Edopoids Temporal range: Late Carboniferous - Late Permian Possible Viséan record in the form of fossil tracks. [1] | |
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Diagram of edopoid skulls | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | † Temnospondyli |
Superfamily: | † Edopoidea Romer, 1945 |
Subgroups | |
see text |
Edopoidea is a clade of primitive temnospondyl amphibians including the genus Edops and the family Cochleosauridae. Edopoids are known from the Late Carboniferous and Early Permian of North America and Europe, and the Late Permian of Africa. They are among the most basal temnospondyls, and possess a number of primitive features that were lost in later members of the group.
Edopoids are relatively large temnospondyls, with many species estimated to have grown several meters in length. The skull of Edops is broad while those of cochleosaurids are narrower and elongated. Distinguishing features of edopoids include the presence of an intertemporal bone that is absent in all other temnospondyls, and the lack of a pineal foramen, a small hole on the skull roof of many early tetrapods (young individuals still possess this hole). Relative to other temnospondyls, edopoids also have enlarged premaxillae, maxillae, and nasal bones in the snout region, which constrict the nostrils to small holes and push them to the sides of the skull. Most edopoids lacked grooves in the skull called sensory sulci, which presumably supported a lateral line system in other temnospondyls. The lack of sensory sulci suggests that most edopoids were adapted to terrestrial lifestyles, as lateral lines are characteristic of aquatic animals. Nigerpeton is the only edopoid to possess sensory sulci, but only in its adult form. The skulls of edopoids have only one occipital condyle connecting them to the vertebrae of the neck, whereas more derived temnospondyls have two occipital condyles. [2]
Edopoidea was named as a superfamily of temnospondyls by American paleontologist Alfred Romer in the second edition of his textbook Vertebrate Paleontology , published in 1945. He recognized a close relationship between the families Edopidae (which includes only Edops) and Cochleosauridae. In the late 1980s and early 1990s, the relationship between these two groups was supported by many phylogenetic analyses. One phylogenetic analysis separated Edops and cochleosaurids, finding the cochleosaurids to group with more derived temnospondyls like Archegosaurus . [3]
However, the skull characteristics used in this analysis are common to almost all temnospondyls with elongated skulls, and are not strong evidence of evolutionary relationships because long snouts could easily have appeared through evolutionary convergence. [4] Most recent phylogenetic analyses support a sister group relationship between Edops and Cochleosauridae, meaning that they are each other's closest relatives. Edopoids are usually placed at the base of Temnospondyli along with other primitive forms like Dendrerpeton , Balanerpeton , and Capetus . Below is a cladogram showing the relationships of edopoids from Sidor et al. (2006): [5]
Most edopoids are known from the Late Carboniferous and Early Permian of Europe and North America, which at the time formed a larger continent called Euramerica. Procochleosaurus , the oldest edopoid, is known from Ireland, while Edops, the most basal edopoid, is known from the United States, strongly suggesting that the group originated in Euramerica. Tropical and subtropical environments were likely widespread across Euramerica during the Carboniferous and Early Permian, meaning that edopoids could easily travel between what are now North America and Europe. [5]
The edopoid Nigerpeton is known from the Late Permian of Africa, extending the time span of edopoids by about 40 million years and expanding their geographic range outside Euramerica. It lived in a mountainous tropical region near the equator that is thought to have been a refugium for temnospondyls during the end of the Permian. At this time, the equatorial region was likely bounded by deserts to the north and south, which were too arid for amphibious animals like edopoids. [2]
The Lissamphibia is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia, the Caudata, and the Gymnophiona.
"Labyrinthodontia" is an informal grouping of extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras. Traditionally considered a subclass of the class Amphibia, modern classification systems recognize that labyrinthodonts are not a formal natural group (clade) exclusive of other tetrapods. Instead, they consistute an evolutionary grade, ancestral to living tetrapods such as lissamphibians and amniotes. "Labyrinthodont"-grade vertebrates evolved from lobe-finned fishes in the Devonian, though a formal boundary between fish and amphibian is difficult to define at this point in time.
Temnospondyli or temnospondyls is a diverse ancient order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian and Triassic periods, with fossils being found on every continent. A few species continued into the Jurassic and Early Cretaceous periods, but all had gone extinct by the Late Cretaceous. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are amphibians, many had characteristics such as scales and large armour-like bony plates (osteoderms) that generally distinguish them from the modern soft-bodied lissamphibians.
Dvinosaurs are one of several new clades of temnospondyls named in the phylogenetic review of the group by Yates and Warren 2000. They represent a group of primitive semi-aquatic to completely aquatic temnospondyls, and are known from the Late Carboniferous to the Early Triassic, being most common in the Permian period. Their distinguishing characteristics are a reduction of the otic notch; the loss of a flange on the rear side of the pterygoid; and 28 or more presacral vertebrae.
Cochleosaurus (“spoon lizard”, from the Latin cochlear "spoon" and Greek sauros “lizard”_ were medium-sized edopoid temnospondyls that lived in Euramerica during the Muscovian period. Two species, C. bohemicus and C. florensis, have been identified from the fossil record.
Edops is an extinct genus of temnospondyl amphibian from the Late Carboniferous - Early Permian periods. Unlike more advanced temnospondyls of the time, such as Eryops, Edops exhibited an archaic pattern of palatal bones, and still possessed various additional bones at the back of the skull. Edopoids also had particularly big premaxillae and proportionally small external nostrils. Within the clade, the most basal member seems to be Edops from the Early Permian Archer City Formation of the US, a broad-skulled animal with large palatal teeth.
