Mammalian jaw. Medical search. Frequent questions

According to research, dentine, a component of the lower jaw, is connected to the ear bones in mammalian embryos. (sydf.org)
Recent reports have suggested that the mammalian premaxilla is derived from embryonic maxillary prominences rather than the frontonasal ectomesenchyme as previously shown in studies of chicken embryos. (bvsalud.org)
When nonhuman mammalian development is compared with human development, the study subjects must be compared at the same developmental stage (fetal, perinatal, postnatal) When collected appropriately, data from experimental studies of nonhuman mammalian embryos elucidate important aspects of human facial development. (medscape.com)

These mammal middle ear bones evolved from the bones of the jaw hinge in their reptilian relatives. (eurekalert.org)
Gastornis , along with some of the mammalian and reptilian members of the Eocene Arctic fauna, likely over-wintered in the Arctic. (nature.com)
The cartilage that ossifies into the reptilian lower jaw (Maeckel's cartilage) does so under the influence of this gene. (islandbiodiversity.com)
Early on echidnas were perceived by scientists to have both reptilian and mammalian features just like their namesake. (mayanfarm.com.au)

In mammals the jaws are made up of the mandible (lower jaw) and the maxilla (upper jaw). (wikipedia.org)
In most vertebrates this protein is expressed in muscles that develop from the first pharyngeal arch, including temporalis , which in mammals is the largest muscle of the jaw. (johnhawks.net)
image: All modern mammals (platypus, opossum and human) have a middle ear separated from the lower jaw (see example from living opossum). (eurekalert.org)
It becomes possible for mammals to have a delicate and highly sensitive ear structure for better hearing, and to have a more robust lower jaw and jaw hinge for better feeding. (eurekalert.org)
The ear bones in Maotherium are partly separated from the jaw, and more similar to those in modern mammals than to mammaliaforms, but still retain the pre-mammalian condition in which the jaw and the ear are connected to each other. (eurekalert.org)
Moreover, the connected jaw-ear structure of Maotherium is similar to the ear structure of modern mammals at embryonic and fetal growth stages. (eurekalert.org)
Mammals have highly sensitive hearing, far better than the hearing capacity of all other vertebrates, and hearing is fundamental to the mammalian way of life. (eurekalert.org)
Paleontologists have long attempted to understand the evolutionary pathway via which these precursor jawbones became separated from the jaw and moved into the middle ear of modern mammals. (eurekalert.org)
but Maotherium 's middle ear has an unusual connection to the lower jaw that is unlike that of adult modern mammals. (eurekalert.org)
This middle ear connection, also known as the ossified Meckel's cartilage, resembles the embryonic condition of living mammals and the primitive middle ear of pre-mammalian ancestors. (eurekalert.org)
This includes the key evolutionary transition from creatures with one ear ossicle and a quadrate-articular jaw joint to mammals with three ear ossicles and a dentary-squamosal jaw joint. (creation.com)
1 Eight years later John Woodmorappe published an analysis of the character traits of 'mammal-like reptiles' (now referred to as non-mammalian synapsids) and fossil mammals. (creation.com)
4 This was purported to be a key step in the evolution of mammals and in particular the evolution of the jaw and middle ear bones, which are some of the defining characteristics of mammals. (creation.com)
Evolutionists believe that mammals evolved from reptilelike therapsid ancestors, which had a jaw similar to reptiles. (creation.com)
At the same time the two jaw bones involved in hearing (articular and quadrate) are believed to have separated from the jaw and become the malleus and the incus, respectively, of living mammals. (creation.com)
Ten times fewer mammalian genera have been identified from the Mesozoic than from the age of mammals that followed it (the Cenozoic era, from roughly 65.5 Myr ago to the present), even though the Cenozoic has lasted less than half the time. (nature.com)
The minute, finely-tuned ear ossicles of mammals arose through a spectacular evolutionary transformation from their origins as a load-bearing jaw joint. (biomedcentral.com)
The freely suspended middle ear of extant adult mammals is considered a derived pattern termed the definitive mammalian middle ear (DMME) [ 8 ]. (biomedcentral.com)
One such example is the evolution of the jaw bones in mammals. (tutorialspoint.com)
However, the jaw bones in mammals have an interesting evolutionary history. (tutorialspoint.com)
However, whether mammalian embryonic frontonasal ectomesenchyme contributes to the premaxillary bone has not been investigated and a tool to trace the contributions of the frontonasal ectomesenchyme to facial structures in mammals is lacking. (bvsalud.org)

