Paleobiota of the Morrison Formation

The Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...

is a distinctive sequence of Late Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

sedimentary rock

Sedimentary rock

Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

that is found in the western United States, which has a wide assortment of taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

represented in its fossil record, including dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

fossils in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. It is composed of mudstone

Mudstone

Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...

, sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

, siltstone

Siltstone

Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...

and limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

and is light grey, greenish gray, or red. Most of the fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic

Jurassic

period.

(mostly from Foster [2003], with additional material in the mammal section after http://home.arcor.de/ktdykes/dryolest.htm; the higher-level classifications will vary as new finds are made.

Amphibians

According to museum curator John Foster, "frogs are known from several sites in the Morrison Formation but are not particularly well represented." The history of Morrison anuran discoveries began with the recovery of remains from Reed's Quarry 9 near Como Bluff Wyoming. The new genus Eobatrachus was erected for some of these remains by O. C. Marsh, but the material was later considered non-diagnostic. Decades later another dubious anuran genus, Comobatrachus was erected for addition fragmentary remains. Despite the erection of multiple new names, scientists only recognize two legitimate frog species from the Morrison, Enneabatrachus hechti and Rhadinosteus parvus.

In addition to formally named taxa, indeterminate anuran remains have been retrieved from Morrison strata in Colorado, Wyoming, and Utah, with the best specimens found in Dinosaur National Monument and Quarry 9. Stratigraphically speaking, indeterminate anurans have been found in stratigraphic zones 2 and 4. Indeterminate anurans with remains diagnostic down to the family level have also been reported from the Morrison. Pelobatids are represented by the illium of an unnamed, indeterminate species. A specimen has been recovered from Quarry 9 of Como Bluff in Wyoming. Pelobatids are present in stratigraphic zones 5 and 6.

Indeterminate salamander remains are present in stratigraphic zones 2, 4, and 5. A distinctive type of salamander known only as Caudata B is present in stratigraphic zone 6.

Name	Species	State	Material	Notes
Comobatrachus Comobatrachus Comobatrachus is a dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Eobatrachus it was among the earliest frog remains from the formation, although the two dubious genera were erected decades...	C. aenigmaticus	Wyoming		A dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Eobatrachus Eobatrachus Eobatrachus is a dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Comobatrachus it was among the earliest frog remains from the formation, although the two dubious genera were erected decades... it was among the earliest frog remains from the formation, although the two dubious genera were erected decades apart.
Comonecturoides Comonecturoides Comonecturoides is an extinct genus of prehistoric amphibian.-See also:* Prehistoric amphibian* List of prehistoric amphibians...	C. marshi	Wyoming	Represented by a single femur.	Considered a nomen dubium because the name is based on non-distinctive remains which cannot be classified in detail.
Enneabatrachus Enneabatrachus Enneabatrachus hechti is an extinct species of an extinct genus of prehistoric frog known from the late Jurassic Morrison Formation. Its remains have been recovered from stratigraphic zone 5. One specimen has been recovered from Quarry 9 of Como Bluff in Wyoming and another specimen was later...	E. hechti	Utah Wyoming		A small discoglossid Discoglossidae Discoglossidae is a family of primitive frogs, with the common name Disc-Tongued Frogs. Most are endemic to Europe, but there are also three species in North-West Africa, and an extinct species formerly occurred in Israel.... frog whose live weight would have only been a few grams.
Eobatrachus Eobatrachus Eobatrachus is a dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Comobatrachus it was among the earliest frog remains from the formation, although the two dubious genera were erected decades...	E. agilis	Wyoming		A dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Comobatrachus Comobatrachus Comobatrachus is a dubious genus of prehistoric frog erected by O. C. Marsh to house fragmentary remains recovered from Reed's Quarry 9 near Como Bluff Wyoming. Along with Eobatrachus it was among the earliest frog remains from the formation, although the two dubious genera were erected decades... it was among the earliest frog remains from the formation, although the two dubious genera were erected decades apart.
Iridotriton Iridotriton Iridotriton hechti is an extinct genus of prehistoric amphibian. A basal salamandroid closely related to today's advanced salamanders. Present in stratigraphic zone 6. Found in Dinosaur National Park.-See also:* Prehistoric amphibian...	I. hechti			A basal salamandroid Salamandroidea Salamandroidea is a suborder of salamanders, referred to as advanced salamanders. The members of the suborder are found worldwide except for Antarctica, Southern Sahara, and Oceania. They differ from suborder Cryptobranchoidea as their angular and prearticular bones in their lower jaw are fused and... closely related to today's advanced salamanders.
Rhadinosteus Rhadinosteus Rhadinosteus parvus is an extinct species of prehistoric frogs that lived during the Late Jurassic. Fossils of the species were found at the Rainbow Park site in Utah's Dinosaur National Monument, from several slabs of rock which contain multiple partial specimens. R...	R. parvus	Utah	Known from several slabs of rock which contain multiple partial specimens in association.	A pipoid and possible rhinophrynid, Rhadinosteus parvus was only about 42 mm (1.6 inches) long in life.

