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1.
A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia 总被引:1,自引:0,他引:1
Butler RJ Smith RM Norman DB 《Proceedings. Biological sciences / The Royal Society》2007,274(1621):2041-2046
Although the group played an important role in the evolution of Late Mesozoic terrestrial ecosystems, the early evolutionary history of the ornithischian dinosaurs remains poorly understood. Here, we report on a new primitive ornithischian, Eocursor parvus gen. et sp. nov., from the Late Triassic (?Norian) Lower Elliot Formation of South Africa. Eocursor is known from a single specimen comprising substantial cranial and postcranial material and represents the most complete Triassic member of Ornithischia, providing the earliest evidence for the acquisition of many key ornithischian postcranial characters, including an opisthopubic pelvis. A new phylogenetic analysis positions this taxon near the base of Ornithischia, as the sister taxon to the important and diverse clade Genasauria. The problematic clade Heterodontosauridae is also positioned basal to Genasauria, suggesting that an enlarged grasping manus may represent a plesiomorphic ornithischian condition. This analysis provides additional phylogenetic support for limited ornithischian diversity during the Late Triassic, and suggests that several major ornithischian clades may have originated later than generally believed. There are few morphological differences between Late Triassic and Early Jurassic ornithischians, supporting previous suggestions that the Early Jurassic ornithischian radiation may simply represent the filling of vacant ecological space following Late Triassic terrestrial extinctions. 相似文献
2.
Ecology and morphology are different, and yet in comparative studies of fossil vertebrates the two are often conflated. The macroevolution of Mesozoic marine tetrapods has been explored in terms of morphological disparity, but less commonly using ecological‐functional categories. Here we use ecospace modelling to quantify ecological disparity across all Mesozoic marine tetrapods. We document the explosive radiation of marine tetrapod groups in the Triassic and their rapid attainment of high ecological disparity. Late Triassic extinctions led to a marked decline in ecological disparity, and the recovery of ecospace and ecological disparity was sluggish in the Early Jurassic. High levels of ecological disparity were again achieved by the Late Jurassic and maintained during the Cretaceous, when the ecospace became saturated by the Late Cretaceous. Sauropterygians, turtles and ichthyosauromorphs were the largest contributors to ecological disparity. Throughout the Mesozoic, we find that established groups remained ecologically conservative and did not explore occupied or vacant niches. Several parts of the ecospace remained vacant for long spans of time. Newly evolved, radiating taxa almost exclusively explored unoccupied ecospace, suggesting that abiotic releases are needed to empty niches and initiate diversification. In the balance of evolutionary drivers in Mesozoic marine tetrapods, abiotic factors were key to initiating diversification events, but biotic factors dominated the subsequent generation of ecological diversity. 相似文献
3.
Abstract: Three new genera including four new species of the bivalve family Mysidiellidae are described from late middle to early late Anisian (Middle Triassic) deposits of Qingyan, Guizhou Province, south-west China. The new taxa Leidapoconcha gigantea gen. et sp. nov., Waijiaoella elegans gen. et sp. nov., Waijiaoella speciosa gen. et sp. nov. and Qingyaniola mirabilis gen. et sp. nov. significantly increase the known taxonomic diversity within the Mysidiellidae. These findings suggest a somewhat endemic evolutionary development within this small bivalve family during the Middle Triassic in south-west China. 相似文献
4.