In non-mammalian jawed vertebrates, the bones homologous to the mammalian middle ear ossicles compose the proximal jaw bones that form the jaw articulation (primary jaw joint). (kcl.ac.uk)
A new developmental mechanism for the separation of the mammalian middle ear ossicles from the jaw [4] "Multiple mammalian lineages independently evolved a definitive mammalian middle ear (DMME) through breakdown of Meckel's cartilage (MC). (edu.au)
2017. A new developmental mechanism for the separation of the mammalian middle ear ossicles from the jaw. (islandbiodiversity.com)

In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw. (wikipedia.org)
Over evolutionary time the more familiar use of jaws (to humans), in feeding, was selected for and became a very important function in vertebrates. (wikipedia.org)
Over time, as fish evolved into tetrapod's (four-limbed vertebrates), the jaw bones underwent significant changes. (tutorialspoint.com)

The type species E. mirabilis was named by paleontologist Robert Broom in 1931 from a skull missing the lower jaw. (wikipedia.org)
The second species, E. liuyudongi, was named by Jun Liu and Fernando Abdala in 2022 based on a well-preserved skull with an associated lower jaw. (wikipedia.org)
Some species have jaw bones completely fused, while others may have joints allowing for mobility of the dentary, quadrate, or maxilla. (wikipedia.org)
Australopithecus and Paranthropus have larger jaw muscles than early Homo species like H. habilis and H. erectus . (johnhawks.net)
Gordodon kraineri is a new genus and species of edaphosaurid eupelycosaur known from an associated skull, lower jaw and incomplete postcranium found in the early Permian Bursum Formation of Otero County, New Mexico, USA. (palaeo-electronica.org)
The platypus and four echidna species are the sole surviving mammalian egg-layers. (biologicaldiversity.org)
Christine Elizabeth Cooper " Myrmecobius fasciatus (Dasyuromorphia: Myrmecobiidae)," Mammalian Species 43(1), 129-140, (28 July 2011). (bioone.org)
In addition to the cyclostome lack of jaws and paired fins hagfish have (depending on species) very simple eyes or no eyes at all. (ericbutlerlab.com)

This jaw-ear separation is an important evolutionary innovation. (eurekalert.org)
The analysis of the new fossil suggests that the evolutionary pattern of the mammalian ear is directly related to timing changes in growth, as well as in changes in genes for mammalian development. (eurekalert.org)
To evolutionary biologists, an understanding of how the sophisticated and highly sensitive mammalian ear evolved may illuminate how a new and complex structure transforms through evolution. (eurekalert.org)
5 , 6 The current evolutionary theory is that the dentary bone increased in size and formed a secondary jaw joint with the squamosal bone. (creation.com)
Gondwanatherians have only been known from isolated teeth and jaw fragments, so the details of their appearance and evolutionary relationships were hard to determine. (iflscience.com)
This is also the oldest and best-documented example of developmental recapitulation of an evolutionary transformation [ 2 - 5 ], as the final separation of the middle ear from the dentary through disappearance of Meckel's cartilage occurs in mammalian development as in evolution [ 6 , 7 ] (Fig. 1 ). (biomedcentral.com)

Epidermal teeth are found in the jawless fish ( e.g., lampreys), on the edges of the jaws of tadpoles (larval frogs and toads), in the mouth of the platypus, where horny plates replace the true teeth before birth, and in sirenians ( e.g., sea cows) accompanying true teeth. (britannica.com)
Many frogs have tiny teeth built into their upper jaws, and few frogs and toads have teeth in the lower jaw. (sachecucine.it)

The hyoid system suspends the jaw from the braincase of the skull, permitting great mobility of the jaws. (wikipedia.org)
This is only the third mammalian skull recovered from the Cretaceous in the southern hemisphere. (iflscience.com)
For his dissertation research, Kaleb investigated the functional effects of skull flattening on the jaw muscles and joints in the lineage leading to crocodylians. (callumross.org)

in fact, even fossil hominins with the largest teeth and jaws probably shared this genetic change with us. (johnhawks.net)
What's fascinating is that the big jaws of many of our fossil ancestors weren't built for nutcracking power. (johnhawks.net)
To these researchers, the estimate held meaning because of its correspondence with early evidence of fossil Homo, which had smaller jaw muscles than earlier hominins. (johnhawks.net)
This new remarkably well preserved fossil, as reported in the October 9 issue of the prestigious journal Science , offers an important insight into how the mammalian middle ear evolved. (eurekalert.org)
Here we employ the first model-based, probabilistic analysis of the evolution of the definitive mammalian middle ear, supported by virtual 3D erosion simulations to assess for potential fossil preservation artifacts. (biomedcentral.com)
Some clues as to the sequence in which the mammalian middle ear evolved come from two additional patterns of the mammalian middle ear in the fossil record [ 7 ]. (biomedcentral.com)

e individual showing a closed Meckel's groove and absence of the connection, and hence, representing the definitive mammalian middle ear. (biomedcentral.com)
Meckel's cartilage refers to ossified cartilage that is related to the jaw. (sydf.org)

