Reptiles are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. The study of these traditional reptile orders, historically combined with that of modern amphibians, is called herpetology. Because some reptiles are more closely related to birds than they are to other reptiles (e.g., crocodiles are more closely related to birds than they are to lizards), the traditional groups of "reptiles" listed above do not together constitute a monophyletic grouping or clade (consisting of all descendants of a common ancestor). For this reason, many modern scientists prefer to consider the birds part of Reptilia as well, thereby making Reptilia a monophyletic class, including all living diapsids.
Introduction
Reptile
Reptile | Introduction
They are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives They are tetrapod animals in the class Reptilia They are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. They are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives.
hypothalamic amenorrhea will result in the increased secretion of thyroid stimulating hormone (tsh)
user
Sorry. I cannot find the answer based on the context.
assistant
what is hypopituitarism?
user
A decreased ("hypo") secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain.
assistant
what are the indications of it?
user
Insufficiency of follicle-stimulating hormone (FSH) and/or luteinizing hormone (LH) leading to sex hormone abnormalities. Growth hormone deficiency is more common in people with an underlying tumor than those with other causes.
assistant
how this can be treated?
user
Removing the underlying cause, treating the hormone deficiencies, and addressing any other repercussions that arise from the hormone deficiencies.
assistant
you mentioned a gland above, where is it located in human body?
user
The bottom of the hypothalamus at the base of the brain.
assistant
what is the size of this gland?
user
The size of a pea
assistant
what is the functions of anterior lobe of this gland?
user
Synthesizes and secretes hormones; regulates several physiological processes including stress, growth, reproduction, and lactation.
assistant
which hormones are synthesized by this lobe?
user
Growth hormone, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), thyroid stimulating hormone (TSH) etc
assistant
how is the posterior lobe different from the anterior lobe?
user
It store and secretes (but does not synthesize) the important endocrine hormones.
assistant
in which other animals this gland can be found?
user
All vertebrates such as mammals, amphibians, reptiles, and birds,
assistant
what is the clinical significance of this gland?
user
There are diseases involving the pituitary gland. The functions of the pituitary gland can be adversely affected by an over- or under-production of associated hormones. The Pituitary gland growth during adolescence can be altered by early life stress such as childhood maltreatment or maternal dysphoric behavior.
assistant
what is the third mentioned vertebrates from the above list?
user
A neuroendocrine system has been observed in all animals with a nervous system and all vertebrates have a hypothalamus-pituitary axis. All vertebrates have a thyroid, which in amphibians is also crucial for transformation of larvae into adult form. All vertebrates have adrenal gland tissue, with mammals unique in having it organized into layers. All vertebrates have some form of a renin–angiotensin axis, and all tetrapods have aldosterone as a primary mineralocorticoid.
Endocrine system | Other animals
The third trochanter is associated with short, robust femora, and is frequently present and well developed in Neanderthals (that were shorter and more robust than anatomically modern humans) but generally absent in higher primates. Studying fossils of "Ardipithecus ramidus" (a Chimpanzee-human last common ancestor candidate), noted that in this species — as well as in "Proconsul", "Nacholapithecus", and "Dryopithecus" (Miocene primates) — homologs to the third trochanter and the hypotrochanteric fossa are present while both traits are absent in extant apes. They concluded that the hominid morphotype is primitive and the femoral shape of apes is derived contrary to what was previously thought.
Third trochanter | Anthropology
List of reptile genera lists the vertebrate class of reptiles by genus, spanning two subclasses.
List of reptile genera | Introduction
In the holotype of "Deinocheirus mirificus", ZPALNo.Mgd-I/6, an injury to the joint between the first and second phalanges of its third finger may be responsible for pits scientists have observed there. A toe bone from an unidentified ornithomimid has a pathology on its far end, causing the joint to appear "mushroomed" compared to healthy specimens. The same pathology may have been found in a specimen of the tyrannosaurid "Gorgosaurus". Remains of an unidentified theropod, which may one day turn out to be "Timimus hermani" or a relative, were recovered from the Strzelecki Group near Inverloch, Victoria. This specimen had a depressed fracture on the bottom of the first phalanx of its third toe.
