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1.
Toarctocera, a new gastropod genus of the family Aporrhaidae (Stromboidea) is described for Rostellaria subpunctata. It occurs in Central Europe (S Germany, N Switzerland, and France) and is commonly one of the most abundant gastropods in Late Toarcian/Early Aalenian soft bottom faunas. Toarctocera subpunctata has extremely elongated apertural spines; this has been interpreted as an adaptation to extremely soft-bottom conditions (snowshoe strategy). The new genus represents one of the earliest certain aporrhaids (Stromboidea). Aporrhaids are probably as old as Late Triassic, and possible Triassic and Early Jurassic species are discussed. Spiniloma is proposed as a nomen novum in order to replace the homonym Spinigera and consequently the family Spinilomatinae replaces the Spinigeridae. The sister group of Stromboidea still needs to be identified. A previously suggested sister group relationship with the Heteropoda is seen as unlikely.  相似文献   

2.
Jobst Wendt 《Palaeontology》2018,61(4):575-595
The first tunicates with a calcareous exoskeleton are reported from Late Triassic buildup‐slope deposits of the Dolomites. Although examples of this group have been known since the early 1900s from the middle–upper Permian of eastern Asia and Sicily as Khmeria, they were erroneously attributed to rugose corals. These early representatives are small, double‐valved, conical skeletons, which evolved into multi‐plated capsules with up to 35 opercula. The latter are joined along zigzag margins, which in life could probably be opened for the atrial and branchial siphons. The construction and shape of these skeletons distinguish them from plants or other invertebrate phyla, while they share several similarities with living tunicates, specifically to sessile ascidians. Apart from a soft‐bodied genus from the lower Cambrian of China, ascidians are known only from isolated spicules, which occur sporadically from the Lower Jurassic onwards. The calcareous skeleton of these Late Triassic tunicates consists of aragonitic fibres, which form spherulitic or clinogonal microstructures. It seems that the stellate aragonitic spicules of Jurassic to Recent ascidians are a vestige of Permian–Triassic ancestors, which after the Carnian lost the ability to construct compound solid skeletons but partly still retain a soft double‐valved or multi‐operculate cellulose‐like tunic. The following taxa are described as new: Order Khmeriamorpha with the genera Khmeria Mansuy and Zardinisoma gen. nov., and the following species: Khmeria stolonifera (late Permian), Khmeria minima (Late Triassic), Zardinisoma japonicum (late Permian), Z. cassianum, Z. pyriforme, Z. polyplacophorum and Z. pauciplacophorum (all Late Triassic).  相似文献   

3.
Otozamites is a representative fossil leaf morphogenus of the extinct Bennettitales, with an extensive distribution during the Mesozoic, especially in China. Understanding the fossil diversity variation and distribution pattern of Otozamites in China will provide information on biodiversity of bennettitalean plants as well as for reconstruction of palaeogeography and palaeoclimate conditions during the Mesozoic. So far, 46 species of this genus have been described in China, excluding unspecified species. The results show that the fossils of Otozamites are extensively recorded in the Late Triassic, and then reach their maximum development in the Early Jurassic, followed by a reduction in diversity in the Middle and Late Jurassic, and finally become extinct at the end of Early Cretaceous. Geographically, they occur in both Northern and Southern Floristic Provinces in the Mesozoic of China, with a relatively higher abundance in the Southern Floristic Province. It implies that the diversity variation and distribution of Otozamites are closely related to the change of the palaeoclimatic conditions. The warm and humid climate prevailed in the Late Triassic and Early Jurassic in South China, propitious to the development of Otozamites. After the Middle Jurassic, dry and hot climate may have caused the lower diversity level and blocked the development of Otozamites; finally at the end of the Early Cretaceous, the frequent arid climate may be a major cause for the extinction of Otozamites.  相似文献   

