The Middle Jurassic coal-forming plants of the Ulug-Khem Basin (Republic оf Tyva, Russia)

Dispersed cuticles of plants from coals of the Middle Jurassic Ulugkhem Formation (locality 229 near Mount Begreda, Ulug-Khem Basin, Republic of Tyva) were studied. As a result of the study of mesofossils using light and scanning electron microscopes, it was found that the coals are composed mainly of the remains of ginkgophytes. They are represented by the leaves of Pseudotorellia cf. angustifolia Doludenko, the female reproductive organs of this plant Umaltolepis sp., as well as the leaves of Eretmophyllum neimengguensis Li, Sun, Wang, Dilcher, Tan, Li, Na. The conifers played subordinate role. The palynospectrum of the coal seam is dominated by the spores of ferns; bisaccate and monosulcate pollen are next in importance. Thus, ginkgophytes and ferns predominated in the Middle Jurassic swamp communities in the Ulugh-Khem Basin. For the first time, the coal-forming role of the genus Eretmophyllum was revealed. The Middle Jurassic flora of Tyva is similar to the floras of the Kansk-Achinsk and Irkutsk basins of Eastern Siberia, Angren Basin of Uzbekistan, and the Ordos Basin of Inner Mongolia, China by predominance of Pseudotorellia. The vegetation was clearly differentiated into the lowland and the slope one. In the latter the leptostrobaleans, ginkgoaleans, and conifers were represented. Pseudotorellia is one of the main components of swamp plant communities in the more northern regions: in the Ulug-Khem and Irkutsk basins, and in the Aban and Pereyaslovka coal fields of the Kansk-Achinsk Basin. This genus disappears in the Nazarovo coal field of the Kansk-Achinsk Basin, being replaced by the leptostrobaleans. Here the compositions of swamp and slope communities practically do not differ. The Late Mesozoic swamp plant communities were characterized by conservatism, as well as by extreme sensitivity to environmental changes, which apparently developed because of their existence in the same conditions of high humidity. Degradation of the swamps led to the disappearance of swamp plant communities.

A new species of the genus Birisia (Dicksoniaceae) from the lower–middle Albian deposits of Southern Primorye, Far East of Russia

A new fern Birisia mandshurica, sp. nov. (Dicksoniaceae) from the lower–middle Albian Frentsevka Formation of southern Primorye, Far East of Russia is described. This species is characterized by short-creeping rhizomes with closely spaced stipes and bipinnate fronds with narrow linear pinnules. A reconstruction of B. mandshurica is proposed. It comes from the autochthonous locality of ferns and herbaceous angiosperms and was a part of pioneer open community, which occupied low flat plains between river channels. Revision of ferns, described as Acanthopteris gothanii Sze from China, shows, that these ferns belongs to Birisia alata (Prynada) Samylina. The name Acanthopteris Sze should be abandoned, due to absence of spore-bearing pinnules and poor preservation of sterile pinnules in type specimens. Based on Chinese and Russian material of good preservation, we provide emended diagnoses of the genus Birisia Samylina and its type species B. alata. Re-examination of various species of the genus Birisia revealed that this genus was widely distributed in the Cretaceous floras (from the Barremian to the Coniacian) of Eastern Siberia, New Siberian Islands, North-East and Far East of Russia, China, Japan, Alaska and Western Canada. B. alata is the most widespread species.

The Late Cretaceous floras of the Zeya-Bureya Basin

A general characterization of the Late Cretaceous floras of the Zeya-Bureya Basin is provided based on floristic assemblages from Russia (Amur Region) and China (Heilongjiang Province). Four phases of floral evolution were revealed: the Turonian-Coniacian (the Sutara flora), the Santonian (the Yong’ancun and Middle Kundur floras), the Campanian (the Taipinglinchang and Late Kundur floras) and the late Maastrichtian (Bureya flora). This long paleofloral succession provides possibility for investigation of different trends in the evolution of the Late Cretaceous taxa, flora, and climate.

The Chingandzha flora of the Okhotsk-Chukotka volcanic belt

The Chingandzha flora comes from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, North-East of Russia). The main localities of the Chingandzha flora are situated in the Omsukchan district of the Magadan Region: on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River). The Chingandzha flora includes 23 genera and 33 species. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created. The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The main genera are Arctop teris, Osmunda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Protophyllocladus, Pseudoprotophyllum, Trochodendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. The Chingandzha flora is distinct from other floras of the Okhotsk-Chukotka volcanic belt (OCVB) in predominance of flowering plants and in absence of the Early Cretaceous relicts such as Podozamites, Phoenicopsis and cycadophytes. According to its systematic composition and palaeoecological features, the Chingandzha flora is similar to the Coniacian Kaivayam and Tylpegyrgynay floras of the North-East of Russia, which were distributed at coastal lowlands east of the mountain ridges of the OCVB. Therefore, the age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Kaivayam phase of the flora evolution and to the Anadyr Province of the Siberian-Canadian floristic realm. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul’ya flora of the Ul’ya Depression.