Arthropods

Name	Species	State	Member	Material	Notes
Tektonargus Tektonargus Tektonargus is a trace fossil ichnogenus from the Late Jurassic Morrison Formation....	T. kollaspilus	Colorado	Brushy Basin	Five specimens were reported in the original description of the ichnogenus.

Choristoderes

Name	Species	State	Member	Material	Notes
Cteniogenys Cteniogenys Cteniogenys is a genus of choristodere, a morphologically diverse group of aquatic reptiles. It had a wide distribution temporally and geographically, from the Middle Jurassic and Late Jurassic of western Europe, to the Late Jurassic-age Morrison Formation of western North America, to the Late...	C. antiquus	Colorado Oklahoma South Dakota Utah Wyoming			A champsosaur Choristodera Choristodera is an order of semi-aquatic diapsid reptiles which ranged from the Middle Jurassic, or possibly Late Triassic, to at least the early Miocene. Choristoderes have been found in North America, Asia, and Europe. The most common fossils are typically found from the Late Cretaceous to the... about 25 to 50 cm in length.

Crurotarsans

Crocodile

A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

s of a variety of sizes and habitats were common Morrison animals. Cursorial

Cursorial

Cursorial is a biological term that describes an organism as being adapted specifically to run. It is typically used in conjunction with an animal's feeding habits or another important adaptation. For example, a horse can be considered a "cursorial grazer", while a wolf may be considered a...

mesosuchia

Mesosuchia

"Mesosuchia" is an obsolete name for a group of terrestrial, semi-aquatic, or fully aquatic crocodylomorph reptiles. The marine crocodile Metriorhynchus had paddle-like forelimbs, Dakosaurus andiniensis had a skull that was adapted to eat large sea reptiles, and Shamosuchus was adapted for eating...

ns, or small terrestrial running crocs, included Hallopus victor
Hallopus
Hallopus was a prehistoric reptile, classified by O. C. Marsh in 1881 as a dinosaur. In fact it was probably a crocodilian or possibly a more primitive crurotarsan, and may be closely related to Junggarsuchus ....

and "Fruitachampsa callisoni
Fruitachampsa
"Fruitachampsa" is an informal name for an as-yet undescribed genus of mesoeucrocodylian from the Upper Jurassic Morrison Formation of Colorado. It is known from multiple specimens that show it to have been a relatively long-limbed terrestrial quadrupedal predator less than long, with a short...

". More derived

Derived

In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...

crocodilians included Goniopholis felix
Goniopholis
Goniopholis is an extinct genus of crocodyliform that lived in North America, Europe and Asia during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles...

(common), G. gilmorei, G. lucasi, G. stovalli, Hoplosuchus kayi
Hoplosuchus
Hoplosuchus is a genus of crocodylomorph. It is so far only known definitely from one specimen, a skeleton collected from sandstone of the Upper Jurassic-age Morrison Formation rocks at Dinosaur National Monument, Utah, during road construction. The individual was small, approximately long,...

, and Macelognathus vagans
Macelognathus
Macelognathus is an extinct genus of sphenosuchian crocodile from the Late Jurassic. Originally it was believed be a theropod dinosaur. It lived in what is now Wyoming, in North America....

.

Name	Species	State	Member
Eutretauranosuchus Eutretauranosuchus Eutretauranosuchus is a genus of goniopholidid mesoeucrocodylian. It is known from several specimens collected from the Late Jurassic-age Morrison Formation, including fossils from Garden Park and Dry Mesa Quarry in Colorado and Como Bluff in Wyoming. The type species is E. delfsi...	E. delfsi	Colorado Wyoming
"Fruitachampsa Fruitachampsa "Fruitachampsa" is an informal name for an as-yet undescribed genus of mesoeucrocodylian from the Upper Jurassic Morrison Formation of Colorado. It is known from multiple specimens that show it to have been a relatively long-limbed terrestrial quadrupedal predator less than long, with a short... "	"F. callisoni"	Colorado	Brushy Basin Member Saltwash Member
Goniopholis Goniopholis Goniopholis is an extinct genus of crocodyliform that lived in North America, Europe and Asia during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles...	G. felix	Colorado
	G. gilmorei	Wyoming
	G. lucasii	Colorado
	G. stovalli	Oklahoma
Hallopus Hallopus Hallopus was a prehistoric reptile, classified by O. C. Marsh in 1881 as a dinosaur. In fact it was probably a crocodilian or possibly a more primitive crurotarsan, and may be closely related to Junggarsuchus ....	H. victor	Colorado
Hatcherichnus Hatcherichnus Hatcherichnus is a trace fossil ichnogenus from the Late Jurassic Morrison Formation....	H. sanjuanensis	Colorado Utah
	Indeterminate	Utah Wyoming	Saltwash Member
Hoplosuchus Hoplosuchus Hoplosuchus is a genus of crocodylomorph. It is so far only known definitely from one specimen, a skeleton collected from sandstone of the Upper Jurassic-age Morrison Formation rocks at Dinosaur National Monument, Utah, during road construction. The individual was small, approximately long,...	H. kayi	Arizona Utah
Macelognathus Macelognathus Macelognathus is an extinct genus of sphenosuchian crocodile from the Late Jurassic. Originally it was believed be a theropod dinosaur. It lived in what is now Wyoming, in North America....	M. vagans	Colorado Wyoming

