Sub-arborescent Lycopsids Research Articles

Omphalophloios wagneri sp. nov., a new sub-arborescent lycopsid from the middle Moscovian (Middle Pennsylvansian) of the Illinois Basin, USA

Described is a new species of sub-arborescent lycopsid, Omphalophloios wagneri sp. nov. from roof shale of the middle Moscovian (Bolsovian/Atokan) (Middle Pennsylvanian) Lower Block Coal in the Illinois Basin, Indiana, USA. Available material represents mostly fragments of 16 to >60 mm wide fertile axes that bear densely spaced sporangia, which are flattened due to compaction into disc-like shape, 2.5–3.1 mm in diameter. The outer sporangial cell wall layer displays a gradual transition from isometric cells in the central parts of adaxial and abaxial sporangial valves, to a narrow belt of elongated cells in the equatorial area, interpreted as a dehiscence zone. Micro- and megasporangia alternate in irregular patches, a single sporangium being attached adaxially to an extended sporophyll base. Cyperites-like sporophyll distal laminae are ~25 mm long at fertile shoot apices but become progressively longer (>110 mm) down the shoots. Based on size distribution of stems, fertile shoots are estimated to bifurcate at least five times, which suggests that O. wagneri formed a relatively dense crown. The entire habit of the plant is difficult to assess from existing material; however, the tree was probably small and interpreted as colonizing low lying to slightly raised peat swamps. Omphalophloios wagneri differs from all other adpression-based species of the genus in having the smallest sporangia and several orders of fertile-axis bifurcations. In situ megaspores of the Zonalesporites brassertii type also are different from all other Omphalophloios megaspores.

A remarkable mass-assemblage of lycopsid remains from the Rio Bonito Formation, lower Permian of the Paraná Basin, Rio Grande do Sul, Brazil

Arborescent and sub-arborescent lycopsids are important floristic elements of the Brazilian early Permian post-glacial environments. However, the taxonomy and systematic position as well as the biology and ecology of these plants are poorly understood. The present study describes a remarkable assemblage of Brasilodendron cf. pedroanum axes preserved in the plant bearing sub-level N8b of the Morro do Papaleo outcrop, Rio Bonito Formation, early Permian of the Parana Basin, Rio Grande do Sul state, Brazil. These axes are massively concentrated, without any preferential depositional orientation, forming a monotypical assemblage. They are unbranched and preserved as impressions. Three morphological patterns, occurring on distinct axes, were described for leaf cushions. This mass-assemblage is probably a result of allochthonous deposition and hydraulic size-sorting. The massive concentration of B. cf. pedroanum suggests that this fossil taxon was an important floristic element somewhere in the upstream area of the braided river system studied here.

Paleoecological analasis of the miospore assemblages from the borehole 39, Moscow region, Russia

Palynological material was obtained from Upper Visean deposits in the borehole No 39 that is located on the left bank of the Oka River, on 105 km to the south-east of the Moscow in the Serpukhov district. The lithological sequence of the borehole generally consist of the limestones, stigmarian limestones, interbedded with clays and siltstones. Total twenty five palynological samples from the sandy siltstones and charcoal clays (deep interval 29.4–33.25 m) have been collected. All samples contained abundant well-preserved miospores. Two palynoassemblages have been defined. The palynoassemblage S1 is described from the sandy siltstone and stigmarian limestones of the depth interval 29.4– 29.59 m. The palynoassemblage S2 is established from the coaly dark clays that occurred at the depth interval 29.64–33.25 m. All palynoassemblages are dominated by Lycospora pusilla. Based on both the presence Cingulizonaes bialatus, Triquitrites comptus, (index-species of the CBd palynozone) and the occurrence of the Late Visean species Tripartites vetustus, Triquitrites marginatus, Schulzospora campyloptera, Calyptosporites arenaceous the age of the palynoassemblages is defined as transitional Aleksinian-Mikhaylovian. The results well corresponded with data of miospore zonal scheme for Carboniferous of Russian Platform (Makhlina 1993). Paleoecological interpretation of the obtained palynoassemblages has been carrying out. General model of the paleoecological analysis is explained by the connection between the Carboniferous miospore taxa and their parent plants. Natural affinity of the miospores is determined by the comparison of dispersed material with the in situ spore findings that are elucidated in paleobotanical articles (more detail see Balme 1995, Orlova et al. 2014). In concordance with the comparison of the dispersed spores and in situ data, the miospore genera of the palynoassemblages have been subdivided into six paleobotanical patterns: arborescent lycopsids (Lycospora-producing plants), sub-arborescent lycopsids were produced the “densospores” (Densosporites, Vallatisporites, Cingulizonates), spores of ferns (Leiotriletes, Punctatisporites, Granulatisporites, Cyclogranisporites, Knoxisporites, Raistrikia, Tripartites, Triquitrites, Acanthotriletes, Convolutispora), miospores (prepollen) of seed ferns (Schulzospora, Remysporites, Geminospora, Rotaspora), spores of the sphenopsids (pars Calamospora) and pattern of unknown natural affinity (Diatomozonotriletes, Camarozonotriletes, Iugisporis, Simozonotriletes, Waltzispora, Calyptosporites). Abovementioned paleobotanical patterns are generalized into three paleoecological units: forest mire (arborescent and sub-arborescent lycopsids), non-forest mire (ferns, seed ferns and sphenopsids) and problematic one (unknown natural affinity). Accordingly, palynoassemblage S1 is dominated by arborescent lycopsids (66%). Sub-arborescent lycopsids (11%) and ferns (13%) were quite common in the plant communities. The seed ferns elements (2%) and sphenopsids (3%) were rare in the local palaeoflora. On the one side the forest-mire related miospores were increased upward the sequence (from 70% up to 88%), on the other side the percentage of the non-forest mire elements (from 26% up to 8%) were constant decreased in the same direction. The high percentage of forest mire unit is largely due to short