Both specimens are missing the lower jaw. (wikipedia.org)
Most of the upper jaw bones (premaxilla, maxilla, jugal, quadratojugal, and quadrate) have been fused to the braincase, while the lower jaw bones (dentary, splenial, angular, surangular, and articular) have been fused together into a unit called the mandible. (wikipedia.org)
In the ape there is a reinforcement to the lower jaw bone called the simian shelf. (wikipedia.org)
In the evolution of the mammalian jaw, two of the bones of the jaw structure (the articular bone of the lower jaw, and quadrate) were reduced in size and incorporated into the ear, while many others have been fused together. (wikipedia.org)
This presumption is supported by the fact that snakes have neither tympanum nor eustachian tube, and the stapes whose proximal end rests in the vestibular window and its distal end attached to the quadrate bone on which the lower jaw swings ( Young, 2003 YOUNG, B. A., 2003. (scielo.br)
By comparison, the middle ear bones are a part of the lower jaw and form the jaw hinge in pre-mammalian relatives (see the example of Morganucodon ). (eurekalert.org)
However, there are problems with the theory that the mammalian middle ear structures which developed at the angle of the lower jaw were transferred to the basicranium, and there is no clear consensus on the origin and evolution of the mammalian eardrum. (creation.com)
In addition, the locality has yielded the first lower jaws and incisors of the genus. (palass.org)
Now, a team led by Stony Brook's David Krause describe a fossilized cranium (no lower jaw) uncovered in an Upper Cretaceous formation in Madagascar. (iflscience.com)
A model of the mechanics of elevation in the mammalian mandible is described, in which rotation of the lower jaw, effected by a couple action between the anterior and posterior adductor muscle groups, takes place around the mandibular attachment of the sphenomandibular ligament. (amnh.org)
More than 200 million years ago, modern frogs' ancestors lost the teeth in their lower jaws. (sachecucine.it)
Unlike the North American Smilodon , Thylacosmilus had flanges on its lower jaws which protected the canines when their mouth was closed. (a-z-animals.com)
The lower jaw develops from the paired mandibular primordia (mandibular prominences). (medscape.com)

In patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ), panoramic and plain radiography of the mandible reveal areas of sclerosis, destruction, sequestration, or pathologic fractures. (medscape.com)

The change in jaw muscles happened long before our genus arose. (johnhawks.net)
Morganucodon ('Glamorgan tooth') is a mammalian genus which supposedly lived during the Late Triassic. (creation.com)

One of the most famous and complicated transformations in vertebrate evolution is the origin of the mammalian middle ear bones (ectotympanic, incus and malleus) from load-bearing post-dentary elements (angular, articular and quadrate) during the evolution of synapsids [ 1 ]. (biomedcentral.com)

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a condition found in patients who have received intravenous and oral forms of bisphosphonate therapy for various bone-related conditions. (medscape.com)
Bisphosphonate-related osteonecrosis of the jaw (BRONJ) manifests as exposed, nonvital bone involving the maxillofacial structures. (medscape.com)
Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is thought to be caused by trauma to dentoalveolar structures that have a limited capacity for bone healing due to the effects of bisphosphonate therapy. (medscape.com)
Surgical intervention for bisphosphonate-related osteonecrosis of the jaw (BRONJ) remains limited because of the impaired ability of the bone to heal. (medscape.com)
Several studies of patients with multiple myeloma and patients with breast cancer who received intravenous aminobisphosphonate therapy for metastatic bone lesions demonstrated 6-11% of the patients developed bisphosphonate-related osteonecrosis of the jaw (BRONJ). (medscape.com)
Although the shark's cartilaginous jaws undergo considerably greater deformation than would jaws constructed of bone, effective bite force is not greatly diminished. (researchgate.net)
A mammal has (among other things) a single jaw bone (the dentary), a dentary-squamosal jaw joint and three ear bones (the malleus, incus, and stapes) which transmit sound from the eardrum, as shown diagrammatically in figure 2. (creation.com)
Reptiles, on the other hand, have a jaw made up of several bones, a jaw joint formed by the articular and quadrate bones and only one ear bone, the columella (sometimes called the stapes), transmitting sound from the eardrum. (creation.com)
Bone- and cartilage-forming cells in the head, called cranial neural crest cells (CNCCs), generally move a long distance from where they are first formed around the back of the neck, to their intended destinations such as the jaw or nose," explained Kawanishi. (scitechdaily.com)
When the bone structure moves from the jaw to the inner ear later in development, detachment occurs. (sydf.org)
A fundamental, yet unresolved, question in craniofacial biology is about the origin of the premaxilla, the most distal bone present in the upper jaw of all amniotes. (bvsalud.org)