4.
A diverse Late Triassic (Late Norian) gastropod fauna is described from the Mission Creek Limestone of the Wallowa terrane (Idaho, USA). Sample standardization by rarefaction analysis indicates that the fauna is even more diverse than the Late Triassic gastropod fauna from the Pucara Formation (Peru) which represents the most diverse gastropod fauna from South America. The gastropod fauna consists of 66 species; several genera are reported for the first time from North America. A high percentage of the species are highly ornamented and several have distinct siphonal canals. This suggests that the appearance of truly Mesozoic elements among the gastropods began before the Mesozoic Marine Revolution in other clades. The fauna is dominated by high-spired strongly ornamented procerithiids, a group more characteristic for the Jurassic. Comparison of the present fauna and the Iranian Nayband Formation gastropod fauna show that the procerithiids underwent a first global radiation in the Late Triassic. The high number of new species in this fauna suggests that sampling of Late Triassic gastropod faunas is still incomplete and hinders palaeobiogeographic considerations. Previous suggesions that gastropod faunas from the Wallowa and Wrangellia terranes resemble each other and are distinct from those of Alexander, Chulitna, and Farewell terranes are basically corroborated. The gastropod fauna of the Mission Creek Limestone differs considerably from that of the western and central Tethys but shares several taxa with the Late Triassic gastropod fauna of the Pucara Formation in Peru. Thus, the Hispanic corridor was probably not present in the Norian but opened only in the Early Jurassic. The subfamily Andangulariinae is introduced and placed in the Zygopleuridae. The generaSpiniomphalus, Nodoconus, Gudrunella, Blodgettella, Idahospira, andSiphonilda and the subgenusCryptaulax (Wallowax) are introduced. 27 species are erected. A lectotype is designated forCryptaulax rhabdocolpoides Haas, 1953.   相似文献   

5.
The exceptional record of well-preserved wood remains from the Middle Jurassic of Svalbard is studied from the taphonomic point of view. These remains were recovered from the Brentskardhaugen Bed, a conglomerate with phosphatic nodules, which constitutes the record of the eroded deposits corresponding to the Toarcian–Early Bathonian gap. The wood remains occur in the cores of these nodules. These wood fragments are preserved as phosphate (francolite) and as charcoals. The well preservation allows us to identify xenoxyloid cross-field pits and xenoxylean pitting on the radial wall of tracheid, characterizing the species Xenoxylon phyllocladoides. Phosphatic nodules originated as the result of early phosphate precipitation filling the inter-particle pore space of the sandy quartz sediment around the wood fragments (and other organic-rich nucleation centers) below the sediment–water interface. This phosphatization involved a sudden burial of the wood remains in the sea-bottom, the subsequent decay of the lignin, and a fast growth of carbonate fluorapatite forming phosphatic inner moulds. Fossil microbial biofilms induced the phosphatization. The dissolution/decay of the lignin is not possible in charcoal, and phosphatic casts did not develop in charcoalified parts. Some remains were not totally charred, with the lignin preserved only in reduced relicts that were later replaced by phosphate. The phosphate precipitation occurred in recurrent episodes during the Toarcian–Callovian as a result of distinct sea-level rises and the associated nutrification of the shelf. The phosphatic nodules were developed and reworked during the transgressive–regressive cycle of the Toarcian–Early Bathonian, as well as during the final transgression of the Late Bathonian–Earliest Callovian, which resulted in the Brentskardhaugen Bed.  相似文献   

6.
Electrohemiphlebia barucheli gen. et sp. nov. and Jordanhemiphlebia electronica gen. et sp. nov. , two new genera and species are described, based on exceptional inclusions of hemiphlebiid damselflies in Cretaceous amber from France and Jordan. The type specimen of E. barucheli was studied using phase contrast X‐ray synchrotron microtomography, giving exceptional images and detailed information. Its comparison with the recent Hemiphlebia mirabilis confirms the attribution of several Cretaceous damselflies to the Hemiphlebiidae, showing that this particular group was widespread in the Early Cretaceous and probably originated in the Late Jurassic or earlier. The ecological niches today occupied by the small coenagrionoid damselflies were occupied during the Triassic and Jurassic by Protozygoptera, hemiphlebiids during the Early Cretaceous, and modern taxa in the Cenozoic.  相似文献   

