Snakes

The term snake are commonly called the reptiles belonging to the suborder Serpentes (or Ophidia). The phylogeny of snakes is closely related to that of lizards (the common name for members of the suborder Sauria reptiles), with whom are the order of Squamata.
The fossil record of snakes are relatively scarce, because of their fragile skeletons that are rarely fossilized. The oldest fossils attributed to snakes date from around 110 million years ago (Lapparentophis) and have been found in North Africa. It is believed that snakes are descended from these ancient animals in the group of lizards, probably forms excavators and underground habits (as suggested by some fossil remains). He knows a form of the Late Cretaceous, Najash rionegrina, which was equipped with two rear legs and sacrum, presumably was a fully terrestrial animal burrows dug in the ground.
The burrowing snakes probably evolved elongated bodies and lost their legs to adapt to an underground habitats. For this reason, moreover, also developed and transparent eyelids fused, as well as the absence of external ears, to avoid damaging the cornea and bring the land into your ears.
Other fossils from the Cretaceous snakes (Haasiophis, Pachyrhachis, Eupodophis), found in strata slightly older than those of Najash, were equipped with hind legs, but were clearly marine forms and the legs were not fully articulated with the pelvis. In the Late Cretaceous, however, were similar to those already existing snakes (Dinilysia), along with giant forms from the uncertain location (Madtsoiidae).
Currently there are several groups of primitive snakes such as pythons and boas, which still have vestigial legs, used exclusively to hold the female mating.
Another hypothesis on the origin of snakes suggests that they were close relatives of the Mosasaurs, large marine lizards of the Cretaceous (also derived from Varanoidea). In this case, the transparent lids and cast would be developed to cope with potentially harmful marine conditions, while the external ears were missing due to a lack of use, according to this hypothesis, the snakes were originally marine animals, which later colonized the land . Pachyrhachis fossils and the like testify the correctness of this hypothesis.
The great diversity of modern snakes began in the Paleocene, after the demise of the dinosaurs, and together with the adaptive radiation of mammals. In this period are known aquatic forms (Palaeophis, Pterosphenus) and giant (Titanoboa, Gigantophis), developed through a hot and humid climate.


The largest known prehistoric snake is Titanoboa cerrejonensis, estimated at 13–15 metres (43–49 ft) in length and 1135 kg - 1819 kg in weight.

Titanoboa, meaning "titanic boa," is an extinct genus of snake that lived approximately 60–58 million years ago, during the Paleocene epoch a 10-million-year period immediately following the dinosaur extinction event.The only known species is Titanoboa cerrejonensis, the largest, longest, and heaviest snake ever discovered,which supplanted the previous record holder, Gigantophis.
In 2009, the remains of the snake found in Columbia measured about 43 ft. But according to other sources, it was found out that Titanoboa measured even longer.
By comparing the sizes and shapes of its fossilized vertebrae to those of extant snakes, researchers estimated that the largest individuals of T. cerrejonensis found had a total length of around 15.2 m (50 ft), 1.1m(3.4ft) wide and weighed about 1,155 kg (2,500 lb; 1.1 long tons).
In 2009, the fossils of 28 individual T. cerrejonensis were found in the Cerrejуn Formation of the coal mines of Cerrejуn in La Guajira, Colombia.Prior to this discovery, few fossils of Paleocene-epoch vertebrates had been found in ancient tropical environments of South America.The snake was discovered on an expedition by a team of international scientists led by Jonathan Bloch, a University of Florida vertebrate paleontologist, and Carlos Jaramillo, a paleobotanist from the Smithsonian Tropical Research Institute in Panama.
Because snakes are ectothermic, the discovery implies that the tropics, the creature"s habitat, must have been warmer than previously thought, averaging approximately 30 °C (90 °F).The warmer climate of the Earth during the time of T. cerrejonensis allowed cold-blooded snakes to attain much larger sizes than modern snakes.Today, larger ectothermic animals are found in the tropics, where it is hottest, and smaller ones are found farther from the equator.
However, several researchers disagreed with the above estimate. For example, a 2009 study in the journal Nature applying the mathematical model used in the above study to an ancient lizard fossil from temperate Australia predicts that lizards currently living in tropical areas should be capable of reaching 33 feet, which is obviously not the case.
In another critique published in the same journal, Mark Denny, a specialist in biomechanics, noted that the snake was so large and was producing so much metabolic heat that the ambient temperature must have been four to six degrees cooler than the current estimate, or the snake would have overheated.

Madtsoiidae
Patagonian Giant Snake - Madtsoia bai

 
Another known very large fossil snake is Gigantophis garstini, estimated at around 10–11.6 metres (33–38 ft) in length.



