Erythrosuchidae
Encyclopedia
Erythrosuchidae are a family of large basal
archosauromorph carnivore
s that lived from the later Early Triassic
(Olenekian
) to the early Middle Triassic (Anisian
). Their fossil remains are known so far from South Africa (Beaufort Group
of the Karoo
Basin), the Perm
region of Russia, and China. They were the apex predator
s of their day, with lengths of 2.5 to over 5 meters.
archosaur
s. For example, they lack teeth on the palate
, which are found in other early archosauriformes such as Doswellia
and euparkeriids
. In erythrosuchids, the centra (central parts of vertebrae) are deeply indented on either side, differing considerably from the usual cylindrical shape of the centra in other early archosauriformes, but similar to later archosaurs.
The heads of erythrosuchids are generally large and deep. One distinguishing feature of erythrosuchids is the shape of the margin of their upper jaw. In all erythrosuchids, the lower margin of the premaxilla
, the bone at the tip of the upper jaw, is higher than the lower margin of the maxilla
, the bone behind the premaxilla. This forms a characteristic "step" which makes erythrosuchids easily distinguishable from all other early archosauriformes, which have smooth jaw margins that are either straight or gradually curved.
Erythrosuchids are notable for being the first archosauriforms to have a triradiate pelvic girdle
with three projecting areas formed from three bones: an illium and an elongated pubis
and ischium. Although it is small, the fourth trochanter
, an ridge on the femur that serves as a muscle attachment in archosaurs, first appears in erythrosuchids. The triradiate pelvis and fourth trochanter are both features which inticate that erythrosuchids had an erect stance similar to later archosaurs. More basal
archosauriforms such as proterosuchids lacked these features and probably had a more sprawling posture.
s of the suborder Proterosuchia
. This classification is no longer used by paleontologists, who now employ a cladistic
approach. In this, erythrosuchids constitute an Archosauriformes
clade
that is an outgroup
to the Archosauria proper. The presence of certain archosaurian features
such as the triradiate pelvic girdle
, the fourth trochanter
, and the third metatarsal longer than the fourth, indicate that erythrosuchids are closer to the true archosaurs than the Proterosuchidae
, which lack these features. Thus the Erythrosuchidae occupy a transitional evolutionary position between the most primitive archisauriformes and more advanced Triassic archosaurs.
from Parrish (1992):
dicynodont
s doubtless constituted much of erythrosuchids' prey. However, the first erythrosuchids appear in the fossil record slightly earlier than the kannemeyeriids do, so it must be assumed that they also fed on other animals as well.
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
archosauromorph carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s that lived from the later Early Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
(Olenekian
Olenekian
In the geologic timescale, the Olenekian is an age in the Early Triassic epoch or a stage in the Lower Triassic series. It spans the time between 249.7 ± 0.7 Ma and 245 ± 0.7 Ma . The Olenekian follows the Induan and is followed by the Anisian.The Olenekian saw the deposition of a large part of the...
) to the early Middle Triassic (Anisian
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from 245 million years ago until 237 million years ago, approximately...
). Their fossil remains are known so far from South Africa (Beaufort Group
Beaufort Group
The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup of geological strata in Southern Africa. It follows conformably after the Ecca Group and consists essentially of sandstones and shales, deposited in the Karoo Basin from the Middle Permian to the early part of the...
of the Karoo
Karoo
The Karoo is a semi-desert region of South Africa. It has two main sub-regions - the Great Karoo in the north and the Little Karoo in the south. The 'High' Karoo is one of the distinct physiographic provinces of the larger South African Platform division.-Great Karoo:The Great Karoo has an area of...
Basin), the Perm
Perm
Perm is a city and the administrative center of Perm Krai, Russia, located on the banks of the Kama River, in the European part of Russia near the Ural Mountains. From 1940 to 1957 it was named Molotov ....
region of Russia, and China. They were the apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
s of their day, with lengths of 2.5 to over 5 meters.
