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1.
Baurusuchids are among the most common and diverse crocodyliform fossils from the Late Cretaceous Bauru Basin of Brazil. This inland continental basin was the habitat of a rich crocodyliform fauna containing five mesoeucrocodylian families, of which the Baurusuchidae represents highly specialized predatory crocodyliforms of terrestrial habits as indicated by their dental, cranial, and postcranial features. The large size they achieved, together with likely predatory adaptations, would suggest they competed and occupied theropod ecological niches in the Bauru Basin. Here we describe Gondwanasuchus scabrosus gen. et sp. nov., a medium-sized baurusuchid with a strongly laterally compressed skull, bearing unique dentition with deep apicobasal sulci and probably well-developed binocular vision. The cranial and dental features in Gondwanasuchus suggest that this active predator would have fed on small vertebrates and took the role of small theropods in terrestrial guild. Gondwanasuchus is the most distinctive baurusuchid known to date and enriches the knowledge on these important Gondwanan terrestrial predatory crocodyliforms. 相似文献
2.
The Cretaceous witnessed the greatest diversity of Gondwanan notosuchian crocodyliforms, which displayed high levels of diversity and a notable array of specialized forms that developed in different ecological niches. Among this diversity, the advanced notosuchians are a clade of mid body sized forms which displays a remarkable abundance but is restricted to two lithological units from the Late Cretaceous of South America, the Adamantina Formation in southeastern Brazil and the Bajo de la Carpa Formation in Patagonia (Argentina). The only exceptions known so far were the Late Cretaceous Labidiosuchus from the Marilia Formation in Brazil and Yacarerani from the Cajones Formation in Bolivia. Herein we report a new Cretaceous crocodyliform, Llanosuchus tamaensis gen. nov. et sp. nov., found in the Los Llanos Formation (Campanian?) in northwestern Argentina (La Rioja Province). The small specimen includes well preserved fragments of the cranium and mandible with an estimated skull size of about 9 cm lengths. This crocodyliform shares several derived characters with Notosuchus terrestris from the Bajo de la Carpa Formation (Patagonia) and it was found in a weakly developed sandy paleosol profile formed in wet local conditions but in a region characterized by semi-arid climate and active eolian sedimentation. The presence of a new advanced notosuchian in the Cretaceous of western Gondwana, and its intermediate geographical region between the known South American species (Brazil, Argentina and Bolivia), has interesting implications, and adds another record of an advanced notosuchian in deposits with inferred warm climates and semi-arid paleoenvironments. Finally, Llanosuchus tamaensis supports a Late Cretaceous age for Los Llanos Formation with important geological implications for La Rioja Province. 相似文献
3.
There are ten known Lower Cretaceous localities for skeletal remains of choristoderes in Siberia (Russia). Choristoderan remains at all these localities are represented by isolated bones, usually by isolated vertebrae of Choristodera indet. Three choristoderan taxa in two geological units were identified: the non-neochoristodere Khurendukhosaurus sp. (possibly closely related to the long-necked Sino-Japanese hyphalosaurids) from the Murtoi Formation, Transbaikalia; cf. Khurendukhosaurus sp. and the “Shestakovo choristodere” with possible neochoristoderan affinities from the Ilek Formation, Western Siberia. All these three choristoderan taxa had a microanatomical organization of vertebrae similar to that of in advanced large neochoristoderes (vertebral centra with tight spongiosa). The Siberian fossil record includes the westernmost (Shestakovo locality, Ilek Formation) and the northernmost (Teete locality, the Sangarian Group) occurrences of the Early Cretaceous choristoderes in Asia. Like in other regions of Asia, Siberian localities are characterized by the absence of neosuchian crocodyliforms. 相似文献
4.
