Late Triassic

Photograph of Museo civico di scienze naturali di Bergamo (MCSNB) 2888, the holotype specimen of Eudimorphodon ranzii ZAMBELLI 1973, a basal pterosaur from the Norian (middle Upper Triassic) of the Italian Alps.[1] ↑ see fig. 8A in Silvio Renesto (2006): A reappraisal of the diversity and biogeographic significance of the Norian (Late Triassic) reptiles from the Calcare di Zorzino. In: Jerry D. Harris, Spencer G. Lucas, Justin A. Spielmann, Martin G. Lockley, Andrew R.C. Milner, James I. Kirkland (eds.): The Triassic-Jurassic Terrestrial Transition. New Mexico Museum of Natural History and Science Bulletin 37:445–456 (online)

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

A reconstruction of Erythrovenator jacuiensis based on a skeletal by Maurissauro. This basal theropod comes from the Late Triassic Candelária Formation of Brazil.

Ahvaytum is a saturnaliid sauropodomorph from the Late Triassic of what is now Wyoming. It is the oldest known dinosaur from the northern continent of Laurasia, challenging previous hypotheses of dinosaur origins and dispersal. Typical of basal dinosaurs from the Triassic, Ahvaytum was a small slender biped, reaching about 1 m in body length.

Pantydraco caducus, a sauropodomorph from the Late Triassic or Early Jurassic of England, after Yates, 2003, pencil drawing, digital coloring

Left maxilla of the silesaurid Agnosphitys cromhallensis from the Late Triassic (Rhaetian) of England.

Life restoration of the Triassic ichthyosaur Callawayia neoscapularis. Three specimens of this ichthyosaur are known, the holotype, ROM 41993, and two referred specimens, TMP 94.380.11 and 94.382.2. The skull is primarily based on ROM 41993, cross-checked against TMP 94.380.11 and TMP 94.382.2. The vertebral column is based primarily on TMP 94.382.2 as it is the most complete of these specimens, while the ribs were based on ROM 41993. The forelimbs were mainly based on those of ROM 41993, with TMP 94.380.11 used to determine their breadth. The hindlimbs were based on TMP 94.380.11, especially the more complete right hindlimb. ROM 41993 was cross-scaled with TMP 94.380.11 by the dimensions of the forelimb epipodials, which produced similar vertebral dimensions. The two TMP specimens were cross-scaled based on femoral length, also producing similar vertebral dimensions. Nicholls & Manabe (2001) stated that no wedge-shaped caudal centra supporting a tailbend were found and that there was no evidence of a bend being present, though considered that they might have existed in the gap in the preserved caudals. Since various other Triassic ichthyosaurs have since been found to have tail bends, one was illustrated here. A modest downturn of roughly 15° was illustrated, comparable to that in Guanlingsaurus, and the location of the bend within the gap in the preserved vertebrae matches well with the location of the bend in Guizhouichthyosaurus. References McGowan, C. (1994). "A new species of Shastasaurus (Reptilia: Ichthyosauria) from the Triassic of British Columbia: The most complete exemplar of the genus". Journal of Vertebrate Paleontology 14 (2): 168–179. DOI:10.1080/02724634.1994.10011550. Nicholls, E. L.; Manabe, M. (2001). "A new genus of ichthyosaur from the Late Triassic Pardonet Formation of British Columbia: Bridging the Triassic-Jurassic gap". Canadian Journal of Earth Sciences 38 (6): 983–1002. Ji, C.; Jiang, D.Y.; Hao, W.; Sun, Y. (2011). "True tailbend occurred in the Late Triassic: Evidence from ichthyosaur skeletons of South China". Acta Scientiarum Naturalium Universitatis Pekinensis 47 (2): 309–314. Shang, Q. H.; Li, C. (2009). "On the occurrence of the ichthyosaur Shastasaurus in the Guanling biota (Late Triassic), Guizhou, China". Vertebrata PalAsiatica 47 (3): 178–193.

Partial skull of Shastasaurus pacificus (UCMP 9017) from the Late Triassic of California, USA, in (A) lateral, (B) dorsal, and (C) anterolateral view. Based on this skull, Shastasaurus has repeatedly been reconstructed with a long, tooth-bearing rostrum. However, note the slenderness of the lower jaw (B, C) and the strong anterior taper of the snout (B), both of which are more consistent with the abbreviated and toothless snout of Shastasaurus liangae comb. nov. than with the traditional long-snouted reconstruction of this skull (as, e.g., in references [22] and [23]).

