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Ane Elise Branco Pavanatto Rodrigo Temp Müller Átila Augusto Stock Da-Rosa Sérgio Dias-da-Silva 《Historical Biology》2016,28(7):978-989
New postcranial remains of Massetognathus ochagaviae are described based on a new specimen collected at the Dinodontosaurus Assemblage Zone from the Middle Triassic of Southern Brazil. Several isolated teeth collected together with the postcranial skeleton allowed a taxonomic assignation of the specimen to M. ochagaviae. Its postcranial morphology is quite similar to Massetognathus pascuali, especially regarding the morphology of the transverse process of presacral vertebrae (i.e. laminar in the anterior most and rounded in the posterior most presacral vertebrae); humerus (i.e. the head is dorsally deflected with a ‘fan-shaped’ distal end a deltopectoral crest abruptly ending at the middle of shaft); and femur (with a bulbous and dorsomedially inclined femoral head, lesser trochanter which abruptly begins near the intertrochanteric fossa and extending up to the middle of the femoral shaft and the medial condyle more pronounced and ventrally projected than the lateral one). On the other hand, the clavicle of M. ochagaviae is less lateromedially elongated than in M. pascuali. 相似文献
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We describe a new trirachodontid cynodont from the base of the Burgersdorp Formation (Subzone A fauna of the Cynognathus Assemblage Zone), of the South African Karoo Basin. Langbergia modisei gen. et sp. nov. is characterized by circular to ovoid in outline upper postcanines and the absence of a maxillary platform lateral to the postcanine series. Apart from the new taxon, we recognize two other species of this family in the Cynognathus Assemblage Zone: Trirachodon berryi and Cricodon metabolus , the latter also represented in the Tanzanian Manda Formation. A phylogenetic analysis of gomphodont cynodonts was conducted using a data matrix of 43 craniodental characters and 18 terminals. Trirachodontidae appears as a monophyletic assemblage, with Langbergia appearing as the sister taxon of Cricodon . The monophyly of trirachodontids is weakly supported, however, with one extra step breaking it. Traversodontid cynodont relationships were also inspected and compared with a recent phylogeny proposed for this group. Considering the resulting phylogeny and the sudden appearance and diversification of Cynognathia representatives, the origin of basal Cynognathia (i.e. Cynognathus , Diademodon , and trirachodontids) is suggested to predate their first appearance in the fossil record. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 383–413. 相似文献
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描述了产自美国北卡罗来纳州上三叠统横齿兽类北方阔齿兽新材料的牙齿。基于牙齿的特征,尤其是犬后齿的形态,这些标本被暂归入杰斐逊北方阔齿兽Boreogomphodon jeffersoni;不过它们的下阔齿型犬后齿前横脊一般有两个而不是3个齿尖。根据牙齿大小、直接替换情况,推测阔齿型齿从后部萌发,从前部脱落。这个类群仅有一代阔齿型犬后齿;至少有一代,可能是两代裂齿型犬后齿。 相似文献
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A BASAL MIXOSAURID ICHTHYOSAUR FROM THE MIDDLE TRIASSIC OF CHINA 总被引：4，自引：0，他引：4
DA-YONG JIANG WEI-CHEN HAO MICHAEL W. MAISCH REAS T. MATZKE YUAN-LIN SUN 《Palaeontology》2005,48(4):869-882
Abstract: New specimens of a mixosaurid ichthyosaur are described from the People's Republic of China. They consist of an almost complete skull, forefin and shoulder girdle of a single individual, and a second partial skull from the Anisian Guanling Formation of Guizhou Province that belongs to the same taxon. A phylogenetic analysis shows this species to be the sister-taxon of all other mixosaurids. It is distinguished from Mixosaurus , Contecotpalatus and Phalarodon by features of its dentition and cranial morphology. There is only one maxillary tooth row. The posterior maxillary teeth are blunt and rounded, and much wider than the premaxillary teeth, but they are not strongly elongated anteroposteriorly. The teeth are subthecodontously implanted. The postorbital skull segment is long. The jugal-quadratojugal notch is deep and these two elements remain separated externally. The postorbital separates supratemporal and postfrontal. There are no postaxial ossifications of the forefin. Autapomorphies include a long ventral process of the postorbital lamina of the postorbital as well as characteristic morphologies of the coracoid and humerus. The material is therefore clearly distinguished from other known mixosaurids. It can be referred, on the basis of the features of the humerus and coracoid, to Mixosaurus maotaiensis Young, 1965. As it is generically distinct from Mixosaurus , a new generic name, Barracudasaurus gen. nov. is proposed. The phylogenetic relevance of the external separation of jugal and quadratojugal in some Triassic ichthyosaurs is discussed and it is concluded that it does not demonstrate the initial presence of a lower temporal fenestra in ichthyosaurs. The new material suggests that mixosaurids could have also originated in the Eastern rather than the Western Tethys, as previously assumed. 相似文献