This study is the first detailed account of freshwater to restricted marine molluscs from the Upper Cretaceous sedimentary rocks in the northern sector of the Neuquén Basin. The fossils are from the Campanian–Maastrichtian Loncoche Formation in southern Mendoza, west-central Argentina, which records the initial connection of the Neuquén Basin to the Atlantic Ocean. Six species of bivalves (Diplodon bodenbenderi, Pleiodon? sp., Isognomon? mechanquilensis, Mactridae? indet., Panopea? sp., and Laternula sp.) and three of gastropods (Paleoanculosa macrochilinoides, Paleoanculosa ameghiniana, and a possible cerithioidean) are described. Specimens were collected from fine to coarse sandstones, which may be massive or with planar stratification, planar-cross stratification or trough-cross stratification, and a few from bioclastic limestones and mudstones. Although the sections are from 50 to 300 m thick, the specimens are found only in the lower 120 m. Molluscs represent autochthonous/parautochthonous assemblages composed of mostly non-broken gastropods and articulated bivalve specimens, some of which show signs of postmortem transport; however, they were not removed far from their original habitat. Review of the habitats of living genera supports the inference of dominantly freshwater palaeoenvironments in the lower and middle part of the Loncoche Formation, with restricted marine influence in the southernmost localities studied where there are a few samples that contain specimens belonging to predominantly marine groups (e.g., Laternula, Panopea). 相似文献
5.
Sampling of Cenomanian fossil-rich horizons within the La Luna Formation of two localities in the Zulia and Trujillo states (northern Venezuela) yielded numerous shark teeth belonging to various species within the order Lamniformes (Mackerel sharks). Twelve lamniform species were identified including three new species (Squalicorax lalunaensis sp. nov., Squalicorax moodyi sp. nov., Acutalamna karsteni gen. et sp. nov.) and the genus Microcarcharias gen. nov. is proposed to accommodate with the peculiar morphology of the small-sized odontaspidid M. saskatchewanensis. Other taxa reported here include Cretoxyrhina mantelli, Cretolamna sp., cf. Nanocorax sp. and five Squalicorax species left in open nomenclature. This is the first report of chondrichthyans from the mid-Cretaceous of Venezuela and one of the few records of this group from the Cenomanian of South America. The composition of these assemblages suggests some degree of endemism in the La Luna Sea but also possible connexions with the Western Interior Seaway. One of the most striking features of these assemblages is the high anacoracid diversity (eight species) despite the corresponding outer shelf/upper slope palaeoenvironments of the La Luna Formation. The high diversity of these opportunistic predators is probably related to the high diversity of medium to large marine vertebrates that provided food resources. 相似文献
6.
Perissocytheridea Stephenson is characteristic of brackish water facies. In 57 samples from the Upper Oligocene to Lower Miocene, from five localities, Pirabas Formation, Pará State, Brazil eleven species have been identified. Among these species, four are new reports: Perissocytheridea punctoreticulata n. sp., Perissocytheridea largulateralis n. sp., Perissocytheridea colini n. sp. and Perissocytheridea pirabensis n. sp.; five species in open nomenclature: Perissocytheridea sp. 1, P. sp. 2, P. sp. 3, P. sp. 4, and P. sp. 5 and two species left in “aff.” abbreviation: Perissocytheridea aff. Perissocytheridea pumila and Perissocytheridea aff. Perissocytheridea brachyforma subsp. excavata. The distributional pattern of the Perissocytheridea combined with the occurrence of foraminifera Elphidium and Ammonia in the studied sections supports the presence of the brackish water facies to the respective layers. Their quantitative variation through the studied sections indicate more than one phase of salinity reduction (about >5 and <30 ppm) and/or the decrease of the sea level, forming lagoon along the Pirabas Formation. This genus has a wide paleobiogeographical occurrence and stratigraphic distribution ranging from the Cretaceous to Recent, and already been recorded in the northern of South America, especially in the Neogene of Solimões Basin, but this is the first report of a neotropical genus to the Oligo-Miocene deposits of Pirabas Formation, northern Brazilian Coast, Pará State. 相似文献
7.
