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 15 毫秒
1.
Permineralized rhizomes of two new species of Solenostelopteris Kershaw, S. leithii, and S. medlynii, are described from the Upper Jurassic Morrison Formation from the Steiner and Scott's localities north of Greybull, Wyoming, and from Fremont Junction, east of Mt. Ellen, and Mussentuchit Wash sites in Utah. The species are characterized by having a heterogeneous (S. leithii) to homogeneous (S. medlynii) pith, rhizomes with branches (S. leithii), a sclerenchymatous (S. leithii) or parenchymatous (S. medlynii) inner cortex, and both with a parenchymatous middle cortex. The outer cortex of S. leithii is parenchymatous, whereas in S. medlynii, it is composed of round to irregularly shaped, thick-walled cells. The C-shaped leaf traces in S. leithii usually arise single ranked, sometimes two ranked, with short leaf gaps and short internodes. Although the rhizomes of S. medlynii are incomplete and lack leaf traces, they still suggest very long internodes. Because fronds and epidermal trichomes are lacking in both, the affinity of these species to modern taxa, such as members of the Loxsomaceae, remains uncertain.  相似文献   

2.
3.
A tyrannosauroid dinosaur from the Upper Jurassic of Portugal   总被引:2,自引:0,他引:2  
Fragmentary theropod remains from the Upper Jurassic (Kimmeridgian) of Guimarota, Portugal, represent a new taxon of theropod dinosaurs, Aviatyrannis jurassica gen. et sp. nov. Together with Stokesosaurus from the Morrison Formation of North America, Aviatyrannis represents the oldest known tyrannosauroid, indicating that tyrannosauroid origins may be found in the Middle–Late Jurassic of Europe/North America. Furthermore, current evidence suggests that early tyrannosaurs were rather small animals, which is in general accordance with their origin amongst the generally rather small coelurosaurs.  相似文献   

4.
A male cone associated with Brachyphyllum expansum (Sternberg) is described from the Middle Jurassic of the Elburz Mountains in Northern Iran (Persia). The cone is described as M. rishra a new species of Masculostrobus Seward and the genus is emended to restrict its use for conifer male cones containing non-saccate pollen. M. rishra is compared with the cones occurring with B. expansum at the type locality of the latter in England. M. rishra contains pollen of the kind known as Classopollis torosus (Ressinger) sensu lat. and it is compared with the male cones of the Jurassic conifers, Cheirolepidium muensteri (Schenk), Brachyphyllum Scotti Kendall and Pagiophyllum connivens Kendall. The possibility that these conifers with similar male cones and pollen all belong to a single family, the Cheirolepidaceae, is suggested.  相似文献   

5.
From the Upper Jurassic flora of Andöya, Northern Norway, which is now under revision, Pseudotorellia heeri sp. nov. is described on cuticular characters. It has been shown that some specimens previously described by Heer as Baiera pulchella and Phoenicopsis latior from the same locality belong to the new species.  相似文献   

6.
A new lacewing species, Leptolingia shartegica sp. nov., (Grammolingiidae), from the Upper Jurassic of the Mongolian Shar-Teg locality is described.  相似文献   

7.
This paper reports two new species of Ginkgoales collected from the Cañada Alejandro and Río Ñumi (Zorrillo and Zorrillo–Taberna Undifferentiated Formations, Middle Jurassic). Thirty-one fossils were selected and compared with 14 species from different localities. A numerical taxonomy analysis was performed through a data matrix formed by 15 characters. Results indicate an important speciation process of the Ginkgoales during the Jurassic in the southeast of Mexico. New evidence suggests the existence of eight species from the Ginkgoidium Yokoyama, 1889 and Sphenobaiera (Florin) Harris and Millington, 1974 genera and two new species Ginkgoidiumnundichii Velasco-de León, Lozano-Carmona, Flores, Martínez and Silva and Sphenobaieramixteca Velasco-de León, Lozano-Carmona, Flores, Martínez and Silva  相似文献   

