共查询到20条相似文献,搜索用时 15 毫秒
1.
A dinosaur vertebra found in the course of road works in the “Chevain Marls” (marine Callovian) of the Vermont outlier, near the village of Béthon (Sarthe, Pays-de-la-Loire, western France) is described and referred to a stegosaur (cf. Lexovisaurus). It is the first record of a dinosaur in the Middle Jurassic of that area. The specimen was probably derived from the floating carcass of an animal that had lived on the emerged areas of the Armorican Massif, near which the Chevain Marls were deposited. This fossil is an addition to the short list of stegosaur remains reported from France. 相似文献
2.
For the first time, remains of post-Triassic temnosponyls are described from the southern Junggar Basin (NW China). Middle Jurassic material from the uppermost part of the Toutunhe Formation consists of several isolated but well preserved skull bones and intercentra from all regions of the body that can be attributed to a brachyopid. The material in part shares important autapomorphies with Gobiops desertus Shishkin, 1991, from the Upper Jurassic of Outer Mongolia, and is consequently referred to this taxon, partially with reservation. This represents the first record of this genus from China. It also yields new anatomical data and permits an emended diagnosis. Ferganobatrachus from the Middle Jurassic of Kirghisia is probably, as also shown by the new material, congeneric with Gobiops. Two fragmentary specimens from the lower part of the Upper Jurassic Qigu Formation are tentatively referred to the Brachyopoidea because of features of the skull, mandible and vertebral column. They probably both represent a single taxon that was larger and more massively built than Gobiops desertus but closely related to this form. 相似文献
4.
Four new ambocoeliid species, Ambocoelia ectypa sp. nov., Echinocoelia tikhiensis sp. nov., Emanuella takwanensis (Kayser), and Ladjia sita sp. nov., from the Givetian of the southern Verkhoyansk Region are described (northeastern Russia). 相似文献
5.
Summary The Sikhor Formation (new) is a predominantly siliciclastic sediment package intercalated between the marly-silty Baghamshah Formation (below) and the calcareous Esfandiar Limestone and Qal'eh Dokhtar Limestone formations (above). All stratigraphic evidence points to an Early Callovian age of the formation. The Sikhor Formation is restricted to the southern and central Shotori Mountains and consists of two members: The Kuh-e-Neygu Member (new) is composed of fluvialdeltaic conglomerates, sandstones, and siltstones grading into marly silt of the Baghamshah Formation. The overlying Majd Member (new) is characterised by mixed siliciclastic-carbonate sediments that record the interfingering of carbonate ramp sediments with fluvialdeltaic sands and silts. Evidence of erosional truncation of the underlying Baghamshah Formation and confinement of the siliciclastic sediment to a comparatively narrow, NNW-SSE elongated strip suggest that the formation had its origin in the asymmetric uplift of a westdipping tilted fault block in the southern Shotori Mountains that shed its sediment predominantly in a northern and eastern direction. After erosional levelling, the former uplifted areas were overgrown by the highly productive Esfandiar Carbonate Platform. The Sikhor Formation thus is evidence of an extensional tectonic pulse in the early Callovian and underlines that this area of the Tabas Block was a tectonically highly unstable area during most of the Jurassic. 相似文献
6.
Two associated incomplete thyreophoran dorsal vertebrae from the Callovian Marnes de Dives Formation of the Vaches Noires cliffs, on the Normandy coast, are referred to an indeterminate stegosaur that appears to be different from Lexovisaurus, previously reported from the Callovian of western France. These vertebrae are the first evidence of thyreophorans from the Vaches Noires and complement the dinosaur assemblage from this locality, which hitherto consisted of several theropod taxa and an indeterminate sauropod. The dinosaur record from the Vaches Noires is heavily dominated by theropods and this imbalance is difficult to explain. A possible explanation may be that the dinosaur sample from the Vaches Noires is too small to be statistically significant and representative of the original faunal assemblage from which it is derived. 相似文献
7.
