نتایج جستجو برای: late maastrichtian
تعداد نتایج: 195833 فیلتر نتایج به سال:
Ecological studies suggest that rare taxa are more likely to go extinct than abundant ones, but the influence of abundance on survivorship in the fossil record has received little attention. An analysis of Late Maastrichtian bivalve subgenera from the North American Coastal Plain found no evidence that survivorship is tied to abundance across the end-Cretaceous mass extinction (65 million years...
Radiolitid rudists belonging to the genera Bournonia FISCHER, Biradiolites D’ORBIGNY and Thyrastylon CHUBB are abundant in the Upper Maastrichtian, Titanosarcolites Limestones (Guinea Corn Formation and other formations) of Jamaica. Although there is a large literature on these Jamaican forms (e.g., WHITFIELD, 1897; TRECHMANN, 1924; CHUBB, 1956, 1967, 1971), little information on their microstr...
Planktonic foraminifera and major palynomorph groups (i.e. terrestrial, marine, and amorphous organic matter) of the Campanian-Selandian strata of the Gurpi Formation were studied to evaluate the changes in the Zagros paleobasin in southwestern Iran. Planktonic foraminifera were categorized into four morphotypes according to their paleodepth, extending from Morphotype 1, comprising surface gene...
The controversial European genus Allodaposuchus is currently composed of two species (A. precedens, A. subjuniperus) and it has been traditionally considered a basal eusuchian clade of crocodylomorphs. In the present work, the new species A. palustris is erected on the base of cranial and postcranial remains from the lower Maastrichtian of the southern Pyrenees. Phylogenetic analyses here inclu...
Angiosperms evolved rapidly in the late Mesozoic. Data from the genetic-based approach called ’molecular clock’ permit an evaluation of the radiation of flowering plants through geological time and of the possible influences of Mesozoic mass extinctions. A total of 261 divergence ages of angiosperm families are considered. The radiation of flowering plants peaked in the Albian, early Campanian,...
The sedimentary history and facies development of southern Egypt during the Latest Cretaceous Early Paleogene is summarized. G . eugubina Zone reported for first time from middle Egypt, where conglomerate usually marking a disconformity at Cretaceous/Tertiary boundary, absent. Uppermost Maastrichtian strata are attributed to M prinsii Zone, Late index foraminifer Abathomphalus mayaroensis (Boll...
Levnesovia transoxiana gen. et sp. nov., from the Late Cretaceous (Middle-Late Turonian) of Uzbekistan, is the oldest well-documented taxon referable to Hadrosauroidea sensu Godefroit et al. It differs from a somewhat younger and closely related Bactrosaurus from Inner Mongolia (China) by a tall sagittal crest on the parietals and the absence of club-shaped dorsal neural spines in adult specime...
Ectotherms have close physiological ties with the thermal environment; consequently, the impact of future climate change on their biogeographic distributions is of major interest. Here, we use the modern and deep-time fossil record of testudines (turtles, tortoises, and terrapins) to provide the first test of climate on the niche limits of both extant and extinct (Late Cretaceous, Maastrichtian...
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