It has a specialized dental apparatus consisting of large, chisel-like incisors in the front of the jaws separated by a long diastema from relatively short rows of peg-like maxillary and dentary cheek teeth. (palaeo-electronica.org)

Mammalian remains from the age of the dinosaurs - the Mesozoic era, from 250 million years (Myr) to 65 Myr ago - are rare. (nature.com)

Mammalian hearing adaptation is made possible by a sophisticated middle ear of three tiny bones, known as the hammer (malleus), the anvil (incus), and the stirrup (stapes), plus a bony ring for the eardrum (tympanic membrane). (eurekalert.org)
Because Maotherium asiaticus is preserved three-dimensionally, paleontologists were able to reconstruct how the middle ear attached to the jaw. (eurekalert.org)
The evolution of the mammalian jaw joint and middle ear is said to be well-documented and includes Morganucodon , which is believed to show a key step in this transition. (creation.com)
This review re-examines Morganucodon and the claim that it had a transitional double jaw joint and a mandibular middle ear. (creation.com)
The evolution of the mammalian jaw and middle ear is said to be well-documented and important as a demonstration of transitional forms and exaptation. (creation.com)
For his dissertation, Alec is investigating the evolution of the mammal jaw and the mammalian middle ear. (callumross.org)
New research into the grey short-tailed opossum Monodelphis domestica has shown that the gene TGF-ßR2 plays a key role in the development of the mammalian middle ear. (islandbiodiversity.com)

Little is known about mammalian evolution in South America during the age of the dinosaurs. (nature.com)
Gondwanatherians, they found, were closely related to multituberculates, a long-lived, successful group of rodent-like mammalian contemporaries of dinosaurs on the northern continents. (iflscience.com)
They were small dinosaurs, about 2 meters (6.6 feet) long and weighing between 15 to 33 pounds (6.8 to 15 kg) 1 ( https://en.wikipedia.org/wiki/Velociraptor ). (sheerepic.com)

Fossils and developmental studies have shown that the malleus and incus are derived from bones of the jaws. (islandbiodiversity.com)
The result of this is the formation of the malleus and incus as separeate bones, isolated from the main part of the jaw. (islandbiodiversity.com)

Other primates express this gene in their jaw muscles, where it strengthens the bite force. (johnhawks.net)
Comparison of hominin crania in superior view, to show the extent of jaw muscles. (johnhawks.net)
In the last sentence of their discussion, Stedman and colleagues advanced a provocative hypothesis: Not only did Homo have smaller jaws and teeth, but reducing the jaw muscles may have enabled the evolution of larger brain size. (johnhawks.net)
To explore multiple bite scenarios, we set four different load cases on a 3D model of the cranium obtained via digital photogram-metry, considering the temporalis and masseter muscles as jaw adductors. (researchgate.net)

The jaw articulates via a hinge joint between the quadrate and articular. (wikipedia.org)

This article looks again at Morganucodon (figure 1), which was claimed to have a double jaw joint. (creation.com)

Many teleost fish have substantially modified jaws for suction feeding and jaw protrusion, resulting in highly complex jaws with dozens of bones involved. (wikipedia.org)

They may also have bony vomerine teeth on top of their mouth behind the ridge of their upper jaw. (sachecucine.it)

The 2014 update of a position paper from the American Association of Oral and Maxillofacial Surgeons (AAOMS) recommended changing the name of bisphosphonate-related osteonecrosis of the jaw (BRONJ) to medication-related osteonecrosis of the jaw (MRONJ), owing to the increased number of maxillary and mandibular osteonecrosis cases that have been linked to other antiresorptive (denosumab) or antiangiogenic treatments. (medscape.com)
The ear bones are believed to have been part of the jaw (the mandibular ear) which were connected to a stapes. (creation.com)

