首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 343 毫秒
1.
Tolmacheva, T.JU., Degtyarev, K.E., Samuelsson, J. & Holmer, L.E., December, 2008. Middle Cambrian to Lower Ordovician faunas from the Chingiz Mountain Range, central Kazakhstan. Alcheringa 32, 443–463. ISSN 0311-5518.

The middle Cambrian to Lower Ordovician back-arc sedimentary succession studied in the Kol'denen River and in the Zerbkyzyl Mountains of the central Chingiz Mountain Range is composed predominantly of siltstones, sandstones and volcaniclastic rocks with rare beds of micritic carbonates, black shales and cherts. Fossil assemblages including conodonts, lingulate brachiopods, arthropods, sponges and probable Tasmanites cysts were recorded both from the carbonate and chert beds showing that richly diverse marine environments existed directly adjacent to the volcanic arcs. The Kol'denen River localities contain a diverse upper Cambrian paraconodont assemblage of the open-sea affinity. The representatives of Rossodus, Cordylodus, Drepanodus and Variabiloconus, having an almost pandemic distribution and characteristic of basinal facies, dominate the Lower Ordovician conodont fauna. The Cambrian–Ordovician boundary transition is characterized by chert production that was more likely caused by a local productivity increase than by general changes in palaeooceanographic and palaeogeographical conditions.  相似文献   

2.
Coutts, F.J., Gehling, J.G. & García-Bellido, D.C., August 2016. How diverse were early animal communities? An example from Ediacara Conservation Park, Flinders Ranges, South Australia. Alcheringa 40, xxx–xxx. ISSN 0311-5518

Fossils of the Ediacara biota record the earliest evidence of animal communities and, as such, provide an invaluable glimpse into the abiotic and biotic processes that helped shape the evolution of complex life on Earth. A diverse community of Ediacaran macro-organisms is preserved with high resolution in a fossil bed recently excavated from north Ediacara Conservation Park (NECP) in the Flinders Ranges, South Australia. Many of the commonly described Ediacaran taxa from the Flinders Ranges are represented on the bed surface and include: Parvancorina, Rugoconites, Spriggina, Dickinsonia, Tribrachidium, Kimberella, Charniodiscus and Yorgia, including two new taxa. Numerous additional fossil-bed fragments from the same locality were analysed that preserve a similar suite of taxa and shared sedimentology. On all surfaces, preserved microbial mat appeared complex, both in topography and in texture, and the unique combination of fine grainsize, high diversity and trace fossils provide insights into the palaeoecology of the ancient organisms that lived during the Ediacaran Period some 550 Ma. Several trace fossils are overlapped by body fossils, indicative of successive events, and complex organismal behaviour. The complexity of this fossil surface suggests that the primordial community was relatively mature and possibly at late-stage succession.

Felicity J Coutts [], School of Biological Sciences, University of Adelaide, Adelaide 5000, South Australia, Australia. James G Gehling [], South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia. Diego C. García-Bellido [], South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia.  相似文献   

3.
A new genus and species of fordilloid pelecypod, Pojetaia runnegari gen. et sp. nov., is described from the lower part of the Parara Limestone, Yorke Peninsula, South Australia. Establishing the age of the sample on an international scale is difficult, as with almost all Early Cambrian formations, but evidence tends to suggest that this is the oldest pelecypod so far recorded. Clearly defined hinge teeth and sockets on both valves and on internal moulds help to confirm the pelecypod placement of fordilloids.  相似文献   

4.
5.
Weihong He, Jianjun Bu, Zhijun Niu & Yang Zhang, June, 2009. A new Late Permian brachiopod fauna from Tanggula, Qinghai-Tibet Plateau and its palaeogeographical implications. Alcheringa 33, 113–132. ISSN 0311-5518.