Capetus is an extinct genus of temnospondyl from the Upper Carboniferous of the Czech Republic. It reached a length of 150 cm.
Sclerocephalus is an extinct genus of temnospondyl amphibian from the lowermost Permian of Germany and Czech Republic with four valid species, including the type species S. haeuseri. It is one of the most completely preserved and most abundant Palaeozoic tetrapods. Sclerocephalus was once thought to be closely related to eryopoid temnospondyls, but it is now thought to be more closely related to archegosauroids. It is the only genus in the family Sclerocephalidae.
Saharastega is an extinct genus of basal temnospondyl which lived during the Late Permian period, around 251 to 260 million years ago. Remains of Saharastega, discovered by paleontologist Christian Sidor at the Moradi Formation in Niger, were described briefly in 2005 and more comprehensively in 2006. The description is based on a skull lacking the lower jaws.
Chenoprosopus is a genus of extinct cochleosauridae that lived during late Carboniferous and early Permian periods. Two known species of Chenoprosopus are C. milleri and C. lewisi. Chenoprosopus lewisi was described in the basis of a virtually complete skull with maximum skull length of 95 mm. It is significantly smaller than Chenoprosopus milleri and was differentiated from that taxon by Hook (1993) based on sutural patterns of the skull roof. Hook also mentioned the reduced size of the vomerine tusks differentiated C. lewisi from C. milleri, but the different size of these tusks may be different ontogenetic stages of growth. Many of other cochleosaurids from the same time period have an elongated vomer and wide and elongate choana. However, Chenoprosopus is distinguished by its more narrowly pointed snout and separation between the nasal from the maxilla by the broad lacrimal-septomaxilla contact.
Nigerpeton is an extinct genus of crocodile-like temnospondyls from the late Permian (Changhsingian) period. These temnospondyls lived in modern-day Niger, which was once part of central Pangaea, about 250 million years ago. Nigerpeton is a member of the Cochleosauridae family, a group of edopoid temnospondyl amphibians known from the late Carboniferous (Pennsylvanian) and early Permian (Cisuralian).
Cochleosauridae is a family of edopoid temnospondyl amphibians, among the most basal of temnospondyls. Most members of this family are known from the late Carboniferous (Pennsylvanian) and early Permian (Cisuralian) of Europe and North America, though Nigerpeton is known from the Late Permian (Lopingian) of Niger in North Africa.
Limnarchia is a clade of temnospondyls. It includes the mostly Carboniferous-Permian age Dvinosauria and the mostly Permian-Triassic age Stereospondylomorpha. The clade was named in a 2000 phylogenetic analysis of stereospondyls and their relatives. Limnarchia means "lake rulers" in Greek, in reference to their aquatic lifestyles and long existence over a span of approximately 200 million years from the Late Carboniferous to the Early Cretaceous. In phylogenetic terms, Limnarchia is a stem-based taxon including all temnospondyls more closely related to Parotosuchus than to Eryops. It is the sister group of the clade Euskelia, which is all temnospondyls more closely related to Eryops than to Parotosuchus. Limnarchians represent an evolutionary radiation of temnospondyls into aquatic environments, while euskelians represent a radiation into terrestrial environments. While many euskelians were adapted to life on land with strong limbs and bony scutes, most limnarchians were better adapted for the water with poorly developed limbs and lateral line sensory systems in their skulls.
Christian Alfred Sidor is an American vertebrate paleontologist. He is currently a Professor in the Department of Biology, University of Washington in Seattle, as well as Curator of Vertebrate Paleontology and Associate Director for Research and Collections at the Burke Museum of Natural History and Culture. His research focuses on Permian and Triassic tetrapod evolution, especially on therapsids.
Adamanterpeton is a genus of Edopoid Temnospondyl within the family Cochleosauridae. The type species A. ohioensis was named in 1998 and is currently the only known species within this genus. Adamanterpeton is rare in the Linton vertebrate assemblage, with other amphibians like Sauropleura, Ophiderpeton, and Colosteus being more common. Unlike other Linton vertebrates, Adamanterpeton may have been adapted to a terrestrial lifestyle.
Bunostegos is an extinct genus of pareiasaur parareptile from the Late Permian of the Agadez Region in Niger. The type species, Bunostegos akokanensis, was named from the Moradi Formation in 2003. It was a cow-sized animal with a distinctive skull that had large bony knobs, similar in form to those of other pareiasaurs but far larger. The species appears to have lived in a desert in the centre of the supercontinent of Pangaea.
Selenocara is an extinct genus of mastodonsauroid temnospondyl. The type species is Selenocara groenlandica, described by Gunnar Säve-Söderbergh in 1935 on the basis of skull bones from the Lower Triassic Wordie Creek Formation of Greenland. Säve-Söderbergh originally described it as a new species of Wetlugasaurus.
The Moradi Formation is a geological formation in Niger. It is of Late Permian age. It is informally divided into three subunits. The lower portion of the formation consists of red mudstone, with muddy calcareous sandstone and quartz-granlule conglomerate present as lenses. The middle portion consists of muddy siltstone in thick beds interbedded with red argillaceous sandstone. The lower two thirds of the upper portion of the formation consist of red siltstone intercalated with channel lag intraformational conglomerates, while the upper third consists of barchanoid shaped lenses of conglomeratic sandstone with ventifacts. These facies are indicatived of deposition under arid conditions, with less than 300 millimetres (12 in) of annual rainfall in the Central Pangean desert, with annual temperatures of 30 to 35 °C, but with ephemeral water presence including lakes.