Silurian

The Silurians, also known as Earth Reptiles, Eocenes, Psionosauropodomorpha, Homo Reptilicus and Homo reptilia were a species native to Earth that pre-dated humanity. Technologically advanced, they lived alongside their aquatic cousins, the Sea Devils. Unlike other species, Silurians showed an important intraspecific variation, with vast differentiation between breeds, such as the number of eyes, the formation of their pupils and the colour of their skin.

Physical appearance
The Silurians were an extremely varied species, with different subspecies and appearances; there were at least ten or eleven Silurian variations. Whilst many of them appeared similar, there were subtle differences which were attributed to caste. There were also clans or families with differentiated physical characteristics, some suited for environments of extreme cold or high plateaus. (PROSE: The Scales of Injustice) In general, they were humanoid reptilians with scaly crests on their head.


 * One group of Silurians was found at Wenley Moor; these had long fingers and three webbed toes on each foot, and their mouths were small and sucker-like. The most noticeable feature of these Silurians were their three eyes. Their main eyes were bright yellow with cat-like pupils, while their third eye was red and high on the forehead, surrounded by a fluted bone structure. They also had rectangular external ears. They were active creatures who spoke quickly in deep voices. (TV: Doctor Who and the Silurians). A tribe fitting this description also lived under the Galapagos Islands. (AUDIO: Bloodtide)
 * Another group was found at Sea Base 4. They looked similar to those of Wenley Moor, but had stockier builds, brown skin, suckers on the tips of their fingers, smaller mouths, ornate, curving spikes around their heads and the third eye on top. The third eye would glow along with their speech, but was not used in attack. They were also slower and spoke in a higher-pitched voice. (TV: Warriors of the Deep)
 * A third tribe, found in Wales, was radically different in appearance. They had only two eyes, more human faces, no external ears, five digits on each hand and crests on their heads and down their neck. They had long tongues which they could flick to inject a venom, which was mutagenic to humans. They moved and spoke much like humans. (TV: The Hungry Earth/Cold Blood) This tribe also appeared to have extended into the London area as well, with the colony Madame Vastra belonged to having been uncovered during an expansion to the London Underground. (TV: A Good Man Goes to War, TV: Vastra Investigates)

There were also distantly related to the Sea Devils. (TV: The Sea Devils) They were genetically divergent enough to create problems for the offspring of matings with Silurians. Offspring suffered from biological problems including sterility and a shorter lifespan, due to cellular degeneration. (PROSE: The Scales of Injustice)

Some Silurians become darker green when blushing. (TV: The Name of the Doctor)

In at least one alternate reality, there was a human-Silurian hybrid. This demonstrated that mating between the two was possible. (PROSE: Spiral Scratch)

Anatomy
Silurians were and could only survive at warmer temperatures. They were sluggish and slow when cold. (PROSE: Blood Heat, TV: The Hungry Earth)

Silurians had a hunter's anatomy, with powerful muscles and hollow bones. Though they were taller than humans, they were also lighter and faster. Silurians were incapable of crying. (PROSE: Blood Heat) The typical lifespan of a Silurian was 200 to 250 years, (PROSE: The Scales of Injustice) though some lived up to 300 years (TV: Cold Blood).

Silurians had an organ analogous to the human. (PROSE: Burning Heart) They had a greater lung capacity than a human. (TV: Deep Breath)

Third eye
Most Silurians possessed a third eye on the forehead. The three eyes provided them with a triple-faceted form of vision. (TV: Doctor Who and the Silurians)

The third eye also allowed them to use a variety of telepathic powers. The Silurians used their third eyes to communicate with other Silurians in a process known as "linking". The third eye would glow along with their emotions, becoming brighter when they were angry. They could sense the presence of other Silurians, even at great distances. Silurians could control the minds of other creatures. (PROSE: Blood Heat) They could hypnotise and coerce humans through a link to a primal part of a subject's mind, though stronger wills could resist this control. (AUDIO: Bloodtide)

