Dinosauromorpha is a
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
of
avemetatarsalian
Avemetatarsalia (meaning "bird metatarsals") is a clade of diapsid reptiles containing all archosaurs more closely related to birds than to crocodilians. The two most successful groups of avemetatarsalians were the dinosaurs and pterosaurs. Dinos ...
archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian d ...
s (reptiles closer to birds than to crocodilians) that includes the
Dinosauria (dinosaurs) and some of their close relatives. It was originally defined to include
dinosauriforms and
lagerpetids,
with later formulations specifically excluding
pterosaurs
Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
from the group.
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
s are the only dinosauromorphs which survive to the present day.
Classification
The name "Dinosauromorpha" was briefly coined by
Michael J. Benton
Michael James Benton One or more of the preceding sentences incorporates text from the royalsociety.org website where: (born 8 April 1956) is a British palaeontologist, and professor of vertebrate palaeontology in the School of Earth Sciences ...
in 1985.
It was considered an alternative name for the group "Ornithosuchia", which was named by
Jacques Gauthier
Jacques Armand Gauthier (born June 7, 1948 in New York City) is an American vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology.
Life and career
Gauthier is the so ...
to correspond to archosaurs closer to dinosaurs than to crocodilians.
Although "Ornithosuchia" was later recognized as a
misnomer
A misnomer is a name that is incorrectly or unsuitably applied. Misnomers often arise because something was named long before its correct nature was known, or because an earlier form of something has been replaced by a later form to which the name ...
(since
ornithosuchids
Ornithosuchidae is an extinct family of pseudosuchian archosaurs (distant relatives of modern crocodilians) from the Triassic period. Ornithosuchids were quadrupedal and facultatively bipedal (e.g. like chimpanzees), meaning that they had the a ...
are now considered closer to crocodilians than to dinosaurs), it was still a more popular term than Dinosauromorpha in the 1980s.
The group encompassed by Gauthier's "Ornithosuchia" and Benton's "Dinosauromorpha" is now given the name
Avemetatarsalia.
In 1991,
Paul Sereno
Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites ...
redefined Dinosauromorpha as a node-based
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
, defined by a
last common ancestor and its descendants. In his definition, Dinosauromorpha included the
last common ancestor of ''
Lagerpeton
''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'' anatomy is somewhat incompletely kn ...
'' (a
lagerpetid
Lagerpetidae (; originally Lagerpetonidae) is a family of basal avemetatarsalians. Though traditionally considered the earliest-diverging dinosauromorphs (reptiles closer to dinosaurs than to pterosaurs), fossils described in 2020 suggest that ...
), ''
Marasuchus'' (a possible
junior synonym
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently.
* In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...
of ''
Lagosuchus),'' ''
Pseudolagosuchus
''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tr ...
'' (now considered a synonym of the
silesaurid ''
Lewisuchus
''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tr ...
''), Dinosauria (including Aves), and all its descendants. This definition was intended to correspond to a clade including lagerpetids and crownward bird-line archosaurs, but not pterosaurs or other archosaurs.
In 2011, Dinosauromorpha was redefined by
Sterling Nesbitt to be a branch-based clade, defined by including reptiles closer to one group than to another. Under this definition, Dinosauromorpha included all reptiles closer to dinosaurs (represented by ''
Passer domesticus'', the house sparrow), rather than pterosaurs (represented by ''
Pterodactylus''), ornithosuchids (represented by ''
Ornithosuchus''), or other
pseudosuchians
Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to ...
(represented by ''
Crocodylus niloticus
''Crocodylus'' is a genus of true crocodiles in the family Crocodylidae.
Taxonomy
The generic name, ''Crocodylus'', was proposed by Josephus Nicolaus Laurenti in 1768. ''Crocodylus'' contains 13–14 extant (living) species and 5 extinct species ...
'', the Nile crocodile). Nesbitt's study supported the hypothesis that Pterosauromorpha (pterosaurs and their potential relatives) was the
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
of Dinosauromorpha. Pterosauromorphs and dinosauromorphs together formed the group
Ornithodira, which encompasses almost all avemetatarsalians.
Dinosauriformes was coined in 1992 by F.E. Novas, who used it to encompass dinosaurs, ''Lagosuchus'', "''Pseudolagosuchus''" (=''Lewisuchus''), and the
herrerasaurids
Herrerasauridae is a Family (biology), family of carnivore, carnivorous dinosaurs, possibly basal (phylogenetics), basal to either theropods or even all of saurischians, or even their own branching from dracohors, separate from dinosauria altoget ...