7.
Noriphyllia gen. n. is a distinctive coral representing the Coryphylliidae, a group of Late Triassic scleractinian corals. Coral faunas of this age are poorly known. The new coral is distinguished from related corals belonging to the reimaniphylliids by key features of septal microstructure as discerned in thin sections. This microstructure consists of a straight/wavy midseptal zone and lateral septal stereome organized into thin fascicles of fibres, producing a fine and sharp micromorphology of the septal sides. The solitary genus Noriphyllia gen. n. contains two Early Norian species: N. anatoliensis sp. n. chosen as the type species and N. dachsteinae sp. n., and a Carnian species referred to as N. monotutoensis sp. n. The new genus is widely distributed in the Late Triassic, Early Norian reef facies of the Tethys region (Northern Calcareous Alps, Austria; Taurus Mountains, Turkey) and it also occurs in the Carnian of Timor. Noriphyllia gen. n. is unique and details of its microstructural features add new understanding to the composition of both Late Carnian and Early Norian corals.  相似文献   

8.
Gaffney, E.S. and Jenkins, F.A., Jr. 2010. The cranial morphology of Kayentachelys, an Early Jurassic cryptodire, and the early history of turtles. — Acta Zoologica (Stockholm) 91 : 335–368 The skull morphology of Kayentachelys aprix Gaffney et al., 1987 , a turtle from the Early Jurassic Kayenta Fm of northern Arizona, demonstrates the presence of cryptodiran synapomorphies in agreement with Gaffney et al. (1987, 1991, 2007) , and contrary to the conclusions of Sterli and Joyce (2007) , Joyce (2007) , Sterli (2008) , and Anquetin et al. (2008) . Specific characters found in Kayentachelys and diagnostic of cryptodires include the processus trochlearis oticum, the curved processus pterygoideus externus with a vertical plate, and the prefrontal–vomer contact, which are confirmed as absent in the outgroups, specifically the Late Triassic Proganochelys. The Joyce (2007) analysis suffers from the reduction of the signal from skull characters, with a consequently greater reliance on shell characters, resulting in pleurodires being resolved at various positions within the cryptodires. Kayentachelys reveals what a primitive cryptodire would be expected to look like: a combination of primitive and derived characters, with the fewer derived characters providing the best test of its relationships to other turtles. Although incompletely known, the Mid‐Late Jurassic Condorchelys, Heckeremys, and Eileanchelys may be early cryptodires close to Kayentachelys. We confirm the Late Triassic Proterochersis as a pleurodire, dating the pleurodire–cryptodire split as Late Triassic or earlier.  相似文献   

9.
A sample of marine invertebrates from the Late Triassic Cassian Formation (north Italy) yielded one of the most diverse Early Mesozoic fossil assemblages ever reported (c. 170 species). The assemblage was found in basin clays, but was transported from nearby carbonate platforms as indicated by fragmentation, microbial encrustation and the presence of coated grains and ooids. Most of the specimens are small (< 1 cm) reflecting both, small adult sizes and size sorting during transport. Rarefaction analysis suggests that diversity of surface collection and bulk sampling is the same. However, rank abundance, species richness and taxonomic composition differ strongly according to sampling method. Low‐grade lithification of the sediments is the main reason that high diversity can be recognized, because it facilitates disaggregation and finding of small molluscs. Sample standardization shows that the studied assemblage is much more diverse than known Early Triassic assemblages. However, its diversity is similar to that of Anisian assemblages. This suggests that recovery from the end‐Permian mass‐extinction was quite advanced in the Middle Triassic and alpha‐diversity remained high until the Late Triassic. According to current models, Early Triassic and Anisian faunas match the niche overlap phase of recovery during which diversity is built up by increasing alpha‐diversity, whereas beta‐diversity rises slowly. Subsequently, habitat width of species contracts because of increasing competition, making beta‐diversity the principal drive of overall diversity increase. The diversity pattern of various Late Triassic Cassian associations meets the predictions for the transition from the niche overlap to the habitat contraction phase.: Triassic, Cassian Formation, palaeoecology, diversity, mollusc dominance.  相似文献   