The third eye was capable of harming organic beings, killing them or leaving them unconscious. Alternatively, they could revive a human that they had rendered unconscious with the third eye. Energies emanating from it allowed them to burn through walls and create tunnels. (TV: Doctor Who and the Silurians, PROSE: Blood Heat)

The Silurians also employed their third eye in less destructive tasks, such as activating their technology, opening passageways or creating forcefields to trap prisoners. (TV: Doctor Who and the Silurians)

Not all Silurians had these third eyes; a tribe found in Wales did not. (TV: The Hungry Earth/Cold Blood)

Culture
The Silurians were generally a peaceful race. Their highest laws forbade outright warfare except for defence. (TV: Warriors of the Deep) There was also great importance placed on the species' pure eugenics, which was believed to be their most important principle and most sacrosanct belief. Breeding between a Silurian and a Sea Devil was considered a crime punishable by death. The eggs of such a union were usually crushed and the parents executed. (PROSE: The Scales of Injustice)

The Silurians were generally led by a Triad, three Silurians who ruled jointly. (TV: Warriors of the Deep, The Hungry Earth/Cold Blood) These Silurians came from different backgrounds and controlled different professions, such as the military and the scientists. Silurians were also split into different tribes. (TV: The Hungry Earth/Cold Blood) The majority of Silurian warriors appeared to be female, just as the females were the more aggressive in some species of lower reptile. (TV: Cold Blood, A Good Man Goes to War)

Silurians communicated by telepathically linking through their third eyes, as well as by body language. Though they could use words, they generally only used speech for effect, when talking to children or to species without telepathic linking abilities. Silurians had little in the way of literature, since their mind linking abilities were a more effective method of transferring ideas. (PROSE: Blood Heat)

A Silurian of advanced age would festoon the third eye with pearls as a form of decoration. (PROSE: Blood Heat) Some Silurians kept early hominids as pets. (PROSE: Doctor Who and the Cave-Monsters) Whilst in the future, some used the term Earth Reptiles, others called themselves Silurians, insisting those that accepted the name of Earth Reptiles were pathetic assimilationists. (PROSE: Burning Heart)

They worshipped a Lizard God. (PROSE: The Crystal Bucephalus) Their myths included Urmungstandra, a devil god (PROSE: The Taking of Planet 5) and the Great Old Ones, including in their ranks Azathoth, a deity revered by the Silurians long before the rise of humanity. (PROSE: All-Consuming Fire) They wrote the Necronomicon. (PROSE: White Darkness) Madame Vastra swore by a Goddess. (TV: The Name of the Doctor, Deep Breath)

Humans
The Silurians did not think much of humans, considering them to be mere monkeys and despising them for destroying the terrestrial environment. (TV: Cold Blood)

Humans had an instinctive fear of Silurians, known as the race memory malaise. (PROSE: Blood Heat)

Technology
The Silurians made many advancements unknown to the humans.

Genetic modification
The Silurians had advanced genetic capabilities. They brought species back from extinction, including many dinosaurs. (PROSE: Blood Heat) They could modify species, as they did with the Myrka. (TV: Warriors of the Deep) They created a genetically engineered plague, which they once used against early humans who invaded their crop settlements. This disease was highly virulent and was used as a form of "pest control". (TV: Doctor Who and the Silurians) Despite this, they had problems with Silurian/Sea Devil hybrids' deficiencies. (PROSE: The Scales of Injustice) They also altered primitive apes to make them breed more often and to improve their flavour when eaten; using these techniques, they ultimately ended up creating the ancestors of humanity. (AUDIO: Bloodtide)

The Silurians processed their own food and didn't rely on harvesting animals or plants (PROSE: The Scales of Injustice) except in times of famine. (PROSE: Blood Heat) The Silurians could bio-program soil, causing it to react to certain events and respond, generally by dragging people underground. (TV: The Hungry Earth)

Medicine
They were capable of advanced decontamination, removing diseases and poisons from the body. (TV: Cold Blood)

Weaponry
Silurians generally relied on their third eye for defensive purposes, using technology to enhance their power. (PROSE: Blood Heat) They used a Battlecruiser for transportation and offensive purposes. (TV: Warriors of the Deep)

