The site of 'Ubeidiya is located in the Jordan Valley, Israel and has been biochronologically dated to 1.5 m.y.
View Article and Find Full Text PDFThe Lower Cretaceous anuran Shomronella jordanica (Pipoidea) is represented by an assemblage of nearly 300 tadpoles of different ages. The size of the assemblage allows a reconstruction of the larval ontogeny of this species. We describe the ossification sequence and growth rates of S.
View Article and Find Full Text PDFDifferences in nuclear DNA content in vertebrates have been shown to be correlated with cell size, cell division rate, and embryonic developmental rate. We compare seven species of anuran amphibians with a three-fold range of genome sizes. Parameters examined include the number and density of cells in a number of embryonic structures, and the change in cell number in the CNS during development.
View Article and Find Full Text PDFComparative embryology of closely related species can shed light on the evolution of developmental processes. An important mechanism in the evolution of developmental processes, which can lead to significant changes in larval or adult form, is variation in the sequence and timing of developmental events. We compared the development of 12 species of anurans, including a wide taxonomic range as well as a number of congeneric species.
View Article and Find Full Text PDFThe Acheulean site of Gesher Benot Ya'aqov in the Dead Sea Rift of Israel documents hominin movements and technological development on a corridor between Africa and Eurasia. New age data place the site at 780,000 years ago (oxygen isotope stage 19), considerably older than previous estimates. The archaeological data from the site portray strong affinities with African stone tool traditions.
View Article and Find Full Text PDFA 95-million-year-old fossil snake from the Middle East documents the most extreme hindlimb development of any known member of that group, as it preserves the tibia, fibula, tarsals, metatarsals, and phalanges. It is more complete than Pachyrhachis, a second fossil snake with hindlimbs that was recently portrayed to be basal to all other snakes. Phylogenetic analysis of the relationships of the new taxon, as well as reanalysis of Pachyrhachis, shows both to be related to macrostomatans, a group that includes relatively advanced snakes such as pythons, boas, and colubroids to the exclusion of more primitive snakes such as blindsnakes and pipesnakes.
View Article and Find Full Text PDFVariations in small game hunting along the northern and eastern rims of the Mediterranean Sea and results from predator-prey simulation modeling indicate that human population densities increased abruptly during the late Middle Paleolithic and again during the Upper and Epi-Paleolithic periods. The demographic pulses are evidenced by increasing reliance on agile, fast-reproducing partridges, hares, and rabbits at the expense of slow-reproducing but easily caught tortoises and marine shellfish and, concurrently, climate-independent size diminution in tortoises and shellfish. The results indicate that human populations of the early Middle Paleolithic were exceptionally small and highly dispersed.
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