, which he did not consider to be "eudinosaurs" (true dinosaurs like
ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...
ns and
saurischians).
Contrary to Novas, most paleontologists since 1992 have considered herrerasaurids to be true dinosaurs, though many other dinosaur-like reptiles still fall within his definition of Dinosauriformes. Novas (1992) defined Dinosauriformes as a node-based clade containing the most recent common ancestor of ''Lagosuchus'' and Dinosauria, and all its descendants.
Nesbitt (2011) provided a roughly equivalent definition, using ''Marasuchus'' and ''Passer domesticus'' (the house sparrow, a representative of dinosaurs). In his analysis, Dinosauriformes included dinosaurs,
silesaurids
Silesauridae is an extinct family of Triassic dinosauriforms. It is most commonly considered to be a clade of non-dinosaur dinosauriforms, and the sister group of dinosaurs. Some studies have instead suggested that most or all silesaurids compri ...
, and ''Marasuchus'', but not
lagerpetids, which were considered to be an earlier-branching family of dinosauromorphs.
Phylogeny
A phylogenetic analysis by Andrea Cau in
2018
File:2018 Events Collage.png, From top left, clockwise: The 2018 Winter Olympics opening ceremony in PyeongChang, South Korea; Protests erupt following the Assassination of Jamal Khashoggi; March for Our Lives protests take place across the United ...
resolved two different topologies for dinosaur origins, depending on whether it was run using
parsimony
Parsimony refers to the quality of economy or frugality in the use of resources.
Parsimony may also refer to
* The Law of Parsimony, or Occam's razor, a problem-solving principle
** Maximum parsimony (phylogenetics), an optimality criterion in p ...
or
bayesian inference
Bayesian inference is a method of statistical inference in which Bayes' theorem is used to update the probability for a hypothesis as more evidence or information becomes available. Bayesian inference is an important technique in statistics, a ...
. Cau coined the term Dracohors for the clade uniting all taxa closer to the theropod ''
Megalosaurus bucklandi
''Megalosaurus'' (meaning "great lizard", from Greek , ', meaning 'big', 'tall' or 'great' and , ', meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years a ...
'' than the basal form ''
Marasuchus lilloensis
''Marasuchus'' (meaning " Mara crocodile") is a genus of basal dinosauriform archosaur which is possibly synonymous with ''Lagosuchus''. Both genera lived during the Late Triassic in what is now La Rioja Province, Argentina. ''Marasuchus'' conta ...
''. The name is derived from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
words for "dragon" and "cohort", ''dracos'' and ''cohors''. Under parsimony results, Dracohors included only
Silesauridae
Silesauridae is an extinct family of Triassic dinosauriforms. It is most commonly considered to be a clade of non-dinosaur dinosauriforms, and the sister group of dinosaurs. Some studies have instead suggested that most or all silesaurids compr ...
and
Dinosauria, the latter including the groups
Herrerasauria,
Sauropodomorpha,
Theropoda
Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally ca ...
and
Ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...
, along with the basal form ''
Eodromaeus
''Eodromaeus'' (meaning "dawn runner") is an extinct genus of probable basal theropod dinosaurs from the Late Triassic of Argentina. Like many other of the earliest-known dinosaurs, it hails from the Carnian-age (~230 Ma) Ischigualasto Formation ...
''. However, under bayesian results, Herrerasauria placed outside Dinosauria within Dracohors, and Dinosauriformes, Dinosauromorpha, and
Pan-Aves
Avemetatarsalia (meaning "bird metatarsals") is a clade of diapsid reptiles containing all archosaurs more closely related to birds than to crocodilians. The two most successful groups of avemetatarsalians were the dinosaurs and pterosaurs. D ...
were synonyms, with ''Marasuchus'' in a clade with lagerpetids. ''Pisanosaurus'' was resolved within Silesauridae. Cau identified the synapomorphies of Dracohors as:
The anterior tympanic recess, the axial epipophyses, the centrodiapophyseal laminae in the presacral vertebrae, the relative size enlargement of the postacetabular process of ilium, the elongation of the pubis, the proximal sulcus and the reduction of the ligament tuber in the femoral head, and the further reduction in length of the fourth metatarsal and toe compared to the third.