8.
The new goniopholidid crocodile Goniopholis baryglyphaeus sp. nov. from the Kimmeridgian of Guimarota/Leiria, Portugal is based on the oldest known relatively complete skeleton of Goniopholis from Europe and consists of a nearly complete skull together with a mandible and various postcranial remains. G. baryglyphaeus shows characters that hitherto have only been described for Goniopholis simus : a caudal expansion of the prefrontal that excludes the frontal from the medial margin of the orbit; and the loss of contact between the paroccipital process and the lateral surface of the squamosal and the quadrate, which exposes the cranioquadrate canal laterally. This new species can be distinguished from other European Goniopholis species by an articular facet placed ventral to the retroarticular process, and directed slightly medioventrally; a caudal margin of the mandible forming almost a right angle at its caudoventral corner; an almost square rostrolateral corner of the cranial table; a straight transverse suture between the parietal and the frontal with a median rostral process; a rostrally tapering wedge-like lacrimal, and a regular heavy skull-sculpturing. The new find of Goniopholis in Portugal shows that this genus was distributed in a larger area, and was present much earlier, than hitherto reported in south-western Europe.  相似文献   

9.
Exceptional fossilization of large tetrapod swimming traces occurs in the Cerin Lagerstätte (Jura Mountains, France). These trackways are imprinted in Jurassic (Late Kimmeridgian) lagoonal fine-grained limestones and are attributed to giant turtles, which swam with a simultaneous movement of their forelimbs like the modern ones. These turtles swam in very shallow waters close to land, perhaps near a nesting area. As a major consequence, these new ichnologic data place the origin of true large marine turtles during the Jurassic period and not during the Cretaceous period as previously considered on the basis of skeletal remains.  相似文献   

10.
Williamsonia nizhonia sp. nov., the first undoubted bennettitalean flower known from the Chinle Formation of Upper Triassic age in the south - western United States, is described in detail. The species is based on a single vertically compressed specimen collected from the Lower Red Member of the Chinle Formation near Fort Wingate in west-central New Mexico. It is rather small, the gynoecium is about 5 mm in diameter and is surrounded by a whorl often persistent sterile bracts about 1–5 cm long. The cuticles of the bracts and interseminal scales are 1 to 2 u thick. Stomata are only slightly sunken on the cuticles of the bracts and interseminal scales. Only a few hairs occur on the bracts. Williamsonia nizhonia cannot be attributed with any degree of confidence to either of the two bennettitalean leaves presently known in the Chinle flora.  相似文献   

11.
A new genus and species of raninoid crab, Carinatus galebishopi, is described from the upper Maastrichtian Prairie Bluff and Owl Creek formations of Mississippi. Carinatus galebishopi gen. et sp. nov. fits best within the Raninidae, Subfamily Symethinae, based upon similar dorsal carapace characteristics of member genera. The new crab possesses distinctive dorsal carapace ornamentation setting it apart from described symethines and warrants establishment of a new genus. Carinatus galebishopi represents the first Cretaceous symethine crab and suggests the subfamily may have migrated eastward across the North Atlantic—Maastrichtian of Mississippi, Danian of New Jersey, and Ypresian of Spain—before dispersing to the Indo-Pacific.  相似文献   

12.
From the Kimmeridgian (Upper Jurassic) of Portugal, the coralline sponge Sobralispongia densespiculata nov. gen. and nov. sp. is described. Main characteristics are a crustose habit, a primary spicule skeleton of very densely packed styles and subtylostyles arranged in a plumose architecture, microscleres of possibly aster-type, and a microgranular to fibrous secondary calcareous skeleton. The primary mineralogy of the calcareous skeleton was probably high-Mg calcitic. An assignment to the demosponge Order Axinellida is proposed.  相似文献   

13.
Gorochov AV 《ZooKeys》2011,(130):131-136
Alexarasniidaefam. n. and Alexarasnia rossicagen. et sp. n. are described from the Upper Permian of European Russia. Systematic position of this enigmatic family within the infraclass Polyneoptera is unclear.  相似文献   

14.
Two new lacewing species, Prohemerobius minor sp. nov. (Prohemerobiidae) and Sogjuta shartegica sp. nov. (Osmylidae), are described from Upper Jurassic deposits of the Mongolian locality Shar-Teg.  相似文献   