Milind P. Kundal 《Journal of the Geological Society of India》2014,83(6):653-656
The present paper records for the first time the bryozoan fragments from 4 m core of the Godhra Formation (early Miocene) and from 4m core and 5 m core of the Chhasra Formation (early middle Miocene) of the Kachchh Offshore Basin, Western India. The Godhra Formation has presence of three bryozoans, viz., ?Crassimarginatella sp., Thalamoporella sp. and Vincularia sp. while the Chhasra Formation has presence of four bryozoans, namely, ?Margaretta sp., Steginoporella sp., ?Thalamoporella sp. and Vincularia sp. 相似文献
8.
A new large conical agglutinating benthic foraminifer is described as Cantabriconus reocinianus n. gen., n. sp. from the upper Aptian-lower Albian Urgonian limestones of the Basque-Cantabrian Basin. It is characterized by a prominent initial trochospire, an undivided marginal zone, an endoskeleton of massive, vertically aligned, and often fused pillars, as well as a thick, most likely pseudo-keriothecal wall structure. Due to the generic characteristics, the new taxon is assigned to the Coskinolinidae. Cantabriconus n. gen. is compared with the Cretaceous Pseudolituonella Marie, and the early Paleogene taxa Coskinolina Stache and Coskinon Hottinger & Drobne as well as the Middle Jurassic Conicopfenderina Septfontaine. Cantabriconus reocinianus n. gen., n. sp. has been observed in the upper Aptian Reocín Formation and in the lower part of the Albian Ramales and Meruelo Formations to the east of Santander. It might therefore be considered an index taxon for Urgonian-type limestones of the Basque-Cantabrian Basin in this time interval. 相似文献
9.
Thirteen decapod crustacean species, eight of which are new, from the mid-Cretaceous (late Albian) limestones of the Koskobilo quarry in northern Spain are described, illustrated, and discussed. They include: Graptocarcinus texanus; Navarrara betsieae gen. nov., sp. nov.; Acareprosopon bouvieri n. comb.; Laeviprosopon hispanicum sp. nov.; L. planum sp. nov.; L. edoi sp. nov.; L. crassum sp. nov.; Viaia robusta; Cretamaja granulata gen. nov., sp. nov.; Koskobilius postangustus gen. nov., sp. nov.; Navarrahomola hispanica; Glytodynomene alsasuensis; and Albenizus minutus gen. nov., sp. nov. Cretamaja and Koskobilius represent the oldest known spider crabs. In total, 36 species are now known from the Koskobilo locality based on 1078 specimens. To discover the magnitude of the diversity of the decapod fauna of Koskobilo, a comprehensive overview of decapod-rich localities and formations from the Cretaceous worldwide was compiled. It appears that Koskobilo is the most diverse decapod fauna from a single locality currently known from the Cretaceous. A rarefaction analysis shows that the maximum number of species is nearly reached. The number of genera, 26, is also unsurpassed for the Cretaceous. Forty-two species are found from localities within the Eguino Formation to which sediments from the Koskobilo quarry are ascribed, which is also unprecedented for a single formation within the Cretaceous. Evidence suggests that the most diverse decapod faunas from the Cretaceous are found in coral-associated limestones. This is consistent with evidence from the Recent, where decapod diversity is high in coral reefs compared to other habitats. This also suggests that the decapod peak diversity in Koskobilo is largely ecological in nature and not caused by a preservational bias. This is one of the most comprehensive studies on Cretaceous decapod diversity so far. Field work in coral-associated strata is expected to yield more decapod-rich faunas. 相似文献
10.