Fish

Although the paleoclimate of the Morrison formation was semiarid with only seasonal rainfall, there were enough bodies of water to support a diverse ichthyofauna. Although abundant, fish remains are constrained to only certain locations within the formation. Microvertebrate sites in Wyoming are dominated by fish remains. Indeterminate ray-finned fish remains have been recovered from Ninemile Hill and a microvertebrate site in the Black Hills. Found in stratigraphic zones 2, 4, and 5. Morrison actinopterygians generally have no close modern relatives. The Wyoming microvertebrate remains are extracted from the sediment by screenwashing. Paleoniscoid remains are geographically present in the western part of Colorado, where remains have been recovered from "a level above the Mygatt-Moore Quarry." Largely complete remains of small individuals have been consistently recovered for over 15 years. So far, Morrison pycnodontoids are represented by a single specimen from Dinosaur National Monument

Dinosaur National Monument

Dinosaur National Monument is a National Monument located on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. Although most of the monument area is in Moffat County, Colorado, the Dinosaur Quarry is located in Utah...

in Utah. Found in stratigraphic zone 4. Only a single specimen from Dinosaur National Monument

Dinosaur National Monument

in Utah has been recovered. Pycnodontoids were "deep-bodied and laterally compressed fish" whose tooth morphology suggest that they preyed on small contemporary invertebrates. They may have resembled modern butterfly fish. A single tooth is the only known remains. Dipnoan remains found at a fossil site not far from Cañon City, Colorado

Cañon City, Colorado

The City of Cañon City is a Home Rule Municipality that is the county seat and the most populous city of Fremont County, State of Colorado. The United States Census Bureau estimated that the city population was 16,000 in 2005. Cañon City is noted for being the location of nine state and four ...

. Remains usually in a state of rather complete preservation. Halecostome remains are geographically present in the western part of Colorado, where remains have been recovered from "a level above the Mygatt-Moore Quarry." Largely complete remains of small individuals have been consistently recovered for over 15 years. Amiid remains found in stratigraphic zones 2, 3, and 4. Found at a fossil site not far from Cañon City, Colorado

Cañon City, Colorado

. Remains usually in a state of rather complete preservation.

Name	Species	State	Member	Material	Notes
Ceratodus Ceratodus Ceratodus was a wide-ranging genus of extinct sarcopterygiian lungfish. Fossil evidence dates back to the Middle Triassic 228 million years ago. A wide range of fossil species from different time periods have been found around the world in places such as the United States, Argentina, England,...	C. fossanovum				A lungfish genus whose members ranged from 1 to 2 m in length and weights of up to 79 pounds, with most Morrison lungfish being on the smaller end of that range. These species are believed to have had similar diets to extant lungfish like the physically similar modern genus Neoceratodus.
	C. ?frazieri
	C. guentheri
	C. robustus
	Indeterminate.		Brushy Basin Saltwash		Represented by tooth plates.
Hulettia Hulettia Hulettia is an extinct genus of prehistoric bony fish found in the Morrison Formation in the western United States, measuring approximately three to four inches in length. Its body was covered in thick prominent scales.-See also:* Prehistoric fish...	H. hawesi	Colorado			A small fish of the division Halecostomi about 7.6 cm in length and 5g of live mass which probably preferred quiet water. Its fossils prominently preserve its thick interlocking scales.
cf. Leptolepis Leptolepis Leptolepis is an extinct genus of teleost fish that lived in the Mesozoic era. It was one of the first teleosts.- Appearance :...	N/A	Colorado		Known only from a single nearly complete skeleton found at Rabbit Valley. Found in stratigraphic zone 5.	A 13 cm (5 inch) fish that was deeper bodied than its co-occurring contemporaries Morrolepis and Hulettia. The Morrison cf. Leptolepis probably had a live mass of about 37g. It is the only teleost fish known from the formation and was morphologically more highly derived than other Morrison fish. It is believed to have fed on contemporary fish and small invertebrates.
Morrolepis Morrolepis Morrolepis is an extinct genus of prehistoric palaeoniscoid bony fish that lived in the Late Jurassic Morrison Formation, measuring approximately 20 centimeters in length.-See also:* Prehistoric fish* List of prehistoric bony fish...	M. schaefferi	Colorado			A palaeoniscoid with forward-set eyes positioned past the front end of the lower jaw. It had a tall dorsal fin set far back on the body and an asymmetrical caudal fin. Adult specimens would reach about 20 cm in length and 113 g (4 oz) in mass.
Potamoceratodus Potamoceratodus Potamoceratodus is an extinct genus of sarcopterygiian lungfish which existed in Colorado, USA, during the late Jurassic. It was first named by Jason D. Pardo, Adam K. Huttenlocker, Bryan J. Small and Mark A. Gorman II in 2010 and the type species is Potamoceratodus guentheri....	P. guentheri	Colorado			Once thought to be a species of Ceratodus Ceratodus Ceratodus was a wide-ranging genus of extinct sarcopterygiian lungfish. Fossil evidence dates back to the Middle Triassic 228 million years ago. A wide range of fossil species from different time periods have been found around the world in places such as the United States, Argentina, England,... .

