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1.
Classification and phylogeny of the diapsid reptiles   总被引:4,自引:0,他引:4  
Reptiles with two temporal openings in the skull are generally divided into two groups–the Lepidosauria (lizards, snakes, Sphenodon , 'eosuchians') and the Archosauria (crocodiles, thecodontians, dinosaurs, pterosaurs). Recent suggestions that these two are not sister-groups are shown to be unproven, whereas there is strong evidence that they form a monophyletic group, the Diapsida, on the basis of several synapomorphies of living and fossil forms. A cladistic analysis of skull and skeletal characters of all described Permo-Triassic diapsid reptiles suggests some significant rearrangements to commonly held views. The genus Petrolacosaurus is the sister-group of all later diapsids which fall into two large groups–the Archosauromorpha (Pterosauria, Rhynchosauria, Prolacertiformes, Archosauria) and the Lepidosauromorpha (Younginiformes, Sphenodontia, Squamata). The pterosaurs are not archosaurs, but they are the sister-group of all other archosauromorphs. There is no close relationship between rhynchosaurs and sphenodontids, nor between Prolacerta or Tanystropheus and lizards. The terms 'Eosuchia', 'Rhynchocephalia' and 'Protorosauria' have become too wide in application and they are not used. A cladistic classification of the Diapsida is given, as well as a phylogenetic tree which uses cladistic and stratigraphic data.  相似文献   

2.
3.
The initial stages of evolution of Diapsida (the large clade that includes not only snakes, lizards, crocodiles and birds, but also dinosaurs and numerous other extinct taxa) is clouded by an exceedingly poor Palaeozoic fossil record. Previous studies had indicated a 38 Myr gap between the first appearance of the oldest diapsid clade (Araeoscelidia), ca 304 million years ago (Ma), and that of its sister group in the Middle Permian (ca 266 Ma). Two new reptile skulls from the Richards Spur locality, Lower Permian of Oklahoma, represent a new diapsid reptile: Orovenator mayorum n. gen. et sp. A phylogenetic analysis identifies O. mayorum as the oldest and most basal member of the araeoscelidian sister group. As Richards Spur has recently been dated to 289 Ma, the new diapsid neatly spans the above gap by appearing 15 Myr after the origin of Diapsida. The presence of O. mayorum at Richards Spur, which records a diverse upland fauna, suggests that initial stages in the evolution of non-araeoscelidian diapsids may have been tied to upland environments. This hypothesis is consonant with the overall scant record for non-araeoscelidian diapsids during the Permian Period, when the well-known terrestrial vertebrate communities are preserved almost exclusively in lowland deltaic, flood plain and lacustrine sedimentary rocks.  相似文献   

4.
福建漳平下二叠统的小有孔虫   总被引:6,自引:3,他引:6  
福建漳平岭兜下二叠统地层发育良好,序列清楚,与ting类共生的小有孔虫化石丰富。根据化石群垂直分布特点,可分为三个小有孔虫组合,自下而上为Geintzina-Pachyphloia组合,Langella-Pseudoglandulina longa组合及Hemigordius qinglongensis-Cribrogenerina celebrata组合。这三个小有孔虫组合在福建均属首次发现。这发现为下二叠统的地层时代归属又提供一佐证。  相似文献   

5.
In spite of the increasing popularity of cladistic methods in studies of primate systematics, few authors have investigated the effects of parallel evolution when such methods are applied to empirical data. To counter the effects of parallelism, cladistic techniques rely on the principle of evolutionary parsimony. When parsimony procedures are used to reconstruct the phylogeny of the Lemuridae, nine highly parsimonious phylogenies can be deduced. Further choice among these competing hypotheses of relationship is determined by the extent to which one embraces the parsimony principle. The phylogeny obtained by the most rigorous adherence to the parsimony principle is one which is wholly consistent with traditional evolutionary classifications of the Lemuridae. Moderate levels of parallelism can lead to the generation of several plausible, alternative phylogenetic hypotheses; less than 25% of the characters analyzed here need have evolved in parallel, yet they are largely responsible for the ambiguity of the nine different lemurid phylogenies. This suggests that phylogeny reconstructions based entirely on cladistic methods do not provide a suitable basis for the construction of classifications for groups such as the order Primates, where the degree of parallelism is likely to be quite high.  相似文献   