Theropod paleopathology | Ornithomimosaurs
As of 1995, the following reptile species are recorded as being present: the shingle back lizard and a species of dragon lizard.
Point Labatt | Fauna
Superorder Crocodylomorpha
List of reptiles | Division <a href="Archosauria">Archosauria</a>
Nearly all vertebrate species possess a pineal gland. The most important exception is a primitive vertebrate, the hagfish. Even in the hagfish, however, there may be a "pineal equivalent" structure in the dorsal diencephalon. The lancelet "Branchiostoma lanceolatum", the nearest existing relative to vertebrates, also lacks a recognizable pineal gland. The lamprey (another primitive vertebrate), however, does possess one. A few more developed vertebrates have lost pineal glands over the course of their evolution. The results of various scientific research in evolutionary biology, comparative neuroanatomy and neurophysiology have explained the evolutionary history (phylogeny) of the pineal gland in different vertebrate species.
Pineal gland | Introduction
The pituitary gland is found in all vertebrates, but its structure varies among different groups. The division of the pituitary described above is typical of mammals, and is also true, to varying degrees, of all tetrapods. However, only in mammals does the posterior pituitary have a compact shape. In lungfish, it is a relatively flat sheet of tissue lying above the anterior pituitary, but in amphibians, reptiles, and birds, it becomes increasingly well developed. The intermediate lobe is, in general, not well developed in any species and is entirely absent in birds. The structure of the pituitary in fish, apart from the lungfish, is generally different from that in other animals.
Pituitary gland | Other animals
Cladistically birds are considered reptiles, but according to traditional taxonomy they are listed separately. Saurischia includes extinct relatives of birds, the "lizard hipped" dinosaurs. See List of bird genera.
List of reptile genera | Order <a href="Saurischia">Saurischia</a>
From the point of view of biological evolution, the pineal gland represents a kind of atrophied photoreceptor. In the epithalamus of some species of amphibians and reptiles, it is linked to a light-sensing organ, known as the parietal eye, which is also called the pineal eye or "third eye."
Pineal gland | Introduction
A third distal tail vertebra, GSI K27/599, has been referred to the species.
Jubbulpuria | Introduction
Remarkable features of the hind limb and pelvic girdle include a large obturator foramen similar in size to that of therians, a large parafibula, and the presence of an epipubic bone. The fully described animal, now named "Adalatherium hui", is a comparatively large sized mammal, compared in size to a large cat. It has more erect limbs than other allotheres.
Gondwanatheria | Biology
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls.
List of mammals of South Ossetia | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
Most living vertebrates have pineal glands. It is likely that the common ancestor of all vertebrates had a pair of photosensory organs on the top of its head, similar to the arrangement in modern lampreys. Some extinct Devonian fishes have two parietal foramina in their skulls, suggesting an ancestral bilaterality of parietal eyes. The parietal eye and the pineal gland of living tetrapods are probably the descendants of the left and right parts of this organ, respectively. During embryonic development, the parietal eye and the pineal organ of modern lizards and tuataras form together from a pocket formed in the brain ectoderm.
Pineal gland | Other animals
lyrifer", along with the smaller species "S. deguili", "S. simplex", and "S. daamsi"; and the hamsters "Hattomys gargantua", "H. nazarii", "Neocricetodon sp.", and "Apocricetus sp." The gymnures (hairy hedgehogs) "Deinogalerix freudenthalli", "D. minor", "D. intermedius", "D. brevirostris", "D. koenigswaldi", and "D. masinii" were also giant, while their smaller relative "Apulogalerix cf. pusillus" is also present. Other mammals include the crocidosoricine shrew "Lartetium cf. dehmi"; the pikas "Prolagus apricenicus" and "P. imperialis"; the deer-like hoplitomerycid "Hoplitomeryx mathei"; and the otter "Paralutra garganensis". There is one reptile genus: a crocodile referred to "Crocodylus". "Garganornis" and the rest of the "Mikrotia" fauna has been dated to the Tortonian stage of the Late Miocene.
