Tiktaalik is a monospecific genus of extinct sarcopterygian from the Late Devonian Period, about 375 Mya, having many features akin to those of tetrapods. Tiktaalik is estimated to have had a total length of 1.25–2.75 metres (4.1–9.0 ft) based on various specimens.
Lagerpeton is a genus of lagerpetid avemetatarsalian, comprising a single species, L. chanarensis. First described from the Chañares Formation of Argentina by A. S. Romer in 1971, Lagerpeton's anatomy is somewhat incompletely known, with fossil specimens accounting for the pelvic girdle, hindlimbs, posterior presacral, sacral and anterior caudal vertebrae. Skull and shoulder material has also been described.
A fossil track or ichnite is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species.
Askeptosaurus is an extinct genus of askeptosauroid, a marine reptile from the extinct order Thalattosauria. Askeptosaurus is known from several well-preserved fossils found in Middle Triassic marine strata in what is now Italy and Switzerland.
Cotylorhynchus is an extinct genus of herbivorous caseid synapsids that lived during the late Lower Permian (Kungurian) and possibly the early Middle Permian (Roadian) in what is now Texas and Oklahoma in the United States. The large number of specimens found make it the best-known caseid. Like all large herbivorous caseids, Cotylorhynchus had a short snout sloping forward and very large external nares. The head was very small compared to the size of the body. The latter was massive, barrel-shaped, and ended with a long tail. The limbs were short and robust. The hands and feet had short, broad fingers with powerful claws. The barrel-shaped body must have housed large intestines, suggesting that the animal had to feed on a large quantity of plants of low nutritional value. Caseids are generally considered to be terrestrial, though a semi-aquatic lifestyle has been proposed by some authors. The genus Cotylorhynchus is represented by three species, the largest of which could reach more than 6 m in length. However, a study published in 2022 suggests that the genus may be paraphyletic, with two of the three species possibly belonging to separate genera.
Peloroplites is a monospecific genus of nodosaurid dinosaur from Utah that lived during the Late Cretaceous in what is now the Mussentuchit Member of the Cedar Mountain Formation. The type and only species, Peloroplites cedrimontanus, is known from a partial skull and postcranial skeleton. It was named in 2008 by Kenneth Carpenter and colleagues. Peloroplites was 6 metres long and weighed 2 tonnes, making it one of the largest known nodosaurids, and came from a time when ankylosaurids and nodosaurids were attaining large sizes.
Hupehsuchia is an order of diapsid reptiles closely related to ichthyosaurs. The group was short-lasting, with a temporal range restricted to the late Olenekian age, spanning only a few million years of the Early Triassic. The order gets its name from Hubei Province, China, from which many specimens have been found. They are probable members of the clade Ichthyosauromorpha.
The Chacarilla Formation is an Oxfordian to Early Cretaceous geologic formation of the Tarapacá Basin in northern Chile, close to the border with Bolivia. The marine and fluvial formation preserves several dinosaur trackways and has been declared a Natural Sanctuary in 2004.
Tambachia is an extinct genus of dissorophoid temnospondyl within the family Trematopidae. It is known from the Early Permian Tambach Formation near the town of Tambach-Dietharz in Thuringia, Germany. Tambachia is the first trematopid to have been discovered outside the United States.
Prorotodactylus is a dinosauromorph or pterosauromorph ichnogenus known from fossilized footprints found in Poland and France. The prints may have been made by a dinosauromorph that was a precursor to the dinosaurs, possibly closely related to Lagerpeton. Fossils of Prorotodactylus date back to the early Olenekian stage of the Early Triassic, making it the oldest known dinosauromorph. Its presence during this time extends the range of the dinosaur stem lineage to the start of the Early Triassic, soon after the Permian-Triassic extinction event. Prorotodactylus is the only ichnogenus within the ichnofamily Prorotodactylidae. Two ichnospecies are known, the type P. mirus and P. lutevensis.
Panguraptor is a genus of coelophysid theropod dinosaur known from fossils discovered in Lower Jurassic rocks of southern China. The type and only known species is Panguraptor lufengensis. The generic name refers to the deity Pangu but also to the supercontinent Pangaea for which in a geological context the same characters are used: 盘古. Raptor means "seizer", "robber" in Latin. The specific name is a reference to the Lufeng Formation. The holotype specimen was recovered on 12 October 2007 from the Lufeng Formation of Yunnan, which is noted for sauropodomorph fossils. It was described in 2014 by You Hai-Lu and colleagues.