《Cretaceous Research》1988,9(4):337-367
A number of dinoflagellate cysts occur in Wealden deposits that are considered to have accumulated in fresh to slightly brackish water conditions. Most of the forms that have been encountered in the Weald Clay Group (Hauterivian-Barremian) of southeast England and the Wessex and Vectis Formations on the Isle of Wight are described and/or illustrated in this paper. Of these, the following are new: Australisphaera longicornis sp. nov., Cassiculosphaeridia parvula sp. nov., Microdinium? fibratum sp. nov., Kallosphaeridium? inornatum sp. nov., K.? spongiosum sp. nov., Pannosiella perforata gen. et sp. nov., Vectensia varians gen. et sp. nov., Corculodinium uniconicum gen. et sp. nov., Lobionella hirsuta gen. et sp. nov. and Spicadinium akidoton gen. et sp. nov. Commonly associated with several of the cysts are chlorococcalean algae referable to the genera Botryococcus, Tetraedron, Pediastrum, Scenedesmus and Tetrastrum. Four of these are also newly diagnosed, namely Tetraedron paraincus, Scenedesmus bifidus, Tetrastrum ciliatum and T. multifilorum. 相似文献
11.
A microfossil assemblage has been detected in phosphorite cherts from the Dengying and Meishucun Formations (610 Ma) of the Sinian System in Jinning County, Yunnan Province, southwest China.A unique type (mode) of microfossil preservation — collophanite or apatite, or even in rare cases, chert-replacement — is reported here for the first time.The size frequency statistics for the assemblage are consistent with the results obtained by Schopf. The assemblage includes 18 genera and 20 species, among which 4 genera and 10 species are new. The assemblage consists of solitary and colonial spheroidal cells and septate or non-septate filaments, mainly Cyanophyta, especially Chroococaceae, Oscillatoriaceae and Nostocaceae.The microfossils described are Bigeminococcus grandis n. sp., Myxococcoides kingii, Myxococcoides grandis, Palaeoanacystis vulgaris, Archaeophycus venustus n.g. et sp., Eomycetopsis robusta, Circulinema jinningense n.g. et sp., Circulinema muirae n.g. et sp., Cyanonema infliatum, Obruchevella parva, Oscillatoriopsis awramikii n. sp., Palaeolyngbya oehlerii n. sp., Palaeolyngbya spiralis n. sp., Palaeotubulus lamellosus n.g. et sp., Veteronostocale sp. 1, Veteronostocale sp. 2, Allantomorphus septatus n.g. et sp., Clonophycus vacus n. sp., Archaeotrichion contortum, Rhienonema antiquum, Micrhystridium setulerum and Protosphaeridium densum. 相似文献
12.
E.A. Mancini 《Cretaceous Research》1982,3(3):241-259
Twenty-seven species of cephalopods are identified from an exposure of the Grayson Formation, Washita Group at the Waco Dam Spillway, McLennan County, north-central Texas. Mariella (Mariella) camachoensis (Böse), (?)Stomohamites sp., Engonoceras serpentinum (Cragin), Puzosia cf. crebrisulcata Kossmat, Mantelliceras cf. cantianum Spath, Mantelliceras saxbii (Sharpe), Sharpeiceras mexicanum (Böse), (?)Paracalycoceras sp., and Neohibolites sp. are reported from the Grayson Formation for the first time. The occurrence of Mantelliceras cf. cantianum, Mantelliceras saxbii, Sharpeiceras mexicanum, and (?)Paracalycoceras sp. indicates an early Cenomanian age for the Grayson exposed at the Waco Spillway locality. Previously, these mantellicerid ammonites have been recorded from the Buda Limestone interval which overlies the Grayson in north-central Texas. 相似文献
13.
We describe remains of a new crocodyliform found from the Lower Cretaceous (Aptian) Khok Kruat Formation, northeastern Thailand. Remains consist of two caudal ends of mandibles, two rostral symphyseal parts of right rami of mandibles, a dorsal part of postorbital, a cranial end of squamosal and one osteoderm. Phylogenetic analyses supported inclusion of this crocodyliform into the Eusuchia as it shares several morphological characters with other eusuchians, such as a dorsocaudally oriented retroarticular process, smooth lateral surface of the caudoventral region of mandible, and a craniocaudally oriented ridge on the dorsal surface of retroarticular process. The shape of symphyseal region showed this crocodyliform had a longirostrine snout shape, which is uncommon in early eusuchians. Finding of this crocodyliform draws back the oldest record of Asian eusuchians, which was Tadzhikosuchus, approximately 30 million years and it is the only Mesozoic eusuchian found in East and Southeast Asia. 相似文献
14.