Garganornis | Paleoecology
Each section, such as on reptiles at the start of Volume II (and the entire work) is introduced with an essay on distinguishing aspects of their zoology. In the case of the reptiles, the essay begins with the observation that their circulation is so arranged that only part of the blood pumped by the heart goes through the lungs; Cuvier discusses the implications of this arrangement, next observing that they have a relatively small brain compared to the mammals and birds, and that none of them incubate their eggs. Next, Cuvier identifies the taxonomic divisions of the group, in this case four orders of reptiles, the chelonians (tortoises and turtles), saurians (lizards), ophidians (snakes) and batracians (amphibians, now considered a separate class of vertebrates), describing each group in a single sentence.
Le Règne Animal | Approach
This list will inevitably be incomplete. Please help by expanding the list. The following species have been listed and/or photographed at this reserve:
Peyrieras Reptile Reserve | Species List
The following mammals have been recorded in Clapgate Pits:
Clapgate Pits | Mammals
A reasonably complete vertebra was found to be the third by the 1993 and 2006 studies, but the fourth by the 2010 study. Another vertebra was interpreted by the three studies as being part of the rear section of the dorsal vertebral column, as the fourth, or as the fifth, respectively. In 1993, two articulated (still connected) vertebrae were thought to be of the rear part of the dorsal column but are interpreted as the sixth and seventh vertebrae in the two later studies. The 2010 study mentioned another vertebra that was not mentioned by the 1993 and 2006 studies; it was presumed to belong to the rear part of the dorsal column.
Argentinosaurus | Vertebrae
In scrotal mammals the epididymis is attached to the testes in an extra-abdominal position where the cauda epididymis extends beyond the lowest extremity of the testis. Hence, the cauda epididymis is exposed to the coolest of temperatures compared to all other reproductive structures. Whereas testicond reptiles contain an excurrent duct system, they lack male reproductive glands (absent seminal vesicles, prostate, bulbourethral glands). Monotreme mammals are also testicond (like reptiles) and contain some, but not all (absent seminal vesicles) of the male reproductive glands observed in most metatherian and eutherian mammals. This combination of reptilian and mammalian structures within the monotreme reproductive tract has informed the evolution of the male reproductive tract in mammals.
Epididymis evolution from reptiles to mammals | Introduction
Other vertebrates from the Berdyanka II locality that lived alongside "Vjushkovisaurus" include capitosauroid temnospondyls and the therapsid "Nothogomphodon", one of the last therocephalians. "Vjushkovisaurus" was likely a top predator in its environment along other large carnivores including "Dongusuchus" and "Erythrosuchus".
Vjushkovisaurus | Paleobiology
This anatomical feature represents an intermediate stage between what is found in platyrrhines, which do not have an ossified ectotympanic tube, and catarrhines, which have a completely ossified ectotympanic tube. Nearly all of what is known about the body proportions and post-cranial morphology of this family are derived from "Pliopithecus vindobonensis", as it is the only species for which a complete skeleton has been found. Still, the majority of fossil material indicates that pliopithecoids were medium sized primates, approximately the size of a howler monkey or a gibbon (8 kg). Köhler estimates a slightly higher average weight of 10 kg.
Pliopithecoidea | Physical characteristics
Reptiles are tetrapod animals in the class Reptilia, comprising today's turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. The study of these traditional reptile orders, historically combined with that of modern amphibians, is called herpetology. List of reptiles lists the vertebrate class of reptiles by family, spanning two subclasses. 'Reptile' here is taken in its traditional (paraphyletic) sense, and thus birds are not included (although birds are considered reptiles in the cladistic sense).
List of reptiles | Introduction
The loss of parietal eyes in many living tetrapods is supported by developmental formation of a paired structure that subsequently fuses into a single pineal gland in developing embryos of turtles, snakes, birds, and mammals. The pineal organs of mammals fall into one of three categories based on shape. Rodents have more structurally complex pineal glands than other mammals.