Description
Erythrosuchids were unusually large and robust archosaurs. Several features set them apart from other archosauriformes and are also seen in later, more derivedDerived
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...
archosaur
Archosaur
Archosaurs are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct non-avian dinosaurs, many extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most...
s. For example, they lack teeth on the palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...
, which are found in other early archosauriformes such as Doswellia
Doswellia
Doswellia is an extinct genus of archosauriform. It has been placed in its own family, Doswellidae, and its own suborder, Doswelliina. It was a terrestrial carnivore that existed in eastern North America during the Carnian stage of the Late Triassic. Fossils have been found from the Poor Farm...
and euparkeriids
Euparkeriidae
Euparkeriidae is a family of small basal archosauromorph carnivores which lived from the Early Triassic to the Middle Triassic . Their fossil remains are known so far from South Africa and Russia...
. In erythrosuchids, the centra (central parts of vertebrae) are deeply indented on either side, differing considerably from the usual cylindrical shape of the centra in other early archosauriformes, but similar to later archosaurs.
The heads of erythrosuchids are generally large and deep. One distinguishing feature of erythrosuchids is the shape of the margin of their upper jaw. In all erythrosuchids, the lower margin of the premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
, the bone at the tip of the upper jaw, is higher than the lower margin of the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, the bone behind the premaxilla. This forms a characteristic "step" which makes erythrosuchids easily distinguishable from all other early archosauriformes, which have smooth jaw margins that are either straight or gradually curved.
Erythrosuchids are notable for being the first archosauriforms to have a triradiate pelvic girdle
Triradiate pelvic girdle
The Triradiate pelvic girdle is a shared feature common to archosaurs. The pelvis has three prongs, with an elongate pubis and ischium. This feature first appeared in the Erythrosuchidae, large basal archosaurian predators of the early Triassic period....
with three projecting areas formed from three bones: an illium and an elongated pubis
Pubis
Pubis may refer to:* Pubis * Mons pubis, a padding of fat that protects the pubis bone...
and ischium. Although it is small, the fourth trochanter
Fourth trochanter
The fourth trochanter is a shared characteristic common to archosaurs. It is a knob-like feature on the medial side of the femur that serves as a muscle attachment....
, an ridge on the femur that serves as a muscle attachment in archosaurs, first appears in erythrosuchids. The triradiate pelvis and fourth trochanter are both features which inticate that erythrosuchids had an erect stance similar to later archosaurs. More basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
archosauriforms such as proterosuchids lacked these features and probably had a more sprawling posture.
Classification
Erythrosuchids were formerly classified as thecodontThecodont
Thecodont , now considered an obsolete term, was formerly used to describe a diverse range of early archosaurs that first appeared in the Latest Permian and flourished until the end of the Triassic period...
s of the suborder Proterosuchia
Proterosuchia
Proterosuchia refers to one of the suborders of Thecodontia; specifically the most primitive and ancestral forms. These were primitive, vaguely crocodile-like, archosaurs that mostly lived during the Early Triassic period....
. This classification is no longer used by paleontologists, who now employ a cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
approach. In this, erythrosuchids constitute an Archosauriformes
Archosauriformes
Archosauriformes is a clade of diapsid reptiles that developed from archosauromorph ancestors some time in the Late Permian...
clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that is an outgroup
Outgroup
In cladistics or phylogenetics, an outgroup is a group of organisms that serves as a reference group for determination of the evolutionary relationship among three or more monophyletic groups of organisms....
to the Archosauria proper. The presence of certain archosaurian features
Autapomorphy
In cladistics, an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group...
such as the triradiate pelvic girdle
Triradiate pelvic girdle
The Triradiate pelvic girdle is a shared feature common to archosaurs. The pelvis has three prongs, with an elongate pubis and ischium. This feature first appeared in the Erythrosuchidae, large basal archosaurian predators of the early Triassic period....
, the fourth trochanter
Fourth trochanter
The fourth trochanter is a shared characteristic common to archosaurs. It is a knob-like feature on the medial side of the femur that serves as a muscle attachment....