Carboniferous floras in siliciclastic rocks of Kashmir Himalaya, India and the evolutionary history of the Tethyan Basin

AbstractThe Fenestella Shale Formation of Jammu and Kashmir Himalaya comprises latest Viséan or Serpukhovian siliciclastic deposits formed along the southern margins of the Palaeotethys Ocean. A sequence of shallowing upward and deepening upward units indicates changes from shoreface to offshore and deeper shelf conditions, probably controlled by eustatic changes in an otherwise passive depositional system. Some of the finer-grained, shallow marine deposits have yielded fossil floras dominated by sub-arborescent lycopsids (Sublepidodendron,Lepidodendropsis) sphenophytes (Archaeocalamites) and pteridophylls (Nothorhacopteris,Triphyllopteris). The assemblage compares with other Gondwanan floras of this age that have been assigned to the Paraca floral realm, and are taken to indicate relatively warm climatic conditions that existed just prior to the onset of the Carboniferous–Permian ice-age.

COMPOSITION AND STRUCTURE OF AN IN SITU MIDDLE PENNSYLVANIAN PEAT-FORMING PLANT ASSEMBLAGE BURIED IN VOLCANIC ASH, RADNICE BASIN (CZECH REPUBLIC)

A three-dimensional reconstruction is provided of the composition, spatial distribution, and structure of a single-aged, Middle Pennsylvanian (Moscovian) peat-forming forest of a high-ash, planar (rheotrophic) mire, buried in situ by volcanic ash and preserved in the Lower Radnice Coal of the Radnice Basin (Czech Republic). The reconstruction is based on a detailed taxonomic and taphonomic analysis of fossils in a ∼0.5-m-thick tuff bed at the base of the Whetstone Horizon excavated over an area of 93.5 m 2 . In all, 24 whole-plant taxa of various growth forms were identified. This assemblage represents a lepidodendrid- and Cordaites borassifolius -dominated forest, with a well-developed understory of subarborescent lycopsids, tree ferns, medullosan pteridosperms, and calamites, as well as herbaceous ground cover. Lycopsids were dominated by Lepidodendron simile bearing Flemingites -type cones and L. lycopodioides ; Lepidophloios cf. acerosus was subdominant. Lianas, mostly lyginopterid pteridosperms and some ferns, were usually found close to upright stems. The ground cover, mostly ferns and sphenophyllaleans, was taxonomically the most diverse stratum, although only a minor contributor to the peat. Based on samples from the coal roof, the palynological record is in agreement with the tuff bed assemblage except for the quantity of certain taxa. To reduce this bias, compression R-values were calculated from the percent cover of aerial plant parts in the excavation and in the dispersed palynoflora. These R-values suggest that in the palynological record, arborescent lycopsids and sphenophylls are greatly overrepresented, ferns and cordaites strongly underrepresented, and calamites are almost the same in both records.

Occurrence of spores from an isoetalean lycopsid of the Polysporia-type in the Late Devonian of Ohio, USA

Thousands of dispersed megaspores of the Valvisisporites auritus-type, some isolated megasporangia still containing them and dispersed microspores of the Endosporites globiformis-type have been found occurring in close association in the Late Devonian (Famennian) of Ohio, USA. Until now, these spores have only been found in the Carboniferous, where they have been shown to have been produced by isoetalean lycopsids assigned to the plant genus Chaloneria and the morphogenus Polysporia. The discovery of dispersed megaspores of the V. auritus-type and microspores of the E. globiformis-type in the Famennian of the USA may indicate that such sub-arborescent lycopsids already existed in the Late Devonian, which thus extends the range of distribution of these taxa, at least in North America. The present work describes, using LM, SEM and TEM, megaspores of V. auritus-type, megasporangia containing these megaspores, and microspores of E. globiformis-type. The comparison with their Carboniferous representatives shows that they are quite similar. This comparative study permits clarification of some ultrastructural features of the megaspores of the Valvisisporites-type, such as the partly lamellate–partly amorphous innermost exospore, demonstrating that this is a characteristic and important ultrastructural feature of this genus.