Partial skull of Shastasaurus pacificus (UCMP 9017) from the Late Triassic of California, USA, in (A) lateral, (B) dorsal, and (C) anterolateral view. Based on this skull, Shastasaurus has repeatedly been reconstructed with a long, tooth-bearing rostrum. However, note the slenderness of the lower jaw (B, C) and the strong anterior taper of the snout (B), both of which are more consistent with the abbreviated and toothless snout of Shastasaurus liangae comb. nov. than with the traditional long-snouted reconstruction of this skull (as, e.g., in references [22] and [23]).

Coelophysis bauri (Cope, 1887) theropod dinosaur from the Triassic of New Mexico, USA. This is a remarkable complete skeleton of the small early theropod Coelophysis. It comes from a nearly monospecific concentration of numerous complete to disarticulated skeletons in reddish-colored fluvial siltstones, often called a "Coelophysis graveyard". This occurrence has been interpreted as a carcass-jammed channel filling following mass mortality of dinosaurs by regional drought (see Schwartz & Gillette, 1994). Stratigraphy: Rock Point Member, Chinle Formation, Upper Triassic Locality: Whitaker Quarry (Coelophysis Quarry), Ghost Ranch, Rio Arriba County, northern New Mexico, USA Some info. from: Hunt, A.P. & S.G. Lucas. 1991. Rioarribasaurus, a new name for a Late Triassic dinosaur from New Mexico (USA). Paläontologische Zeitschrift 65: 191-198. Schwartz, H.L. & D.D. Gillette. 1994. Geology and taphonomy of the Coelophysis Quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico. Journal of Paleontology 68: 1118-1130. Theropod were small to large, bipedal dinosaurs. Almost all known members of the group were carnivorous (predators and/or scavengers). They represent the ancestral group to the birds, and some theropods are known to have had feathers. Some of the most well known dinosaurs to the general public are theropods, such as Tyrannosaurus, Allosaurus, and Spinosaurus.

Coelophysis bauri (Cope, 1887) theropod dinosaur from the Triassic of New Mexico, USA. This is a remarkable complete skeleton of the small early theropod Coelophysis. It comes from a nearly monospecific concentration of numerous complete to disarticulated skeletons in reddish-colored fluvial siltstones, often called a "Coelophysis graveyard". This occurrence has been interpreted as a carcass-jammed channel filling following mass mortality of dinosaurs by regional drought (see Schwartz & Gillette, 1994). Stratigraphy: Rock Point Member, Chinle Formation, Upper Triassic Locality: Whitaker Quarry (Coelophysis Quarry), Ghost Ranch, Rio Arriba County, northern New Mexico, USA Some info. from: Hunt, A.P. & S.G. Lucas. 1991. Rioarribasaurus, a new name for a Late Triassic dinosaur from New Mexico (USA). Paläontologische Zeitschrift 65: 191-198. Schwartz, H.L. & D.D. Gillette. 1994. Geology and taphonomy of the Coelophysis Quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico. Journal of Paleontology 68: 1118-1130. Theropod were small to large, bipedal dinosaurs. Almost all known members of the group were carnivorous (predators and/or scavengers). They represent the ancestral group to the birds, and some theropods are known to have had feathers. Some of the most well known dinosaurs to the general public are theropods, such as Tyrannosaurus, Allosaurus, and Spinosaurus.

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.

Musango is a basal sauropodomorph dinosaur that lived during the Late Triassic period in what is now Zimbabwe. Typical of early sauropodomorphs, or "prosauropods," it was an obligate biped with a long neck, and a long tail for counterbalance. Musango grew to approximately 5 m in total body length.

Global and temporal distribution of silesaurids shown on a Middle and Late Triassic (Ladinian-Norian) map of the northern and southern regions of Pangea.

A reconstruction of Erythrovenator jacuiensis based on a skeletal by Maurissauro. This basal theropod comes from the Late Triassic Candelária Formation of Brazil.

Ahvaytum is a saturnaliid sauropodomorph from the Late Triassic of what is now Wyoming. It is the oldest known dinosaur from the northern continent of Laurasia, challenging previous hypotheses of dinosaur origins and dispersal. Typical of basal dinosaurs from the Triassic, Ahvaytum was a small slender biped, reaching about 1 m in body length.