A new Bergeria(Lepidodendrales, Flemingitaceae), B. wenquanensis sp. nov., is described in this paper, typically characterized by the longest and elongated leaf cushions ever found. The specimen, collected from the Mi...A new Bergeria(Lepidodendrales, Flemingitaceae), B. wenquanensis sp. nov., is described in this paper, typically characterized by the longest and elongated leaf cushions ever found. The specimen, collected from the Mississippian of Wenquan County, Xinjiang Uygur Autonomous Region, China, is represented by a fossil stem about two meters long, with distinct leaf cushions. The genus Bergeria has usually been assigned to partially decorticated Lepidodendron stems. Although Cathaysian Lepidodendron have been extensively reported in China, most of them were found in the central, eastern and southern parts of the country, rarely in northwestern China. This new species is so far the westernmost record and the most isolated representative from the Cathaysian Lepidodendron center.Based on the distribution of the Cathaysian Lepidodendron during the Mississippian, most of the species were in the South China Plate near the Equator, while the new species is discrete in the north, far from the Equator. According to the spatiotemporal distribution of Cathaysian Lepidodendron, this genus appeared during the Mississippian, a period which was represented by rather few species, it flourished and expanded northwards during the Pennsylvanian, taking the north block of the South China Plate as the center. Since the Cisuralian to the Guadalupian, the genus became gradually sparser in all areas of distribution, probably due to strong climate change. During the Lopingian, the genus migrated southwards to the South China block and had a broader distribution range again, and it became extinct to the end of this interval. The new species is also significant for the evolution of Lepidodendron leaf cushions. During the Mississippian, the primitive species of Lepidodendron usually had narrow, fusiform leaf cushions, while the Pennsylvanian or Permian species were more variable in shape of leaf cushions, from inverted water-drop, rhomboidal, hexagonal, trapeziform to horizontal rhomboidal.展开更多
The isolated and anatomically_preserved lepidodendralean leaf cushions were described from coal balls in Wangjiazhai Formation (upper Upper Permian) in western Guizhou Province. These leaf cushions are very similar t...The isolated and anatomically_preserved lepidodendralean leaf cushions were described from coal balls in Wangjiazhai Formation (upper Upper Permian) in western Guizhou Province. These leaf cushions are very similar to Lepidodendron lepidophloides Yao both in size and morphology. They probably belong to the same species in different preservative condition. Comparisons on morphology and anatomy of L. lepidophloides and lepidodendralean leaf cushion genera, such as Lepidodendron, Lepidophloios, Sigillaria and Cathaysiodendron revealed that L. lepidophloides possesses mixed features of all these genera and it can not be assigned into any of them without doubt. It probably represents a new genus. Because the anatomical features of the other parts of the stem as well as the fertile organs related to these leaf cushions are unknown, the specific name L. lepidophloides is adopted. We leave this taxonomic problem open till the relationship between these leaf cushions and the stem and fertile organs become clear. This is the first report on the detailed anatomical features of the Cathaysian lepidodendralean leaf cushions.展开更多
This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The...This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The leaf cushion is slightly rhomboid in outline with a height of 9 - 10 mm and a width of 7.5 9.0 mm and its lower sides are slightly longer than the upper ones. The top and basic angles of the leaf cushion are truncate and the basic angle is slightly elongate. The upper part of the leaf cushion is strongly high-rising. The leaf sear is large and lenticular in shape. The leaf trace is wide and V-shaped in the leaf scar, and horizontally elongate within the leaf cushion. The leaf trace and lateral parichnos strand extend at a nearly horizontal course outward within the leaf cushion. The ligular pit is deep and extends outward at an oblique course and its aperture is located near the top angle of the leaf scar. No infrafoliar parichnos strands are present. The stem is probably siphonostelic and its pith is probably parenchymatous. The primary xylem is exarch with a nearly smooth outer margin. Only the outer cortex is present and it consists of alternately-arranged radial cell bands and gaps within which the are-shaped or V-shaped leaf traces can be seen. The concave side of the leaf trace is toward the center of the stem. No bundle sheath is developed. Periderm is well-developed and consists of phelloderm and phellem in nearly equal thickness. Compared with the lepidodendralean stems of the Cathaysian and Euramerican Floras, the present specimens are most close to an impression-compression species Lepidodendron pulchrum Zhang in morphology of the leaf cushion and they are put into this species temporarily. Whether the present specimens or the type specimens of L. pulchrum are very different from Lepidodendron Sternburg sensu DiMichele, thus the correct nomenclature and classification of L. pulchrum needs to be reconsidered based on the study of better- and anatomically-preserved stems and fertile organs 展开更多