Pineal gland | Other animals
Finally a set of three narrow "coronoid bones" lie above the prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular as well. This complex primitive pattern has, however, been simplified to various degrees in the great majority of vertebrates, as bones have either fused or vanished entirely. In teleosts, only the dentary, articular, and angular bones remain, while in living amphibians, the dentary is accompanied only by the prearticular, and, in salamanders, one of the coronoids. The lower jaw of reptiles has only a single coronoid and splenial, but retains all the other primitive bones except the prearticular and the periosteum.
Mandible | Other vertebrates
The defining characteristic of a vertebrate is the vertebral column, in which the notochord (a stiff rod of uniform composition) found in all chordates has been replaced by a segmented series of stiffer elements (vertebrae) separated by mobile joints (intervertebral discs, derived embryonically and evolutionarily from the notochord). However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon and coelacanth. Jawed vertebrates are typified by paired appendages (fins or legs, which may be secondarily lost), but this trait is not required in order for an animal to be a vertebrate.
Vertebrate | Vertebral column
The pituitary gland, in humans, is a pea-sized gland that sits in a protective bony enclosure called the sella turcica. It is composed of two lobes: anterior and posterior, with the intermediate lobe that joins the two regions. In many animals, these three lobes are distinct. The intermediate is avascular and almost absent in human beings. The intermediate lobe is present in many animal species, in particular in rodents, mice and rats, that have been used extensively to study pituitary development and function. In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary, which is an extension of the hypothalamus.
Pituitary gland | Structure
This part likely represents the deposits of an environment of estuaries, tidal flats or coastal plains. The climate would have been seasonal with both dry and humid periods. The most common vertebrates collected include ceratodontid lungfish, turtles, crocodiles, plesiosaurs, dinosaurs, lizards, snakes and mammals. Some of the snakes that have been found belong to the families Boidae and Madtsoidae, such as "Alamitophis argentinus". Turtles are represented by at least five taxa, four from Chelidae (Pleurodira) and one from Meiolaniidae (Cryptodira). Among the marine reptiles is the plesiosaur "Sulcusuchus erraini" of the family Polycotylidae. Mammals are represented by "Reigitherium bunodontum", which was considered the first record of a South American docodont, and "Argentodites coloniensis", possibly of Multituberculata.
Carnotaurus | Age and paleoecology
The following are the regional reptiles lists by continent.
Lists of reptiles by region | Introduction
This list of fossil reptiles described in 2019 is a list of new taxa of fossil reptiles that were described during the year 2019, as well as other significant discoveries and events related to reptile paleontology that occurred in 2019.
2019 in reptile paleontology | Introduction
There is a recorded hypocone on the third premolar. In the bottom premolars, the first premolar has one cusp although it can be bicuspid. The second and third premolar generally have 2-3 cusps, although the second bottom premolar has an entoconid and hypoconid and the third bottom premolar in belzebuth has five cusps with a small hypoconulid. Upper molars generally have four cusps although the third molar may not have a hypocone (might even have only two cusps). With the bottom molars, there are generally four cusps and a fifth cusp on the third molar.
White-bellied spider monkey | Dentition
Mammals (from Latin "mamma" "breast") are a group of vertebrate animals constituting the class Mammalia (), and characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Carboniferous, approximately 300 million years ago. Around 6,400 extant species of mammals have been described. The largest orders are the rodents, bats and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (apes including humans, monkeys, and others), the Artiodactyla (cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others).
Mammal | Introduction
Species Subspecies Subpopulations
List of critically endangered reptiles | <a href="Trionychidae">Trionychids</a>
The weight of even-toed ungulates is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 noncetacean artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Argentina | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates and cetaceans)
The third cervical vertebra has a deep, rimmed, ovoid pleurocoels on the anterolateral surfaces of both the centrum and the neural arch.
Daemonosaurus | Description
Other diverse vertebrates, including chondrichthyans, osteichthyans, albanerpetontid amphibians, turtles, lizards, rhamphorhynchid pterosaurs, and docodont and dryolestid mammals (including "Henkelotherium guimarotae") are also present. Invertebrates are represented by ostracods and molluscs.