A brachiopod fauna described from the Late Permian of the Gongri and Lizai villages, northwest of the Qoima Co Lake, Tanggula area, southern Qinghai, northwest China, includes ten species in nine genera. This fauna from the (Qiangtang Block) has a strong affinity to coeval faunas of South China, sharing 74% of its species. In addition, the Late Permian Tanggula brachiopod assemblages also demonstrate a clear link with the Middle Permian brachiopod faunas of neighbouring microcontinents including the Indochina block (Malaysia and Cambodia) and the Shan-Thai block (Thailand), as suggested by the presence of Caricula sp. cf. C. salebrosa, Transennatia termierorum and Strophalosiina. This phenomenon indicates that there were relatively narrow seaways between these microcontinents to enable ready interchange of brachiopods during the Permian, and that brachiopods tended to retreat towards the palaeoequatorial region throughout the period.  相似文献   

6.
Yang, T.L., He, W.H., Zhang, K.X., Wu, S.B., Zhang, Y., Yue, M.L., Wu, H.T. & Xiao, Y.F., November 2015. Palaeoecological insights into the Changhsingian–Induan (latest Permian–earliest Triassic) bivalve fauna at Dongpan, southern Guangxi, South China. Alcheringa 40, xxx–xxx. ISSN 0311-5518.

The Talung Formation (latest Permian) and basal part of Luolou Formation (earliest Triassic) of the Dongpan section have yielded 30 bivalve species in 17 genera. Eight genera incorporating 11 species are systematically described herein, including three new species: Nuculopsis guangxiensis, Parallelodon changhsingensis and Palaeolima fangi. Two assemblages are recognized, i.e., the Hunanopecten exilisEuchondria fusuiensis assemblage from the Talung Formation and the Claraia dieneri–Claraia griesbachi assemblage from the Luolou Formation. The former is characterized by abundant Euchondria fusuiensis, an endemic species, associated with other common genera, such as Hunanopecten, which make it unique from coeval assemblages of South China. A palaeoecological analysis indicates that the Changhsingian bivalve assemblage at Dongpan is diverse and represented by various life habits characteristic of a complex ecosystem. This also suggests that redox conditions were oxic to suboxic in deep marine environments of the southernmost Yangtze Basin during the late Changhsingian, although several episodes of anoxic perturbations and declines in palaeoproductivity saw deterioratation of local habitats and altered the taxonomic composition or population size of the bivalve fauna.

Tinglu Yang [], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Weihong He* [] and Kexin Zhang [], State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China; Shunbao Wu [], Yang Zhang [], Mingliang Yue [], Huiting Wu [] and Yifan Xiao [], School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Hongshan, Wuhan 430074, PR China.  相似文献   


7.
Benson, R.B.J., Fitzgerald, E.M.G., Rich, T.H. & Vickers-Rich, P., 2013. Large freshwater plesiosaurian from the Cretaceous (Aptian) of Australia. Alcheringa 37, 1–6. ISSN 0311-5518

We report a large plesiosaurian tooth from the freshwater early–middle Aptian (Early Cretaceous) Eumeralla Formation of Victoria, Australia. This, combined with records of smaller plesiosaurian teeth with an alternative morphology, provides evidence for a multitaxic freshwater plesiosaurian assemblage. Dental and body size differences suggest ecological partitioning of sympatric freshwater plesiosaurians analogous to that in modern freshwater odontocete cetaceans. The evolutionarily plastic body plan of Plesiosauria may have facilitated niche differentiation and helped them to exclude ichthyosaurs from freshwater environments during the Mesozoic. However, confirmation of this hypothesis requires the discovery of more complete remains.

Roger B.J. Benson [roger.benson@earth.ox.ac.uk], Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK; Erich M.G. Fitzgerald [efitzgerald@museum.vic.gov.au], Thomas H. Rich [trich@museum.vic.gov.au], Museum Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia; Thomas H. Rich and Patricia Vickers-Rich [pat.rich@monash.edu], School of Geosciences, Monash University, Clayton, Victoria 3800, Australia. Received 30.10.2012; revised 27.1.2013; accepted 31.1.2013.  相似文献   

8.
Anderson, H.M., Barbacka, M., Bamford, M.K., Holmes, W.B.K. & Anderson, J.M., 3 July 2019. Pteruchus (microsporophyll): part 2 of a reassessment of Gondwana Triassic plant genera and a reclassification of some attributed previously. Alcheringa XXX, X–X. ISSN 0311-5518

The microsporophyll genus Pteruchus, belonging to the pteridosperms (seed ferns) in the family Umkomasiaceae (Corystospermaceae), is reassessed comprehensively worldwide and emended. All records are analysed, and some fertile structures previously attributed are reclassified. The Lower Jurassic record of Pteruchus from Germany is ascribed to a new genus as Muelkirchium septentrionalis. Pteruchus is shown to be restricted to the Triassic of Gondwana and is clearly affiliated with the megasporophyll genus Umkomasia and the vegetative leaf genus Dicroidium. It is well represented from Argentina, Antarctica, Australia and southern Africa; the Molteno Formation of southern Africa is by far the most comprehensively sampled, yielding three species and 425 specimens from 22 localities. Nomenclatural problems with the species of Pteruchus are addressed. A key to Pteruchus species is provided; geographic and stratigraphic distributions are tabulated.

