Lepidosauria (lizards, snakes, tuatara) is a globally distributed and ecologically important group of over 9,000 reptile species. The earliest fossil records are currently restricted to the Late Triassic and of
The DNA sequences in primate C are significantly different from those of primate A. From this information, the biologist may infer that • Primates A and B are more closely related to each other than either is to primate C. What is the idea developed by Charles Lyell which ...
Several subsequent analyses using more recent methods have also recovered estimates from within the Permian, 289 and 265 Mya [36–39]. However, other molecular dating analyses provide dates in the Late or Middle Triassic with one as recent/shallow as 226 Mya [39–43]. This range of estimates...
for which each unit is defined by its beginning and ending points, and (2) a correlated scale of rock sequences (using systems, series, stages, and chronozones). These schemes, when used in conjunction with other dating methods—such as radiometric dating (the measurement of radioactive decay...
If vermiform microstructure is in fact the fossilized tissue of keratose sponges, the material described here would represent the oldest body-fossil evidence of animals known to date, and would provide the first physical evidence that animals emerged before the Neoproterozoic oxygenation event and ...
the earth’s two supercontinents―Laurasia in the north and Gondwanaland in the south―were in the process of pulling apart, cutting dinosaur populations off from each other and interrupting migratory patterns. The fossilized bones, found by paleontologist Doug Wolfe of the Mesa Southwest Museum in...
While pelagornithid or ‘bony-toothed’ bird fossils representing multiple species are known from Antarctica, a new dentary fragment of a pelagornithid bird from the middle Eocene Submeseta Formation on Seymour Island, Antarctica represents a species wit
(Additional file1: Figure S3). The posterior margin of at least the anterior trunk segments is “collar-like,” producing short and rounded pleural extensions on each lateral side (ra1, Additional file1: Figure S3e, f). The anterior circumference of the segments is marked by the presence of...
35. The proportion of each phase is controlled by the environmental conditions prevailing, with the formation of Ni-sulfide precipitation enhanced by sulphidic conditions and the incorporation within the organic fraction enhanced in non-sulphidic, anoxic conditions35. Raman spectra do not evidence ...
Several subsequent analyses using more recent methods have also recovered estimates from within the Permian, 289 and 265 Mya [36–39]. However, other molecular dating analyses provide dates in the Late or Middle Triassic with one as recent/shallow as 226 Mya [39–43]. This range of estimates...