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The Jurassic Portal

Introduction

The Jurassic (/dʒʊˈræsɪk/ juu-RASS-ik) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.

The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Stage started around 183 million years ago and is marked by the Toarcian Oceanic Anoxic Event, a global episode of oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear, definitive boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined.

By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses: Laurasia to the north and Gondwana to the south. The climate of the Jurassic was warmer than the present, and there were no ice caps. Forests grew close to the poles, with large arid expanses in the lower latitudes. (Full article...) (Full article...)

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The Marchantiophyta are a division of non-vascular bryophyte land plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information.

It is estimated that there are about 9000 species of liverworts. Some of the more familiar species grow as a flattened leafless thallus, but most species are leafy with a form very much like a flattenedmoss. Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, including their single-celled rhizoids. Leafy liverworts also differ from most (but not all) mosses in that their leaves never have a costa and may bear marginal cilia (very rare in mosses). Other differences are not universal for all mosses and liverworts, but the occurrence of leaves arranged in three ranks, the presence of deep lobes or segmented leaves, or a lack of clearly differentiated stem and leaves all point to the plant being a liverwort.

Liverworts are typically small, usually from 2–20 mm wide with individual plants less than 10 cm long, and are therefore often overlooked. However, certain species may cover large patches of ground, rocks, trees or any other reasonably firm substrate on which they occur. They are distributed globally in almost every available habitat, most often in humid locations although there are desert and arctic species as well. (see more...)

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Edward Drinker Cope (left) and Othniel Charles Marsh (right).

The Bone Wars is the name given to a period of intense fossil speculation and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh. The two paleontologists used underhanded methods to out-compete the other in the field, resorting to bribery, theft, and destruction of bones. The scientists also attacked each other in scientific publications, attempting to ruin the other's credibility and cut off his funding.

Originally colleagues who were civil to each other, Cope and Marsh became bitter enemies after several personal slights between them. Their pursuit of bones led them west to rich bone beds in Colorado, Nebraska, and Wyoming. From 1877 to 1892, both paleontologists used their wealth and influence to finance their own expeditions and to procure services and fossils from dinosaur hunters. By the end of the Bone Wars, both men exhausted their funds in fueling their intense rivalry.

Cope and Marsh were financially and socially ruined by their efforts to disgrace each other, but their contributions to science and the field of paleontology were massive; the scientists left behind tons of unopened boxes of fossils on their deaths. The feud between the two men led to over 142 new species of dinosaurs being discovered and described. Several historical books and fictional adaptations have also been published about this period of intense paleontological activity. (see more...)

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A cluster of the ammonoid Dactylioceras from Schlaufhausen, Germany on display in the Naturkundemuseum Ostbayern in Regensburg.
Photo credit: High Contrast

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Did you know?

... that major discoveries in the history of ceratosaur research include horned predators like Ceratosaurus (pictured), Majungasaurus, and Carnotaurus, as well as a bonebed of the projecting-toothed Masiakasaurus?
... that the discovery of the extinct golden silk orb-weaver species Nephila jurassica extended the fossil record of the genus by 130 million years?
... that shartegosuchid crocodyliforms made up an endemic Central Asian Mesozoic fauna that existed after the breakup of Pangaea?
... that Ambondro, which lived in Madagascar about 167 million years ago, is the oldest known mammal with modern, tribosphenic molars?
... that the shell of the extinct sea urchin Pelanechinus corallina was composed of separate groups of fused plates which resulted in its being flexible?