Heidi M. Anderson [], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; Maria Barbacka [], W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland; Hungarian Natural History Museum, Botanical Department, H-1431 Budapest, Pf. 137, Hungary; Marion K. Bamford [], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa; W.B. Keith Holmes* [], 46 Kurrajong Street, Dorrigo, NSW 2453, Australia; John M. Anderson [], Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg 20150, South Africa. *Also affiliated with: University of New England, Armidale, NSW 2351, Australia.  相似文献   

9.
Brea, M., Zamuner, A.B., Matheos, S.D., Iglesias, A. & Zucol, A.F., December, 2008. Fossil wood of the Mimosoideae from the early Paleocene of Patagonia, Argentina. Alcheringa 32, 427–441. ISSN 0311-5518.

An anatomically preserved mature stem from the Salamanca Formation (early Paleocene) at Palacio de Los Loros, central Patagonia, Argentina, is described and assigned to Paracacioxylon frenguellii sp. nov. The material was preserved by siliceous permineralization and shows features of the secondary xylem typical of subfamily Mimosoideae. This species represents the oldest record of the genus and of the Leguminosae along the western border of Gondwana, and is the world's second oldest record of Leguminosae wood. The species is characterized by ring-porous to semi-ring-porous vessels that are solitary, in multiples of 2–4 and clustered, simple perforation plates, alternate and vestured inter-vessel pitting, homocellular 1–6 seriate rays, tyloses, crystals and diffuse apotracheal, vasicentric paratracheal and confluent axial parenchyma. Paracacioxylon frenguellii has anatomical similarities to Acacia Miller. The presence of Paracacioxylon frenguellii associated with pulvinate leaves suggests that the legumes might have been a component of mesothermal forests developed along the western margin of the Golfo San Jorge Basin during the early Paleocene.  相似文献   

10.
Aye Ko Aung, Ng Tham Fatt, Kyaw Kyaw Nyein & Myo Htut Zin, 2013. New Late Permian rugose corals from Pahang, peninsular Malaysia. Alcheringa 37, 422–434. ISSN 0311-5518.

Late Permian rugose corals are described from a limestone unit of the Gua Musang Formation at Selborne Estate, Padang Tengku area, Pahang, peninsular Malaysia. These include one genus, Iranophyllum, which is reported for the first time from Malaysia, with two new species Iranophyllum aequabilis and I. pahangense belonging to Waagenophyllidae. A Late Permian age is confirmed by a Paleofusulina–Colaniella–Reichelina foraminiferal fauna co-preserved with the corals.

Aye Ko Aung [akaung.mm@gmail.com], Ng Tham Fatt [thamfatt@gmail.com], Kyaw Kyaw Nyein [konyein@gmail.com], Department of Geology, University of Malaya, 50603, Kuala Lumpur, Malaysia and Myo Htut Zin [myohtutgreat@googlemail.com], Lab. Services, Pte. Co. Ltd., Singapore. Received 16.10.2012; revised 5.1.2013; accepted 17.1.2012.  相似文献   

11.
Li, L.-Y., Zhang, X.-L., Yun, H. & Li, G.-X., October 2015. New occurrence of Cambroclavus absonus from the lowermost Cambrian of North China and its stratigraphical importance. Alcheringa 40, xxx–xxx. ISSN 0311-5518.

