BACKGROUND Extant cubozoans are voracious predators characterized by their square shape, four evenly spaced outstretched tentacles and well-developed eyes. A few cubozoan fossils are known from the Middle Cambrian Marjum Formation of Utah and the well-known Carboniferous Mazon Creek Formation of Illinois. Undisputed cubozoan fossils were previously unknown from the early Cambrian; by that time ...

The fossil record of the earliest animals has been enlivened in recent years by a series of spectacular discoveries, including embryos, from the Ediacaran to the Cambrian, but many issues, not least of dating and interpretation, remain controversial. In particular, aspects of taphonomy of the earliest fossils require careful consideration before pronouncements about their affinities. Neverthele...

The Great Basin of the western United States has proven important for studies of Proterozoic and Paleozoic geology [2500 to 245 million years ago (Ma)] and has been central to the development of ideas about the mechanics of crustal shortening and extension. An understanding of the deformational history of this region during Mesozoic and Cenozoic time (245 Ma to the present) is required for pali...

The early Cambrian Guanshan biota of eastern Yunnan, China, contains exceptionally preserved animals and algae. Most diverse and abundant are the arthropods, of which there are at least 11 species of trilobites represented by numerous specimens. Many trilobite specimens show soft-body preservation via iron oxide pseudomorphs of pyrite replacement. Here we describe digestive structures from two ...

The South China Block is situated in the Eastern Asian margin. Since Neoproterozoic, its tectonic evolution was constrained by successive consumption-closure processes of Paleo-South China, Proto-Tethys, Paleo-Tethys, and Paleo-Pacific oceans. Studies suggest that this block initially formed Neoproterozoic assembly Yangtze Cathaysia blocks following subduction-accretion Ocean. Then after, it ex...

Stratigraphic correlations presented here for the ductilely deformed and metamorphosed rocks exposed in the Shadow Mountains indicate that they formed on the North American continental margin and are not exotic or significantly displaced from their site of origin. These strata represent a depositional history that spans Late Proterozoic and Paleozoic passive margin development, late Paleozoic t...

The early–middle Cambrian (Fortunian to Age 4) is characterized by a significant increase in metazoan diversification. Furthermore, this interval is marked by a prominent environmental and ecological expansion of arthropodand echinoderm-rich biotas. Recent redox work has suggested that this shift occurred during stable or decreasing marine oxygen levels, suggesting that these paleobiological an...

Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (approximately 505 million years old) Marjum Form...

This study reviews the available data on Phanerozoic plume activity (Large Igneous Provinces (LIP’s) size and frequency) geochemistry of their igneous rocks. A major goal this review is to try find changes in intensity mantle plumes linked Earth’s evolution galactic seasonality that was supposed authors’ previous publications. The indicate Cambrian–Ordovician Jurassic–Cretaceous summers were as...