15.
A new fossil fish species, Aphanius yerevanicus (Cyprinodontiformes, Cyprinodontidae), is described based on a well-preserved, articulated skeleton from the early Upper Miocene of Yerevan, Armenia (Eastern Paratethys). The fish-bearing sediments contain a fossil assemblage indicative of a euryhaline environment. The new species differs from previously described fossil Aphanius species by the possession of caudal ribs articulating with the first haemal spine, a remarkably low number of abdominal vertebrae, and the morphology of the tricuspid jaw teeth. Co-occurrence of A. yerevanicus with Prolebias mutilus Bogachev, 1936 at Yerevan suggests that sympatric occurrence of several members of the Cyprinodontiformes continued successfully throughout the Miocene in euryhaline environments where competition between these forms and other fishes was low because of the unstable salinity.  相似文献   

16.
The Upper Kimmeridgian—basal Tithonian clastic sequence at Santa Cruz, Estremadura, represents environments ranging from river channels and flood plains to lagoons and protected bays showing a deltaic influence. Within the marginal marine environments, five benthic macroinvertebrate associations are recognized and analysed in terms of diversity and species composition. All five are thought to be controlled largely by salinity and to represent lowered and/or fluctuating salinity regimes. They can be grouped along a salinity gradient in which the Mesosaccella dammariensis—Corbulomima suprajurensis association, occurring in prodelta silts and marls, represents the closest approach to fully marine conditions and in which the Eomiodon securiformis association, typical of delta front sands, extends into the oligohaline regime. Banks of the Isognomon lusitanicum association and patch reefs of the Praeexogyra pustulosa—Nanogyra nana association are thought to be typical of brachy-to mesohaline conditions occurring in brackish bays and lagoons. Characteristic of the latter salinity regimes is also the Jurassicorbula edwardi association. The integrated approach, using benthic faunas, trace fossils and sedimentological data, leads to a detailed interpretation of the sedimentary sequences and the construction of a biofacies model which can also be used for other parts of the Lusitanian Basin.  相似文献   

17.
18.
A new species of Pseudotorellia Florin, Pseudotorellia papillata sp. nov., from the Middle Jurassic of Eastern Mangyshlak (Western Kazakhstan, Tonasha Formation) is described. The main distinction of the new species from the other species of this genus is the relief cutinization of periclinal walls of cells of the lower epidermis, especially within stomatal bands, expressed in prominent cuticular ridges and papillae of irregular shape.  相似文献   

19.
《Palaeoworld》2022,31(4):646-657
A few specimens previously assigned to Eretmophyllum, based on the gross leaf morphology, lack cuticular structures. In this paper, we describe a new species of Eretmophyllum from the Middle Jurassic Xishanyao Formation in the Turpan-Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, based on fossil leaves preserved as compressions, and characterized by paddle shapes with conspicuous petioles, retuse apices, entire margins and two veins dichotomously branched from near the base. Leaf amphistomatic, the cuticles are composed of stomatal and non-stomatal bands. Based on a detailed comparison of the gross morphology and cuticular structures with previously reported fossils, Eretmophyllum hamiensis n. sp. is erected. The presence of Eretmophyllum indicates that Middle Jurassic climate in the Turpan-Hami Basin was likely warm and humid. On the basis of the geological history and geographical distributions of Eretmophyllum, we conclude that the genus probably originated in Europe and migrated from Siberia to northwestern China during the Middle Jurassic.  相似文献   

20.
A new species of structurally preserved fern rhizome, Ashicaulis plumites (Osmundaceae, Filicales), is described from the Middle Jurassic Tiaojishan Formation in western Liaoning Province, NE China. The new species is characterized by a peculiar sclerenchyma mass in the petiolar vascular bundle concavity. This sclerenchyma mass varies from a linear-shape to a mushroom-like shape with a remarkable outward protuberance, which distinguishes the present new species from other Ashicaulis species. Such a protuberance is very rare among osmundaceous ferns, and should represent a unique type for sclerenchymatous tissue in the osmundaceous vascular bundle concavity. Recognition of the peculiar structure of this new fossil species enriches anatomical diversity of permineralized osmundaceous ferns, indicating that the family Osmundaceae might have experienced a remarkable diversification during the Middle Jurassic in NE China. The new species show anatomical similarities to Osmunda pluma Miller from the Palaeocene of North America. The occurrence of A. plumites in the Middle Jurassic of China provides a new clue for understanding the evolution of some members of the living subgenus Osmunda.  相似文献   

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