10.
Reconstructing the feeding ecology of fossil fishes can be difficult, but new mechanical approaches enable reasonably reliable inferences by comparison with living forms. Here, the feeding ecology of one of the most iconic and abundant actinopterygians of the Early Jurassic, Dapedium, is explored through detailed anatomical study and functional analyses of jaw mechanics. Mathematical models derived from modern teleost functional morphology are applied, to ascertain the transmission of force through the jaws of Dapedium. A number of features not previously identified in the genus are described, and the dentition is described in full for the first time. The analysis of the functional morphology of Dapedium, in combination with its jaw anatomy and dentition, indicates that the genus was well adapted to a durophagous feeding habit, although indirect evidence suggests a more generalist feeding mode. Being a generalist durophage may explain the success of the genus in the aftermath of the end‐Triassic extinction event and its radiation in the Early Jurassic, as indicated by the ubiquity of Dapedium fossils throughout the Lower Lias.  相似文献   

11.
Abstract: Pleurotomaria species from lower Bajocian (Middle Jurassic) sediments of south‐western Luxembourg housed in the National Natural History Museum of Luxembourg are described. Seven species are recognized, one of which is new, Pleurotomaria faberi sp. nov. A more detailed definition of the diagnostic characters of the genus is proposed and the morphological continuity between Talantodiscus and Pleurotomaria is demonstrated, suggesting that the former cannot be considered as a distinct taxon. The palaeoecology, evolution and palaeobiogeographical history of Pleurotomaria are outlined. Pleurotomaria presumably first appeared in late Middle Triassic of New Zealand where it underwent a relative diversification up to the Hettangian (Early Jurassic). From early Hettangian, most of its evolutionary history took place in Europe and western Tethys. In the European epicontinental seas, Pleurotomaria experienced two important radiations. The first occurred in the Early Jurassic, with a peak in the late Pliensbachian, and was marked by an expansion of the distribution to the central part of western Tethys. After a collapse in species diversity, probably related to the early Toarcian anoxic event, a second radiation occurred. This culminated in the early Bajocian and was mainly confined in a region encompassing southern England, Paris Basin and southern Germany. Low‐spired species, formerly attributed to Talantodiscus, probably originated independently and iteratively during the history of Pleurotomaria. The facies and associated benthic faunas suggest that Pleurotomaria probably lived on shallow soft bottoms composed of mixed calcareous–siliciclastic sediments. The two main Early Jurassic and early Middle Jurassic radiations of the genus took place in these environments. Records of the genus in Jurassic carbonate platform deposits are very few and concern mainly post‐Bajocian species.  相似文献   

12.
13.
Based on the study of the ammonite collection assembled by A.S. Sakharov from the Middle Jurassic Armkhi Formation of the Gerchyoch Mountain Pass (northern Ingushetia) and on literature sources, the species composition and stratigraphic position of northern Caucasian Cadoceras are discussed. Early Callovian C. tchegemicum Lominadze, C. tschernyschewi Sokolov, and C. suevicum Callomon et Dietl are identified; the name C. loginovae Lominadze, 2004 is synonymized under C. stupachenkoi Mitta, 1998. The Late Bathonian species are identified as C. sakharovi sp. nov. and C. aff. perrarum Voronetz. The presence of Upper Bathonian sediments is substantiated for the northern Caucasus; the theory of the inversion of the Kepplerites beds is shows to be erroneous.  相似文献   

