Orobates Temporal range: Cisuralian | |
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Holotype specimen | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | † Diadectomorpha |
Family: | † Diadectidae |
Genus: | † Orobates Berman et al., 2004 |
Type species | |
Orobates pabsti Berman et al., 2004 |
Orobates is an extinct genus of diadectid reptiliomorphs that lived during the Early Permian. Its fossilised remains were found in Germany. [1] A combination of primitive and derived traits (i.e. autapomorphic and plesiomorphic) distinguish it from all other well-known members of Diadectidae, a family of herbivorous reptiliomorphs. It weighed about 4 kg and appears to have been part of an upland fauna, browsing on high fibre plants. [1] [2]
The trace fossil species Ichniotherium sphaerodactylum, from Bromacker in Germany, has been attributed to Orobates. [3] A study in 2015 found that the genus was characterized by a long body and tail, with fairly short legs and a short skull compared to the more derived Diadectes . This indicates Orobates was less specialised for long treks compared to Diadectes. A three-dimensional digital reconstruction of the holotype specimen allowed further analysis of the postcranium. [2] An analysis of the mobility of the hip joint of the reconstructed holotype indicated that its limb function was similar to that of modern salamanders. [2]
A detailed multidisciplinary study published in 2019 found that Orobates moved more like modern caimans than salamanders. The study began with the digitization of its holotype specimen using CT scanning to figure out the range of motion of its joints. A digital model of its fossil trackways helped narrow down the possibilities. The researchers also studied the locomotion of four extant sprawling tetrapods using X-ray motion analysis. The extant tetrapods chosen for the study were axolotls, blue-tongued skinks, green iguanas, and spectacled caimans. [4]
The biomechanical data of the locomotion of the extant tetrapods and the digital models of Orobates' holotype and fossilized trackways were then used to create a dynamic simulation. It allowed the researchers to account for physical factors like gravity, friction, and balance. The simulation was then validated under real-world conditions with a life-sized robot called OroBOT. The researchers tested 512 different gaits and found that Orobates moved most like a caiman. It had a relatively erect posture and walked with a slight side-to-side motion. [4] [5] [6] A follow-up study focused on the muscle strains occurring within the muscles of the hindlimb in modelled strides at different postures. [7] While results remained inconclusive towards favouring a single posture during locomotion, the overall results did not contradict the previous study based on OroBOT.
A tetrapod is any four-limbed vertebrate animal of the superclass Tetrapoda. Tetrapods include all extant and extinct amphibians and amniotes, with the latter in turn evolving into two major clades, the sauropsids and synapsids. Some tetrapods such as snakes, legless lizards, and caecilians had evolved to become limbless via mutations of the Hox gene, although some do still have a pair of vestigial spurs that are remnants of the hindlimbs.
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibian ancestors during the Carboniferous period and further diverged into two groups, namely the sauropsids and synapsids. They are distinguished from the other living tetrapod clade — the non-amniote lissamphibians — by the development of three extraembryonic membranes, thicker and keratinized skin, and costal respiration.
"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.
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Diadectes is an extinct genus of large reptiliomorphs or synapsids that lived during the early Permian period. Diadectes was one of the first herbivorous tetrapods, and also one of the first fully terrestrial vertebrates to attain large size.
Diadectidae is an extinct family of early tetrapods that lived in what is now North America and Europe during the Late Carboniferous and Early Permian, and in Asia during the Late Permian. They were the first herbivorous tetrapods, and also the first fully terrestrial animals to attain large sizes. Footprints indicate that diadectids walked with an erect posture. They were the first to exploit plant material in terrestrial food chains, making their appearance an important stage in both vertebrate evolution and the development of terrestrial ecosystems.
Diadectomorpha is a clade of large tetrapods that lived in Euramerica during the Carboniferous and Early Permian periods and in Asia during Late Permian (Wuchiapingian), They have typically been classified as advanced reptiliomorphs positioned close to, but outside of the clade Amniota, though some recent research has recovered them as the sister group to the traditional Synapsida within Amniota, based on inner ear anatomy and cladistic analyses. They include both large carnivorous and even larger herbivorous forms, some semi-aquatic and others fully terrestrial. The diadectomorphs seem to have originated during late Mississippian times, although they only became common after the Carboniferous rainforest collapse and flourished during the Late Pennsylvanian and Early Permian periods.
Embolomeri is an order of tetrapods or stem-tetrapods, possibly members of Reptiliomorpha. Embolomeres first evolved in the Early Carboniferous (Mississippian) Period and were the largest and most successful predatory tetrapods of the Late Carboniferous (Pennsylvanian) Period. They were specialized semiaquatic predators with long bodies for eel-like undulatory swimming. Embolomeres are characterized by their vertebral centra, which are formed by two cylindrical segments, the pleurocentrum at the rear and intercentrum at the front. These segments are equal in size. Most other tetrapods have pleurocentra and intercentra which are drastically different in size and shape.
Ichniotherium is an ichnogenus of tetrapod footprints from between the Late Carboniferous period to the Early Permian period attributed to diadectomorph track-makers. These footprints are commonly found in Europe, and have also been identified in North America and Morocco. Three ichnospecies of Ichniotherium have been proposed as valid: I. cotta, I. sphaerodactylum, and I. praesidentis.
Limnoscelis was a genus of large diadectomorph tetrapods from the Late Carboniferous of western North America. It includes two species: the type species Limnoscelis paludis from New Mexico, and Limnoscelis dynatis from Colorado, both of which are thought to have lived concurrently. No specimens of Limnoscelis are known from outside of North America. Limnoscelis was carnivorous, and likely semiaquatic, though it may have spent a significant portion of its life on land. Limnoscelis had a combination of derived amphibian and primitive reptilian features, and its placement relative to Amniota has significant implications regarding the origins of the first amniotes.
Reptiles arose about 320 million years ago during the Carboniferous period. Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic, excluding endothermic animals like birds that are descended from early traditionally-defined reptiles. A definition in accordance with phylogenetic nomenclature, which rejects paraphyletic groups, includes birds while excluding mammals and their synapsid ancestors. So defined, Reptilia is identical to Sauropsida.
Ambedus is an extinct genus of possible diadectid reptiliomorph. Fossils have been found from the Early Permian Dunkard Group of Monroe County, Ohio. The type species A. pusillus was named in 2004. The genus name comes from the Latin word ambedo meaning "to nibble", in reference to its herbivorous diet. The specific name pusillus means "tiny" in Latin.
Oradectes is an extinct genus of diadectid reptiliomorph. It is known from a single partial skeleton collected from the Early Permian Cutler Formation of Colorado in the United States. The type species, O. sanmiguelensis, was originally named as a species of Diadectes in 1965. It was given its own genus in 2010.
Stephanospondylus is an extinct genus of diadectid reptiliomorph from the Early Permian of Germany. Fossils have been found in deposits of the Lower Rotliegend near Dresden. The type species S. pugnax was originally referred to the genus Phanerosaurus in 1882 but was placed in its own genus in 1905.
The Tambach Formation is an Early Permian-age geologic formation in central Germany. It consists of red to brown-colored sedimentary rocks such as conglomerate, sandstone, and mudstone, and is the oldest portion of the Upper Rotliegend within the Thuringian Forest Basin.
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