6.
The holotype of the Upper Permian gliding reptile Weigeltisaurus jaekeli is redescribed. Comparison with the Madagascan reptile Coelurosauravus shows that the two forms are congeneric. Coelurosauravus Piveteau, 1926 has priority. The Upper Permian genus Gracilisaurus Weigelt, 1930 is reviewed and referred to Coelurosauravus.  相似文献   

7.
The earliest Permian faunal successions of central Patagonia show compositional changes that probably reflected the environmental warming at the end of the Gondwana glaciations. Bivalves of Asselian to probably Early Tastubian age are described. A new genus,Sueroa, is proposed to reunite a previously known species and a new species,Sueroa andreisi n. sp. Another five new species:Parallelodon? quichaurensis n. sp.,Heteropecten cortignasi n. sp.,Etheripecten saraviae n. sp.,Streblopteria montgomeryi n. sp. andPraeundulomya moreli n. sp. are described. Two previously known species:Malimania patagoniensis (González) andEuchondria sabattiniae González are revised and new occurrences are reported. A further eleven species are described, but they are left in open nomenclature being because they are insufficiently known; these are:Phestia? n. sp.,Modiolus sp.,Palaeoneilo sp.,Stutchburia sp.,Schizodus sp.,Vacunella? sp.,Edmondia sp.,Myonia? n. sp.,Myonia? sp. andPachymyonia? n. sp.  相似文献   

8.
The Permian terebratulids of Eurasia are revised. The taxonomic composition of the Permian terebratulids of the Russian Platform, Northern Caucasus, Transcaucasia, northern and southeastern Pamirs, and northern China (Inner Mongolia) is elucidated. Fifty-one species (13 described here as new), 21 genera (3 described here as new), 7 families, and 6 superfamilies are described. During the progress of the study, the author (Smirnova, 2004a, 2004b, 2006a, 2006b) and Smirnova and Grunt (2002, 2003a, 2003b) described for the first time 19 species, nine genera, two families, and one superfamily. Morphofunctional analysis reveals a great diversity of internal structures, of the time of their appearance in the ontogeny, and of their taxonomic significance. Ontogenetic study reveals phylogenetic relationships between the Permian and Meso-Cenozoic terebratulids, the presence of the superfamilies Terebratuloidea and Loboidothyroidea in the Permian, and a new type of brachidium ontogeny characterizing the superfamily Compositelasmatoidea. This book is intended for paleontologists and biologists interested in problems of taxonomy and phylogeny, and includes 5 plates, 80 figures, and 75 bibliographic references.  相似文献   

9.
Fossilised traces of swimming amphibians, assigned to Batrachichnus delicatulus and Serpentichnus robledoensis igen. et isp. nov., are described from the Lower Permian of the Robledo Mountains, southern New Mexico. The B. delicatulus specimen is interpreted as a trackway of a small 'amphibian' (temnospondyl, nectridean, microsaur or juvenile embolomere) swimming straight ahead. S. robledoensis consists of repeated pes imprints separated by discontinuous, L-shaped imprints (body traces). It is interpreted as a trackway of an 'amphibian' swimming in a similar manner to the motion of a side-winding snake. The producer of S. robledoensis is more distinctive than in B. delicatulus , and is suggestive of the lysorophian Brachydectes . This is the first locomotory trace to be assigned to this 'amphibian' group.  相似文献   

10.
New taxa of detached seeds are described from the Kungurian (Lower Permian) of the Middle Cis-Urals: Laevigatospermum compressum gen. et sp. nov., Hirsutospermum paniculatum gen. et sp. nov., Rugosospermum callosum gen. et sp. nov., and Craspedosperma filiferum sp. nov. The systematic position of the new taxa is discussed.  相似文献   