Following the discovery and description of more cranial and postcranial material of the genera ''
Kongonaphon
''Kongonaphon'' is an extinct genus of lagerpetid avemetatarsalians from the Middle to Late Triassic of Madagascar. It contains a single species, ''Kongonaphon kely'', which is known from a fragmentary partial skeleton. This fossil hails from th ...
'', ''
Ixalerpeton
''Ixalerpeton'' (meaning "leaping reptile") is a genus of lagerpetid avemetatarsalian containing one species, ''I. polesinensis''. It lived in the Late Triassic of Brazil alongside the sauropodomorph dinosaur ''Buriolestes''.
Discovery and nami ...
'' and ''
Lagerpeton
''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'' anatomy is somewhat incompletely kn ...
'', it was found that lagerpetids shared many features with the basal taxa of
Pterosauria. Features of the
maxillary bone, teeth,
braincase
In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skul ...
and forelimb meant that the
2020
2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of events, COVID- ...
phylogenetic analysis of Ezcurra and colleagues placed Lagerpetidae next to pterosaurs within Pterosauromorpha, removing the family from Dinosauromorpha. The contents of Dinosauromorpha was thus restricted to only Silesauridae, Dinosauria, and individual genera like ''
Lagosuchus''.
Simultaneously, Rodrigo Müller and MaurÃcio Garcia published novel results that reduced the family Silesauridae to a grade of basal dinosaurs in
Ornithischia
Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek s ...
. ''
Pisanosaurus
''Pisanosaurus'' () is an extinct genus of early dinosauriform, likely an ornithischian or silesaurid, from the Late Triassic of Argentina. It was a small, lightly built, ground-dwelling herbivore, that could grow up to an estimated long. Onl ...
'', considered by various authors to be either a silesaurid or basal ornithischian, was found to be intermediate between the grade of silesaurids and true ornithischians, explaining its peculiar combination of silesaurid and ornithischian features that has resulted in its phylogenetic inconsistency. ''
Lewisuchus
''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tr ...
'', a carnivorous form, was found to be the most primitive form of ornithischian, which was almost universally considered to be an only-herbivorous clade before. Dinosauromorpha was reduced to only including Lagerpetidae and ''Lagosuchus'' as a result of the reclassification of silesaurids.
Below are the results of:
Cau (2018, parsimony results):
Cau (2018, bayesian results):
Ezcurra ''et al.'' (2020):
Müller and Garcia (2020):
A variety of individual species and taxa have at times been found to place within Dinosauromorpha and its subgroups, but outside Dinosauria. The taxon ''Marasuchus'' has been consistently recovered as a dinosauromorph between lagerpetids and silesaurids, but may also be a junior synonym of the coexisting form ''
Lagosuchus'', another dinosauromorph.
''Pisanosaurus'', traditionally considered an ornithischian, was recovered in an unpublished analysis as a dinosauriform outside other clades,
but has since been recovered only as a member of Silesauridae or Ornithischia.
''
Saltopus
''Saltopus'' ("hopping foot") is a genus of very small bipedal dinosauriform containing the single species ''Saltopus elginensis'' from the late Triassic period of Scotland. It is one of the most famous Elgin Reptiles.
Description
''Saltopus e ...
'', an enigmatic taxon from the
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...
of
Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...
, has been placed closer to dinosaurs than ''Marasuchus'', in a polytomy with Silesauridae and Dinosauria,
as a sister taxon to ''Marasuchus'',
or within Dinosauria as a basal saurischian.
The British taxon ''
Agnosphitys'' was originally described as a dinosauriform closer to Dinosauria than ''
Herrerasaurus
''Herrerasaurus'' is a genus of saurischian dinosaur from the Late Triassic period. This genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the rancher who discovered the first specimen in ...
'',
[Nicholas C. Fraser, Kevin Padian, Gordon M. Walkden and A. L. M. Davis, 2002. Basal dinosauriform remains from Britain and the diagnosis of the Dinosauria. Palaeontology. 45(1), 79-95.] but has also been classified as a dinosauriform more derived than silesaurids but basal to
Herrerasauridae and Dinosauria,
a silesaurid,
or a basal saurischian.
The genus ''
Nyasasaurus'' from the early Late Triassic of
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
is known from multiple incomplete specimens, making it difficult to classify. It has been found as the direct sister taxon of Dinosauria, the basalmost ornithischian, a basal theropod,
or a deeply-nested sauropodomorph.
