Trias

Skull of the Middle Triassic North-American ichthyosaur Cymbospondylus petrinus, preserved in three dimensions. This specimen is cataloged under the number UCMP 9913. More information is available from the source link.

Skull of the Middle Triassic North-American ichthyosaur Cymbospondylus petrinus, preserved in three dimensions. This specimen is cataloged under the number UCMP 9913. More information is available from the source link.

Thalattosaurus alexandrae (left) and Nectosaurus halinus (right) of Late Triassic California

Holotype specimen (PIMUZ A/III 1274) of Prosantosaurus scheffoldi gen. et spec. nov. from the upper Prosanto Formation (Early Ladinian, Middle Triassic) of Ducanfurgga locality no. 4, southwest of Davos, Canton of Grisons, south-eastern Switzerland. A Nearly complete specimen as prepared in dorsal view. The posterior part of the tail was lost prior to burial. Both forearms are not visible but lie below the trunk region, pointing in an anteromedial direction (see Additional file 1: Fig. S3A). B Detail of skull and anterior neck region. C Outline sketch of skull sutures. D Detail of shoulder girdle (claviculae, scapulae) and anterior dorsal vertebrae and ribs. E Detail of right humerus. F Detail of posterior dorsal vertebrae and ribs, sacral vertebrae and ribs, and anterior caudal vertebrae and ribs. G Detail of left ilium and hindlimb. ar articular; as astragalus; bo basioccipital; cal calcaneus; cl clavicula; co coracoid; d dentary; en external naris; eo exoccipital; fe femur; fi fibula; fr frontal; hu humerus; il ilium; in internal naris; is ischium; j jugal; mx maxilla; na naris; o orbit; pa parietal; pl palatine; pmx premaxilla; pof postfrontal; po postorbital; prf prefrontal; pt pterygoid; pu pubis; q quadrate; qj quadratojugal; ti tibia; sacr sacral rib; sc scapula; so supraoccipital; sp splenial; sq squamosal; su surangular; utf upper temporal fenestra; v vomer

Fossil with teeth of Macroplacus raeticus from Triassic of Germany, on display at the Museo Civico di Storia Naturale di Milano

Natural-colour satellite image of part of the Kaiparowits Basin (a central portion of Grand Staircase-Escalante). The branch-like shapes are networks of canyons carved by rivers that dried up millions of years ago. The ridge running roughly north-south through the scene is the Cockscomb, which is surrounded by distinct rock formations deposited at different times in the geologic past. West of the Cockscomb is the Navajo Sandstone, dating from the Triassic. East of the Cockscomb are two formations from the Cretaceous: the light-toned Wahweap and darker Kaiparowits.

Eubrontes dinosaur track from the Jurassic of Connecticut, USA. Trace fossils are any indirect evidence of ancient life. They refer to features in rocks that do not represent parts of the body of a once-living organism. Traces include footprints, tracks, trails, burrows, borings, and bitemarks. Body fossils provide information about the morphology of ancient organisms, while trace fossils provide information about the behavior of ancient life forms. Interpreting trace fossils and determination of the identity of a trace maker can be straightforward (for example, a dinosaur footprint represents walking behavior) or not. Sediments that have trace fossils are said to be bioturbated. Burrowed textures in sedimentary rocks are referred to as bioturbation. Trace fossils have scientific names assigned to them, in the same style & manner as living organisms or body fossils. This track was made by a theropod, a group of small to large, carnivorous, bipedal dinosaurs. The specimen comes from a Triassic to Jurassic terrestrial sedimentary succession that filled up a half graben, many of which occur along America's eastern seaboard. Such half-graben basins formed during the Triassic as the Pangaea supercontinent tried to rift apart, but failed. Pangaea successfully broke apart during the Jurassic. Stratigraphy: East Berlin Formation, Newark Supergroup, Lower Jurassic Locality: unrecorded / undisclosed site at or near the town of Rocky Hill, central Connecticut, USA Info. at: mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=CTJeb%3B0 and en.wikipedia.org/wiki/Eubrontes

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.

