The genus Trochodendroides, recognized by its ovate or elliptical leaves with palmate brochidodromous venation, is well represented in the late Albian-Maastrichtian floras of North-East of Russia. The study of recently collected materials and revision of previous data allow us to introduce one new species (T. montana P. Alekseev, sp. nov.) and to offer 6 new combinations (T. ochotica (Vachr. et Herman) Golovn. et Gnilovskaya, comb. nov., T. barykovensis (Moiseeva) Golovn., comb. nov., T. gigantea (Moiseeva) Golovn., comb. nov., T. terranea (Moiseeva et Herman) Golovn., comb. nov., T. campanica (Abramova) Golovn. et Yudova, comb. nov., T. crenata (Herman) Golovn., comb. nov.). The new names were proposed for two species (T. samyliniae P. Alekseev, nom. nov., T. magadanica Golovn., nom. nov.). The diagnoses of 10 species are emended. The species Trochodendroides pekulneensis Philipp. and Zizyphus anadyrensis Philipp. are joined under the name Trochodendroides pekulneensis Philipp. emend. Yudova. The species Zizyphus microphylla Philipp. and Trochodendroides armanensis Philipp. are joined under the name T. magadanica Golovn. The species Macclintockia ochotica Vachr. et Herman and Trochodendroides longifolia Golovn. are joined under the name Trochodendroides ochotica (Vachr. et Herman) Golovn. et Gnilovskaya. In the whole, 21 species are recognized in the Late Cretaceous floras of North-East of Russia. Their stratigraphic and geographic ranges were analized. The systematic and morphology diversity of Trochodendroides was comparatively low in the late Albian–Turonian and the findings of these leaves are rare. During the Coniacian this genus reached the highest systematic and morphologic diversity. In the Santonian the abundance of Trochodendroides leaves was decreasing. In this time the lanceolate or narrow-ovate leaf morphotypes were most usual. The abundance of Trochodendroides leaves was increased again in the Campanian and decreasing in the Maastrichtian. Between 21 species, 18 species were distributed only in North-East of Russia. Many species were recorded only in single floristic assemblage. Species T. deminii and T. sachalinensis were characterised by wide stratigraphic ranges (from the late Albian to the Maastrichtian and from the Coniacian to the Campanian consequently).
On the basis of new records and reexamination of described fossils a revision of morphology and systematics of fructifications, found in co-occurrence with Trochodendroides Berry leaves was undertaken. The general construction of racemose infructescences and fruits of all known specimens is practically identical. This similarity indicates that these plants were closely related with minor differences that are not sufficient for separate generic designation. We suggest applying the name Jenkinsella Reid et Chandler for dispersed follicular fruits, to fruits in racemes and to infructescences attached to the shoots. This is the earliest appropriate generic name designated for fruits with distinguishable morphology and critical details of inner structures. The diagnosis of the genus Jenkinsella is emended and five new species are described: Jenkinsella krassilovii Golovneva et P. Alekseev, sp. nov., J. knowltonii Golovneva et P. Alekseev, sp. nov., J. conferta P. Alekseev et Golovneva, sp. nov., J. makulbekovii Golovneva et P. Alekseev, sp. nov., J. vilyuensis Golovneva et P. Alekseev, sp. nov. Three new combinations (J. filatovii (Samylina) Golovneva et P. Alekseev, comb. nov., J. jiayinensis (G.P. Feng, C.S. Li, Zhilin, Y.F. Wang et Gabrielyan) Golovneva et P. Alekseev, comb. nov., J. gardnerii (Chandler) Golovneva et P. Alekseev, comb. nov.) are created. Investigation of infructescence arrangement in different species of Jenkinsella provides new data, allowing reinterpretation of fertile shoots construction in Joffrea speirsii.
New findings of the genus Dalembia from Late Cretaceous sediments are described: Dalembia sp. from lower part of the Sym Formation (Coniacian – Santonian) of Eastern Siberia; Dalembia sp. from upper part of the Timmerdyakch Formation (Turonian – Coniacian) of Western Siberia; D. vachrameevii E. Lebedev et Herman and the new species D. argentea Yudova et Golovneva from the Chingandzha Formation (Turonian – Coniacian) of Okchotsk-Chukotka volcanogenic belt (Northeastern Russia). The stratigraphic range of the genus Dalembia stretch from the late Albian to Campanian. The geographical area includes the territories of Alaska, northern China, Northeastern Russia, Western and Eastern Siberia. The highest quantity of occurrences associated with Nothern Pacific region.
The analisys of morphological variability of Pinaceae pollen cones from Baltic amber confirm the presence of four Pinus species: P. wredeana (Goepp. et Berendt) Casp., P. reichiana (Goepp. et Berendt) Conw., P. kleinii Conw and P. multicellularis Casp. et Klebs. The taxonomical position of Piceites schenkii Casp. et Klebs is remain unclear. The factor analysis was efficient for separation of taxa with overlapping features. New data confirm that ancient Pinus species were source of resin transformed in Baltic amber.