11.
New Catillocrinidae Allocatillocrinus rarus sp. nov., with a previously unknown tegmenal structure, Paracatillocrinus shamovi sp. nov., and P. shakhtauensis sp. nov., with an unusual relative position of the crown and stem are described from the Artinskian Stage (Lower Permian) of the western slope of the Middle and Southern Ural Mountains (Boets, Krasnoufimsk, and Shakh-Tau localities). The genus Allocatillocrinus has not previously been recorded from the Permian, while Paracatillocrinus has only previously been reported from the Upper Permian of Timor Island.  相似文献   

12.
More than 300 megaspore specimens have been recovered from samples from the Late Permian, Lower Whybrow coal seam of the Wittingham Coal Measures of the Sydney Basin. Only two species are recognised: Singhisporites surangei (Singh) Potonié, emend. and a new species of Singhisporites. Species distribution within the seam is controlled by a major fire event, as recognised by coal petrology and mesofossil content: Singhisporites surangei is dominant before the event, but following it, it is subordinate to the new species.

The abundance of megaspores recovered has allowed recognition of the full range of morphologic variation of Singhisporites surangei, which encompasses specimens assigned previously to Singraulispora Pant & Mishra, 1986 and Mammilaespora Pant & Srivastava, 1961; both are regarded as junior synonyms of Singhisporites Potonié, emend. Ultrastructurally, the new species shows affinities with Mesozoic isoetalean megaspores.  相似文献   


13.
The postcranial skeleton of the reptile Gephyrosaurus bridensis is described. The material was extracted from the Lower Jurassic fissure infillings of South Wales and comprises the broken and dissociated bones of many different individuals. The skeleton, like the skull, retains many primitive features which justify the inclusion of Gephyrosaurus within the Eosuchia. A comparison of the skeleton with that of other genera supports the conclusion that Gephyrosaurus represents a separate eosuchian lineage. The skeleton is that of a small, unspecialized terrestrial reptile which could move quickly in pursuit of prey.  相似文献   

14.
内蒙古乌达地区早二叠世晋囊蕨属一新种   总被引:3,自引:0,他引:3  
通过扫描电镜研究,建立了内蒙古中部乌达地区下二叠统山西组晋囊蕨诉一个新种Chansitheca wudaensis sp .onv.。新种的小心片Sphenopteris型,囊群椭圆形,由4~10个孢子囊组成,着生一示羽片背面,位于中脉的两侧。环带横列于孢子囊的上部,完全,单排细胞,细胞数目约为18个,这些特征表明新种属于里白科。  相似文献   

15.
This work describes stage by stage the biostratigraphy of the Middle to Late Permian in Mexico and Guatemala. Roadian deposits are very poorly represented, as a consequence of tectonic movements at the end of the Kungurian/Leonardian stage. In fact Middle and Late Permian deposits are almost completely lacking in South Mexico and the whole Latin America, due to a probable climatic barrier. The main data concern the Las Delicias sequences from Coahuila, North Mexico, and the Mixteca Terrane, South central Mexico, with some precisions on the Wordian-Capitanian from Los Hornos (Puebla) and from Olinalá, Guerrero, respectively with the discoveries of Parafusulina sellardsi and Polydiexodina capitanensis. New data are provided on Capitanian mudmounds from Olinalá. A hypothetical reconstruction of the different terranes of Mexico at the Pangea stage, is finally presented.  相似文献   

16.
Traditional taxonomy of Hominoidea collides head on with the latest proposals of classification, grounded on molecular studies. Therefore, the common-sense meaning of “hominidae” does not fit some of the current technical meaning anymore. Besides, there is no consensus among molecular scholars about what genera should be placed into the Hominidae family. Some possible solution to this problem are examined in this article. It is eventually proposed a tentative classification of humans and great apes that, keeping the traditional Hominidae family (Simpson), might be accepted from the point of view of cladistic and molecular studies.  相似文献   

