''Orobates'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

diadectid 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 f ...

reptiliomorph Reptiliomorpha (meaning reptile-shaped; in PhyloCode known as ''Pan-Amniota'') is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was defi ...

s that lived during the

Early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...

. Its

fossilised A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved i ...

remains were found in

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. A combination of primitive and derived traits (i.e. autapomorphic and

plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, an ...

) 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. Orobates BW

Locomotion

The

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

species ''Ichniotherium sphaerodactylum'', from Bromacker in Germany, has been attributed to ''Orobates''. 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 ''Diadectes'' (meaning ''crosswise-biter'') is an extinct genus of large reptiliomorphs or synapsids that lived during the early Permian period ( Artinskian- Kungurian stages of the Cisuralian epoch, between 290 and 272 million years ago). ''Dia ...

''. 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. An analysis of the mobility of the hip joint of the reconstructed holotype indicated that its limb function was similar to that of modern

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s. A detailed

multidisciplinary An academic discipline or academic field is a subdivision of knowledge that is taught and researched at the college or university level. Disciplines are defined (in part) and recognized by the academic journals in which research is published, ...

study published in 2019 found that ''Orobates'' moved more like modern

caiman A caiman ( (also spelled cayman) from Taíno language, Taíno ''kaiman'') is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family (biology), family, the other being alligators. ...

s than salamanders. The study began with the digitization of its

holotype specimen A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was Species description, formally described. It is either the single such physical example (or illus ...

using CT scanning to figure out the range of motion of its

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...

s. A digital model of its fossil trackways helped narrow down the possibilities. The researchers also studied the locomotion of four

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

sprawling

tetrapod A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetr ...

s using

X-ray motion analysis X-ray motion analysis is a technique used to track the movement of objects using X-rays. This is done by placing the subject to be imaged in the center of the X-ray beam and recording the motion using an X-ray image intensifier, image intensifier a ...

. The extant tetrapods chosen for the study were

axolotl The axolotl (; from ) (''Ambystoma mexicanum'') is a neoteny, paedomorphic salamander, one that Sexual maturity, matures without undergoing metamorphosis into the terrestrial adult form; adults remain Aquatic animal, fully aquatic with obvio ...

blue-tongued skink Blue-tongued skinks comprise the Australasian genus ''Tiliqua'', which contains some of the largest members of the skink family (biology), family (Scincidae). They are commonly called blue-tongued lizards or simply blue-tongues or blueys in Aust ...

green iguana The green iguana (''Iguana iguana''), also known as the American iguana or the common green iguana, is a large, arboreal, mostly Herbivory, herbivorous species of lizard of the genus ''Iguana''. Usually, this animal is simply called the iguana. ...

s, and

spectacled caiman The spectacled caiman (''Caiman crocodilus''), also known as the white caiman, common caiman, and speckled caiman, is a crocodilian in the family Alligatoridae. It is brownish-, greenish-, or yellowish-gray colored and has a spectacle-like ridge ...

s. 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 Dynamical system simulation or dynamic system simulation is the use of a computer program to model the time-varying behavior of a dynamical system. The systems are typically described by ordinary differential equations or partial differential equ ...

. It allowed the researchers to account for physical factors like

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

, and

balance Balance may refer to: Common meanings * Balance (ability) in biomechanics * Balance (accounting) * Balance or weighing scale * Balance, as in equality (mathematics) or equilibrium Arts and entertainment Film * Balance (1983 film), ''Balance'' ( ...

. The simulation was then validated under real-world conditions with a life-sized robot called OroBOT. The researchers tested 512 different

gait Gait is the pattern of Motion (physics), movement of the limb (anatomy), limbs of animals, including Gait (human), humans, during Animal locomotion, locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on s ...

s and found that ''Orobates'' moved most like a caiman. It had a relatively erect posture and walked with a slight side-to-side motion. A follow-up study focused on the muscle strains occurring within the muscles of the hindlimb in modelled strides at different postures. While results remained inconclusive towards favouring a single posture during locomotion, the overall results did not contradict the previous study based on OroBOT.

References

{{Taxonbar, from=Q772545 Diadectidae Artinskian genera Cisuralian tetrapods of Europe Permian Germany Fossils of Germany Fossil taxa described in 2004