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Ji Liu-xiang 《植物学报(英文版)》1990,32(8)
The micropaleoflora from the Middle Carbonate Rock Formation of Jiezha Group has been firstly studied in this paper. The abundance sporopollen and variform acritarch characterizing the formation contain 62 genera and 91 species, in which 20 gen. and 31 sp. belong to sporopollen, 42 gen and 60 sp. acritarch. Among them one is affinis, twelve conformis and five species, in addition, four species indeterminata. The sporopollen assemblage is consisted of the dominant gymnospermous pollen of 49.0% in the amount, spore 18.8% and acritarch 32.2%. In detail, the spore is mainly made from Punctatisporites, Apiculatisporis, Marattisporites, the pollen Pinaceae, Ovalipollis, Cycadopites and a few Chordasporites, Taeniaesporites, the acritarch Hystrichosphaeridium, Micrhystridiura, Favososphaeridium, besides Leiofusa Quadratimorpha, Scolecodonts, Taenitum, Lignum and so on. The geological time is middle upper Triassic. The Carbonate Rock Formation is composed of a suite of the epicontinental sedimentary strata being 1303 m thickness and formed in the stably olepositional enviroment. The region should, then, lie in the shore of Paleomediterranean sea or near the geosyncline round the Pacific. Based on the abundance gymnospermous spore fron Jiezha Group, the climate at that time should be humid torrid or subtorrid zone marine. 相似文献
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FRANK STILLER 《Palaeontology》2011,54(6):1415-1433
Abstract: The isocrinid sea lily Tyrolecrinus wugangi sp. nov. from uppermost middle to lowermost upper Anisian (lower Middle Triassic) strata of Leidapo near Qingyan, Guizhou Province, south‐west China, provides new data on the early phylogeny of the order Isocrinida. The new species is the earliest unequivocal representative of the family Isocrinidae. It predates all other known species of the genus Tyrolecrinus that come from upper Ladinian to Rhaetian strata and also all other known taxa of the Isocrinidae. Nevertheless, its stem is of fully developed isocrinid type and is characteristic of the genus, with consistently synostosial, rarely cryptosymplectial, distal nodal articular facets. These findings indicate that the Isocrinidae evolved prior to the late middle Anisian in the far‐eastern part of the Palaeotethys ocean, perhaps in the region forming today’s south‐west China, and spread to various other regions later in the Middle and Late Triassic. The genus Tyrolecrinus is revised and the new genus Bakonycrinus gen. nov. is erected. 相似文献
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Max C. Langer Martin D. Ezcurra Jonathas S. Bittencourt Fernando E. Novas 《Biological reviews of the Cambridge Philosophical Society》2010,85(1):55-110
The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis, and Panphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister‐group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid‐Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node‐based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as “all descendants of the most recent common ancestor of birds and Triceratops”. Recent cladistic analyses of early dinosaurs agree that Pisanosaurus mertii is a basal ornithischian; that Herrerasaurus ischigualastensis and Staurikosaurus pricei belong in a monophyletic Herrerasauridae; that herrerasaurids, Eoraptor lunensis, and Guaibasaurus candelariensis are saurischians; that Saurischia includes two main groups, Sauropodomorpha and Theropoda; and that Saturnalia tupiniquim is a basal member of the sauropodomorph lineage. On the contrary, several aspects of basal dinosaur phylogeny remain controversial, including the position of herrerasaurids, E. lunensis, and G. candelariensis as basal theropods or basal saurischians, and the affinity and/or validity of more fragmentary taxa such as Agnosphitys