Lizards

Name	Species	State	Notes
Dorsetisaurus Dorsetisaurus Dorsetisaurus was a genus of prehistoric lizard of the Late Jurrasic Morrison Formation of Western North America.Present in stratigraphic zones 2, 4, and 5....		Wyoming	An anguimorph Anguimorpha Anguimorphs of the infraorder Anguimorpha include the anguids , monitor lizards, the extinct mosasaurs, and helodermatids . The infraorder was named by Fürbringer in 1900 to include all autarchoglossans closer to Varanus and Anguis than Scincus... lizard.
Paramacellodus Paramacellodus Paramacellodus was a genus of prehistoric lizard of the Late Jurrasic Morrison Formation of Western North America.Present in stratigraphic zones 4 and 5....		Colorado Wyoming	A small scincomorph Scincomorpha Scincomorpha is an infraorder of saurians.... lizard with blunt teeth.
Parviraptor Parviraptor Parviraptor was a genus of prehistoric lizard of the Late Jurrasic Morrison Formation of Western North America.Present in stratigraphic zone 4....	P. gilmorei	Colorado	An anguimorph Anguimorpha Anguimorphs of the infraorder Anguimorpha include the anguids , monitor lizards, the extinct mosasaurs, and helodermatids . The infraorder was named by Fürbringer in 1900 to include all autarchoglossans closer to Varanus and Anguis than Scincus... lizard.
Saurillodon Saurillodon Saurillodon was a genus of prehistoric lizard of the Late Jurrasic Morrison Formation of Western North America.Present in stratigraphic zone 4....	Indeterminate	Colorado	A scincomorph Scincomorpha Scincomorpha is an infraorder of saurians.... lizard whose remains have been found in Middle Jurassic strata in England and Scotland as well as Late Jurassic strata in Portugal in addition to the Morrison formation remains.
Schilleria Schilleria Schilleria was a genus of prehistoric lizard of the Late Jurrasic Morrison Formation of Western North America.Possibly present in stratigraphic zone 5....	S. utahensis	Utah	A small scincomorph Scincomorpha Scincomorpha is an infraorder of saurians.... lizard of otherwise uncertain evolutionary affinities. It is the only lizard genus endemic to the Morrison Formation.

Mammals

Many types of early mammals are known from the Morrison; almost all of them were small, rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

-like animals. Unclassified types include the digger Fruitafossor windscheffelia
Fruitafossor
Fruitafossor was a termite-eating mammal endemic to North America during the Late Jurassic epoch , existing for approximately ....

. Docodonts

Docodonta

Docodonta is an order of extinct proto-mammals that lived during the mid- to late-Mesozoic era. Their most distinguishing physical features were their relatively sophisticated set of molars, from which the order gets its name. In the fossil record, Docodonta is represented primarily by isolated...

included the common genus Docodon
Docodon
Docodon was an omnivorous mammal from the middle to upper Jurassic Period that lived in Europe and North America approximately 175.6 to 144 million years ago. Docodon likely inhabited woodland and stayed in trees out of the reach of predators...

, represented by D. victor, D. striatus, and D. superbus, and Peraiocynodon sp. Multituberculates

Multituberculata

The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

, a common type of early mammal, were represented by Ctenacodon serratus
Ctenacodon
Ctenacodon is a genus of extinct mammal that lived in what is now North America during the Upper Jurassic period. It's a member of the family Allodontidae within the order Multituberculata. Ctenacodon,also known as Allodon , was named by Othniel Charles Marsh in 1879. At least four species are...

, C. laticeps, C. scindens, "C." brentbaatar, Glirodon grandis
Glirodon
Glirodon is a genus of extinct mammal from the Upper Jurassic. It was a relatively early member of the also-extinct order of Multituberculata, suborder "Plagiaulacida". These mammals lived in North America during the Mesozoic, also known as the "age of the dinosaurs".The genus Glirodon has been...

, Psalodon fortis
Psalodon
Psalodon is an extinct genus of North American mammal that lived during the Upper Jurassic period. It's a member of the family Allodontidae within the order Multituberculata. The genus Psalodon was named by Simpson in 1926. There are perhaps three species...