基金supported by the National Natural Science Foundation of China under the Grant 41271070the West Light Foundation of Chinese Academy of Sciences under Grant 2015-XBQN-B-25
文摘A new Bergeria(Lepidodendrales, Flemingitaceae), B. wenquanensis sp. nov., is described in this paper, typically characterized by the longest and elongated leaf cushions ever found. The specimen, collected from the Mississippian of Wenquan County, Xinjiang Uygur Autonomous Region, China, is represented by a fossil stem about two meters long, with distinct leaf cushions. The genus Bergeria has usually been assigned to partially decorticated Lepidodendron stems. Although Cathaysian Lepidodendron have been extensively reported in China, most of them were found in the central, eastern and southern parts of the country, rarely in northwestern China. This new species is so far the westernmost record and the most isolated representative from the Cathaysian Lepidodendron center.Based on the distribution of the Cathaysian Lepidodendron during the Mississippian, most of the species were in the South China Plate near the Equator, while the new species is discrete in the north, far from the Equator. According to the spatiotemporal distribution of Cathaysian Lepidodendron, this genus appeared during the Mississippian, a period which was represented by rather few species, it flourished and expanded northwards during the Pennsylvanian, taking the north block of the South China Plate as the center. Since the Cisuralian to the Guadalupian, the genus became gradually sparser in all areas of distribution, probably due to strong climate change. During the Lopingian, the genus migrated southwards to the South China block and had a broader distribution range again, and it became extinct to the end of this interval. The new species is also significant for the evolution of Lepidodendron leaf cushions. During the Mississippian, the primitive species of Lepidodendron usually had narrow, fusiform leaf cushions, while the Pennsylvanian or Permian species were more variable in shape of leaf cushions, from inverted water-drop, rhomboidal, hexagonal, trapeziform to horizontal rhomboidal.
文摘The isolated and anatomically_preserved lepidodendralean leaf cushions were described from coal balls in Wangjiazhai Formation (upper Upper Permian) in western Guizhou Province. These leaf cushions are very similar to Lepidodendron lepidophloides Yao both in size and morphology. They probably belong to the same species in different preservative condition. Comparisons on morphology and anatomy of L. lepidophloides and lepidodendralean leaf cushion genera, such as Lepidodendron, Lepidophloios, Sigillaria and Cathaysiodendron revealed that L. lepidophloides possesses mixed features of all these genera and it can not be assigned into any of them without doubt. It probably represents a new genus. Because the anatomical features of the other parts of the stem as well as the fertile organs related to these leaf cushions are unknown, the specific name L. lepidophloides is adopted. We leave this taxonomic problem open till the relationship between these leaf cushions and the stem and fertile organs become clear. This is the first report on the detailed anatomical features of the Cathaysian lepidodendralean leaf cushions.
文摘This study reports the anatomical structures of a kind of lepidodendralean stem in coal balls from the early Early Permian Taiyuan Formation in Yanzhou Mining District, southwestern Shandong Province, North China. The leaf cushion is slightly rhomboid in outline with a height of 9 - 10 mm and a width of 7.5 9.0 mm and its lower sides are slightly longer than the upper ones. The top and basic angles of the leaf cushion are truncate and the basic angle is slightly elongate. The upper part of the leaf cushion is strongly high-rising. The leaf sear is large and lenticular in shape. The leaf trace is wide and V-shaped in the leaf scar, and horizontally elongate within the leaf cushion. The leaf trace and lateral parichnos strand extend at a nearly horizontal course outward within the leaf cushion. The ligular pit is deep and extends outward at an oblique course and its aperture is located near the top angle of the leaf scar. No infrafoliar parichnos strands are present. The stem is probably siphonostelic and its pith is probably parenchymatous. The primary xylem is exarch with a nearly smooth outer margin. Only the outer cortex is present and it consists of alternately-arranged radial cell bands and gaps within which the are-shaped or V-shaped leaf traces can be seen. The concave side of the leaf trace is toward the center of the stem. No bundle sheath is developed. Periderm is well-developed and consists of phelloderm and phellem in nearly equal thickness. Compared with the lepidodendralean stems of the Cathaysian and Euramerican Floras, the present specimens are most close to an impression-compression species Lepidodendron pulchrum Zhang in morphology of the leaf cushion and they are put into this species temporarily. Whether the present specimens or the type specimens of L. pulchrum are very different from Lepidodendron Sternburg sensu DiMichele, thus the correct nomenclature and classification of L. pulchrum needs to be reconsidered based on the study of better- and anatomically-preserved stems and fertile organs