Brachiopods from the Kasimovian Stage of the Moscow Region that for more than 70 years were referred to the genus Linoproductus (family Linoproductidae) are revised and redescribed. New characters connected with the ornamentation and inner structure of the dorsal valve are used for the first time in the analysis of the taxonomic structure of the group. Six species from three genera are described; four of them are new: one species of Linispinus Lazarev, 2006, three species of Linipalus Lazarev, 2007, and two species of Sublinoproductus gen. nov. The new genus is considered to be transitional between the genera Linispinus and Linoproductus. 相似文献
8.
Microencrusters and microtaphonomic features of the Oxfordian spongiolithic limestones of the External Prebetic were studied using thin-section analysis. The spongiolithic limestone is a bioclastic-rich packstone with common echinoderm, mollusc and brachiopod remains. The bioclasts show a high fragmentation index and frequent microborings. The encrustation index ( E i) is higher for fragments of serpulids, ammonoids and bivalves, and increases with the initial grain-size of bioclasts. The main microencrusters consist of benthic microbial communities (BMC) and nubeculariids, as well as subordinate calcareous and siliceous agglutinated foraminifera, serpulids and bryozoans. BMC are usually the first colonizers, and encrusting foraminifera mainly appear on bioclasts larger than 2 mm. BMC dominate in well-developed encrustations on upward facing surfaces of larger bioclasts that are also colonized by foraminifera (nubeculariids and Subdelloidina). Bullopora, serpulids and bryozoans are more common on lower surfaces. The fact that the values of encrustation index, encrustation thickness and diversity of the microencrusters increase with the size of bioclasts is related to a higher stability and exposure time of the available bioclastic substrate. The microencruster distribution on upper and lower surfaces of large bioclasts may be related to photic control, space competition and/or predation avoidance. 相似文献
9.
The genus Eckhardites Mitta 1999, with the type species Macrocephalites pavlowi Smorodina, 1928 is discussed and its diagnosis and assignment to the family Cardioceratidae are substantiated. Eckhardites is compared to the genus Macrocephalites Zittel (family Sphaeroceratidae), to which some workers presently assign the type species of Eckhardites. Three species of Eckhardites are recorded from the basal Callovian elatmae Zone of the Russian Platform, one of which ( E. menzeli (Mönnig)) was originally described from the synchronous beds in Germany. A new species E. dietli sp. nov. is described. 相似文献
10.
Callovian strata in northern Lithuania (Papilė area) have yielded some crinoid taxa [Chariocrinus andreae ( Desor), Balanocrinus berchteni Hess — Pugin, B. subteres ( Münster in Goldfuss) and Isocrinus nicoleti ( Desor)], which have not been described from this area. The only form known previously was Balanocrinus pentagonalis ( Goldfuss). Palaeocomaster jaegeri n. sp. is the first free-living crinoid recorded from the Callovian of eastern Europe. It is characterized by possessing a very low, strongly flattened and narrow radial cavity. A very similar crinoid assemblage is known from the Callovian glacially-derived clays exposed in the Łuków region (eastern Poland), which were originally located near the Baltic Sea during the Middle Jurassic. It is considered that the allochthonous Callovian deposits from Poland are facies equivalents of the deposits known from Lithuania. The sole significant exception is the domination of free-moving comatulids (Comatulida) in the sediments known from the Papilė region, which may suggest that the Lithuanian sea basin was a little shallower than that located farther west in the Baltic area. 相似文献
11.
A new specimen of the widespread Middle Jurassic to Lower Cretaceous Asian gonipholidid crocodilian genus Sunosuchus is described on the basis of a partial skeleton from the Upper Toutunhe Formation (Middle Jurassic, ?Bathonian-Callovian) of Liuhonggou, SW of Urumqi, Xinjiang Uygur Autonomous Region, People’s Republic of China. The specimen is represented by a partial mandible, teeth, vertebrae, limb and girdle bones and osteoderms. It can be distinguished from other nominal species of the genus by a unique combination of characters: slightly heterodontous dentition, strongly sculptured posteroventral part of the mandible, short fenestra mandibularis, convex dorsal surface of the retroarticular process, keeled cervical vertebral centra and ventral osteoderms with a distinctive sculpture of wide pits and narrow ridges. The heterodontous dentition is a potential autapomorphy of this form. The new specimen is closest in morphology to material described recently from the Callovian of Kirghisia as Sunosuchus sp. It represents the second Middle Jurassic record of the genus, the first crocodile from the Toutunhe Formation, the first substantial crocodile find from the Mesozoic of the Southern Junggar Basin, and the first Middle Jurassic record of Sunosuchus from China. This extends both the paleobiogeographical distribution of the genus in Asia and its stratigraphic distribution in China considerably. 相似文献
12.