Plate XII(XIX). Fig. 1. Coelophysis bauri COPE. Sacrum, consisting of three vertebrae and last dorsal vertebra. COPE’s original. Triassic, New Mexico. Preserved in American Museum of Natural History, New York. Nat. size, from a cast in Tübingen. a, right lateral view; b, left lateral view; c, ventral view. Fig. 2. Thecodontosaurus skirtopodus SEELEY sp. Right humerus. Original in Vienna Hofmuseum (Coll. ADLER 1886). Upper Karroo, Cape Colony, South Africa. 1/2 nat. size, from a cast in Tübingen. Fig. 3. Same. Ditto. Proximal end of a right humerus in posterior view. 1/2 nat. size (the lateral part is missing). Fig. 4. Same. Ditto. Distal end of a left humerus in anterior view. 1/2 nat. size. Fig. 5. Same. Ditto. Distal end of a left femur in posterior view. 1/2 nat. size. Fig. 6. Same. Ditto. Proximal end of a left tibia, lateral view. 1/2 nat. size. Fig. 7. Thecodontosaurus browni SEELEY sp. Left femur in posterior view. SEELEY’s original. From the Stormberg Beds of the Telle River near Aliwal North, Cape Colony, South Africa. (From casts in the British Museum and Tübingen.) 1/2 nat. size. Fig. 8. Same. Ditto. Right femur, medial view.

Original figure caption: Trackway S1 (Eosauropus sp.), here attributed to a sauropod trackmaker based on pedal synapomorphies; trackmaker is moving towards the south-west. Two consequtive pes impressions of a tridactyl Grallator [i.e. a theropod] trackway can be seen left to the S1 trackway. Note: The tracks are preserved on a bedding plane of a thin siltstone bed of the Late Triassic Fleming Fjord Formation of East Greenland. A) shows a photograph of the trackway(s) as preserved on the bedding plane (i.e. as concave epireliefs); B) shows a color shaded relief map based on a high-resolution photogrammetric 3D-model of the bedding plane; C) is an interpretative outline drawing of the S1 trackway; abbreviations: LM = left manus (i.e. forefoot), LP = left pes (i.e. hindfoot), RM = right manus, RP = right pes, numbers increase in walking direction.

Californosaurus perrini, an ichthyosaur from the Late Triassic of North America, pencil drawing

Californosaurus perrini, an ichthyosaur from the Late Triassic of North America, pencil drawing

Lower Triassic fossil footprint (ichnite) of the ichnogenus Chirotherium, probably caused by an early archosaur, and first discovered 1833 in Hildburghausen (Thuringia, Germany). This specimen, however, ist from the Helsby Sandstone of the Storeton Quarry near Liverpool. Its species name is Chirotherium storetonense.[1]

Lower Triassic fossil footprint (ichnite) of the ichnogenus Chirotherium, probably caused by an early archosaur, and first discovered 1833 in Hildburghausen (Thuringia, Germany). This specimen, however, ist from the Helsby Sandstone of the Storeton Quarry near Liverpool. Its species name is Chirotherium storetonense.[1]

Lower Triassic fossil footprint (ichnite) of the ichnogenus Chirotherium, probably caused by an early archosaur, and first discovered 1833 in Hildburghausen (Thuringia, Germany). This specimen, however, ist from the Helsby Sandstone of the Storeton Quarry near Liverpool. Its species name is Chirotherium storetonense.[1]

Lower Triassic fossil footprint (ichnite) of the ichnogenus Chirotherium, probably caused by an early archosaur, and first discovered 1833 in Hildburghausen (Thuringia, Germany). This specimen, however, ist from the Helsby Sandstone of the Storeton Quarry near Liverpool. Its species name is Chirotherium storetonense.[1]