cromhallensis, Alwalkeria maleriensis, Chindesaurus bryansmalli, Saltopus elginensis, and Spondylosoma absconditum. The identification of dinosaur apomorphies is jeopardized by the incompleteness of skeletal remains attributed to most basal dinosauromorphs, the skulls and forelimbs of which are particularly poorly known. Nonetheless, Dinosauria can be diagnosed by a suite of derived traits, most of which are related to the anatomy of the pelvic girdle and limb. Some of these are connected to the acquisition of a fully erect bipedal gait, which has been traditionally suggested to represent a key adaptation that allowed, or even promoted, dinosaur radiation during Late Triassic times. Yet, contrary to the classical “competitive” models, dinosaurs did not gradually replace other terrestrial tetrapods over the Late Triassic. In fact, the radiation of the group comprises at least three landmark moments, separated by controversial (Carnian‐Norian, Triassic‐Jurassic) extinction events. These are mainly characterized by early diversification in Carnian times, a Norian increase in diversity and (especially) abundance, and the occupation of new niches from the Early Jurassic onwards. Dinosaurs arose from fully bipedal ancestors, the diet of which may have been carnivorous or omnivorous. Whereas the oldest dinosaurs were geographically restricted to south Pangea, including rare ornithischians and more abundant basal members of the saurischian lineage, the group achieved a nearly global distribution by the latest Triassic, especially with the radiation of saurischian groups such as “prosauropods” and coelophysoids. 相似文献
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Nanogomphodon wildi n. gen., n. sp. is based on a tiny lower postcanine tooth from the lower Lettenkeuper (Lower Keuper or Erfurt Formation;
Ladinian) of Michelbach an der Bilz (Baden-Württemberg). It represents the first record of a traversodont cynodont from the
Middle Triassic of Europe and exhibits a distinctive combination of dental features. Along with recent discoveries of other
traversodont taxa from the Upper Triassic of eastern North America,Nanogomphodon indicates the existence of a distinct lineage of these cynodonts in the Northern Hemisphere.
相似文献
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Cajus G. Diedrich 《Historical Biology》2013,25(4):391-409
The oldest record of Cyamodus is a skull of Cyamodus tarnowitzensis (Gürich 1884, Zt dt Geol Ges. 36:125–144) from Pelsonian shallow marine deposits. During the middle Illyrian, placodonts disappeared from the Germanic Basin. With renewed upper Illyrian transgression, Cyamodus rostratus (Münster 1839, Über einige ausgezeichnete fossile Fischzähne aus dem Muschelkalk bei Bayreuth. Birner, Bayreuth, p. 14) appeared which was found in terebratulid shell-rich shallow marine deposits. Abundant remains of Cyamodus muensteri (Agassiz 1839), traditionally referred to as Cyamodus hildegardis and here synonymised with C. muensteri, have been reported from the upper Illyrian/middle Fassanian. Skeletal remains of this species are from the Grenzbitumenzone of the Monte San Giorgio lagoons. The youngest species, Cyamodus kuhnschnyderi (Nosotti and Pinna 1993, Compt Rend Acad Sci Paris. 317:847–850), has been found in the upper Fassanian/lower Longobardian of the southern Germanic Basin or Burgundian Gate when marine facies in the Germanic Basin had nearly disappeared. These successive species provide evidence of monophylogenetic development with a trend towards anterior upper and lower jaw teeth reduction, along with a shortening of the rostrum, over an interval of five million years (243–238 Ma). This evolutionary trend most probably reflects adaptation to specialised feeding on seaplants. The Cyamodus osteoderm carapace was not fused to the vertebral column, and appears to have been primarily a body enhancement that produced neutral or negative buoyancy to facilitate long-period diving. 相似文献