The sub-arborescent lycopsid genus Polysporia Newberry and its spores from the Pennsylvanian (Bolsovian–Stephanian B) continental basins of the Czech Republic

About fifty compression specimens belonging to four species of Polysporia from the Kladno–Rakovník Basin of the central and western Bohemian Carboniferous continental basins and Intra-Sudetic Basin of the Czech Republic were studied macromorphologically and for in situ spores. Their stratigraphic range is from the Bolsovian to the Stephanian B. Polysporia rothwellii sp. nov., P. drabekii sp. nov. and P. radvanicensis sp. nov. are proposed as new species. Polysporia is reconstructed as a sub-arborescent plant with a principal axis with sterile and fertile apical portions. P. rothwellii and P. drabekii are preserved only as clusters of micro- and megasporophylls on specimens not in connection to an axis, and their identification and classification is based mainly on in situ spores. Micro- and megasporangia of some specimens of Polysporia occur together on axes, however, usually they are not arranged in a distinct pattern and only occasionally the distinct transition among micro- and megasporangia is to be seen. In situ megaspores are correlated with the dispersed species Valvisisporites auritus ( Polysporia radvanicensis and P. drabekii), Expansisporites westphalensis ( Polysporia rothwellii) and Triletisporites bohemicus ( Polysporia robusta). In situ microspores are correlated with the dispersed species Endosporites zonalis ( Polysporia robusta), E. globiformis ( Polysporia rothwellii) and E. cf. formosus ( Polysporia drabekii). Some of Kidston's type material of Polysporia from UK was re-examined and yields megaspores of the Expansisporites valvatus-type and microspores of the Endosporites globiformis-type. A review of in situ and dispersed occurrences Valvisisporites, Pseudovalvisisporites, Triletisporites, Expansisporites megaspores and Endosporites miospores is given.

Spencerites leismanii sp. nov., a new sub-arborescent compression lycopsid and its spores from the Pennsylvanian of the Czech Republic

A new sub-arborescent lycopsid species Spencerites leismanii sp. nov. is proposed for compression specimens yielding spores of the Spencerisporites-type. Macrofossils of Spencerites leismanii were studied as well as in situ spores. All specimens are from the Tlustice relict within the Bolsovian strata of the Radnice Member, Pennsylvanian. Spencerites leismanii is interpreted as a relatively small sub-arborescent lycopsid – probably more than 1 m high – with at least three orders of branching. Its sporangia are borne singly on peltate sporophylls, attached distally by a narrow base. In situ pseudosaccate trilete spores possess striate sculpture on the proximal and distal surfaces of the central body. The pseudosaccus is reticulate with a narrow rim on the margin. Spores isolated from Spencerites leismanii can be classified as Spencerisporites cf. striatus. A reconstruction of Spencerites leismanii is presented and palaeoecology of Spencerites species from the Czech Republic is discussed.

Vegetation patterns of Westphalian and Lower Stephanian mire assemblages preserved in tuff beds of the continental basins of Czech Republic

Several volcanoclastic beds in coal-bearing strata of the Late Palaeozoic continental basins in the Czech Republic contain in situ buried peat-forming plant ecosystems the study of which provides a unique insight into their structural pattern and species composition. Middle Pennsylvanian peat-forming plant assemblages at 14 localities in basins of central and western Bohemia and from the Intra-Sudetic Basin (NE Bohemia) were characterised based on collections of plants preserved in five successive tuff beds: the tuff of the 3rd Žd'árky Coal (Duckmantian), the Whetstone Horizon in the roof of the Lower Radnice Coal (Bolsovian), the Velká opuka intercalated in the Upper Radnice Coal (Bolsovian), the Z-tuff capping the Lower Lubná Coal (Bolsovian), and the tuff of the Chotíkov Coal (Westphalian D/Cantabrian). Analysis of plant remains preserved in these beds reveals the co-existence of several ecologically controlled plant assemblages ranging from structurally simple, low-diversity to high-diversity phytocoenoses, with complex structural patterns and synecological relationships. Most of these assemblages represent variations of the basic lepidodendrid-dominating forest with co-dominance or sub-dominance of other basic plant groups. This pattern is comparable to the forests of the paralic basins located in coastal settings. An assemblage dominated by the sub-arborescent lycopsid Omphalophloios feistmantelii (Feistmantel) comb. nov. was recognised in the Upper Radnice Coal. Only a few assemblages are poor in lycopsids. These are mostly mixed fern–calamites or pteridosperm-dominated phytocoenoses. The assemblages described represent various stages of hydroseral succession. The initial stage consists of a low-diversity fern–calamites-dominated assemblage of 5 species, not higher then 1–1.5 m which re-colonised the previously drowned mire. The climax stage of the succession is represented by high-diversity lepidodendrid forests with well-developed ground-cover and shrubs. The number of taxa of such assemblages varies between 20 and 30 species within an area of about 100 m 2. A comparison of the peat-forming flora with the clastic substrate floras preserved in mudstones or roof shales revealed substrate preference of individual species. Most of them grew in both types of substrates; only a few were adapted to only one type of substrate.