Origins
Dinosauromorphs appeared putatively around 242 to 244 million years ago by the
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...
stage of the
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
, splitting from other ornithodires.
Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...
footprints reported in October 2010 from the
Świętokrzyskie (Holy Cross) Mountains of Poland may belong to a dinosauromorph. If so, the origin of dinosauromorphs would be pushed back into the Early
Olenekian, around 249 Ma. The oldest Polish footprints are from a small quadrupedal animal named ''
Prorotodactylus
''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 ...
'', but footprints belonging to the
ichnogenus ''
Sphingopus
''Sphingopus'' is an ichnogenus of dinosauromorph footprints found in sediments dating to 250 and 228 Ma. The exact species which created the ''Sphingopus'' tracks have not been identified.
Specimens
''Sphingopus'' type footprints are known fr ...
'' that have been found from Early Anisian strata show that moderately large bipedal dinosauromorphs had appeared by 246 Ma. The tracks show that the dinosaur lineage appeared soon after the
Permian-Triassic extinction event. Their age suggests that the rise of dinosaurs was slow and drawn out across much of the Triassic.
The oldest known dinosauromorph is ''
Asilisaurus'', a
silesaurid which may have lived as early as the
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...
age of the middle
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
period, about 245 million years ago,
although it is possible that ''Nyasasaurus'' is a dinosaur of the same age, pushing the origins of the groups back further.
Putative basal dinosauromorphs include ''
Saltopus
''Saltopus'' ("hopping foot") is a genus of very small bipedal dinosauriform containing the single species ''Saltopus elginensis'' from the late Triassic period of Scotland. It is one of the most famous Elgin Reptiles.
Description
''Saltopus e ...
'',
''
Marasuchus'', the perhaps identical ''
Lagosuchus'', the
lagerpetid
Lagerpetidae (; originally Lagerpetonidae) is a family of basal avemetatarsalians. Though traditionally considered the earliest-diverging dinosauromorphs (reptiles closer to dinosaurs than to pterosaurs), fossils described in 2020 suggest that ...
''
Lagerpeton
''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'' anatomy is somewhat incompletely kn ...
'' from the
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic).
...
of
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
and ''
Dromomeron
''Dromomeron'' (meaning "running femur") is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and nort ...
'' from the
Norian
The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.
Stratigraphic defi ...
of
Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, AlÄ á¹£onak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
,
New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, Ker ...
, and
Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
(all in the United States), ''
Ixalerpeton polesinensis'' and an unnamed form from the
Carnian (
Santa Maria Formation) of
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
, and the
silesaurids, which include ''
Silesaurus
''Silesaurus'' is a genus of silesaurid dinosauriform from the Late Triassic, of what is now Poland.
Discovery
Fossilized remains of ''Silesaurus'' have been found in the Keuper Claystone in Krasiejów near Opole, Silesia, Poland, which is al ...
'' from the
Carnian of
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
, ''
Eucoelophysis
''Eucoelophysis'' (meaning "true hollow form") is a genus of silesaurid dinosauriform from the Late Triassic ( Norian) period Chinle Formation of New Mexico. It was assumed to be a coelophysid upon description, but a study by Nesbitt ''et al. ...
'' from the Carnian-Norian of New Mexico, ''
Lewisuchus
''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tr ...
'' and the perhaps identical ''
Pseudolagosuchus
''Lewisuchus'' is a genus of archosaur that lived during the Late Triassic (early Carnian). As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs (possibly tr ...
'' from the Ladinian of
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
,
''
Sacisaurus
''Sacisaurus'' (" Saci lizard") is a silesaurid dinosauriform from the Late Triassic ( Norian) Caturrita Formation of southern Brazil. The scientific name, ''Sacisaurus agudoensis'', refers to the city where the species was found, Agudo in the ...
'' from the Norian of
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
,
''
Technosaurus
''Technosaurus'' (meaning "Tech lizard", for Texas Tech University) is an extinct genus of Late Triassic silesaurid dinosauriform, from the Late Triassic Cooper Canyon Formation (Dockum Group) of Texas, United States.
For about 20 years after ...
'' from the Carnian of Texas,
''
Asilisaurus'' from the
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...
of
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
,
and ''
Diodorus'' from the Carnian(?) to Norian of
Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...
.
References
External links
*
*
*
{{Portal bar, Dinosaurs, Reptiles, Animals, Paleontology, Biology
Anisian first appearances
Extant Middle Triassic first appearances
Taxa named by Michael Benton