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The tetrapod faunas from the terrestrial Middle–Late Triassic basins of Africa and South America are among the richest in the world, especially in non‐mammalian cynodonts. Despite the great abundance of cynodont specimens found in these basins, there are few known taxa that exhibit interbasinal distributions. Here we describe a new species of traversodontid cynodont of the genus Scalenodon from the Triassic Dinodontosaurus Assemblage Zone of the Santa Maria Supersequence, from the state of Rio Grande do Sul, Brazil. Scalenodon ribeiroae sp. nov. is based on a partial skull that possesses a combination of features not observed in any other South American traversodontid: ellipsoid upper postcanines with the transverse crest formed by three cusps, lacking a mesiobuccal accessory cusp, and with lingual cusp projected lingually creating a concave lingual surface on the upper postcanines; the paracanine fossa is positioned medially to the upper canine, and jugal lacks a suborbital process. A phylogenetic analysis places the new taxon in a basal position within the Family Traversodontidae, with the African Scalenodon angustifrons as sister‐taxon. The new specimen of Scalenodon represents the first record of this genus outside of the Manda Beds of Tanzania, and reinforces the biostratigraphical and biogeographical connection between Gondwanan Middle–Late Triassic tetrapod faunas. Although recent advances have been made, our current knowledge of these faunas is limited by the lack of absolute dates for most units and by uncertainties in the taxonomy and stratigraphical provenance of key fossils. 相似文献
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The trace fossil Zoophycos has been described from the Middle Triassic carbonates of the German Basin for the first time. It occurs in a calcilutite bed at the top of a shallowing-upward cycle (parasequence) in the transgressive systems tract of the Middle to Upper Muschelkalk sequence of Thuringia (Germany). Based on sedimentological and palaeontological features, the studied interval is interpreted as deposited in a marine nearshore environment with proximal storm deposits (tempestites). Zoophycos occurs in a very simple planar form with lobate spreiten, which were most likely produced by a worm-like animal by strip mining. The upper tier of the ichnofabric consists of Zoophycos, whereas the lower tier is occupied by cylindrical trace fossils of unknown taxonomic affiliation and with decreasing size towards the bottom. Associated trace fossils such as Rhizocorallium, Balanoglossites and Trypanites indicate a partly firm to hard substrate. No mixed layer is developed at the top of the trace fossil bearing succession. The ichnofabric together with the sedimentological features (disseminated pyrite, blue-grey colour) and palaeontological circumstances (poor benthic fauna, meiofauna with a small body size) support an interpretation of a dysaerobic environment. In the view of evolutionary change, Palaeozoic Zoophycos occurs in both deep and shallow marine deposits, whereas Mesozoic and Cenozoic Zoophycos is only common in shelfal and deeper-marine deposits. The new finding from the shallow-marine Middle Triassic represents the first reliable occurrence of Zoophycos after the end-Permian mass extinction and shows close similarities to its Palaeozoic precursors. It demonstrates that the producer survived the end-Permian mass extinction, became re-established in the nearshore realm and progressively colonized deeper-marine environments during the Mesozoic and Cenozoic. 相似文献
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中三叠世青岩生物群的群体古生态学初步研究 总被引：3，自引：0，他引：3
根据群体古生态学的初步研究,认为青岩生物群的富集是因为发育一个较为特殊的生态环境,即位于斜坡与台地交接处的一个小型盆地－护障性浅海中,生态类型分析结果表明,此处为低能稳定的水域,水溶在正常浪基面之下,风暴浪基面之上,海水清澈,氧气充足,营养丰富,并可能富产海藻,因而十分有利于海相底栖生物繁衍。 相似文献
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The present paper deals with the exteral form and the cuticle structure of Ctenozamites drepanoides Chen et Duan sp. nov. The specimens were collected from the upper Triassic coal series of Liuzhi district, Guizhou province. Main characters of the new species: Leaf bipinnate, ultimate pinna lanceolate, pinnules drepaniform, entire, apex obtuse, pinnules arising from the upper side of pinna rachis. Cuticles rather thick. Stomatal apparatus haplocheilic, smaller, confined to the lower epidermis, scattered in the areas between veins, variably orientated, 70–80 per sq. mm. 相似文献
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意外裸鱼(Gymnoichthys inopinatus)于2010年由Tintori等首次记述并归入基干新鳍鱼类。依据在云南省曲靖地区罗平县大凹子村中三叠世关岭组二段发现的新材料,对意外裸鱼进行了补充描述,并重新讨论了其系统发育关系。在意外裸鱼的新标本上,可见其续骨前端很可能与关节骨相关节,并有确切无疑的单一辅上颌骨,表明意外裸鱼应为鲱亚部(Halecomorphi)鱼类。此外,意外裸鱼的体表无鳞、椎体未骨化、髓棘和髓弓的结构和排列方式以及牙齿和尾脉棘的形状都与金尾鱼超科鱼类(caturoids)一致。系统发育分析结果表明意外裸鱼属于金尾鱼超科的基干类群。之前金尾鱼类主要见于欧洲和北美的侏罗系,现在公认的金尾鱼超科鱼类主要包括Liodesmidae中的Liodesmus属和金尾鱼科(Caturidae)中的Caturus和Amblysemius两属。意外裸鱼的发现不仅使金尾鱼类的出现提前了40Ma,而且填补了我国相关材料的空缺。 相似文献