Late Middle Jurassic dinoflagellate cyst assemblages are documented from a section in Kandern and in samples from additional localities in southern Germany. The changes in the composition of the marine microfloras through the Callovian sections are related to fluctuations in sea-levels and changes in depositional environments. The Lower Callovian claystones, which represent inner shelf, soft bottom deposits, contain rich, diverse and well preserved dinoflagellate cyst assemblages. In the Kandern section a marked transition from the Lower Callovian claystone facies to the Anceps-oolite occur within the Calloviense zone. This transition was caused by a regression, and coincides with the LZA−3.1/LAZ−3.2 boundary on the cycle chart of Haq et al. (1987). Diverse dinoflagellate cyst assemblages also occur in the Anceps-oolite, but they are not so abundant as the acritarchs which dominate the overall palynofloras. The Anceps-oolite is interpreted as representing an offshore, but shallow marine environment. The transition to the overlying Upper Callovian “Renggeri Clay” is more gradual, but accompanied by marked changes in the overall composition of the marine microfloras. The “Renggeri Clay”, which represent an outer shelf, soft bottom depositional environment, shows a higher species diversity and abundance of dinoflagellate cysts than the underlying sequences. The distribution pattern of selected species through the Kandern section indicates that some species were related to specific environments, i.e. open marine forms, and that others could have been opportunistic forms, tolerating more shallow marine environments. The distribution of the dinoflagellate cysts from southern Germany is related to the standard Northwest European ammonite zonation. The ranges of selected biostratigraphic key species are compared with ranges previously reported from the British and northwest European Jurassic. There are several discrepancies with respect to the earliest appearance and extinction datums, the only relevant Callovian palynostratigraphic “events” coinciding in southern Germany and Britain being: The extinction of Aldorfia aldorfensis at the top of the Calloviense zone, and the earliest incoming of Belodinium spp. and Liesbergia scarburghensis at the base of the Lamberti zone. 相似文献
13.
The four sections richest in bivalves from the Middle and Upper Jurassic of the Iberian Range (Spain) were selected for a quantitative palaeoecological analysis of the bivalve fraction of the macrobenthos. Five bivalve associations and two assemblages were recognized with the help of a Q-mode hierarchical cluster analysis (Ward method). The main environmental factors controlling bivalve associations are thought to be substrate, water energy and distribution of organic matter. The bivalves exhibit a distinct spatial and temporal distribution pattern within the Aragonian Branch of the Iberian Range. Four of the bivalve associations occur in the Upper Oxfordian (Sot de Chera Fm) and one association in the Lower Callovian (Chelva Fm). In the Sot de Chera and Loriguilla formations, the abundance of bivalves decreases from NW to SE i.e., from relatively close to the shore line towards the distal-most part of the carbonate platform. In the Chelva Fm, bivalves are abundant in the Ariño region, interpreted as a palaeogeographic high. The spatial distribution of bivalves might have been largely controlled by the availability of nutrients. 相似文献
14.
Compressed seed cones and pollen cones of Sewardiodendron laxum are described from the Middle Jurassic of Yima, Henan, central China. They are either organically attached to or associated with leafy shoots. Seed cones are terminally borne. Each cone is ovate to elongated, up to 6.5 cm long and 3.5 cm wide, and consists of a stout axis and numerous helically arranged bract-scale complexes. The bract protrudes beyond and is partially fused with the reduced ovuliferous scale. The ovuliferous scale bears approximately six inverted, small, and flattened seeds. Pollen cones are borne in terminal clusters. Microsporophylls are helically arranged, each bearing three abaxial, basally fused pollen sacs. Pollen is assaccate, rounded, and with an inconspicuous pore. Morphological, structural, and cuticular features of seed cones, pollen cones, and leafy shoots of S. laxum are compared with those of fossil and extant conifers. S. laxum is included in Taxodiaceae and believed to have its closest affinities with a Mesozoic conifer Elatides and a group of Cunninghamia-like conifers. It is reconstructed as a half-evergreen tree that lived in a humid, warm-temperate climate. 相似文献
15.