by ZULMA GASPARINI 《Palaeontology》2009,52(3):661-669
Abstract: A new pliosaurid, Gallardosaurus iturraldei gen nov. et sp. nov., was found in the Viñales area, western Cuba, in sediments of the Jagua Formation, middle–late Oxfordian. This new taxon is characterized by: wide participation of the premaxilla in the outer margin of the external naris; frontal not participating in the orbital margin; postorbital in contact with the jugal and squamosal; presence of anterior pterygoid vacuity; cultriform process of parasphenoid convex and exposed in palatal view; pterygoid flanges high; jaw articulation low relative to tooth row; trihedral teeth in cross-section and with smooth ridges at least in the labial face. A phylogenetic analysis suggests that Gallardosaurus forms a clade with Peloneustes , the most common pliosaurid genus occurring in the Oxford Clay. The Caribbean Seaway was, at least since the Oxfordian, a corridor that permitted the interchange for marine biota between Western Tethys and Eastern Pacific realms. Among vertebrates, bony fish and long-necked plesiosaurs prevailed. However, marine pleurodiran turtles, metriorhynchid crocodilians, ophthalmosaurian ichthyosaurs, and pliosaurids ( G. iturraldei gen. nov. et sp. nov.) have also been found, as well as at least two species of pterosaurs, and one camarasaurian dinosaur. Among these reptiles there were off-shore pelagic forms such as the ichthyosaurs and metriorhynchids, together with the pliosaurid G. iturraldei gen. nov. et sp. nov.; other taxa were presumably less pelagic, such as the pleurodiran turtles and the cryptoclidid plesiosauroids. Gallardosaurus iturraldei gen. nov. et sp. nov. would have played the role of an active predator taking advantage of nectonic fish recorded in the area. 相似文献
5.
Valentin Fischer Robert M. Appleby Darren Naish Jeff Liston James B. Riding Stephen Brindley Pascal Godefroit 《Biology letters》2013,9(4)
Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed. 相似文献
6.
J?rg Fr?bisch 《PloS one》2008,3(11)
The end-Permian biotic crisis (∼252.5 Ma) represents the most severe extinction event in Earth''s history. This paper investigates diversity patterns in Anomodontia, an extinct group of therapsid synapsids (‘mammal-like reptiles’), through time and in particular across this event. As herbivores and the dominant terrestrial tetrapods of their time, anomodonts play a central role in assessing the impact of the end-Permian extinction on terrestrial ecosystems. Taxonomic diversity analysis reveals that anomodonts experienced three distinct phases of diversification interrupted by the same number of extinctions, i.e. an end-Guadalupian, an end-Permian, and a mid-Triassic extinction. A positive correlation between the number of taxa and the number of formations per time interval shows that anomodont diversity is biased by the Permian-Triassic terrestrial rock record. Normalized diversity curves indicate that anomodont richness continuously declines from the Middle Permian to the Late Triassic, but also reveals all three extinction events. Taxonomic rates (origination and extinction) indicate that the end-Guadalupian and end-Permian extinctions were driven by increased rates of extinction as well as low origination rates. However, this pattern is not evident at the final decline of anomodont diversity during the Middle Triassic. Therefore, it remains unclear whether the Middle Triassic extinction represents a gradual or abrupt event that is unique to anomodonts or more common among terrestrial tetrapods. The end-Permian extinction represents the most distinct event in terms of decline in anomodont richness and turnover rates. 相似文献
7.
本文描述古蝉科化石2新属、6新种,即Liaocossushuegen.etsp.nov.,L.beipiaoensisgen.etsp.nov,L.exiguusgen.etsp.nov,L.fengningensisgen.etsp.nov,L.Pingquanensisgen.etsp.nov.,Miracossusingentiusgen.etsp.nov.。这批化石保存有完整的虫体标本,使作者能够进一步研究古蝉类化石的虫体特征。化石采于冀北和辽西晚侏罗世义县组地层中,保存在中国地质博物馆。 相似文献
8.
The origin and early evolution of amniotes (fully terrestrial vertebrates) led to major changes in the structure and hierarchy of terrestrial ecosystems. The first appearance of herbivores played a pivotal role in this transformation. After an early bifurcation into Reptilia and Synapsida (including mammals) 315 Ma, synapsids dominated Paleozoic terrestrial vertebrate communities, with the herbivorous caseids representing the largest vertebrates on land. Eocasea martini gen. et sp. nov., a small carnivorous caseid from the Late Carboniferous, extends significantly the fossil record of Caseidae, and permits the first clade-based study of the origin and initial evolution of herbivory in terrestrial tetrapods. Our results demonstrate for the first time that large caseid herbivores evolved from small, non-herbivorous caseids. This pattern is mirrored by three other clades, documenting multiple, independent, but temporally staggered origins of herbivory and increase in body size among early terrestrial tetrapods, leading to patterns consistent with modern terrestrial ecosystem. 相似文献
9.