Knoetschkesuchus | "K. guimarotae"
Most reptiles are diurnal animals. The vision is typically adapted to daylight conditions, with color vision and more advanced visual depth perception than in amphibians and most mammals. Reptiles usually have excellent vision, allowing them to detect shapes and motions at long distances. They often have only a few Rod cells and have poor vision in low-light conditions. At the same time they have cells called “double cones” which give them sharp color vision and enable them to see ultraviolet wavelengths. In some species, such as blind snakes, vision is reduced. Many lepidosaurs have a photosensory organ on the top of their heads called the parietal eye, which are also called third eye, pineal eye or pineal gland.
Reptile | Vision
The amphibian remain findings belong to the genre of "Discoglossus", "Alytidae" and "Bufo" although the determination to the level of species could be done only for the last one. These species are "B. bufo" and "B. calamites". The reptiles are represented by "Chalcides", "Timon" ("T. lepidus"), "Podarcis", "Blanus" ("B. cinereus"), "Coronella", "Malpolon" ("M. monspessulanus"), "Hemorrhois" ("H. hippocrepis") and "Testudo" ("T. hermanni"). The presence of some of these taxa is particularly relevant, since they are bioindicators, allowing to take a first approach of the paleoclimatic context of the site. In concrete, "T. hermanni", "T. lepidus", "B. cinereus", "M. monspessulanus" and "H.
Cave of the Angel | Herpetofauna
Research concerning more than one group of reptiles listed above.
2019 in reptile paleontology | General research
A basic cladogram of the origin of mammals. Important developments in the transition from reptile to mammal were the evolution of warm-bloodedness, of molar occlusion, of the three-ossicle middle ear, of hair, and of mammary glands. By the end of the Triassic, there were many species that looked like modern mammals and, by the Middle Jurassic, the lineages leading to the three extant mammal groups — the monotremes, the marsupials, and the placentals — had diverged.
Evolution of reptiles | Mammalian evolution
Reptiles developed a distinct three-layered structure of medial and dorsal portions of their pallium, a morphological schema referred to with the concept of allocortex. In contrast, the lateral and ventral pallium sectors of reptiles adopted hypopallial structure (superficial olfactory cortex, covering deep pallial nuclei). The hypopallial region is also known as the dorsal ventricular ridge, described as having anterior and posterior (amygdaloid) regions. Birds essentially show much increased cellularity, keeping within the reptilian morphological schema, which leads to the apparent disappearance of layering within its medial and dorsal pallial sectors. The olfactory cortex is much reduced, whereas the hypopallial or dorsal ventricular ridge nuclei increase significantly in size and relative differentiation.
Pallium (neuroanatomy) | In reptiles and birds
This was not the only possible classification scheme: In the Hunterian lectures delivered at the Royal College of Surgeons in 1863, Huxley grouped the vertebrates into mammals, sauroids, and ichthyoids (the latter containing the fishes and amphibians). He subsequently proposed the names of Sauropsida and Ichthyopsida for the latter two groups. In 1866, Haeckel demonstrated that vertebrates could be divided based on their reproductive strategies, and that reptiles, birds, and mammals were united by the amniotic egg. The terms "Sauropsida" ('lizard faces') and "Theropsida" ('beast faces') were used again in 1916 by E.S. Goodrich to distinguish between lizards, birds, and their relatives on the one hand (Sauropsida) and mammals and their extinct relatives (Theropsida) on the other.
Reptile | Research history
Coelacanth remains are referred to "Mawsonia lavocati" and to the genus "Axelrodichthys". Several taxa of Cladistia and two genera of seminiomorphs (an unnamed "Lepidotes"-like species and "Oniichthys falipoui") are recovered in the Kem Kem beds. Teleosteans are represented by "Cladocyclus pankowskii", "Palaeonotopterus greenwoodi", "Erfoudichthys rosae" and "Concavotectum moroccensis". Amphibians are also present: "Kababisha" sp., the pipid frog "Oumtkoutia anae" and non-pipids frogs. Turtles are represented by several species: "Dirqadim schaefferi", the podocnemidids "Hamadachelys escuilliei", the bothremydids "Galianemys whitei" and "G. emringeri", and the araripemydids "Araripemys" sp. Crocodilians are commonly found; four species are present: "Elosuchus cherifiensis", a genus belonged to the Trematochampsidae, "Araripesuchus rattoides" and "Laganosuchus maghrebensis".