14.
The higher‐level phylogeny of Pentatomomorpha, the second largest infraorder of true bugs (Hemiptera: Heteroptera), which includes many important agriculture and forestry pests, has been debated for decades. To investigate the phylogeny and evolutionary history of Pentatomomorpha, we assembled new mitochondrial genomes for 46 species through next‐generation sequencing of pooled genomic DNA. Based on a much broader taxon sampling than available previously, Bayesian analyses using a site‐heterogeneous mixture model (CAT+GTR) resolved the higher‐level phylogeny of Pentatomomorpha as (Aradoidea + (Pentatomoidea + (Coreoidea + (Lygaeoidea + Pyrrhocoroidea)))). There was a transition from trnT/trnP to trnP/trnT in the common ancestor of Pyrrhocoroidea, which indicates that this gene rearrangement could be an autapomorphy for Pyrrhocoroidea. Divergence time analyses estimated that Pentatomomorpha originated c. 242 Ma in the Middle Triassic, and most of the recognized superfamilies originated during the Middle Jurassic to Early Cretaceous. The diversification of families within Pentatomomorpha largely coincided with the radiation of angiosperms during the Early Cretaceous.  相似文献   

15.
The Elikah River section spanning the Lopingian (Late Permian) to the Griesbachian (Early Triassic) time interval in the Central Alborz Mountains (north Iran) was sampled for ostracod analysis. We report 79 species distributed among 38 genera. Four new species are described: Acratia? pervagata Forel sp. nov., Microcheilinella alborzella Forel sp. nov., Basslerella superarella Crasquin sp. nov. and Cavellina nesenensis Crasquin sp. nov. The ontogeny of 13 species is described and sexual dimorphism in the genus Microcheilinella is here undoubtedly recognized for the first time. Six species show precocious sexual dimorphism of their carapace as early as A‐5 juvenile. The Lilliput effect is for the first time recorded and quantified for two species. Rare long‐time span Palaeocopida species, known throughout the entire Permian, document relatively long‐term evolution, including the size and growth rate modifications associated with the earlier appearance of carapace sexual dimorphism through time. These patterns might be related to the Guadalupian–Lopingian events and/or to climatic modifications occurring during the Permian interval.  相似文献   

16.
Gastropod faunas from the Early Jurassic (Late Pliensbachian–Early Toarcian) marine deposits of Chubut Province, Argentina, are described from Lomas Occidentales, Cerro La Trampa and Puesto Currumil localities, representing eight species, three of them new. These are Scurriopsis? sp., Chartronella gradata sp. nov., Calliotropis? sp., Pleurotomaria sp., Leptomaria sp., Hamusina? wahnishae sp. nov., Colpomphalus musacchioi sp. nov. and Jurassiphorus? cf. triadicus Haas. The gastropod assemblage reported here testifies paleobiogeographical connections with other coeval gastropod associations from the western Tethys. However, Chartronella, Hamusina and Jurassiphorus may represent survivors of Triassic associations, considering the ancient seaway from Peru as the most plausible hypothesis for biotic exchange of these faunas during the Late Triassic–Early Jurassic boundary. An abundant and diverse invertebrate fauna such as corals, echinoderms, cephalopods, brachiopods, bivalves and other gastropods found in association with the gastropods described here characterises a shallow marine environment for the gastropod-bearing rocks.http://www.zoobank.org/urn:lsid:zoobank.org:pub:7B8EAFC0-3AC0-4F91-97A5-22AAC6A19909  相似文献   