, and the third metatarsal longer than the fourth, indicate that erythrosuchids are closer to the true archosaurs than the Proterosuchidae
Proterosuchidae
Proterosuchidae is an early, possibly paraphyletic, assemblage of basal archosauriformes whose fossils are known from the Latest Permian of Russia and the Early Triassic of southern Africa, Russia, China, Australia, and Antarctica...
, which lack these features. Thus the Erythrosuchidae occupy a transitional evolutionary position between the most primitive archisauriformes and more advanced Triassic archosaurs.
Genera
| Genus | Status | Age | Location | Description | Images |
|---|---|---|---|---|---|
Chalishevia Chalishevia Chalishevia is an extinct genus of Erythrosuchidae from Middle Triassic of Russia.-Reference:* Benton, M. J.; Shishkin, M. A.; Unwin, D. M.; Kurochkin, E. N. . Cambridge University Press, 2001. 672 p.... |
Valid. | Middle Triassic 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. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma... . |
Eastern Europe Eastern Europe Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"... . |
 |
|
Erythrosuchus Erythrosuchus Erythrosuchus is an extinct genus of archosauriform reptile from the Triassic of South Africa and Namibia. Remains have been found from the Cynognathus Assemblage Zone of the Beaufort Group in the Karoo of South Africa as well as the Omingonde Formation in Namibia.Erythrosuchus was the largest... |
Valid. | Early Triassic Early Triassic The Early Triassic is the first of three epochs of the Triassic period of the geologic timescale. It spans the time between 251 ± 0.4 Ma and 245 ± 1.5 Ma . Rocks from this epoch are collectively known as the Lower Triassic, which is a unit in chronostratigraphy... . |
South Africa South Africa The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans... . |
 |
|
Fugusuchus Fugusuchus Fugusuchus is an extinct genus of erythrosuchid archosauriform. It was one of the earliest and most basal erythrosuchids. The genus is known from a single fossil from the middle Early Triassic Heshankou Formation in Shanxi, China. The partial skeleton consists of an incomplete skull, parts of the... |
Valid. | Early Triassic Early Triassic The Early Triassic is the first of three epochs of the Triassic period of the geologic timescale. It spans the time between 251 ± 0.4 Ma and 245 ± 1.5 Ma . Rocks from this epoch are collectively known as the Lower Triassic, which is a unit in chronostratigraphy... . |
China China Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture... . |
||
Garjainia |
Valid. | Early Triassic Early Triassic The Early Triassic is the first of three epochs of the Triassic period of the geologic timescale. It spans the time between 251 ± 0.4 Ma and 245 ± 1.5 Ma . Rocks from this epoch are collectively known as the Lower Triassic, which is a unit in chronostratigraphy... . |
Eastern Europe Eastern Europe Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"... . |
 |
|
Shansisuchus Shansisuchus Shansisuchus was an erythrosuchid, a type of carnivorous prehistoric reptile that lived some 220 million years ago during the middle Triassic Period in what is now Shansi Province in China.... |
Valid. | Middle Triassic 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. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma... . |
China China Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture... . |
 |
|
Vjushkovia Vjushkovia Vjushkovia is an extinct genus of erythrosuchid archosauromorph.... |
Valid. | Middle Triassic 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. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma... . |
Eastern Europe Eastern Europe Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"... . |
 |
|
Phylogeny
CladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
from Parrish (1992):
Paleobiology
The large contemporary kannemeyeriidKannemeyeriidae
Kannemeyeriidae is a family of large, stocky, beaked and sometimes tusked dicynodonts. They were the dominant large terrestrial herbivores through most of the Triassic period...
dicynodont
Dicynodont
Dicynodontia is a taxon of anomodont therapsids or mammal-like reptiles. Dicynodonts were small to large herbivorous animals with two tusks, hence their name, which means 'two dog tooth'...
s doubtless constituted much of erythrosuchids' prey. However, the first erythrosuchids appear in the fossil record slightly earlier than the kannemeyeriids do, so it must be assumed that they also fed on other animals as well.
External links
- Erythrosuchidae
- Erythrosuchidae - list of species (Mikko's Phylogeny Archive)