrichtian and Prospects for Detailed Stratigraphy

The Campanian and Maastrichtian radiolarian assemblages are known from many regions of the Tethyan Superrealm. Unfortunately, only some of them are reliably dated and completely studied as paleontological assemblages. The analysis of evolution of radiolarians is based on Campanian to Maastrichtian assemblages from Crimea, Cyprus, and Serbia properly dated and studied in detail with addition of data from California, Turkey, the World Ocean, and other regions. It is concluded that renewal of assemblages took place in the Campanian and Maastrichtian relatively slowly. The biodiversity was slowly reduced at the generic level. The history of radiolarian evolution in the end of the Late Cretaceous can be subdivided to several stages: late Santonian–early Campanian, early Campanian–late Campanian, late Campanian–early Maastrichtian, and late Maastrichtian.

A Possible Phylogenetic Relationship of Two Species of Hyphantoceras (Ammonoidea, Nostoceratidae) in the Cretaceous Yezo Group, Northern Japan

A possible phylogenetic relationship of two species of Hyphantoceras (Ammonoidea, Nostoceratidae) was proposed, based on newly found specimens with precise stratigraphic occurrences in the Kotanbetsu and Obira areas, northwestern Hokkaido. Two closely related species, Hyphantoceras transitorium and H. orientale, were recognized in the examined specimens from the Kotanbetsu and Obira areas. Specimens of H. transitorium show wide intraspecific variation in the whorl shape. The stratigraphic occurrences of the two species indicate that they occur successively in the Santonian–lowermost Campanian, without stratigraphic overlapping. The similarity of their shell surface ornamentations and the stratigraphic relationships possibly suggest that H.orientale was derived from H. transitorium. The presumed lineage is likely indigenous to the northwestern Pacific realm in the Santonian–earliest Campanian. Hyphantoceras venustum and H. heteromorphum might stand outside a H. transitorium–H. orientale lineage, judging from differences of their shell surface ornamentation.

The genus Hausmannia (Dipteridaceae) in the Cretaceous of the North-East of Russia and its paleobiogeographic implications

The genus Hausmannia disappeared at end of the Early Cretaceous in most regions of the Earth, but in the North-East of Russia this genus was abundant during all the Late Cretaceous and even persisted into the Paleocene. In the Late Cretaceous the genus Hausmannia was represented by three endemic species: H. bipartita Samylina and Shczepetov (early Albian–Santonian), H. dublicato-crenata Samylina (Santonian–early Campanian) and H. olaensis Golovneva and Grabovskiy, sp. nov. (Santonian–early Campanian). A leaf fragment from the Paleocene Rarytkin Formation was determined only as Hausmannia sp. A high abundance of Hausmannia in the North-East of Russia was probably related with relict types of plant communities, dominated by Sphenobaiera, Baiera and Phoenicopsis, which survived in the highlands of the Okhotsk-Chukotka volcanic belt and its surroundings.

Late Santonian-early Campanian lake-level fluctuations in the Songliao Basin, NE China and their relationship to coeval eustatic changes

In contrast to glacio-eustasy, which is mainly controlled by the waxing and waning of continental ice sheets during icehouse climate stages, the concept of aquifer or limno-eustasy suggests that the effects of groundwater storage and release may have been the main driver of short-term (10s kyr to a few Myr) sea-level changes in the Cretaceous ice-free world. Presumably climate-controlled hydrological cycling could change the water volumes of continental reservoirs and oceans by transporting water between continents and oceans, resulting in out-of-phase relation between lake and sea levels.In the present study, we present lake-level fluctuations in Members 1 and 2 of the Nenjiang Formation (late Santonian-early Campanian) in the Songliao Basin that are indicated by basin-scale correlations of Fischer Plots based on natural gamma-ray logging data. Meanwhile, the Al/K ratios of the SK1 core indicate that changes in precipitation forced lake-level fluctuations in the basin. Compared to global sea-level changes, lake-level fluctuations show an out-of-phase relation with sea-level variations in the lacustrine phase of the basin, suggesting that climate-driven water transport between continents and oceans controlled short-term sea-level changes in the late Santonian-early Campanian. During the phase of marine-lake connectivity (basal Nenjiang Member 1), although the marine regression-driven decrease in lake-level corresponds to salinity stratification and strongly reducing water conditions, increasing precipitation in the basin implies that the hydrological cycle transported more water from the oceans toward continents. Based on the results we suggest that limno-eustasy controlled water levels in the Songliao basin in the late Santonian-early Campanian.