The problematic Small Shelly Fossil Cambroclavus absonus is described from the Xinji Formation in the Longxian area, which is located near the southwestern margin of the North China Platform. The Xinji Formation, the basal rock unit of the Cambrian in the studied area, yields an assemblage of skeletal fossils that share many common elements with contemporary faunas from South Australia. Sclerites of C. absonus reported herein represent the first occurrence of the species outside Australia, thus extending the palaeogeographic range of the taxon to northern China. To date, palaeogeographic occurrences of Cambroclavus sclerites are restricted to the Peri-Gondwana realm, including South China, Australia, Tarim, Kazakhstan, North China and Western Europe. These occurrences are divided into a Southern Group realm and Northern Group realm. Stratigraphically, Cambroclavus occurs mostly in Cambrian Stage 3 and has three occurrences in Stage 5, separated by Stage 4 in which Cambroclavus has not yet been found. The first appearance datum of Cambroclavus in Cambrian Stage 3 is of importance for regional and inter-regional correlations. In particular, the presence of Cambroclavus absonus in North China allows species-level correlation between North China and South Australia.

Luoyang Li [], Xingliang Zhang [], Hao Yun [], Early Life Institute and State Key Laboratory Of Continental Dynamics, Department of Geology, Northwest University, Xian 710069, PR China; Guoxiang Li [], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, PR China.  相似文献   


12.
Ghobadi Pour, M., 21 June 2019. Ordovician trilobites from Deh-Molla, eastern Alborz, Iran. Alcheringa 43, 381–405. ISSN 0311-5518

Seventeen species from 14 genera of Tremadocian and Darriwilian trilobites, plus two taxa recognizable only down to family level, have been documented from the Lower to Middle Ordovician succession of the Deh-Molla area, southeast of Shahrud in northern Iran. Two species, Asaphellus intermedius and Conophrys multituberculatus, are new to science. Unlike previously documented Iranian faunas, the early Tremadocian trilobite assemblage is characterized by proliferation of the olenid Chungkingaspis sinensis, which is also known as the eponymous taxon of the basal Ordovician trilobite biozone in South China. This is the first record of the occurrence of the olenid biofacies in the Ordovician of Iran. Overall, both the Tremadocian and Darriwilian trilobite assemblages show distinct similarity to the contemporaneous faunas of South China down to species level. Trilobite-based correlation with the Ordovician succession of South China confirms the existence of a hiatus at the base of the Ordovician succession in the eastern Alborz and a significant gap, with the upper Tremadocian, Floian and Dapingian parts of the succession completely missing in Deh-Molla.

Mansoureh Ghobadi Pour and ], Department of Geology, Faculty of Sciences, Golestan University, Gorgan 49138-15739, Iran. *Also affiliated with Department of Natural Sciences, Natural Museum of Wales, Cardiff, Cathays Park, Cardiff CF10 3NP, UK.  相似文献   

13.
?erňanský, A. & Hutchinson, M.N., 2012. A new large fossil species of Tiliqua (Squamata; Scincidae) from the Pliocene of the Wellington Caves (New South Wales, Australia). Alcheringa, 1–6. ISSN 0311-5518.

We describe an isolated frontal bone referable to a new species, Tiliqua laticephala (Scincidae), from the Pliocene Big Sink doline of the Wellington Caves, central eastern New South Wales, Australia. The bone is very robust, is unusually broad and thick, especially around the bases of the subolfactory processes and represents a large and heavily built lizard. The fossil has multiple fragmentary osteoderms in the frontal region, showing asymmetry in shape and thickness that do not correspond to the more regularly arranged anterior head shields of other scincoids. The specimen shares two unusual character states with extant Tiliqua, especially the large armoured species, T. rugosa. Other large skinks related to T. rugosa (other Tiliqua spp., Corucia zebrata, Egernia cunninghamii, Bellatorias major, Liopholis kintorei) are less similar in terms of frontal shape, thickness, sculpture, osteoderm ornamentation, and positioning of adjacent bones.  相似文献   

14.
Pan, B., Skovsted, C.B., Sun, H.J. & Li, G.X., 18 June 2019. Biostratigraphical and palaeogeographical implications of Early Cambrian hyoliths from the North China Platform. Alcheringa 43, 351–380. ISSN 0311-5518.