《Australian Journal of Earth Sciences》2013,60(5):701-741
The Late Oligocene Kangaroo Well Local Fauna from the Ulta Limestone (new name), northwestern Lake Eyre Basin correlates best with vertebrate assemblages from the Etadunna, Namba and Wipajiri Formations of the central Lake Eyre Basin, and from the Carl Creek Limestone (Karumba Basin) of northwestern Queensland. The biochronologically informative marsupials, Neohelos tirarensis (Diprotodontidae, Zygomaturinae), Marlu sp. cf. M. kutjamarpensis and Pildra sp. cf. P.magnus (Pseudocheiridae), and Ektopodon ulta sp. nov. (Ektopodontidae), indicate that the Kangaroo Well Local Fauna may be slightly older than the Kutjamarpu Local Fauna (Wipajiri Formation) and slightly younger than the Ngama Local Fauna (zone D of the Etadunna Formation) of Late Oligocene age. A new species of primitive ?Wynyardiidae, Ayekaye jaredi sp. nov., is described, and the nomenclature of two extinct gastropods, Glyptophysa rodingae (McMichael) and Cupedora Iloydi (McMichael) (new combinations), the type localities of which are in the Ulta Limestone, is revised in line with current taxonomy. The Ulta Limestone, an alluvial calclithite composed primarily of caliche fabrics, and its correlatives were deposited during the Miocene oscillation climatic event. Palaeoclimatic modelling using sedimentological data, crocodilians and extant analogs of fossil terrestrial gastropods indicates that the average annual temperature at Kangaroo Well during the Late Oligocene was probably between 14 and 20°C, while mean annual rainfall was probably <600 mm. Similar associations from central parts of the Lake Eyre Basin, from Riversleigh, northwestern Queensland, and from Bullock Creek, north‐central Northern Territory, indicate that such conditions were widespread during depositional phases of the Miocene oscillation. Palaeoclimatic indicators do not support the presence of widespread closed forests in northwestern Queensland and across the inland of the Northern Territory and South Australia during the Miocene oscillation. 相似文献
15.
A new species, Procretevania mitis sp. nov., is described from the Early Cretaceous of Yixian Formation at the Huangbanjigou, Beipiao City, western Liaoning, China. Based on new morphological data, a key of Procretevania Zhang and Zhang, 2000 is provided. Forewing venations, body and forewing lengths, localities and horizons of various genera of Evaniidae in amber and compression fossils are summarized for comparison. Evaniidae have a high degree of venational diversity, while more complex forewing venations for Lebanevania and Mesevania suggest that they may represent the stem group of the Evaniidae. High diversity of Evaniidae in the Early Cretaceous implies that Evaniidae might have radiated before the Early Cretaceous. Furthermore, comparison of body and forewing lengths of amber and fossil genera indicate that the amber specimens have relatively smaller size. 相似文献
16.
A selachian fauna is described for the first time from the Late Cretaceous (Campanian–Maastrichtian) of Senegal. So far, the Campanian Paki Formation has only yielded a single tooth of Rhombodus sp. whereas the Cap de Naze Formation has yielded a more diverse fauna including juvenile Cretalamna cf. Cretalamna biauriculata, Serratolamna serrata, Carcharias cf. Carcharias heathi, ?Carcharias sp., Squalicorax pristodontus, Schizorhiza stromeri, Parapaleobates sp., Rhombodus binkhorsti and Rhombodus andriesi. Teeth of juvenile Cretalamna largely dominate the assemblage. Such an assemblage confirms a Late Maastrichtian age for the unit 3 in the Cap de Naze Formation. The assemblage, although composed of cosmopolitan taxa, is similar to the contemporaneous selachian assemblage from the phosphates of Morocco. 相似文献
17.