Gigantophis garstini was a giant prehistoric snake which may have measured more than 10 metres (33 ft),larger than any living species of snake. Before Titanoboa was discovered in Colombia in 2002, Gigantophis was regarded as the largest snake ever. Gigantophis lived approximately 40 million years ago in the northern Sahara, where Egypt and Algeria are now located.
The species is known only from a small number of fossils, mostly vertebrae.
Gigantophis is classified as a member of the madtsoiid family.
Jason Head, of the Smithsonian Institution in Washington, D.C., has compared the fossil vertebrae of a Gigantophis to those of the largest modern snakes, and concluded that the extinct snake could grow from 9.3 metres (31 ft) to 10.7 metres (35 ft) in length. If 10.7 metres (35 ft), it would have been more than 10 percent longer than its largest living relatives. This species was once thought to be the largest species of snake in Earths history, but was later replaced by the Titanoboa.


Wonambi

At 6 to 9 meters long, Wonambi would have been able to tackle any small to medium sized animal it chose. The Aboriginal people living in Australia at the same time as Wonambi were certainly aware of the presence of large snakes and indeed warned their children about going to watering holes alone. This was a very sensible precaution as Wonambi"s hunting method seems to have been to frequent watering holes where it knew that it was only a matter of time before its prey came to it.
Wonambi was a constrictor which means that it did not use venom but instead wrapped itself around its prey and tightened its grip so that its prey could not breathe in. Another theory however is that the pressure of the snake squeezing the chest actually causes cardiac arrest (where the heart stops beating). No matter how exactly the prey dies, death still comes quickly and as anyone who"s ever been on the wrong side of a large python will tell you, there is not a lot you can do to stop its grip.
Once Wonambi was sure its prey was dead it would them clamp its jaws over its prey, probably head first, and then start sliding its prey down its throat. Reconstructions of Wonambi reveal it to have sharp recurved teeth that when bitten into prey would stop the animal from sliding out of Wonambi"s mouth. This way Wonambi could slowly slide itself over its victim like an anaconda does today.
Despite its killing efficiency Wonambi probably could not tackle larger animals due to the small size of its skull. In addition to this the jaw is also not thought to have been capable of being fully disarticulated like in some snakes that we see today. These restrictions meant that even the larger examples of Wonambi would have had to choose their prey carefully.
Wonambi was just one member of the Madtsoiidae group of prehistoric snakes, some of which such as Madtsoia seem to have grown to truly giant sizes. Another Australian snake of this group is Yurlunggur.

 
Yurlunggur

Yurlunggur is another representative of the madtsoiid group of prehistoric snakes. Yurlunggur was a constrictor which means it coiled around its prey and squeezing it to death. One thing that makes Yurlunggur stand out from other snakes related to it is the fact it has perhaps one of the most completely preserved skulls so far recovered. This skull came from a fresh water area, suggesting that Yurlunggur may have lurked in the water while hunting its prey.

 
However, a close rival in size to Gigantophis is a fossil snake, Palaeophis colossaeus, which may have been around 9 metres (30 ft) in length.

Pterosphenus (above),Palaeophis (below)
Palaeophis ("ancient snake") is an extinct genus of marine snake whose fossils have been found in England, France, Denmark, Morocco and Mali,dating back to the late Paleocene and Eocene epochs. The species P. colossaeus, known from a single vertebra, was originally estimated to exceed 9 m (30 ft) in length, making it one of the largest known snakes, however most species of the genus were not as big (e.g. P. casei being slightly over one metre).
Palaeophis, like most members of its clade, was a specialised aquatic animal, occurring mostly on marine sites, though at least some estuarine remains have also been found. Its known species varied broadly in size; Palaeophis casei is the smallest at 1.3 metres of length, while Palaeophis colossaeus is the largest at the estimated size limits for the genus at over 9 m. Likely, individual species occupied a vast variety of ecological niches.Studies on Palaeophis vertebrae show a high degree of vascularisation, suggesting that it had a considerably faster metabolism and growth rate than modern snakes. This may suggest that palaeophiids, like other marine reptiles such as mosasaurs, might had developed towards endothermy.
Pterosphenus schucherti is known from coastal regions from New Jersey to Texas. The vertebrae are narrow, lightly constructed (have large marrow cavities), and long neural spines suggesting this snake was not capable of locomotion on land. Hutchinson (1985) reports remains from Florida that were associated with whale remains and were probably deposited more than 300 km from land in the Middle Eocene. Holman (2000) suggested this large sea going snake drank sea water, had salt glands, and had a life style similar to modern sea snakes. He reports the length of the largest vertebrae was 24 mm, assuming 270 vertebrae this snake may have exceeded 6 m.

Crotalus giganticus