Peat-forming environments of Westphalian A coal seams from the Lower Silesian Coal Basin of SW Poland based on petrographic and palynologic data

The petrographic and palynologic compositions of coal seams of the Żacler formation (Upper Carboniferous, Westphalian A) from northwestern and southeastern part of the Lower Silesian Coal Basin (LSCB) were examined. Coals studied are highly volatile bituminous coal, where R o ranges from 0.91% to 1.09%. Seam 430 from the northwestern part of the basin contains high vitrinite percentage with rather low inertinite and liptinite contents, while percentage of mineral matter is variable. This petrographic composition is associated either with a predominance of Lycospora in miospore assemblage, or with a miospore assemblage of mixed character. The abundance of Lycospora reflects vegetation composed of the arborescent lycopsids while the mixed miospore assemblage is connected with diverse palaeoplant communities, namely, arborescent lycopsids, calamites and ferns. Seams 409 and 412/413 from the southeastern part of the LSCB are rich in inertinite and liptinite, while the vitrinite content is moderate. Their characteristic feature is the occurrence of a diagnostic crassisporinite (densosporinite). Amount of the mineral components in these coals is very low. Densosporites and related crassicingulate genera are main components of these miospore assemblages and were produced by herbaceous and/or sub-arborescent lycopsids. These petrographic and palynologic features were the basis for distinguishing three maceral–miospore associations: an arborescent lycopsid and mixed associations, occurring in the seam 430 and a herbaceous and/or sub-arborescent lycopsid association which was recorded in seams 409 and 412/413. The first two assemblages are interpreted as having been deposited in a planar rheotrophic mire, whereas the herbaceous and/or sub-arborescent lycopsid association is thought to have developed in an ombrotrophic, domed mire.

Earliest Triassic origin of Isoetes and quillwort evolutionary radiation

Isoetes beestonii new species is the most ancient known species of this living genus. In earliest Triassic shales of the Sydney and Bowen Basins of Australia it is locally abundant as circlets of transversely wrinkled leaves. It was heterosporous with megaspores of Maiturisporites rewanensis and microspores of Lundbladispora sp. cf. L. springsurensis.Isoetes thus predates Pleuromeia from which it has been thought to have evolved. Australian Pleuromeia-like subarborescent lycopsids are here reviewed as whole plants, with names based on fertile structures, and include Cylostrobus sydneyensis Helby and Martin from the Sydney Basin, Pleuromeia dubia (Seward) Retallack from the Sydney and Canning Basins, and Cylostrobus indicus (Lele) new combination and Pleuromeia sternbergii (Münster) Corda for Germar, newly recorded from the Canning Basin.There are in addition an array of cormose lycopsids that formed compact conelike plants when fertile, intermediate in stature between Isoetes and Pleuromeia. One of these is Tomiostrobus australis (Ash) Sadovnikov, formerly regarded as a cone, but here reinterpreted as a small pioneering plant of oligotrophic lakes and ponds, like Isoetes. Its megaspores are Horstisporites and its microspores are the stratigraphically important Aratrisporites tenuispinosus. Other similar forms are Tomiostrobus polaris (Lundblad) new combination from the early Triassic of Greenland, T. mirabilis (Snigirevskaya) new combination from the early Triassic of the Tunguska Basin of Siberia, T. taimyrica (Sadovnikov) new combination from the Early Triassic of the Taimyr region of Siberia, Lepacyclotes ermayinensis (Wang) new combination from the middle Triassic of China, L. convexus (Brik) new combination from the middle-late Triassic of Kazachstan, and L. zeilleri (Fliche) new combination from the middle Triassic of France and Germany.The diversity of isoetaleans in early Triassic floras and the weak vascular system of permineralized Tomiostrobus and Pleuromeia contradict the traditional view that Isoetes evolved by reduction in size from Pleuromeia and that its opportunistic life style allowed it to avoid plant competition. It is now more likely that Isoetaceae were weedy survivors of Permian-Triassic extinctions. The adaptive radiation and decline of Triassic quillworts matches the recovery from near-extinction, then decline of therapsid reptiles, for which these plants may have been an important food.