Vertebrate remains from the Upper Cretaceous (Santonian) Ajka Coal Formation (Bakony Mountains, western Hungary) are described. Macro- and microfossils collected from two boreholes and from isolated chunks of sediment/matrix dumped on spoil heaps of the Jókai Mine represent pycnodontiform and lepisosteiform fishes, bothremydid turtles, the mosasauroid Pannoniasaurus inexpectatus, the crocodyliforms cf. Theriosuchus, Iharkutosuchus makadii and cf. Allodaposuchus, as well as ankylosaurian and theropod dinosaurs. This unit was deposited in a swampy lacustrine environment, in contrast with the neighbouring and contemporaneous floodplain deposit of the vertebrate-bearing Csehbánya Formation at Iharkút. Despite significant environmental differences, the faunal composition of the Ajka Coal Formation assemblage completely overlaps with that of the Csehbánya Formation, suggesting the occurrence of the same semi-aquatic and terrestrial species in both settings. The ankylosaurian remains further strengthen the previous view that ankylosaurus preferred wetland habitats such as fluvial systems and coastal regions. 相似文献
18.
New plant macrofossil localities are found in the middle-upper part of the Albian Upper Hatira Formation of Makhtesh Qatan, an erosion crater in the northern Negev. These are so far the only outcrop localities in the Negev containing plant compressions and well-preserved sporomorphs. Their age assignments are controlled by the ammonite Knemiceras records below and above the plant-bearing sequence in the adjacent Makhtesh Hatira. The macrofossil assemblages are strikingly different in the sandy fluvial and shaly lacustrine facies, the former being dominated by Araucaria, Athrotaxopsis, Brachyphyllum and pinnatifid Sapindopsis, comparable at the plant assemblage and leaf morphological levels to the early to early late Albian assemblage of the North American Potomac flora. The lacustrine shale macrofossil assemblages appear archaic on account of their diverse pteridophyte component and sparse angiosperm remains. A new supposedly gnetophytic genus and species Qataniaria noae Krassilov, gen. et sp. nov. is dominant in the shale horizon. The sporomorph assemblages are strongly dominated by psilate trilete spores (87-93%). In the absence of elaterate forms, the angiosperm pollen Afropollis jardinus, Pennipollis, Tricolpites spp. and Walkeripollis sp. is consistent with the early Albian age. The abundance and diversity of conifers and the prominence of the fern bog assemblage suggest a relatively humid phase of the regional Albian climates. 相似文献
19.
Pernelle Turmine-Juhel Richard Wilks David Brockhurst Peter A. Austen Christopher J. Duffin Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2019,130(6):752-769
Ashdown Brickworks, near Bexhill, East Sussex, has produced a large number of vertebrate fossils from the Wadhurst Clay Formation, part of the Wealden Supergroup (Hastings Group; Valanginian; Lower Cretaceous). Here we describe the microvertebrate fauna of the ‘conglomerate bed’, representing a rich sample of taxa. While most of the recovered teeth and bones are abraded, some heavily, most can be identified to species level. The taxa include four species of hybodont sharks (Egertonodus basanus, Planohybodus ensis, Polyacrodus parvidens, P. brevicostatus), three taxa of bony fishes (an unidentified Lepidotes-like semionotiform, the pycnodontiform Ocloedus, and an albuliform), three taxa of crocodyliforms (the goniopholid Hulkepholis, a bernissartiid, and the atoposaurid Theriosuchus), and the theropod dinosaurs Baryonyx and an allosauroid. Sediments of the Wadhurst Clay Formation as a whole indicate freshwater to very slightly brackish-water environments of deposition, and the mainly aquatic time-averaged mixture of fishes and tetrapods recovered from the ‘conglomerate bed’, together with isolated terrestrial species, confirms this interpretation. 相似文献