, ?P. marshi, P. potens, and Zofiabaatar pulcher
Zofiabaatar
Zofiabaatar is a genus of extinct mammal from the Upper Jurassic period. It was a relatively early member of the extinct order Multituberculata within the suborder "Plagiaulacida". It lived in North America along with dinosaurs such as Diplodocus and Allosaurus.The primary species is named...

. Triconodonts

Triconodonta

Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition...

present included Aploconodon comoensis
Aploconodon
Aploconodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

, Conodon gidleyi (AKA Phascolodon and Phascolotheridium), Priacodon ferox
Priacodon
Priacodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 4–6.-See also:* Prehistoric amphibian** List of prehistoric amphibians* Paleobiota of the Morrison Formation-References:...

, P. fruitaensis, P. gradaevus, P. lulli, P. robustus, Triconolestes curvicuspis
Triconolestes
Triconolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 4.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

, and Trioracodon bisulcus
Trioracodon
Trioracodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

.

Symmetrodonts

Symmetrodonta

Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,...

were represented by Amphidon superstes
Amphidon
Amphidon is an extinct genus of Late Jurassic mammal from the Morrison Formation. It is present in stratigraphic zone 5. The only species in the genus is Amphidon aequicrurius, found by Simpson in 1925.-See also:* Prehistoric mammal...

, Eurylambda aequicrurius (probably Tinodon), and Tinodon bellus
Tinodon
Tinodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

(including T. lepidus). Finally, two families of Dryolestoidea

Dryolestoidea

Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a...

were present: Paurodontidae

Paurodontidae

Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania....

, including Araeodon intermissus
Araeodon
Araeodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...

, Archaeotrigon brevimaxillus
Archaeotrigon
Archaeotrigon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...

, A. distgamus, Comotherium richi
Comotherium
Comotherium is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...

, Euthlastus cordiformis
Euthlastus
Euthlastus is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 5 and 6. It is represented by only five upper molars.-See also:* Prehistoric mammal...

, Foxraptor atrox
Foxraptor
Foxraptor is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...

, Paurodon valens
Paurodon
Paurodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

, Pelicopsis dubius, and Tathiodon agilis
Tathiodon
Tathiodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...

; and Dryolestidae

Dryolestidae

Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually....

, including Amblotherium gracilis
Amblotherium
Amblotherium is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 2, 3, and 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

, Dryolestes obtusus
Dryolestes
Dryolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 2, 5, and 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

(common genus), D. priscus, D. vorax, Laolestes eminens
Laolestes
Laolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 5 and 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

, L. grandis, and Miccylotyrans minimus
Miccylotyrans
Miccylotyrans is an extinct genus of Late Jurassic mammal from the Morrison Formation.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...

.

In 2009

2009 in paleontology

-Anomalocaridids:-Arachnids:-Insects:-Cephalopods:Three new species of extinct Octopoda discovered in 2009. The species - Keuppia hyperbolaris, Keuppia levante, and Styletoctopus annae - lived about 95 million years ago, and bear a strong resemblance to modern octopuses, suggesting that the...

, a study by J. R. Foster was published which estimated the body masses of mammals from the Morrison Formation by using

Regression analysis

In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...

the ratio of dentary length to body mass of modern marsupials as a reference. Foster concludes that Docodon
Docodon
Docodon was an omnivorous mammal from the middle to upper Jurassic Period that lived in Europe and North America approximately 175.6 to 144 million years ago. Docodon likely inhabited woodland and stayed in trees out of the reach of predators...

was the most massive mammal genus of the formation at 141g and Fruitafossor
Fruitafossor
Fruitafossor was a termite-eating mammal endemic to North America during the Late Jurassic epoch , existing for approximately ....

was the least massive at 6g. The average Morrison mammal had a mass of 48.5g. A graph of the body mass distribution of Morrison mammal genera produced a right-skewed curve, meaning that there were more low-mass genera.

Symmetrodonts

Name	Species	State	Notes
Amphidon Amphidon Amphidon is an extinct genus of Late Jurassic mammal from the Morrison Formation. It is present in stratigraphic zone 5. The only species in the genus is Amphidon aequicrurius, found by Simpson in 1925.-See also:* Prehistoric mammal...	A. superstes	Wyoming	A small symmetrodont Symmetrodonta Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,... .
Eurylambda	E. aequicrurius	Wyoming	A symmetrodont Symmetrodonta Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,... similar in appearance to Tinodon Tinodon Tinodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... .
Tinodon Tinodon Tinodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	T. bellus	Wyoming	Symmetrodonts Symmetrodonta Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,... .
	T. lepidus	Wyoming