Late Cretaceous tectono-sedimentary events in NW Europe

Late Cretaceous sedimentary history has been strongly influenced by both sea-level fluctuations and inversion tectonics. Evidence for tectonic movements, originally identified in German Late Cretaceous basins, is applied to the UK successions. Two periods of movement are conspicuous: a Middle Turonian episode involving huge loss of section along anticlinal axes in southern England and a Late Santonian-Early Campanian episode also involving section loss on structure and section gain off structure. This pattern is repeated where folds or blocks are underlain by inversion thrust faults (e.g. the Purbeck Fault in Dorset, the Falmer Fault in Sussex, the Portsdown Fault in Hampshire and the Bray Fault in Upper Normandy). Other episodes of inversion in the Late Turonian to Middle Coniacian and the late Early Campanian are investigated and are a probable cause of slump beds and slides. These tecto-sedimentary episodes can be applied to structures in Northern Ireland, Inner Hebrides, North Sea and Yorkshire as well as southern Britain. Beyond NW Europe the Late Santonian – Early Campanian event is widely recognised in the Carpathians, southern Europe, Africa and the Levant and coincides with the end of the Long Cretaceous Quiet Zone (Chron 34N to 33R) perhaps representing a major change in Earth dynamics related to Mid-Ocean Ridge crustal production and intra-continental crust tectonism.

The Ammonite GenusGaudrycerasfrom the Santonian—Campanian of Antarctica: Systematics and Biostratigraphy

Abstract. Belying previous interpretations on its rarity in southern latitudes, Gaudryceras de Grossouvre is well represented in the Santonian—Campanian of Antarctica. The study of more than 300 specimens from the Santa Marta, Rabot and Snow Hill Island Formations designates five species that characterize four successive stratigraphic intervals: 1) Gaudryceras cf. G. strictum, Santonian, Alpha Member, lower part of the Santa Marta Formation; 2) Gaudryceras santamartense sp. nov., Santonian—early Campanian, Alpha Member, lower mid part of the Santa Marta Formation; 3) Gaudryceras brandyense sp. nov., late early Campanian—?basal mid Campanian, Beta Member, upper part of the Santa Marta Formation; and 4) Gaudryceras cf. G. mite and Gaudryceras rabotense sp. nov., mid Campanian—late Campanian, upper middle part of the Rabot Formation and lower part of the Hamilton Point Member of the Snow Hill Island Formation. There are two differently ornamented neanoconchs characterized by exhibiting dense or sparse strong...

Anurans (Amphibia: Anura) from the Upper Cretaceous (Santonian–lower Campanian) Bostobe Formation of Northeastern Aral Sea Region, Kazakhstan

The newly collected specimens from the Upper Cretaceous (Santonian–early Campanian) Bostobe Formation at the Shakh-Shakh locality in the Northeast Aral Sea Region, Kazakhstan, increase the diversity of anurans in this stratigraphic unit and now two taxa can be recognized there: gobiatid Gobiates sp. and large anuran Discoglossidae indet. The faunal association of gobiatids+discoglossids is characteristic for Cenomanian–Campanian vertebrate assemblages of Middle Asia and Kazakhstan. In the Late Cretaceous of Asia, large sized anurans appeared in the Cenomanian and became a common element of anuran assemblages from the Turonian onwards, earlier than in North America where large sized anurans began dominating assemblages in the late Campanian.

A new species of the genus Sequoiadendron Buchholz (Cupressaceae) from the Upper Cretaceous of the Enmyvaam River Basin, Central Chukotka

A new conifer species, Sequoiadendron tchucoticum A. Sokolova from the Emuneret Formation on the Enmyvaam River (Anadyr River Basin) is described. It is established based on a thorough study of the morphology and epidermal features of shoot impressions, using scanning electron microscopy. The new species has polymorphic shoots with helical branching and three main leaf types: scalelike, subulate, and falcate. Leaves are amphistomatic; amphicyclic stomata are mostly obliquely arranged; ordinary epidermal cells are rectangular, frequently with oblique end walls, and their length-to-width ratio reaches 15: 1. Shoots of the new species prevail among conifers of the Ust’-Emuneret Assemblage. The age of the deposits enclosing the assemblage is debated; according to the latest data, it is estimated as Santonian–Early Campanian.