Aoufous Formation | Vertebrate assemblage
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls.
List of mammals of Guyana | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Bolivia | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The following species are recognized as being valid, according to the Reptile Database. "Nota bene": A binomial authority in parentheses indicates that the species was originally described in a genus other than "Amphibolurus".
Amphibolurus | Species
The following databases maintain (more or less) up-to-date lists of vertebrate species:
Vertebrate | Vertebrate species databases
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Eswatini | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Syria | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The following is a list of the heaviest living reptile species, which is dominated by the crocodilians. Unlike the upper weights of mammals, birds or fish, mass in reptiles is frequently poorly documented and many are subject to conjecture and estimation.
List of largest reptiles | Table of heaviest living reptiles
This is a list of reptiles of Sudan in simple alphabetical order by scientific name.
List of reptiles of Sudan | Introduction
Reptiles often retain the primitive intercentra, which are present as small crescent-shaped bony elements lying between the bodies of adjacent vertebrae; similar structures are often found in the caudal vertebrae of mammals. In the tail, these are attached to chevron-shaped bones called haemal arches, which attach below the base of the spine, and help to support the musculature. These latter bones are probably homologous with the ventral ribs of fish. The number of vertebrae in the spines of reptiles is highly variable, and may be several hundred in some species of snake. In birds, there is a variable number of cervical vertebrae, which often form the only truly flexible part of the spine.
Vertebral column | Other vertebrates
Archosaurs are a group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs.
List of reptile genera | Division <a href="Archosauria">Archosauria</a>
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Jordan | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
This list of fossil reptiles described in 2020 is a list of new taxa of fossil reptiles that were described during the year 2020, as well as other significant discoveries and events related to reptile paleontology that occurred in 2020.
2020 in reptile paleontology | Introduction
There are 74 species and three subspecies in the order Veneroida assessed as data deficient.
List of data deficient invertebrates | <a href="Veneroida">Veneroida</a>
The following is a list of largest mammals by family.
List of largest mammals | Introduction
The even-toed ungulates are ungulates – hoofed animals – which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing posteriorly.
List of mammals of Puerto Rico | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
[[Image:Mazama americana.jpg|thumb|[[Red brocket]]]] The even-toed ungulates are [[ungulate]]s whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in [[perissodactyls]]. There are about 220 artiodactyl species, including many that are of great economic importance to humans. Other lists of fauna of Venezuela
List of mammals of Venezuela | Order: [[Artiodactyla]] (even-toed ungulates)
The reptilian nervous system contains the same basic part of the amphibian brain, but the reptile cerebrum and cerebellum are slightly larger. Most typical sense organs are well developed with certain exceptions, most notably the snake's lack of external ears (middle and inner ears are present). There are twelve pairs of cranial nerves. Due to their short cochlea, reptiles use electrical tuning to expand their range of audible frequencies.
Reptile | Nerves
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Greece | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
[[Image:Collared peccary02 - melbourne zoo.jpg|thumb|[[Collared peccary]]]] [[Image:Mazama americana.jpg|thumb|[[Red brocket]]]] The even-toed ungulates are [[ungulate]]s whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in [[perissodactyls]]. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Nicaragua | Order: [[Artiodactyla]] (even-toed ungulates)
As of September 2016, the International Union for Conservation of Nature (IUCN) lists 910 data deficient reptile species. 18% of all evaluated reptile species are listed as data deficient. Of the subpopulations of reptiles evaluated by the IUCN, two species subpopulations have been assessed as data deficient. This is a complete list of data deficient reptile species evaluated by the IUCN. Species which have data deficient subpopulations (or stocks) are indicated.