Eutriconodonts

Name	Species	State	Notes
Aploconodon Aploconodon Aploconodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	A. comoensis	Wyoming	An amphilestid Amphilestidae Amphilestidae is a family of Late Jurassic mammals from England.... eutriconodont Triconodonta Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition... .
Comodon Comodon Comodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	C. gidleyi	Wyoming	An amphilestid Amphilestidae Amphilestidae is a family of Late Jurassic mammals from England.... eutriconodont Triconodonta Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition... slightly larger in size than Aploconodon Aploconodon Aploconodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... .
Phascalodon	P. gidleyi	Wyoming
Triconolestes Triconolestes Triconolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 4.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	T. curvicuspis	Utah	An amphilestid Amphilestidae Amphilestidae is a family of Late Jurassic mammals from England.... eutriconodont Triconodonta Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition... similar to Comodon Comodon Comodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... in appearance.
Trioracodon Trioracodon Trioracodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	T. bisulcus	Wyoming	A triconodontid Triconodontidae Triconodontidae is an extinct family of actively mobile mammal, endemic to what would be North America, Europe, and Africa during the Jurassic through Cretaceous periods from 155.7—70.6 mya, existing for approximately .-Taxonomy:... eutriconodont Triconodonta Triconodonta is the generic name for a group of early mammals which were close relatives of the ancestors of all present-day mammals. Triconodonts lived between the Triassic and the Cretaceous. They are one of the groups that can be classified as mammals by any definition... similar to Priacodon Priacodon Priacodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 4–6.-See also:* Prehistoric amphibian** List of prehistoric amphibians* Paleobiota of the Morrison Formation-References:... .

Multituberculates

Name	Species	State
Allodon	A. fortis
Ctenacodon Ctenacodon Ctenacodon is a genus of extinct mammal that lived in what is now North America during the Upper Jurassic period. It's a member of the family Allodontidae within the order Multituberculata. Ctenacodon,also known as Allodon , was named by Othniel Charles Marsh in 1879. At least four species are...	"C." brentbaatar	Wyoming
	C. laticeps	Wyoming
	C. nanus
	C. potens
	C. scindens
	C. serratus	Wyoming
Glirodon Glirodon Glirodon is a genus of extinct mammal from the Upper Jurassic. It was a relatively early member of the also-extinct order of Multituberculata, suborder "Plagiaulacida". These mammals lived in North America during the Mesozoic, also known as the "age of the dinosaurs".The genus Glirodon has been...	G. grandis	Colorado Utah
Priacodon Priacodon Priacodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 4–6.-See also:* Prehistoric amphibian** List of prehistoric amphibians* Paleobiota of the Morrison Formation-References:...	P. ferox	Wyoming
	P. fruitaensis	Colorado
	P. gradaevus	Wyoming
	P. lulli	Wyoming
	P. robustus	Wyoming
Psalodon Psalodon Psalodon is an extinct genus of North American mammal that lived during the Upper Jurassic period. It's a member of the family Allodontidae within the order Multituberculata. The genus Psalodon was named by Simpson in 1926. There are perhaps three species...	P. fortis
	?P. marshi
	P. potens
Zofiabaatar Zofiabaatar Zofiabaatar is a genus of extinct mammal from the Upper Jurassic period. It was a relatively early member of the extinct order Multituberculata within the suborder "Plagiaulacida". It lived in North America along with dinosaurs such as Diplodocus and Allosaurus.The primary species is named...	Z. pulcher	Wyoming

Others

Name	Species	State
Docodon Docodon Docodon was an omnivorous mammal from the middle to upper Jurassic Period that lived in Europe and North America approximately 175.6 to 144 million years ago. Docodon likely inhabited woodland and stayed in trees out of the reach of predators...	D. affinis
	D. crassus
	D. striatus
	D. superus
	D. victor
Fruitafossor Fruitafossor Fruitafossor was a termite-eating mammal endemic to North America during the Late Jurassic epoch , existing for approximately ....	F. windscheffeli	Colorado

