Jurassic

A lampshell of the genus Acanthothiris, Class Rhynchonellata, Order Rhynchonellida, Family Acanthothirididae, 20mm along the axis, view of the hinge, from Woodeaton, Oxfordshire, UK, middle Middle Jurassic (Bathonian)

A lampshell of the genus Acanthothiris, Class Rhynchonellata, Order Rhynchonellida, Family Acanthothirididae, 20mm along the axis, view of the brachial valve, from Woodeaton, Oxfordshire, UK, middle Middle Jurassic (Bathonian)

An atypical (without intertidal and supratidal environment) carbonate platform settles down along the margin. Shallow water oolithes and oncoids are deposited in a narrow zone between a basin with Cancellophycus to the north and a marine/swampy plain with abundants mollusc fauna. However the Mytilus formation, rich in bathonian and callovian foraminifera (Septfontaine, 1984 etc.), develop thick limestone beds tenth of meter above, wrongly attributed to the upper Jurassic. See discussion in Septfontaine (1984).

Coelurus fragilis, a coelurosaur from the Late Jurassic of North America, pencil drawing, digital coloring

Life restoration of the German Jurassic ichthyosaur Suevoleviathan disinteger. The dorsal and caudal fins are loosely based on those of Stenopterygius. References Maisch, M.W. (2020). "The best-preserved skeleton of Suevoleviathan integer (Bronn, 1844)(Reptilia: Ichthyosauria) from the lower Jurassic of south-western Germany, with a discussion of the genus". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 297 (2): 153–172. Maisch, M.W. (1998). "A new ichthyosaur genus from the Posidonia Shale (Lower Toarcian, Jurassic) of Holzmaden, SW-Germany with comments on the phylogeny of post-Triassic ichthyosaurs". Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 209 (1): 47–78.

Muraenosaurus? Reedii, Sp. Nov. and Tricleidus? Laramiensis Knight, American Jurassic Plesiosaurs

Fossil samples – e.g. ‘primitive’ bony fish (1, 2), a skull of a temnospondyl ‘amphibian’ (probably a metoposauroid) in dorsal view (3), a skull of an archosaur of the crocodile lineage (probably a phytosaur) in palatal view (4), holotype of the “gliding reptile” Icarosaurus siefkeri [1] (5) and Atreipus-Grallator-type dinosaur tracks (bottom right) – from the Newark Supergroup, i.e. a series of mainly Late Triassic to Early Jurassic sedimentary rocks of eastern North America ↑ Edwin H. Colbert: A gliding reptile from the Triassic of New Jersey. American Museum Novitates, 2230. American Museum of Natural History, New York 1966, digitallibrary.amnh.org, cf. fig. 3 therein.

Paddle of the British Jurassic pliosaurid plesiosaur Eardasaurus housed at the Oxford University Natural History Museum.

A map showing the distribution of paraves in Late Jurassic with the respective paleogeographic setting.

Figure 1. Evolution of macroecological traits in Dinosauria. Large scale event in dinosaur evolution (a); the origin of dinosaurs (star), hyperthermals (volcano), the earliest fossil Avialae (bird), the earliest fossil angiosperm (flower), the Cretaceous/Palaeogene mass extinction (asteroid). Phylogeny of dinosaurs (b) redrawn from Sereno and adapted to the current consensus and upon which an ancestral state reconstruction of temperature niche (mean annual temperature) after Chiarenza et al. is plotted; Mesozoic palaeogeographies (c) for Triassic (T), Jurassic (J) and Cretaceous (K). Silhouette colours symbolize body mass for each of the taxa represented; information on dietary habits are plotted after Barrett and Zanno & Makovicky; numbers represent clades discussed through this study: 1, Ornithischia; 2, Thyreophora; 3, Ornithopoda; 4, Hadrosauroidea; 5, Marginocephalia; 6, Ceratopsia; 7, Saurischia; 8, Sauropodomorpha; 9, Sauropoda; 10, Theropoda; 11, Ceratosauria; 12, Tetanurae; 13, Coelurosauria; 14, Maniraptoriformes; 15, Maniraptora; 16, Deinonychosauria; 17, Avialae; 18, Ornithothoraces. Palaeogeographies modified from original plots via R package ‘mapast’ using plate models by Scotese.

Diagram illustrating the "Temporal paradox" in paleontology. First given it's nickname by Alan Feduccia, the paradox is made up by the fact that almost all feathered dinosaurs are dated to have lived millions of years after Archaeopteryx, the oldest bird (late Jurassic, believed to have existed about 150 million years ago). Only a few of the feathered dinosaurs/birdlike dinosaurs are given an older date than Archaeopteryx.

Restoration of Early Jurassic environment preserved at the SGDS, with the theropod Dilophosaurus wetherilli in bird-like resting pose, demonstrating the manufacture of SGDS.18.T1 resting trace.

Geographic and geologic map showing the location and involved strata of the studied fossil sites in the Xinhe Formation. (A, B) location of the fossiliferous localities in the Gansu Province. (C) Geological map of the involved strata of the studied fossil site (from State Bureau of Surveying and Mapping, GS (2016)2884). White star=Jinchuanloong niedu. Black star=plesiosaur fossils. (D) Stratigraphic chart of the Jurassic at the localities.

Life restoration of Tanycolagreus topwilsoni. Based on Figure 2.16 of "New small theropod from the Upper Jurassic Morrison Formation of Wyoming" by Kenneth Carpenter, Clifford Miles, and Karen Cloward (The Carnivorous Dinosaurs pp. 23-48, Indiana University Press).

Pencil drawing of Coelurus, a coelurosaurian dinosaur that lived from the Late Jurassic period (North America).

Coelurus fragilis, a coelurosaur from the Late Jurassic of North America, pencil drawing, digital coloring