17.
A new species of artiodactyl, Amphirhagatherium edwardsi sp. nov., is described from the Late Eocene (Priabonian) Headon Hill Formation of the Hampshire Basin, southern England. The Haplobunodontidae, in which Amphirhagatherium is usually placed, has recently been combined with the monotypic Choeropotamidae, both essentially European endemic families. New anatomical information is forthcoming from both the new species and recently published data on related species. A cladistic analysis of taxa included in the two families, the possible anthracotheriid Thaumastognathus and the enigmatic Tapirulus , was conducted to test the relationships implied by observed morphological similarities. The genus Anthracobunodon is shown to be paraphyletic and is here synonymized with Amphirhagatherium . Choeropotamus and Thaumastognathus are sister taxa nested with three species of Haplobunodon and Haplobunodon is paraphyletic and polyphyletic, but this clade is too weakly resolved internally for reliable taxonomic changes. Lophiobunodon Tapirulus are sister taxa nested with a fourth species of Haplobunodon . The synonymy of the Haplobunodontidae with the Choeropotamidae is upheld and close relationship of the family with the Anthracotheriidae is argued to be unlikely. Choeropotamids are inferred to have had mixed frugivorous and browsing herbivorous diets. They seem to have diversified in the northern parts of Europe, some terminal taxa having originated following southward dispersal.  相似文献   

18.
Lower Permian Bryozoan fauna of Jamal Formation, exposed in Bagh-e Vang (Shotori Mountains, northeast Iran) includes six species. Three species – Streblotrypa (Streblascopora) marmionensis (Etheridge 1926), Rhabdomeson bispinosum (Crockford 1944) and Alternifenestella kungurensis (Stuckenberg 1898) – indicate the Lower Permian (Artinskian to Kungurian) age of the formation. Three additional taxa – Fistulipora sp. 1, Fistulipora sp. 2 and undetermined timanodictyid bryozoan ?Timanodictya sp. could not be identified at the species level. The investigated fauna refers to Uralian and Australian palaeobiogeographic provinces.  相似文献   

19.
The Lower Permian ichnofauna in the Collio Formation (Artinskian) in the Val Trompia (Brescian Prealps, North Italy) has been studied for a long time, but the studies have focused mainly on vertebrate prints. In this study, the invertebrate ichnofauna of the Collio Formation, and in the epiclastites of the Monte Luco Formation (Artinskian) cropping out in the Monte Luco area (Trentino Alto Adige region), is systematically analyzed for the first time. This ichnocoenosis consists of: Permichnium isp., Paleohelcura tridactyla, Diplichnites gouldi (Types A and B), Diplopodichnus biformis, Circulichnis montanus, Helminthopsis hieroglyphica, Gordia marina, Acripes cf. multiformis, Cruziana cf. problematica, Cochlichnus anguineus, Palaeophycus tubularis, Planolites isp. and ?Scoyenia isp. The ichnoassociation from the Collio Formation belongs to the Scoyenia ichnofacies, while that from the Mt. Luco Formation belongs to the Mermia ichnofacies. The latter, because of the lack of complete data, can be linked only to one of several submersion phases of the intravolcanic basin and is not referred to the complete continental Permian sequence in this zone. The composition of the ichnoassociation here analysed is similar to those of other European (especially France and Germany) and extra-European areas (especially North America and Argentina).  相似文献   

20.
This project undertakes the first molecular-based phylogenetic study of subfamily Epidendroideae (Orchidaceae). Approximately 1200 nucleotides (from the 3' half of the chloroplast gene ndhF for 34 orchid taxa and a lilioid monocot, Clivia miniata (Amaryllidaceae), were subjected to phylogenetic analysis using parsimony and maximum likelihood methods. Oryza sativa (Poaceae), a nonlilioid monocot, was designated as outgroup. Trees from both parsimony and maximum likelihood methods suggest that subfamily Epidendroideae is monophyletic, with Listera (Neottieae) as sister. Although subtribal relationships are typically well resolved and have strong branch support, intertribal relationships are generally poorly resolved. Perhaps this general lack of resolution among tribes reflects a rapid species radiation that coincided with anatomical, physiological, and anatomical adaptations that initiated large-scale epiphytism in the ancestral Epidendroideae. Six taxa in this study exhibit deletions that are not evenly divisible by three and result in extensive sequence frameshifts. For example, one deletion is 227 bp in length and is flanked by the short direct repeat sequence; TCAATAGGAATTTCTTTT. Multiple deletions and frameshifts suggest that ndhF may be a pseudogene, in at least some orchid taxa.  相似文献   

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