Analytical data on fauna of the beetles and flora of vascular plants from Baltic amber are given. The community of the amber forest is reconstructed on the basis of these data. It was a thermophilic, humidmixed forest similar to modern subtropical forests of Eastern and Southeastern Asia. The existing reconstructions representing this community as a mountain forest predominated by conifers are not confirmed.
The Cretaceous floras of northern Asia represented by the Antibes flora of the Chulym-Yenisei area of West Siberia, Kaivayam flora of northwestern Kamchatka, and Grebenka flora of the Anadyr River basin in Chukotka are reviewed. These floras characterize the Late Cretaceous Siberian-Canadian Paleofloristic Region, where they developed in humid warm temperate climatic environments. Two new angiosperm genera are described: genus Chachlovia P. Alekseev et Herman with species C. kiyensis P. Alekseev, sp. nov. and C. dombeyopsoida (Herman) Herman, comb. nov. and genus Soninia Herman et Shczepetov with species S. asiatica P. Alekseev, sp. nov. and S. integerrima Herman et Shczepetov, sp. nov. The species Chachlovia kiyensis and Soninia asiatica were characteristic components of the Antibes flora. Chachlovia dombeyopsoida and Soninia integerrima were constituents of the Kaivayam and Grebenka floras, respectively.
On the basis of study of fossil plants, the climate in southwestern Siberia in the Early Senonian was reconstructed to be warm temperate humid with the mean annual temperature of about 13°C. The CLAMP analysis (Climate Leaf Analysis Multivariate Program) was applied for the first time to Cretaceous floras of Western Siberia. The comparison results of climatic variables estimated show that the climate in Western Siberia in the Early Senonian was more humid and warmer than in Northeast Asia.
The paper presents new data about the Antibes flora, which is one of the richest Cretaceous floras in Western Siberia. Five new species of angiosperms from the localities Antibes and Archekas (Kemerovo region) are described: Archaeampelos senonica P. Alekseev sp. nov., Camptodromites sibiricus P. Alekseev sp. nov., Celastrinites lanceolatus P. Alekseev sp. nov., Cissites basicordatus P. Alekseev sp. nov. and Juglandiphyllites microdentatus P. Alekseev sp. nov.
Seventeen species of the genus Trochodendroides and one species of the genus Nyssidium are described from the Albian-Maastrichtian deposits of the Chulym-Yenisei depression (Western Siberia), Lena-Vilyui depression (Eastern Siberia) and Kolyma River basin. The study of recently collected materials and revision of previous data allow us to describe 4 new species (T. buorensis Golovn., sp. nov, T. beketovii Golovn., sp. nov., T. rostrata Golovn. et P. Alekseev, sp. nov.) and to offer 6 new combinations (T. tiungensis (Budants.) Golovn., comb. nov., T. heterophylla (Budants.) Golovn., comb. nov., T. kemensis (Ananjev) Golovn., comb. nov., T. sibirica (Tcherepnin) P. Alekseev, comb. nov., T. bajkovskae (I. Lebed.) Golovn., comb. nov., T. gromovii (E. Lebed.) Golovn., comb. nov). The new names were proposed for two species (T. budantsevii Golovn., nom. nov., T. ananjevii Golovn., nom. nov.). The morphological diversity, variability and value of different characters for distinction of species are discussed. The epidermal features were firstly examined for T. heterophylla and T. ananjevii. They are mostly similar to epidermal features of Cercidiphyllum. The genus Trochendroides firstly appeared in Siberia in the early-middle Albian as a minor component of the conifer-dominated Mesophytic floras. The determination of this genus is verified by the findings of Nyssidium fruits. During the Late Cretaceous the genus Trochodendroides was common member in floras of the Siberian-Canadian phythogeographic region. The systematic and morphology diversity of Trochodendroides was comparatively low in the late Albian–Cenomanian and the findings of these leaves are rare. The abundance of Trochodendroides leaves was increased in the Turonian and the Coniacian. During the Coniacian this genus reached the highest systematic and morphologic diversity (the Antibes and the Vilyui floras). In the Santonian-Campanian the abundance of Trochodendroides leaves was decreasing again. In this time the lanceolate or narrow-ovate leaf morphotypes were most usual. They were often described as Macclintockia, Zizyphus or Paliurus. Genus Trochodendroides is not presented in the Cretaceous deposits of Europe and firstly appeared there in the Tertiary. This genus is rare in the Late Cretaceous deposits of the Turan province, near the boundary between Siberian-Canadian and Euro-Sinian phythogeographic regions.
Leaves of Liriodendrites Johnson were found in the Gyliakian (Santonian) and Boshnyakovo (Danian) floras of Sakhalin Island, Rarytkin, Koryak, and Kakanaut (Maastrichtian) floras of the Koryak Upland, and Antibes (Coniacian) flora of western Siberia. The study of new finds and revision of earlier collections resulted in the erection of a new species, L. occidentalis P. Alekseev, sp. nov., and creation of two new combinations, L. sachalinensis (Krysht.) P. Alekseev, comb. nov. and L. aeternus (Golovn.) P. Alekseev, comb. nov. The geographical and stratigraphic ranges of Liriodendrites in the Northern Hemisphere were reviewed.