The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of humans and most animals. (wikipedia.org)
In humans, these are known to become parts of the nose and jaw. (scitechdaily.com)

The mammalian ear evolution is important for understanding the origins of key mammalian adaptations. (eurekalert.org)

We show that this change in role of Bapx1 following the transition to the mammalian ossicle configuration is not due to a change in expression pattern but results from an inability to regulate Gdf5 and Gdf6, two genes predicted to be essential in joint formation. (kcl.ac.uk)

They also possess movable quadrate bones, making it possible to move the upper jaw relative to the. (absoluteastronomy.com)

and most of the mesenchyme at the ancestral upper jaw tip has become a protruded mammalian nose. (wikipedia.org)

Not all frogs have teeth, but many have tiny maxillary teeth along the top jaw. (sachecucine.it)
The upper jaw develops from the following 5 main buds of tissue: a single median frontonasal mass (sometimes present as the median nasal processes or frontonasal prominences), the 2 lateral nasal prominences on both sides, and, flanking these, the 2 maxillae (maxillary prominences). (medscape.com)

Epithelial to mesenchymal transition during mammalian neural crest cell delamination. (stowers.org)

These jaw bones were simple structures that served to grasp and manipulate prey. (tutorialspoint.com)

Single-cell transcriptomic signatures and gene regulatory networks modulated by W1s in mammalian midline facial formation and clefts. (stowers.org)

Frogs that go after larger morsels are often equipped with a row of teeth on their upper jaw and a toothy, serrated palate on the top of their mouths, which helps keep wiggling prey from escaping. (sachecucine.it)
The teeth and bones along the jaw are used to trap prey. (sachecucine.it)
The size of its head and jaws meant this carnivore had a significant bite force-sufficient to take down big prey. (a-z-animals.com)
Velociraptors, as solitary hunters, relied on ambush and surprise to catch their prey 3 ( https://en.wikipedia.org/wiki/Deinonychus ). (sheerepic.com)
Gray wolves, on the other hand, hunt in packs, working together to outsmart and tire out their prey before moving in for the kill 4 ( https://en.wikipedia.org/wiki/Hunting_behavior_of_gray_wolves ). (sheerepic.com)

The original selective advantage offered by the jaw may not be related to feeding, but rather to increased respiration efficiency. (wikipedia.org)

Karydomys wigharti predominantly occurs at localities that are correlated with the upper part of the Mammalian Neogene biozone MN 5. (palass.org)

Three-dimensional computer analysis of white shark jaw mechanics: How hard can a great white bite? (researchgate.net)

We demonstrate that a simple change in TGF-β signalling is sufficient to inhibit MC breakdown during opossum development, indicating that changes in TGF-β signalling might be key during mammalian evolution. (edu.au)
Dynamic regulation and requirement for ribosomal RNA transcription during mammalian development. (stowers.org)

When those forces were relaxed by reducing the jaw musculature, brain size was free to increase. (johnhawks.net)

Neither its bite force, nor how such force might be delivered using relatively elastic cartilaginous jaws, have been quantified or described. (researchgate.net)

Each unit of the jaw holds a single, perpetually growing tooth composed of crystalline calcium carbonate. (wikipedia.org)

We have digitally reconstructed the jaws of a white shark to estimate maximum bite force and examine relationships among their three-dimensional geometry, material properties and function. (researchgate.net)

The discovery of 100-million-year-old skulls confirms that mammalian faunas were endemic in southern continents at this time. (nature.com)
We know next to nothing about early mammalian evolution on the southern continents," Krause says in a news release . (iflscience.com)

the dentition is variable between individuals and even between the 2 sides of the jaw of the same individual. (bioone.org)

Anatomy4

Organisms1

Diseases9

Phenomena and Processes1

Information Science2

Embryos3

Reptilian4

Mammals21

Ossicles3

Vertebrates3

Species8

Evolutionary6

Frogs and toads2

Skull3

Fossil6

Meckel's2

Lower13

Mandible1

Genus2

Vertebrate evolution1

Bone11

Dentary1

Mesozoic1

Middle7

Dinosaurs3

Incus2

Muscles4

Articular1

Morganucodon1

Bones involved1

Bony1

Mandibular2

Humans2

Origins1

Genes1

Quadrate bones1

Nose1

Maxillary2

Transition1

Structures1

Gene1

Prey5

Selective1

Upper1

Mechanics1

Development2

Brain1

Cartilaginous1

Tooth1

Bite force1

Continents2

Sides1