SIDNEY R. ASH 《Palaeontology》2006,49(2):237-245
Abstract: A seed-bearing pinnate leaf found in the Chinle Formation of Late Triassic age in Arizona appears to be an archaic seed fern that more closely resembles typical Carboniferous–Permian seed fern leaves than any younger form. The fossil, which is described here as Chilbinia lichii gen. et sp. nov., incorporates characters of several Palaeozoic taxa. These characters include pinnules that have reticulate venation resembling that in some species of Lonchopteris , cordate bases similar to those found in many species of Sphenopteris , and, except for a significant difference in size, linear ovate seeds that resemble the radially symmetrical seeds found attached to a species of Alethopteris in the Permian of China. The presence of this fossil in strata of Late Triassic age is further evidence that plant extinctions after the Permian–Triassic ecological crisis followed a stepwise pattern and apparently continued for at least 20–25 myr after the end of the Permian in western parts of the Triassic paratropical belt. 相似文献
10.
The rich fauna of Late Devonian (Late Frasnian) siliceous sponges from the Holy Cross Mountains, Poland is composed of 15 species and 11 genera. Both astylospongid demosponges (lithistids) and hexactinosan hexactinellids are present. The following new genera and/or species are proposed: D regulara Rigby and Pisera sp. nov., Jazwicella media Rigby and Pisera gen. et sp. nov., Astyloscyphia irregularia Rigby and Pisera gen. et sp. nov., A. turbinata Rigby and Pisera gen. et sp. nov., Astylotuba modica Rigby and Pisera gen. et sp. nov., Paleoregulara cupula Rigby and Pisera gen. et sp. nov., Paleoramospongia bifurcata Rigby and Pisera gen. et sp. nov., Cordiospongia conica Rigby and Pisera gen. et sp. nov., Paleocraticularia elongata Rigby and Pisera gen. et sp. nov., P gigantia Rigby and Pisera gen. et sp. nov., Polonospongiadevonica Rigby and Pisera gen. et sp. nov., P fistulata Rigby and Pisera gen. et sp. nov., Urnospongia modica Rigby and Pisera gen. et sp. nov., and Conicospongia annulata Rigby and Pisera gen. et sp. nov. The investigated fauna contains the youngest astylospongiids known and the oldest well-preserved, and most diversified Palaeozoic hexactinosans. The sponge fauna constituted a significant element of a brachiopod-coral-sponge assemblage that inhabited a deep slope of the local Dyminy Reef structure, during its final phase of growth, in a clearly hemipelagic setting. This fauna is limited to the intrashelf depression within an incipiently drowned carbonate platform. 相似文献
11.
中国东北晚侏罗世蝎蛉化石研究(长翅目:蚊蝎蛉科,直脉蝎蛉科)(英文) 总被引:1,自引:0,他引:1
本文描述蝎龄化石1新属4新种。新属Megabittacus2新种,即Megabittacuscolosseussp.nov.,Megabittacusbeipiaoensissp.nov,新种Sibirobittacusatalussp.nov.属于现生的蚊蝎蛉科,新种Orthophlebialiaoningensissp.nov.属于绝灭的直脉蝎蛉科。化石采于辽宁省北票市晚侏罗世义县组地层中。这些新的化石属种,其虫体特征包括触角、喙、足和翅脉特征均完整的保存。模式标本保存在中国地质博物馆。 相似文献
12.