SVGm – a new tool for measuring linear dimensions with quality characteristics of objects: applications in biology

The advantages and disadvantages of a number of specialized computer programs for obtaining dimensional characteristics of biological objects by analysis of their digital images are considered in comparative terms. The authorial methodology of using a vector graphics editor Inkscape and a new online service SVGm (Scalable Vector Graphics measurer, https://svgm.cf) is proposed to measure the linear parameters of the objects in the images and to prepare the quantitative characteristics of objects and their different qualitative characteristics for the subsequent statistical analysis. An algorithm for working with Inkscape editor and SVGm online service is described in detail. Object images imported into Inkscape editor are measured using vector elements (lines, rectangles, circles, ellipses, polygons) and saved in the standard SVG format. Properties of vector figures of SVG files are converted by the online service SVGm in the measurement results shown in the table. The potential of the method is shown by the example of morphological measurements of various botanical objects.

Fossil evidence of initial radiation of Cercidiphyllaceae

Cercidiphyllaceae-like leaves and fruits from the Lower Cretaceous deposits of Northeastern Asia were restudied. In the result one species of Jenkinsella fruits and five species of Trochodendroides leaves were recognized, including Trochodendroides potomacensis (Ward) Bell, T. buorensis Golovneva, T. sittensis Golovneva, sp. nov., T. vachrameeviana (Iljinskaja) Golovneva, comb. nov., and T. denticulata (Budantsev et Kiritchkova) Golovneva, comb. nov. Two new combinations and one new species are published. These plants had very small leaves and probably were shrubs. Fruits of Nyssidium orientale Samylina from the Barremian-Aptian Starosuchan Formation (Primorye, Russia) have no follicular characters as Jenkinsella fruits. Their affinity, not only to Cercidiphyllum-like plants, but to angiosperms in general, is doubtful. Leaves and fruits of Cercidiphyllum sujfunense Krassilov from the lower-middle Albian Galenki Formation (Primorye) also can not be assigned to Cercidiphyllaceae. Leaves have pinnate, brochidodromous venation and are comparable with those of Asiatifolium elegans Sun, Guo et Zheng, which were recorded from the Frentsevka Formation of the Partizansk coal basin, Primorye, Russia, and from the Chengzihe Formation, Northeastern China. Thus, the first reliable records of the genus Trochodendroides appear in the early-middle Albian. The relationship of these leaves with Cercidiphyllaceae is confirmed by finds of associated fruits Jenkinsella filatovii and by significant diversity of Trochendroides in the Late Albian-Cenomanian. In the early-middle Albian the genus Trochendroides was a minor component of the conifer-dominated Mesophytic floras. These fossils reflect the early radiation of Cercidiphyllaceae and indicate that this family began to diversify more then 30 million years before the Tertiary. Investigation of the early-middle Albian Cercidiphyllaceae provides important new data for our understanding of the early evolution of eudicots.

Sorosaccus sibiricus Prynada (Ginkgoales) from the Middle Jurassic deposits of the Irkutsk Coal Basin, Eastern Siberia

New findings of pollen cones of Sorosaccus sibiricus Prynada were studied in detail from the Aalenian—Bajocian Prisayan Formation of two localities in the Irkutsk coal basin (Ust’-Baley and Vladimirovka). Specimens of S. sibiricus previously described from Ust’-Baley (Heer, 1876) were reexamined. It was revealed that S. sibiricus differs from other species of Sorosaccus in a shape of the apical (free from the microsporangia) part of the microsporophylls. Microsporophylls of S. sibiricus consist of a petiole and a wide-oval distal lamina with acute apex, commonly bending upward. The lamina was often folded and became lanceolate, linear, or fan-shaped with uneven to toothed margin. Microsporangia (6—8) are oval in outline, helically attached to the petiole. Pollen grains were extracted from S. sibiricus microsporangia for the first time. They are oval to boat-shaped in outline, monosulcate and differ from other known Sorosaccus pollen grains by the verrucate surface of the exine. The diagnosis of the species Sorosaccus sibiricus is emended.

The distribution of Sphenobaiera biloba Prynada in the Cretaceous of Northeastern Asia

A revision of Sphenobaiera biloba Prynada from Northeastern Asia is based on restudy of the type material from the Zyryanka River Basin (Prynada’s collection), as well as additional specimens from the type locality (Samylina’s collection) and collections from the Ul’ya and Anadyr rivers. A new extended diagnosis of S. biloba based on the leaf morphology and epidermal structure is proposed. Geographic and stratigraphic distribution of this species in Northern Asia is discussed. S. bilobais known in the Aptian of Eastern Siberia (Lena River Basin) and from the early-middle Albian to Coniacian of northeastern Russia. In the Late Cretaceous this species was considered as relict and related with volcanogenic deposits of the Okhotsk-Chukotka volcanic belt.

The genus Birisia (Dicksoniaceae) in Cretaceous flora of Siberia and North-East of Russia

In the result of the re-examination of type material of the genus Birisia from the Cretaceous deposits of Siberia and North-East of Russia, we include only three species in this genus: B. alata (Prynada) Samylina (early-middle Albian — Coniacian), B. onychioides (Vassilevskaja et Kara-Mursa) Samylina (Aptian), and B. acutata Samylina (early-middle Albian). Species B. ochotica and B. alata are united under the name B. alata. Species B. jelisejevii, B. samylinae and B. oerstedtii are excluded from the genus Birisia as mismatching to the generic diagnosis. Species of Birisia are distinguished each other in size and degree of dissection of pinnules, in shape, presence and number of lobes, as well as the number of branches of the lateral veins inside the lobes. The pinnules of the Birisia are characterized by the significant variability and have a slightly different structure depending on their location on the leaf blade. Therefore, for a more accurate species identification of Birisia, it is necessary to have the most complete leaves with branching of two or three orders and the fertile pinnules.