List of data deficient reptiles | Introduction
"Homo sapiens, Pan troglodytes, Mus musculus, Rattus norvegicus, Canis lupus familiaris, Bos taurus, Gallus gallus, Xenopus tropicalis, Danio rerio"
HomoloGene | <a href="Vertebrates">Vertebrates</a>
The deformities of the humerus and the third finger may have been due to osteodysplasia, which had not been reported from non-avian dinosaurs before, but is known in birds. Affecting juvenile birds that have experienced malnutrition, this disease can cause pain in one limb, which makes the birds prefer to use the other limb instead, which thereby develops torsion. The number of traumatic events that led to these features is not certain, and it is possible that they were all caused by a single encounter, for example by crashing into a tree or rock during a fight with another animal, which may have caused puncture wounds with its claws.
Dilophosaurus | Paleopathology
Mammals – which appear in the fossil record after the first fishes, amphibians, and reptiles – are the only vertebrates to possess the evolutionarily recent, outermost part of the cerebral cortex known as the neocortex. The neocortex of monotremes (the duck-billed platypus and several species of spiny anteaters) and of marsupials (such as kangaroos, koalas, opossums, wombats, and Tasmanian devils) lack the convolutions – gyri and sulci – found in the neocortex of most placental mammals (eutherians). Within placental mammals, the size and complexity of the neocortex increased over time. The area of the neocortex of mice is only about 1/100 that of monkeys, and that of monkeys is only about 1/10 that of humans.
Central nervous system | Mammals
Another hypothesis, supported by its original 2014 description, considers it to be somewhat more "advanced" than those groups, instead being closer to "Ticinosuchus" and paracrocodylomorphs (the group containing "rauisuchians" and the ancestors of modern crocodilians). This classification scheme is justified by the presence of "staggered" osteoderms, heart-shaped "spine tables", and a groove on the femoral head. Regardless of these hypotheses, it is clear that "Nundasuchus" represents a previously unknown group of reptiles with a mixture of features both plesiomorphic and derived with respect to suchian archosaurs.
Nundasuchus | Introduction
Goodrich supported this division by the nature of the hearts and blood vessels in each group, and other features, such as the structure of the forebrain. According to Goodrich, both lineages evolved from an earlier stem group, Protosauria ("first lizards") in which he included some animals today considered reptile-like amphibians, as well as early reptiles.
Reptile | Research history
It also has pairs of digestive glands similar to those of basal arthropods.
Megadictyon | Introduction
The focus of Vences' work is on the amphibians and reptiles of Madagascar. He works together with Frank Glaw on many taxonomic species descriptions; together they have described over 200 new species of frogs, and numerous new species of snakes, chameleons, and other reptiles. In 1992, they produced a field guide to the reptiles and amphibians of Madagascar. In 1994 they produced a second edition of this guide, including the descriptions of numerous new taxa, and a significantly expanded reptile section. In 2007, a third edition was produced, which did not describe any new species, but included colour photographs and short text descriptions of over 100 unnamed species.
Miguel Vences | Scientific work
Note: Species listed above are presumed to be supported by all references unless otherwise cited.
List of amphibians and reptiles of Dominica | References
The even-toed ungulates are ungulates – hoofed animals – which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing posteriorly.
List of mammals of the Dominican Republic | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
latus". The third named "Amphicoelias" species, "A. fragillimus", was known only from a single, incomplete tall neural arch, either last or second to last in the series of back vertebrae. Based only on an illustration published in 1878, this vertebra would have measured tall in life. However, it has been argued that the scale bar in the published description contained a typographical error, and the fossil vertebra was in fact only tall. In addition to this vertebra, Cope's field notes contain an entry for an "[i]mmense distal end of femur”, located only a few tens of meters away from the giant vertebra.
Amphicoelias | Previously assigned species
While human tears are high in potassium, most phylogeneticists disagree with the association.
Salt gland | In reptiles
Animal species are in bold. Devonian Carboniferous
The Age of Reptiles | Species depicted
Although initially identified as a third neck vertebra, these traits supports the identification of the vertebra as coming from the rear of the neck, more specifically as being the seventh vertebra.
Hatzegopteryx | Cervical vertebrae
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Svalbard and Jan Mayen | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Paraguay | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Sudan | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Metropolitan France | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
We have at present a very few, and these perhaps highly modified, descendants of a large and diverse group of mammals."