N. D. Sinitshenkova 《Paleontological Journal》2013,47(1):84-88
Two new monotypic mayfly genera from Permian-Triassic deposits of the Khungtukun-2 and Khungtukun-4 localities on the Nizhnyaya Tunguska River, Evenkia are described; one, Tunephemera tungussica Sinitshenkova gen. et sp. nov., is based on a wing fragment and assigned to the family Sharephemeridae Sinitshenkova, 2002; and the other, Khungtukunia sibirica Sinitshenkova gen. et sp. nov., is based on nymphs and assigned to the family Vogesonymphidae Sinitshenkova et Papier, 2005. The mayflies described suggest Early Triassic rather than Late Permian age of the deposits. 相似文献
13.
Fossil Woods From Williams Point Beds, Livingston Island, Antarctica: A Late Cretaceous Southern High Latitude Flora 总被引:2,自引:0,他引:2
The wood flora from Williams Point, Livingston Island, contains 12 wood types of gymnosperm and angiosperm origin. Recent collections of material have increased the biodiversity of a postulated species-rich vegetation. The gymnosperm wood can be readily assigned to four form-genera: Araucarioxylon Kraus, Araucariopitys Jeffrey, Podocarpoxylon Gothan and Sahnioxylon Bose and Sah. This indicates a diversity of coniferous araucarian and podocarp trees alongside woods of uncertain affinity ( Sahnioxylon ; Bennettitales). Two angiosperm morphotypes are assigned to the organ genera Hedycaryoxylon Su¨ss (Monimiaceae) and Weinmannioxylon Petriella (Cunoniaceae). The remaining four taxa of angiosperm wood cannot be confidently placed in extant families as they exhibit features that suggest relationships with the Magnoliidae, Hamamelidae and Rosidae. This paper presents the first comprehensive taxonomic revision of the wood flora from Livingston Island and discusses the palaeoecology that prevailed at a latitude of about 60 degrees south during the Late Cretaceous. Newly described taxa are Araucarioxylon chapmanae sp. nov., Araucariopitys antarcticus sp. nov., Podocarpoxylon chapmanae sp. nov., P. verticalis sp. nov., P. communis sp. nov., Weinmannioxylon ackamoides sp. nov., Antarctoxylon livingstonensis gen. et sp. nov., A. multiseriatum gen. et sp. nov., A. heteroporosum gen. et sp. nov. and A. uniperforatum gen et sp. nov. 相似文献
14.
描述中三叠统青岩组化石海绵3 新属,即硬海绵类:Cohartmanina gen. nov.;六射海绵类:Para hexactinoderma gen. nov.和Micraulospongia gen. nov.,及所属种Cahartmanina bangtoupoensis(Stiller, 1998),Parahexactinoderma leidapoensis gen. et sp. nov.,Micraulospongia qingyanenis gen.et sp. nov.。 相似文献
15.
The paper describes structural features of megaspores from the Middle Gondwana (Middle Triassic) beds of Nidhpuri. These include two species of Srivastavaesporites Bharadwaj et Tiwari viz. S. triassicus sp. nov. and S. major sp. nov.; Grambastisporites nidhpurensis gen. et sp. nov.; Trikonia emarginata gen. et sp. nov.; one species of Mamillaespora Pant et Srivastava, M. sidhiensis sp. nov.; Nidhitriletes spinosa gen. et sp. nov. 相似文献
16.
Five new gall midge taxa of the subfamilies Porricondylinae and Lasiopterinae are described from the Late Eocene Rovno amber: Adsumyia integra gen. et sp. nov. (Dicerurini), Gratomyia inexigentis gen. et sp. nov. (Holoneurini), Winnertzia recusata sp. nov. (Winnertziini), Kovaleviola injusta gen. et sp. nov., and Spungisiola insuperabilis gen. et sp. nov. (Brachineurini). 相似文献
17.