Dryolestoids

Name	Species	State	Notes
Amblotherium Amblotherium Amblotherium is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 2, 3, and 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	A. gracilis	Colorado	A small Dryolestid Dryolestidae Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Araeodon Araeodon Araeodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...	A. intermissus	Utah Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... , somewhat smaller than Archaeotrigon Archaeotrigon Archaeotrigon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation... and Paurodon Paurodon Paurodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... .
Archaeotrigon Archaeotrigon Archaeotrigon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...	A. brevimaxillus	Wyoming	Paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoids Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... similar in appearance to Paurodon Paurodon Paurodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... .
	A. distagmus
Comotherium Comotherium Comotherium is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...	C. richi	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Dryolestes Dryolestes Dryolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 2, 5, and 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	D. obtusus		Dryolestid Dryolestidae Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually.... dryolestoids Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
	D. priscus	Wyoming
	D. tenax
Euthlastus Euthlastus Euthlastus is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 5 and 6. It is represented by only five upper molars.-See also:* Prehistoric mammal...	E. cordiformis	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Foxraptor Foxraptor Foxraptor is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...	F. atrox	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... similar in size to Paurodon Paurodon Paurodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:... .
Herpetairus	H.
Kepolestes	K.	Colorado
Laolestes Laolestes Laolestes is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zones 5 and 6.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	L. eminens		Common Dryolestid Dryolestidae Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually.... dryolestoids Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
	L. grandis
Malthacolestes	M.
Melanodon	M.
Miccylotyrans Miccylotyrans Miccylotyrans is an extinct genus of Late Jurassic mammal from the Morrison Formation.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	M. minimus	Morrison	A Dryolestid Dryolestidae Dryolestidae was an abundant and diverse group of Mesozoic mammals. These mammals were different from their relatives by having the following two characteristics:*Their upper and lower molars were shortened mesiodistally and widened labiolingually.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Paurodon Paurodon Paurodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation-References:...	P. valens	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Pelicopsis	P. dubius	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .
Tathiodon Tathiodon Tathiodon is an extinct genus of Late Jurassic mammal from the Morrison Formation.Present in stratigraphic zone 5.-See also:* Prehistoric mammal** List of prehistoric mammals* Paleobiota of the Morrison Formation...	T. agilis	Wyoming	A paurodontid Paurodontidae Paurodontidae is a family of Late Jurassic to Early Cretaceous mammals in the order Dryolestida. Remains of paurodontids have been found in the USA, Britain, Portugal, and Tanzania.... dryolestoid Dryolestoidea Dryolestoidea is an extinct clade of Mesozoic mammals that only contains two orders. It has been suggested that this group contained the ancestors of modern therian mammals. They are mostly represented by teeth, fragmented dentaries and parts of the rostrum. The Jurassic forms retained a... .

Pterosaurs

Pterosaur

Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s are very uncommon fossils in the Morrison, because the fragility of their thin walled bones often prevented their remains from being preserved. Despite being uncommon they are geographically widespread; indeterminate pterosaur remains have been found in stratigraphic zones 2 and 4-6. In addition to indeterminate remains, several species have been identified from both the rhamphorhynchoids

Rhamphorhynchoidea

The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represent an evolutionary grade of primitive members of this group of flying reptiles. This suborder is paraphyletic in relation to the Pterodactyloidea, which arose from within the Rhamphorhynchoidea, not from a more distant...

(long-tailed pterosaurs) and pterodactyloids

Pterodactyloidea

Pterodactyloidea forms one of the two suborders of pterosaurs , and contains the most derived members of this group of flying reptiles...

(short-tailed pterosaurs). Since the 1970s and 80s, pterosaur finds have become more common, but are still rare. Most Morrison pterosaurs have been found in marine and shoreline deposits. Pterosaur tracks have been found in both the Tidwell and Saltwash members. Morrison pterosaurs probably lived on fish, insects and scavenged dinosaur carcasses.

Name	Species	State	Member	Material	Notes
Comodactylus Comodactylus Comodactylus is a genus of "rhamphorhynchoid" pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Wyoming, USA, named for a single wing metacarpal....	C. ostromi	Wyoming	Brushy Basin	1 specimen.	Nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
Dermodactylus Dermodactylus Dermodactylus was a genus of pterodactyloid pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Wyoming, USA...	D. montanus	Wyoming	Brushy Basin	1 specimen.	Nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
Harpactognathus Harpactognathus Harpactognathus was a genus of pterosaur found in the Late Jurassic-age Morrison Formation of Albany County, Wyoming, USA. It is based on NAMAL 101, a partial skull consisting of the snout, recovered from near Bone Cabin Quarry in 1996...	H. gentryii	Wyoming	Brushy Basin	1 specimen.	A large rhamphorhynchoid Rhamphorhynchoidea The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and represent an evolutionary grade of primitive members of this group of flying reptiles. This suborder is paraphyletic in relation to the Pterodactyloidea, which arose from within the Rhamphorhynchoidea, not from a more distant... with a wingspan of about 2.5 m and live mass of about 1.5 kg (3.3 lbs). Harpactognathus was related to the Solnhofen genus Scaphognathus Scaphognathus Scaphognathus was a pterosaur that lived around Germany during the Late Jurassic. It had a wingspan of about one meter.-Naming:The first known Scaphognathus specimen was described in 1831 by August Goldfuss who mistook the tailless specimen for a new Pterodactylus species: P. crassirostris. The... .
Kepodactylus Kepodactylus Kepodactylus is an extinct genus of pterodactyloid pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Colorado, USA....	K. insperatus	Colorado	Brushy Basin	1 specimen.	A large pterodactyloid Pterodactyloidea Pterodactyloidea forms one of the two suborders of pterosaurs , and contains the most derived members of this group of flying reptiles... with a 2.5 m (8 foot) wingspan and a live weight of about 1.5 kg (3 lbs). Kepodactylus may be related to the Asian dsungaripteroid Dsungaripteroidea Dsungaripteroidea is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of families and genera after Unwin 2006 unless otherwise noted.* Superfamily Dsungaripteroidea Herbstosaurus Kepodactylus... pterosaurs.
Laopteryx Laopteryx Laopteryx is the name assigned to a pterosaur from the Upper Jurassic Morrison Formation of Wyoming, USA; it was originally thought to be a bird....	L. priscus	Wyoming	Brushy Basin	1 specimen.	Nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application... initially misidentified as a bird.
Mesadactylus Mesadactylus Mesadactylus is an extinct genus of pterosaur from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Colorado, USA....	M. ornithosphyos	Colorado	Brushy Basin
Pteraichnus Pteraichnus Pteraichnus is an ichnogenus that has been attributed to pterosaurs. It has been found in, among other units, the Lower Jurassic Aztec Sandstone....	P. saltwashensis'*	Arizona Oklahoma	Saltwash
Utahdactylus Utahdactylus Utahdactylus was a genus of extinct reptile from the Kimmeridgian-Tithonian-age Upper Jurassic Morrison Formation of Utah, USA. Based on DM 002/CEUM 32588 , Czerkas and Mickelson identified it as a...	U. kateae	Utah	Tidwell	1 specimen.	Nomen dubium Nomen dubium In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application... . All that can be said for certain about its identity is that it is a diapsid reptile.