Samples were taken from the top 10 cm of soils from 24 points in the Ein Gedi area. Among 329 isolates, 142 species were identified: 11 genera of ascomycetes, one genus of coelomycetes, 28 genera of hyphomycetes, 7 genera of zygomycetes and one yeast, in addition to some unidentified basidiomycetes. The hyphomycetes were represented by 17 dematiaceous, 9 mucedinaceous and two tuberculariaceous. Melanconiaceous and stilbellaceous genera were not found. Two new varieties of Microascus recently described were reisolated. No strict thermophiles or halophiles were obtained. There is apparently no very characteristic or specific fungal flora of the Dead Sea Oases although it was different from that found in the desert soil surrounding this area. 相似文献
16.
New brachiopods of the suborder Delthyridina Ivanova (order Spiriferida) from the Lower and Middle Devonian of northeastern Russia, Ivanothyris costatus sp. nov. (subfamily Delthyridinae), Eoreticularia lata sp. nov., Yania gen. nov. with the type species Y. tumida sp. nov. (subfamily Eoreticulariinae), Reticulariopsis equitans Modzalevskaya, and R. (?) borealis sp. nov. (subfamily Reticulariopsinae) are described. 相似文献
17.
A tetradactyl pes impression and tridactyl manus impression are described as the type specimen of Hatcherichnus sanjuanensis ichnogen. et ichnosp. nov., a probable large crocodilian ichnite from the Salt Wash Member of the Upper Jurassic Morrison Formation in eastern Utah. A similar pes track from the Morrison Formation at Garden Park, Colorado, may also belong to this ichnogenus. The type specimen from Utah consists of plaster replicas of natural casts of a left pes impression and a left manus impression. Associated with the type specimen were possible tail and body drag impressions. The tracks do not appear to be part of a walking trackway and may be swim tracks associated with an animal in shallow water. The tracks occur at a visible contact between slightly fining‐upward channel sandstone units. 相似文献
18.
New paleontological data on Sestrosphaera liasina (Pia) based on material collected in the type-locality, Malga Mandrielle (Italian Southern Alps) are supplied. All the features of the alga are reexamined; the occurrence in the stalk region of an unusual primary lateral inner swelling is confirmed. The structure formed by the inner enlarged portion of the laterals is here indicated as inner pseudocortex. A new diagnosis of S. liasina is proposed and a lectotype is chosen from Pia's material. Finally, a paleontological reconstruction is supplied taking into account all the main biometrical values. 相似文献
19.
Four new species of mayfly nymphs, Furvoneta relicta sp. nov., Clavineta eximia sp. nov. (originally Mesoneta antiqua), Mesobaetis latifilamentacea sp. nov., and Stackelbergisca cylindrata sp. nov. are described from the Jurassic of China. All these species may have inhabited lakes rather than flowing water. The geological age and stratigraphical correlation of the nymph-bearing strata are briefly reviewed. 相似文献
20.
Cryptocleidus ? cuervoi caroliDE LA TORRE & ROJAS, 1949, a partial skull with associated mandible and atlas-axis from the Oxfordian of Cuba, has been completely prepared for the first time. It is here redescribed and assigned to a new cryptoclidid genus, Vinialesaurus, for which the species caroli is retained. Vinialesaurus is mainly diagnosed by palatal characters such as double internal nares, an anteriorly rounded vomer and a lack of anterior interpterygoid vacuities. It shares with other cryptoclidids large orbits and external nares, a small vertical jugal and a reduced tooth ornamentation. The occurrence of Vinialesaurus caroli in association with pliosauroids, ophthalmosaurian ichthyosaurs, metriorhynchid crocodilians and pleurodiran marine turtles, strongly suggests that a marine seaway was present in the Caribbean during the Oxfordian, connecting the western Tethys with the Oriental Pacific. 相似文献
|