17.
An assemblage of abundant and well-preserved tetrapod footprints has been discovered in the Tanamert Member (T3) of the Triassic Timezgadiouine Formation (Argana basin, western High Atlas, Morocco). It is the first fossil record from T3. Surfaces from different localities show a uniform tetrapod ichnofauna that consists of chirotherian and small lacertoid forms. The chirotherians are assigned to the plexus Protochirotherium—Synaptichnium, their trackmakers interpreted as basal archosaurs. The lacertoid imprints show close affinities with Rhynchosauroides and may reflect archosauromorphs or lepidosauromorphs. Protochirotherium—Synaptichnium assemblages are characteristic of the Early Triassic and were known previously only from units of this age in central Europe. Biostratigraphically, the European record implies a wide-spread pre-Anisian Protochirotherium—Synaptichnium dominated assemblage preceding the first appearance of Chirotherium barthii near the Olenekian-Anisian boundary. The stratigraphic position of T3 between Late Permian (uppermost T2) and Middle Triassic (T4) and the European correlatives suggest an Early Triassic age of this unit. It is the first record of Early Triassic continental deposits in Morocco. The surfaces from T3 open up perspectives for further contributions to ecology, biogeography and locomotion of early archosaurs. Furthermore, excellent outcrops and quality of footprint preservation in the Argana basin offer a potential for clarification of ichnotaxonomic and biostratigraphic issues.  相似文献   

18.
Abstract: The sauropod dinosaur ‘Bothriospondylus’, originally named on the basis of Late Jurassic remains from England, is demonstrated to be invalid, and the characters used to diagnose it are shown to be obsolescent features which are widespread throughout Sauropoda. Material referred to this genus spans a temporal range from the Middle Jurassic until the early Late Cretaceous and has been described from five different countries, across three continents. These remains represent a wide array of sauropod groups, comprising non‐neosauropod eusauropods, a macronarian, titanosauriforms (including at least one definite brachiosaurid) and a rebbachisaurid. The type material of the Middle Jurassic ‘B. madagascariensis’ represents a derived non‐neosauropod eusauropod and possesses two potential autapomorphies. However, as a result of the fragmentary nature of the material and the uncertainty surrounding its association, a new taxon is not erected. Of the numerous specimens referred to ‘Bothriospondylus’, however, several remains are considered diagnostic: Ornithopsis hulkei (Early Cretaceous, UK), Lapparentosaurus madagascariensis (Middle Jurassic, Madagascar) and Nopcsaspondylus alarconensis (early Late Cretaceous, Argentina). At least three types of sauropod were present in the Bathonian (Middle Jurassic) of north‐west Madagascar, with a basal eusauropod (Archaeodontosaurus), a more derived eusauropod (‘B. madagascariensis’) and a titanosauriform (Lapparentosaurus) all approximately contemporaneous. Palaeocontinental reconstructions suggest that Middle Jurassic Madagascan sauropods would still have been capable of global biotic interchange, and this is perhaps reflected in their diverse assemblage. Re‐evaluation of these Malagasy forms has shed new light on this important time period in sauropod evolution.  相似文献   

19.
Clevosaurus was a cosmopolitan Rhynchocephalia genus restricted to the Late Triassic and the Early Jurassic. In Brazil, C. brasiliensis is one of the most conspicuous species collected from the Candelária Sequence (Riograndia Assemblage Zone, Norian age) of the Santa Maria Supersequence. Several jaws of C. brasiliensis are housed in the Laboratório de Paleontologia de Vertebrados of the Instituto de Geociências-UFRGS. Some of these jaws bear a relatively small protuberant bony callus on the anterolateral margin of the dentary, evidenced by a different tissue pattern incorporating small pits and discrete grooves. This pattern closely resembles a common bone infection known in the mandible of the extant Sphenodon punctatus. Although this similarity, the infection may be the result of two possible processes: as consequence of orthal jaw shearing movements during feeding at the moments that the dentary impacts with the enlarged premaxillary tooth or due to injuries produced after fights between conspecific individuals (as is the case for S. punctatus). If the second hypothesis is correct, the same pathological processes probably occurred in the Late Triassic C. brasiliensis indicating that similar ethological conditions were already present at the beginning of the Mesozoic, during the initial radiation of the lepidosaurian clade.  相似文献   

20.
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