نتایج جستجو برای: middle cretaceous
تعداد نتایج: 163403 فیلتر نتایج به سال:
The fossil record for neoceratopsian (horned) dinosaurs in the Lower Cretaceous of North America primarily comprises isolated teeth and postcrania of limited taxonomic resolution, hampering previous efforts to reconstruct the early evolution of this group in North America. An associated cranium and lower jaw from the Cloverly Formation (?middle-late Albian, between 104 and 109 million years old...
Here we report on angiosperm-like pollen and Afropollis from the Anisian (Middle Triassic, 247.2-242.0 Ma) of a mid-latitudinal site in Northern Switzerland. Small monosulcate pollen grains with typical reticulate (semitectate) sculpture, columellate structure of the sexine and thin nexine show close similarities to early angiosperm pollen known from the Early Cretaceous. However, they differ i...
A new taxon of peirosaurid crocodyliform, Rukwasuchus yajabalijekundu, gen. et sp. nov., is described on the basis of a well-preserved partial skull from the middle Cretaceous Galula Formation exposed in southwestern Tanzania. The skull is distinguished from those of other crocodyliforms by the presence of a mediolaterally narrow, elongate, and septate internal narial fenestra (choana) located ...
A molecular phylogenetic analysis recovers a pattern consistent with a drift vicariance scenario for the origin of Greater Antillean cichlids. This phylogeny, based on mitochondrial and nuclear genes, reveals that clades on different geographic regions diverged concurrently with the geological separation of these areas. Middle America was initially colonized by South American cichlids in the Cr...
In 1840, John Phillips invented the term Mesozoic, which means “Middle Animal”. The Mesozoic Era was a geological time period that lasted 180 million years and is composed of three smaller time periods, Triassic, Jurassic and the Cretaceous. The cretaceous period lasted 81 million years, which during that time there was a continual rule of dinosaurs and other reptiles, the start of flowering pl...
A cervical vertebra from the Early Cretaceous of Victoria represents the first Australian spinosaurid theropod dinosaur. This discovery significantly extends the geographical range of spinosaurids, suggesting that the clade obtained a near-global distribution before the onset of Pangaean fragmentation. The combined presence of spinosaurid, neovenatorid, tyrannosauroid and dromaeosaurid theropod...
The fossil record of Australian pterosaurs is sparse, consisting of only a small number of isolated and fragmentary remains from the Cretaceous of Queensland, Western Australia and Victoria. Here, we describe two isolated pterosaur teeth from the Lower Cretaceous (middle Albian) Griman Creek Formation at Lightning Ridge (New South Wales) and identify them as indeterminate members of the pteroda...
This paper presents evidence on Mesozoic inversion of basin bounding faults within the Taleqan-Gajereh-Lar Paleograben (TGLP) in Central Alborz Range. For this purpose, well documented stratigraphy data across the TGLP together with the new acquired structural data on the geometry and kinematics of the paleograben basin bounding faults are utilized. The TGLP has evolved through the Early and Mi...
this paper presents evidence on mesozoic inversion of basin bounding faults within the taleqan-gajereh-lar paleograben (tglp) in central alborz range. for this purpose, well documented stratigraphy data across the tglp together with the new acquired structural data on the geometry and kinematics of the paleograben basin bounding faults are utilized. the tglp has evolved through the early and mi...
three granitoid bodies, shirkuh batholith, kaffe abad and ader bolandan are exposed in nw yazd, cutting across the naiband formation (upper triassic), and overlain by cretaceous formations. shirkuh batholith is most likely of jurassic age. it seems to be the first and the most significant episode of magmatism in studied area which occurred in middle jurassic (late cimmerian) time. on the other ...
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