Myrmecophagy | In vertebrates
For a full list of species, see list of reptiles of the Houtman Abrolhos.
Houtman Abrolhos | Reptiles
Crocodilians and rhynchocephalians (the latter represented solely by the tuatara, "Sphenodon") retain a quadratojugal. Turtles also seem to possess a quadratojugal. Among living amphibians, a quadratojugal is known to be present in some frogs and caecilians. However, it is notably absent in salamanders.
Quadratojugal bone | In reptiles and amphibians
Despite the jumping spider having a huge brain for its size, it is minuscule in absolute terms, and humans have a much higher EQ despite having a lower raw brain-to-body weight ratio. Mean EQs for reptiles are about one tenth of those of mammals. EQ in birds (and estimated EQ in dinosaurs) generally also falls below that of mammals, possibly due to lower thermoregulation and/or motor control demands. Estimation of brain size in "Archaeopteryx" (one of the oldest known ancestors of birds), shows it had an EQ well above the reptilian range, and just below that of living birds. Biologist Stephen Jay Gould has noted that if one looks at vertebrates with very low encephalization quotients, their brains are slightly less massive than their spinal cords.
Encephalization quotient | Comparisons with non-mammalian animals
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Guinea-Bissau | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Switzerland | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
Diamond observes in his book that this would provide food for thought to people passing this side of the bars of a cage with the label "Homo".
The Third Chimpanzee | The chimpanzee's closest relatives (part one)
The parietal eye uses a different biochemical method of detecting light from that of rod cells or cone cells in a normal vertebrate eye. Many of the oldest fossil vertebrates, including ostracoderms, placoderms, crossopterygians, and even early tetrapods, had a socket in the skull that appears to have held a functional third eye. This socket remains as a foramen between the parietal bones even in many living amphibians and reptiles, although it has vanished in birds and mammals.
Parietal eye | Anatomy
Triopticus is a genus of archosauriform reptile from the Late Triassic of Texas, United States. It contains a single species, Triopticus primus, described in 2016 by Stocker "et al". It has an unusually domed head reminiscent of the later pachycephalosaurian dinosaurs in an example of convergent evolution.
Triopticus | Introduction
Vertebrates () comprise all species of animals within the subphylum Vertebrata () (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates include such groups as the following: Extant vertebrates range in size from the frog species "Paedophryne amauensis", at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, the lampreys, do.
Vertebrate | Introduction
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Djibouti | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The following is a list of the heaviest living reptile species ranked by average weight, which is dominated by the crocodilians. Unlike mammals, birds, or fish, the mass of large reptiles is frequently poorly documented and many are subject to conjecture and estimation.
Largest organisms | Heaviest living reptiles
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of South Sudan | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
This list is extracted from the Reptile Database. Stub form in simple alphabetical order by scientific name.
List of reptiles of Kazakhstan | Introduction
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of the Democratic Republic of the Congo | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
They are thought to be the sister-group to pituriaspids, and together, these two taxa of jawless vertebrates are the sister-group of gnathostomes. Several synapomorphies support this hypothesis, such as the presence of: sclerotic ossicles, paired pectoral fins, a dermal skeleton with three layers (a basal layer of isopedin, a middle layer of spongy bone, and a superficial layer of dentin), and perichondral bone. Most osteostracans had a massive cephalothorac shield, but all Middle and Late Devonian species appear to have had a reduced, thinner, and often micromeric dermal skeleton. This reduction may have occurred at least three times independently because the pattern of reduction is different in each taxon.
Osteostraci | Introduction
This is an incomplete list of prehistoric mammals. It does not include extant mammals or recently extinct mammals. For extinct primate species, see: list of fossil primates.
List of prehistoric mammals | Introduction
Through the study of the lightly differentiated castings of the portions of the brain, it was assumed that D. Patagonica was a terrestrial reptile due to the level of development of the olfactory sensory bulb within the casted brain.
Dinilysia | Theories of Origin
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of El Salvador | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.
List of mammals of Tajikistan | Order: <a href="Artiodactyla">Artiodactyla</a> (even-toed ungulates)