Sphenodonts

Name	Species	State	Notes
Eilenodon Eilenodon Eilenodon is a Late Jurassic genus of sphenodont reptile from the Morrison Formation of western North America, present in stratigraphic zone 4.-See also:* Prehistoric reptile* Paleobiota of the Morrison Formation...	E. robustus	Colorado	A sphenodontia Sphenodontia Sphenodontia is an order of lizard-like reptiles that includes only one living genus, the tuatara , and only two living species... n of relatively large size.
Opisthias Opisthias Opisthias is a Late Jurassic genus of sphenodont reptile from the Morrison Formation of western North America, present in stratigraphic zones 2 and 4-6.-See also:* Prehistoric reptile* Paleobiota of the Morrison Formation...	O. rarus	Colorado Utah Wyoming	A sphenodontia Sphenodontia Sphenodontia is an order of lizard-like reptiles that includes only one living genus, the tuatara , and only two living species... n similar in appearance to the modern Tuatara Tuatara The tuatara is a reptile endemic to New Zealand which, though it resembles most lizards, is actually part of a distinct lineage, order Sphenodontia. The two species of tuatara are the only surviving members of its order, which flourished around 200 million years ago. Their most recent common...
Theretairus Theretairus Theretairus is a Late Jurassic genus of sphenodont reptile from the Morrison Formation of western North America, present in stratigraphic zones 5 and 6.-See also:* Prehistoric reptile* Paleobiota of the Morrison Formation...	T. antiquus	Wyoming	A small sphenodontia Sphenodontia Sphenodontia is an order of lizard-like reptiles that includes only one living genus, the tuatara , and only two living species... n.

Turtles

Turtle

Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...

s (Testudines) are very common fossils in the Morrison, due to their bony shells.
The most common were Glyptops plicatus
Glyptops
Glyptops is an extinct genus of cryptodire turtle dating from the Late Jurassic and Early Cretaceous periods 155 to 99 m.y.a. Fossils have been found in South Dakota, Wyoming, Colorado, Utah, New Mexico, Oklahoma, and Texas from both the Morrison and Cedar Mountain formations. The type species is G...

(very common) and Dinochelys whitei
Dinochelys
Dinochelys is an extinct genus of paracryptodiran turtle from the Late Jurassic Morrison Formation....

(also common, but not as common as Glyptops). Also present were Dorsetochelys buzzops
Dorsetochelys
Dorsetochelys is an extinct genus of turtle from the Late Jurassic Morrison Formation....

and Uluops uluops
Uluops
Uluops is an extinct genus of turtle from the Late Jurassic Morrison Formation....

.

Name	Species	State	Member
Chelonipus Chelonipus Chelonipus is a trace fossil ichnogenus from the Late Jurassic Morrison Formation....		Colorado Utah	Saltwash Member
Compsemys Compsemys Compsemys is a genus of prehistoric turtle from the Late Cretaceous and Paleocene of North America. Although several species have been described, they are all considered synonyms of one species, C. victa, first described by Joseph Leidy in 1856...	C. plicatulus	Colorado
Dinochelys Dinochelys Dinochelys is an extinct genus of paracryptodiran turtle from the Late Jurassic Morrison Formation....	D. whitei	Colorado Utah Wyoming
Dorsetochelys Dorsetochelys Dorsetochelys is an extinct genus of turtle from the Late Jurassic Morrison Formation....	D. buzzops
Glyptops Glyptops Glyptops is an extinct genus of cryptodire turtle dating from the Late Jurassic and Early Cretaceous periods 155 to 99 m.y.a. Fossils have been found in South Dakota, Wyoming, Colorado, Utah, New Mexico, Oklahoma, and Texas from both the Morrison and Cedar Mountain formations. The type species is G...	G. plicatulus	Colorado Wyoming
	G. ornatus	Wyoming
	G. utahensis	Utah
Uluops Uluops Uluops is an extinct genus of turtle from the Late Jurassic Morrison Formation....	U. uluops	Wyoming