ZHAO Li-Jun 《古脊椎动物学报》2008,(3)
中国已知的楯齿龙目(Placodontia)化石仅见于贵州省西南部地区,其中豆齿龙亚目(Cya- modontoidea)产自关岭地区的法郎组瓦窑段,时代为晚三叠世卡尼期;楯齿龙亚目(Placodon- toidea)产自盘县的关岭组Ⅱ段,时代为中三叠世安尼期。本文记述的豆齿龙类新属种——康氏雕甲龟龙(Clyphoderma kangi gen.et sp.nov.)产于云南富源的法郎组竹杆坡段,属中三叠世拉丁期。正型标本保存于浙江自然博物馆(编号:M 8729),其头骨高度愈合,代表一个完全成年之个体,根据以下特征明显区别于我国的Psephochelys和欧洲的Psephoderma:1)头骨枕部具3枚大型的锥状鳞;2)背甲甲片结构更为复杂,具明显的放射状沟/脊结构。到目前为止,康氏雕甲龟龙是龟龙科(Placochelyidae)中惟一的中三叠世属种,该科的其他成员全部发现于上三叠统。 相似文献
18.
中国已知的檐齿龙目(Placodontia)化石仅见于贵州省西南部地区,其中豆齿龙亚目(Cya-modontoidea)产自关岭地区的法郎组瓦窑段,时代为晚三叠世卡尼期;楯齿龙亚目(Placodon-toidea)产自盘县的关岭组Ⅱ段,时代为中三叠世安尼期.本文记述的豆齿龙类新属种--康氏雕甲龟龙(Glyphoderma kangi gen.et sp.nov.)产于云南富源的法郎组竹杆坡段,属中三叠世拉丁期.正型标本保存于浙江自然博物馆(编号:M 8729),其头骨高度愈合,代表一个完全成年之个体,根据以下特征明显区别于我国的Psephochelys和欧洲的Psephoderma:1)头骨枕部具3枚大型的锥状鳞;2)背甲甲片结构更为复杂,具明显的放射状沟/脊结构.到目前为止,康氏雕甲龟龙是龟龙科(Placochelyidae)中惟一的中三叠世属种,该科的其他成员全部发现于上三叠统. 相似文献
19.
In this paper, five new pollen genera and twenty new pollen species of angiospermae from the Late Cretaceous of a certain basin in central China are described. Four new organ genera and their species include: Morinoipollenites normalis gen. et sp. nov., Morinoipollenites minor gen. et sp. nov., Morinoipollenites polyprojectus gen. et sp. nov., Morinoipollenites rhombiformis gen. et sp. nov., Jianghanpollis ringens gen. et sp. nov., Jianghanpollis, mikros gen. et sp. nov., Jianghanpollis radiatus gen. et sp. nov., Jianghanpollis sayangensis gen. et sp. nov., Jianghanpollis arciformis gen. et sp. nov., Myoporumpollonites variabilis gen. et sp. nov., Myoporumpollenites striatus gen. et sp. nov., Lythraites giganteus Yu, Guo et Mao gen. et sp. nov. Lythraites clavatus sp. nov., Lythraites dilutus sp. nov., Lythraites magnus sp. nov., Lythraites varrustriatus sp. nov., Lythraites pachyrrhachis sp. nov.; the new-form genus and its species are: Crassimarginpollenites reticulatus gen. et sp. nov., Crassimerginpollenites mirus gen. et sp. nov., Crassimarginpollenites psilatus gen. et sp. nov. The new pollen genera and their species described herein have been compared in some details with recent pollens and considered their affinity with such recent families as Dipsacaceae, Myoporaceae, Apocynaceae and Lythraceae. According to the age of the pollen-bearing strata, a preliminary discussion is made regarding to the taxonomy of the recent plants families with which our new described pollens are related. Hence, this study may provide some mieropalaeobotanical information for deciphering 'the phylogeny of these plants. 相似文献
20.
A low-diversity cockroach assemblage from the Upper Jurassic of the Houtiyn-Hotgor locality in Mongolia is described, comprising Solemnia alexandri gen. et sp. nov. (Caloblattinidae), Blattula choutinensis sp. nov. (Blattulidae) and a presumed Triassic relict Irreblatta relicta gen. et sp. nov. (incertae familiae). The carnivorous Raphidiomimidae supposedly originated directly from the Caloblattinidae. 相似文献