Petroleum potential and kinetic models for hydrocarbon generation from the Upper Cretaceous to Paleogene Latrobe Group coals and shales in the Gippsland Basin, Australia

Pyrolysis experiments (open and closed systems) and kinetic modelling of primary cracking of kerogen have been carried out to investigate hydrocarbon generation characteristics and source rock facies variability within the Upper Cretaceous to Paleogene Latrobe Group in the Gippsland Basin. On the basis of Rock-Eval data, the interbedded coals, coaly shales and carbonaceous shales contain different types of kerogen (Type III, Type II–III, Type II) with variable potential for both gas and liquid hydrocarbon generation. Open system pyrolysis–gas chromatography data indicate that the organically lean marginal marine shales of the Santonian–early Campanian Tricolporites apoxyexinus and Nothofagidites senectus biozones produce gas and condensate. However, coal and coaly to carbonaceous shales sampled from the Paleocene Lygistepollenites balmei, Maastrichtian Forcipites longus, late Campanian Tricolporites lilliei and Turonian Phyllocladidites mawsonii palynological biozones are heterogeneous with the capacity to generate both low and high wax paraffinic–naphthenic–aromatic (P–N–A) oils, and paraffinic oils with a high wax content. The main phase of petroleum formation from these later biozones, assuming a constant geological heating rate of 3.3°C/Ma, is predicted to occur between 150–179°C, indicating different orders of kinetic stability as a result of different types of organic matter and their state of preservation. The thermally immature shales have variable bulk kinetic characteristics, but the measured compositional kinetics and phase behaviour show that they have the potential to generate black oils at early stages of kerogen cracking, and either light oils or wet gases at higher levels of thermal stress. These findings suggest that upon thermal maturation, the interbedded shales of the Latrobe Group may have contributed significant volumes of hydrocarbons to the oil and gas accumulations in the Gippsland Basin. In addition, this study not only supports the premise that over-reliance on Rock-Eval/TOC data alone can be misleading for assessment of petroleum generation, but also represents a strategy for kerogen type and generative potential determination for fluvio-deltaic coals and subordinate lithologies.

Silicoflagellate double skeletons in the geologic record

Abstract Modern silicoflagellates are known to produce double skeletons, which are considered as pre-division stages; members of modern doublets are aligned at basal corners, using either pikes or organic material between the abbasal surfaces of the basal rings to hold together. In contrast, fossil doublets from the Cretaceous and Paleogene often have the corners of each skeleton oriented between those of the paired member in what is known as the Star-of-David configuration. Until recently, however, virtually nothing was known about the fine structure of fossil double skeletons. As a follow-up to our recent study on extant silicoflagellate doublets, we present a compilation of data on the fossil record of silicoflagellate double skeletons, with particular focus on the Cretaceous and Paleogene. Fossil silicoflagellate double skeleton specimens are extremely rare, with the oldest being from the late Santonian–early Campanian. In order to test whether silicoflagellates may have produced doublets prior to that time, we have constructed three-dimensional computer models of silicoflagellate double skeleton morphologies. Our findings indicate that doublet formation was part of the silicoflagellate reproductive cycle already since early in the evolutionary history of the group, before the development of the basal ring. Two distinct double skeleton configurations developed at some point in this evolution, with the Star-of-David group likely becoming extinct in the Oligocene, and the corner-aligned group represented by the Neogene and modern silicoflagellates. At present, the doublet configuration in fossil silicoflagellates can only be determined confidently with paired skeletons, but the occurrence, position and orientation of pikes may offer useful clues to interpret the doublet configuration from single skeletons. Unusual pike morphologies of some silicoflagellates from the Eocene strongly suggest a Star-of-David configuration. Silicoflagellate skeletal morphologies with pikes appear to be less abundant in the fossil record as double skeletons, and may disassociate more readily than morphologies that lack pikes and are instead held together by organic material between the basal rings.