Dromopus is a reptilian ichnogenus commonly found in assemblages of ichnofossils dating to the late Pennsylvanian to the late Permian. It has been found throughout Europe, as well as in the United States, Canada, and Morocco. Several ichnospecies have been named; only the type ichnospecies D. lacertoides is definitively recognized.
Gwyneddichnium is an ichnogenus from the Late Triassic of North America and Europe. It represents a form of reptile footprints and trackways, likely produced by small tanystropheids such as Tanytrachelos. Gwyneddichnium includes a single species, Gwyneddichnium major. Two other proposed species, G. elongatum and G. minore, are indistinguishable from G. major apart from their smaller size and minor taphonomic discrepancies. As a result, they are considered junior synonyms of G. major.
Bellatoripes is an ichnogenus of footprint produced by a large theropod dinosaur so far known only from the Late Cretaceous of Alberta and British Columbia in Canada. The tracks are large and three-toed, and based on their size are believed to have been made by tyrannosaurids, such as Albertosaurus and Daspletosaurus. Fossils of Bellatoripes are notable for preserving trackways of multiple individual tyrannosaurids all travelling in the same direction at similar speeds, suggesting the prints may have been made by a group, or pack, of tyrannosaurids moving together. Such inferences of behaviour cannot be made with fossil bones alone, so the record of Bellatoripes tracks together is important for understanding how large predatory theropods such as tyrannosaurids may have lived.
Protochirotherium, also known as Protocheirotherium, is a Late Permian?-Early Triassic ichnotaxon consisting of five-fingered (pentadactyl) footprints and whole tracks, discovered in Germany and later Morocco, Poland and possibly also Italy. The type ichnospecies is P. wolfhagenense, discovered by R. Kunz in 1999 alongside Chirotherium tracks, was named and described in 2004 and re-evaluated in 2007; a second ichnospecies, P. hauboldi, also exists, which was initially described as an ichnospecies of Brachychirotherium. Protochirotherium-like prints have also been documented from the Late Permian of Italy, possibly representing the oldest known fossils of mesaxonic archosauromorphs.
Wakinyantanka is an ichnogenus of footprint produced by a large theropod dinosaur from the Late Cretaceous Hell Creek Formation of South Dakota. Wakinyantanka tracks are large with three long, slender toes with occasional impressions of a short hallux and narrow metatarsals. Wakinyantanka was the first dinosaur track to be discovered in the Hell Creek Formation, which remain rare in the preservational conditions of the rocks. The potential trackmakers may be a large oviraptorosaur or a small tyrannosaurid.
Thinopus is the name given to a trace fossil (ichnotaxon) found in late Devonian rocks in Pennsylvania. The only specimen was described by paleontologist Othniel Charles Marsh in a brief note published in 1896, with the only ichnospecies Thinopus antiquus. Marsh interpreted it as the fossil footprints of an early amphibian, making it the oldest evidence for tetrapods known at the time. Later research, however, argued that the fossil is better interpreted as the impressions of coprolites of fish. This would make Thinopus the earliest published name of a fish coprolite.
Brachychirotherium is an ichnogenus, a form taxon based on footprints. It is a type of chirothere, a term referring to the footprints of five-toed Triassic reptiles with a short fifth digit, leaving an appearance similar to a reverse human hand print. Brachychirotherium was first characterized from fossils found in Triassic beds in Germany, but has since been found in France, South Africa, Argentina, Peru, Bolivia, and North America.
Amphisauropus is an amphibian ichnogenus commonly found in assemblages of ichnofossils dating to the Permian to Triassic. It has been found in Europe, Morocco, and North America.
The Zachelmie trackways are a series of Middle Devonian-age trace fossils in Poland, purportedly the oldest evidence of terrestrial vertebrates (tetrapods) in the fossil record. These trackways were discovered in the Wojciechowice Formation, an Eifelian-age carbonate unit exposed in the Zachełmie Quarry of the Świętokrzyskie Mountains (Holy Cross Mountains]. The discovery of these tracks has complicated the study of tetrapod evolution. Morphological studies suggest that four-limbed vertebrates are descended from a specialized type of tetrapodomorph fish, the epistostegalians. This hypothesis was supported further by the discovery and 2006 description of Tiktaalik, a well-preserved epistostegalian from the Frasnian of Nunavut. Crucial to this idea is the assumption that tetrapods originated in the Late Devonian, after elpistostegalians appear in the fossil record near the start of the Frasnian. The Zachelmie trackways, however, appear to demonstrate that tetrapods were present prior to the Late Devonian. The implications of this find has led to several different perspectives on the sequence of events involved in tetrapod evolution.