A succession of diverse hyolith assemblages comprising 10 genera and 14 species are reported from the lower Cambrian Shangwan and Sanjianfang sections of the Xinji Formation, and Xiaomeiyao section of the Houjiashan Formation, which crop out along the southern margin of the North China Platform. Most of the specimens are represented by both conchs and opercula. The identified orthothecids include Conotheca australiensis, Cupitheca holocyclata, C. costellata, Neogloborilus applanatus, N. spinatus, Tegminites hymenodes, Triplicatella disdoma, T. xinjia sp. nov. and Paratriplicatella shangwanensis gen. et sp. nov. The hyolithids comprise Protomicrocornus triplicensis gen. et sp. nov., Microcornus eximius, M. petilus, Parkula bounites and Parakorilithes mammillatus. Some anomalous taxa possess characteristics of both Hyolithida and Orthothecida, such as C. australiensis, Neogloborilus and P. triplicensis. Protomicrocornus may constitute a sister group of other hyolithids. The teeth of Parkula bounites and clavicles of Parakorilithes mammillatus are documented for the first time. The hyolith assemblages from North China are probably coeval, and can be correlated with the Cambrian upper Stage 3–lower Stage 4. Many taxa are also globally distributed and have significant potential for biostratigraphical correlations. In accordance, the hyoliths from North China reveal closest compositional similarities to faunas from eastern Gondwana, and especially South Australia. However, some taxa are shared with Laurentian assemblages suggesting cosmopolitanism, and possibly planktonic larval dispersal.

Bing Pan* [], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, PR China; Christian B. Skovsted [], Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden; Haijing Sun [], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, PR China; Guoxiang Li [], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, PR China. *Also affiliated with: University of Science and Technology of China, Hefei 230026, PR China and Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden.  相似文献   

15.
A small assemblage of isolated Microdictyon plates is described from the lower Cambrian Ajax Limestone, Mt Scott Range (Flinders Ranges), South Australia. Microdictyon plates are primarily known from single, isolated, perforated phosphatic sclerites; only one species (M. sinicum) from the Chengjiang Lagerstätte is known from soft-bodied preservation of the complete organism. The isolated plates from South Australia display a wide range of morphologies potentially reflecting: 1, considerable diversification within the group at this time; 2, extensive intraspecific morphological variation; 3, different plate morphotypes along the trunk of the animal; or 4, significant ontogenetic variation in successive growth stages. The South Australian specimens are similar to several individual sclerites described from other Cambrian palaeocontinents, but appear closest to faunas described from South China. Problems associated with the taxonomy of isolated Microdictyon plates are discussed, including the lack of knowledge associated with intraspecific and/or ontogenetic variability and how individual plate morphology may relate to size or relative position along the length of the complete organism.  相似文献   

16.
Wang, Z-B., Gao, J-H., Wang, G-H. &; Kang, Z-H., June 2018.2018. Foraminiferal biostratigraphy and facies analysis of the Permian Longge Formation in the Rongma Area, Tibet, China: implications for the palaeogeography of the South Qiangtang Block. Alcheringa XX, x–x.

The Permian Longge Formation in the South Qiangtang Block, Tibet, is overwhelmingly composed of carbonate rocks with various skeletal (brachiopods, foraminifers, gastropods, echinoderms, ostracods, corals, bivalves, algae, and bryozoans) and non-skeletal (intraclasts and ooids) components. Three stratigraphic sections of the Longge Formation in the Rongma area of north-central Tibet—known as South Yibug Caka, Niushan and East Yibug Caka—were selected for this study, which examined both sedimentary facies and foraminiferal assemblages. The foraminifers in these sections consist of at least 38 species belonging to 18 genera. Based on the distribution of the foraminifers throughout the composite section, two foraminiferal assemblages were established, and the age of the Longge Formation was determined to be late Kungurian to Capitanian. During lithological studies, ten microfacies were identified using depositional textures, petrographic analysis and faunal content: mudstone, bioclast wackestone, bioclast perforated-foraminifera packstone, bioclast crinoid grainstone, intraclast wackestone, breccia, intraclast grainstone, ooid grainstone, fine crystalline dolostone and residual-grain dolostone. These microfacies are interpreted to represent four depositional environments—restricted lagoon, open marine, shoal and slope—which together suggest a shoal-rimmed carbonate platform. The non-fusuline foraminifers show transitional palaeobiogeographic affinities (Tethyan Cimmerian subregion), and the assemblage is considered to be influenced by the northward drift of the South Qiangtang Block, the climatic warming after the Late Paleozoic Ice Age and warm-water oceanic currents caused by the newly formed Neotethys Ocean. This indicates that the South Qiangtang Block was located in a relatively warm-water, low-latitude area during the middle Permian. The Permian depositional sequences in the Rongma area were also influenced by the palaeogeographic evolution of the South Qiangtang Block.