Tylosaurine mosasaurs (Squamata) from the Late Cretaceous of northern Germany

AbstractTwo genera of tylosaurine mosasaurs, Tylosaurus and Hainosaurus, are recorded for the first time from Germany. Tylosaurus sp. is represented by two isolated tooth crowns, originally described as Mosasaurus? alseni (here considered a nomen dubium) from the latest Santonian–Early Campanian, which are very similar to T. ivoensis and T. gaudryi. The material of Hainosaurus sp. comprises a maxillary with associated postorbitofrontal, two pterygoid teeth and several indeterminate cranial fragments. The specimen from the Late Campanian is slightly less derived than H. bernardi from the Maastrichtian in retaining labiolingually less compressed anterior maxillary teeth and unserrated pterygoid teeth with only very weak carinae. Despite only minor skeletal differences, the genus Hainosaurus is considered to be distinct from Tylosaurus because of its significant modification of the dental apparatus compared to the plesiomorphic condition in the latter. This dental morphology suggests a phylogenetic trend from a generalised-piercing marginal dentition in Tylosaurus towards the increasingly labiolingually compressed, symmetrical, strongly bicarinate cutting marginal teeth in Hainosaurus spp. from the Early through Late Campanian and Maastrichtian. A similar trend is also present in pterygoid teeth with very indistinct unserrated carinae in the Campanian Hainosaurus sp. towards serrated ones in the Maastrichtian H. bernardi. A short review indicates the presence of Hainosaurus in northern, central and western Europe (Sweden to Spain) since the Early Campanian, and the occurrence of Tylosaurus spp. in the same area until the Late Campanian. Hainosaurus persisted until the end of the Maastrichtian; outside Europe it may have been present in the Late Campanian of the USA and the Maastrichtian of the Democratic Republic of Congo. Judging from a simple, uni- to bicarinate, stoutly conical tooth morphology in aigialosaurs and very basal mosasaurs as well as phylogenetic patterns, the development of blade-like cutting tooth crowns appears to have been convergent in several clades of large-bodied Campanian–Maastrichtian mosasaurids. These include both mosasaurines ('Leiodon' mosasauroides, Prognathodon? sectorius, Prognathodon? kianda, Eremiasaurus heterodontus) and tylosaurines (Hainosaurus spp.).

Nannofossils, foraminifera and microforaminiferal linings in the Cenozoic diamictites of Cape Lamb, Vega Island, Antarctica

AbstractMicropaleontological and palynological samples from three Cenozoic diamictites at Cape Lamb, Vega Island, James Ross Basin were analysed. Fossiliferous samples yielded reworked and autochthonous assemblages of Mesozoic calcareous nanno− fossils, impoverished Cretaceous foraminifera together with Neogene species, as well as Late Cretaceous dinoflagellate cysts, pollen, spores and abundant Cenozoic micro− foraminiferal linings. The recovered nannoflora indicates Early Cretaceous (Hauteri− vian-Albian) and Late Cretaceous (Santonian-Early Campanian) ages, suggesting an in− tensive reworking of marine sediments. The presence of the Early Cretaceous species Nannoconus circularis Deres et Acheriteguy in the diamictite represents its first record for the James Ross Basin. The scarce foraminiferal fauna includes Pullenia jarvisi Cushman, which indicates reworking from lower Maastrichtian-lower Paleocene sediments, and also the Neogene autochthonous Trochammina sp. aff. T. intermedia. The in− ner−organic layer observed inside this specimen appears to be identical to microfora− miniferal linings recovered from the same sample. Palynomorphs found in the studied samples suggest erosion from the underlying Snow Hill Island and the Lopez de Bertodano Formation beds (upper Campanian-upper Maastrichtian). These recovered assemblages indicate either different periods of deposition or reworking from diverse sources during Cenozoic glaciation, originating in James Ross Island and the Antarctic Peninsula with the influence of local sediment sources.

Геданский флористический комплекс из верхнемеловых отложений хольчанской свиты Охотско-Чукотского вулканогенного пояса

The Gedan floristic assemblage occurs from upper layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at the Gedan River in the middle part of the Arman River basin. The Gedan assemblage is composed of 6 taxa: Cladophlebis sp., Sphenobaiera sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Taxodium amguemensis (Efimova) Golovn., Metasequoia sp., Pagiophyllum sp. The similarity of the Gedan floristic assemblage with the Karamken and the Khirumki floristic assemblages from the Kholchan Formation of the Okhotsk sector of the OCVB allows us to join them in the Kholchan flora. This flora is distinct from more ancient Arman flora, which dated as the Turonian-Coniacian and from younger Ola flora, which dated as the Santonian-early Campanian. The age of the Kholchan flora is estimated as the Coniacian on the basis of stratigraphic position, presence of Podozamites, Metasequoia and Quereuxia and also isotopic data. This flora is equivalent with the Chaun flora of Central Chukotka, with the Aleeki flora from the Villigha and Toomahni Rivers interfluve and with the Ulya flora from the southern part of the Okhotsk-Chukotka volcanogenic belt.