Zhong-Bao Wang [] and Zhi-Hong Kang [] School of Energy Resource, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China; Jin-Han Gao* [] and Gen-Hou Wang [] School of Earth Sciences and Resources, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China.  相似文献   

17.
Meor, H.A.H., Yong, A.M., Zakaria, M.Z.Z. & Ghani, A.A., 2.6.2015. First record of Homoctenus (Tentaculitoidea, Homoctenida) from the Late Devonian of northwest Peninsular Malaysia. Alcheringa 39, 550–558. ISSN 0311-5518.

The homoctenid tentaculitoid genus Homoctenus is reported for the first time from Peninsular Malaysia. The fossils derive from the Upper Devonian Sanai Limestone, exposed in the state of Perlis, northwest Peninsular Malaysia. The fossils are closely related to Homoctenus tenuicinctus tenuicinctus and are described as Homoctenus sp. cf. H. tenuicinctus. The homoctenids were recovered from an interval containing a rich conodont assemblage, indicating a Frasnian age (Palmatolepis linguiformis Zone).

Meor Hakif Amir Hassan [], Yong Adilah Mustafa [], Mohamad Z.Z. Zakaria [], Azman A. Ghani [], Geology Department, University of Malaya, 50603 Kuala Lumpur, Malaysia. Received 12.4.2015; revised 27.5.2015; accepted 2.6.2015.  相似文献   

18.
Camilleri, T.A., Warne, M.T., Holloway, D.J. & Weldon, E.A., 10 May 2019. Revision of the ostracod genus Velibeyrichia Henningsmoen, 1954 from the Silurian and Lower Devonian of North America. Alcheringa XXX, X–X. ISSN 0311-5518.

Known occurrences of the ostracod genus Velibeyrichia are restricted to a number of Silurian to Lower Devonian geological strata in North America: the McKenzie Member of the Mifflintown Formation of Maryland and West Virginia; the Tonoloway Limestone of Maryland, West Virginia, Virginia and Pennsylvania; the Bloomsburg Formation of Maryland, Virginia and Pennsylvania; the Manlius Limestone of New York; and the Decker Limestone of New Jersey and New York. The genus includes six species: V. moodeyi (type species), V. mesleri, V. paucigranulosa, V. reticulosaccula, V. tonolowayensis and V. tricornia. The diagnostic combination of characters for this genus are: distinct deflection of the velum where it crosses the crumina in heteromorphs (adult female specimens), dorsal nodes on lobes L1 and L3, sexual dimorphism of the velum, and in tecnomorph specimens, either a shallow sulcus on lobe L3 or a zygal ridge (in adult tecnomorph specimens) extending from lobe L2 to lobe L3. The presence of one or the other of the latter two characters defines two distinct species groups.

Tamara T.A. Camilleri* [], Mark T. Warne* [] and Elizabeth A. Weldon [], Deakin University, Geelong, School of Life and Environmental Sciences & Centre for Integrative Ecology (Melbourne Campus), 221 Burwood Highway, Burwood, Victoria 3125, Australia; David J. Holloway [], Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia. *Also affiliated with: Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia.  相似文献   

19.
Wang Yi, Fu Qiang, Xu Honghe, & Hao Shougang, June, 2007. A new Late Silurian plant with complex branching from Xinjiang, China. Alcheringa 31, 111-120. ISSN 0311-5518.

A new fossil plant is described from the middle part of the Wutubulake Formation (late Pridoli) of Xinjiang, China. This plant demonstrates at least two orders of branching. The first-order axis has pseudomonopodial branching with alternately attached second-order axes. Fertile units are alternately inserted along the second-order axis, and consist of a branching system and two sporangia at each tip. Sporangia are narrowly obovate with rounded apex and tapering base. This plant is characterized by more complex branching than other Silurian and Early Devonian plants, and is named Wutubulaka multidichotoma gen. et sp. nov., and placed under open higher-order nomenclature.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号