Chondrichthyans from the Menuha Formation (Late Cretaceous: Santonian–Early Campanian) of the Makhtesh Ramon region, southern Israel

Exposures of the Menuha Formation (Santonian–Early Campanian, Mount Scopus Group) in the Makhtesh Ramon region of the southern Negev have produced numerous chondrichthyan teeth. The isolated teeth represent at least ten different species: Cretalamna appendiculata, Cretoxyrhina mantelli, Squalicorax falcatus?, S. kaupi, Scapanorhynchus rapax, S. raphiodon?, Carcharias samhammeri, Carcharias cf. C. holmdelensis?, and two other fish (Hadrodus priscus and a pycnodont). This assemblage has important implications for Late Cretaceous chondrichthyan palaeobiogeography. The majority of teeth were contained within a glauconite-rich, yellow-brown, soft chalk that included oysters (Pycnodonte vesicularis?), trace fossils (Planolites, Thalassinoides, and Chondrites), phosphatic peloids, and foraminiferans (globigerinids). The teeth were collected mainly through surface-sampling and sieving. The Menuha Formation probably represents a temperate to subtropical, shallow, open-shelf environment deposited during the formation of the Ramon anticline. Reworked conglomeratic chalks in the western section represent marginal facies derived from this structural uplift. With little to no published material describing the chondrichthyan fauna of the Menuha Formation, these data improve interpretations of its palaeoenvironment. Interpretation of the palaeoenvironment of the formation is important for understanding the larger stratigraphic/tectonic framework of the Ramon monocline region of southern Israel.

Bertilanthus scanicus, a New Asterid Flower from the Late Cretaceous (Late Santonian–Early Campanian) of Scania, Sweden

A new genus and species of fossil flowers, Bertilanthus scanicus, is described from the Late Cretaceous of southern Sweden. The flowers of B. scanicus are actinomorphic and bisexual with an inferior ovary. Perianth and androecium are pentamerous. The sepals are small and free, and calyx aestivation is apert; petals are larger, and aestivation of corolla is imbricate. The androecium consists of a single whorl of stamens opposite the petals. The anthers are dithecate, tetrasporangiate, sagittate, and dorsifixed. Pollen observed in the flower is minute and oblate to spheroidal with three colpi and a tectate-punctate pollen wall. The gynoecium is formed from two carpels, and there are two free and stout styles. The epidermal cells of the styles are palisade shaped and form a distinct radiating pattern. The ovary is unilocular with numerous anatropous ovules borne on two intruding parietal placentae. There is a distinct five-parted nectary disk inserted between perianth and styles. The fruit was probably dry and capsular with apical dehiscence between the styles. Bertilanthus scanicus shares the presence of the unusual radiating palisade cells of the styles with Silvianthemum suecicum, another taxon described from the Åsen locality based on fossil flowers. Other critical features shared between Bertilanthus and Silvianthemum, including minute, tectate-punctate pollen, papillate-spiny extension of the palisade cells, free and stout styles, unilocular ovary, parietal placentation with placentae extending almost to the center of the ovary, and numerous anatropous ovules with reticulate surface, indicate that the two genera are closely related and also link these fossils to extant Quintinia, currently placed in the Paracryphiaceae (Paracryphiales) in the asterid clade.

Позднемеловая флора Хатангской впадины (северная Сибирь)

Fossil plants from the Late Cretaceous deposits of the Khatanga depression are joined in three floristic assemblages: the Ledyanaya assemblage (the Turonian-Coniacian), the Kheta assemblage (the late Coniacian-early Santonian) and Mutino assemblage (the late Santonian-early Campanian). The Ledyanaya floristic assemblage contains ferns (Anemia rarinervis Abramova), cycadophytes (Nilssonia sp.), ginkgoales (Ginkgo ex gr. sibirica Heer), conifers (Taxodium sp., Sequoia tenuifolia (Schmalh.) Sveshn. et Budants.) and angiosperms (Pseudoprotophyllum hatangaense Abramova, Liriodendropsis simplex (Newb.) Newb., Trochodendroides sp., ะกissites sp., Dicotylophyllum sp.). The characteristic features of this assemblage are depauperated composition of angiosperms and survival of the Early Cretaceous relic elements. The Kheta floristic assemblage contains only Taxodium sp. and Trochodendroides sp. The Mutino floristic assemblage contains Sequoia tenuifolia, Pseudoprotophyllum hatangaense, Quereuxia angulata (Newb.) Krysht. ex Baik. and Cobbania corrugata (Lesq.) Stockey, Rothwell et Johnson. The Ledyanaya floristic assemblage is very similar with the Newsiberian flora from the Derevyannye Gory Formation of New Siberia Island. The Mutino floristic assemblage have common elements with Kundur flora (the Campanian) from the Kundur Formation of Amur region. The abundance of large leaves of Pseudoprotophyllum in the Mutino flora is evidence of the preservation of humid warm-temperate climate in the northern part of Siberia up to the Campanian. The presence of water plants Quereuxia angulata and Cobbania corrugada indicates the westward migration of some characteristic elements of the Pacific ocean lowlands.