The Silurians found in Wales used guns reminiscent of Sea Devil guns which could fire fatal energy beams. They also wore armour and used special masks that covered their faces and allowed them to scan objects. (TV: The Hungry Earth / Cold Blood)

Miscellaneous technology
Silurians had cryogenic technology which they used to preserve their civilisation when they believed the Earth was in danger. (TV: Doctor Who and the Silurians) These had alarms for when the colony was threatened. (TV: The Hungry Earth/Cold Blood)

They could use gravity bubbles to travel to and from the surface. (TV: The Hungry Earth/Cold Blood) They also had mechanical airships, which Bernice used and found to be of high quality. (PROSE: St Anthony's Fire) They had some holographic technology. (PROSE: The Scales of Injustice)

They could modify the atmosphere, increasing the temperature in certain areas. (PROSE: Blood Heat) They had the ability to disperse the Van Allen belt using a molecular disperser, which would have left Earth defenceless against cosmic radiation in an attempt to exterminate humanity. (TV: Doctor Who and the Silurians)

Silurians could create force fields to trap an entire village, controlling the amount of light that got in (effectively making it night). (TV: The Hungry Earth) They also had wrist devices, (TV: Warriors of the Deep) and flew in aeroplanes (PROSE: Doctor Who and the Cave-Monsters) and sophisticated spaceships. (TV: Dinosaurs on a Spaceship)

They invented candles which could induce lucid dreams, allowing people to communicate across time and space. (TV: The Name of the Doctor) They used sonic lanterns to corral dinosaurs. (TV: Deep Breath)

Dominance
The Silurians were the original masters of Earth. (TV: Doctor Who and the Silurians) They were led by the Triad and used the Sea Devils as soldiers. (TV: Warriors of the Deep) In the early era of their rule, there were many stories of the rise of their civilisation. One noted legendary warrior chieftain was Masz K'll of the Third Dynasty, who fought against his evil alter-ego, the legendary Two-Faced Lizard. Another figure was Panun E'Ni, who was the leader of the Southern Clan and conquered much of the world, which he ruled cruelly for a brief period until his defeat at the hands of Tun W'lzz. Following that event, the previously imprisoned and cast out tribes came together in a new, more unified civilisation that ate their foes. Whether these were folk stories or historical facts was of no importance to them, as they inspired the Earth Reptiles for a millennium, with many of these writings left within their Hall of Heroes. (PROSE: The Scales of Injustice)

In this era, the Silurians co-existed in groups of clans that lived alongside the original ape primitives that were developing on their planet. As a lesser species, these hominids became the primary livestock of the Silurians. In order to improve their flavour, a Silurian scientist by the name of Tulok began to genetically engineer the apes. This led to a faster breeding cycle as well as intelligence, creating early Homo sapiens. For his genetic crimes, the Silurians banished Tulok and his creations to die in the coming cataclysm. (AUDIO: Bloodtide) These primitive, ape-like men began to hunt in packs and attacked the Silurians. (COMIC: Twilight of the Silurians) They also began to prey on the crops of the Silurians, leading the Earth Reptiles to use plagues to exterminate them. (TV: Doctor Who and the Silurians) The Silurians were also afflicted by the plagues of the red leech. (TV: The Crimson Horror)

At the height of their civilisation, the Silurians lived in cities of metal millions of years old, and had uncontested dominion over the planet. However, this era was cut short. Some of their scientists, such as Doctor Wolik, believed that a small planetoid was destined to crash into their world. Some Silurians doubted this coming disaster; a few believed it to be a simple scare story. (COMIC: Twilight of the Silurians) Other scientists instead calculated that the planetoid would "sweep by Earth", (PROSE: Doctor Who and the Cave-Monsters) drawing off its atmosphere and wiping out "all life". (TV: Doctor Who and the Silurians) Eventually, the Silurians panicked. They entered hibernation units so their civilisation could survive the coming disaster and reclaim their world once the danger had passed. (TV: Doctor Who and the Silurians, COMIC: Twilight of the Silurians)

One group of Silurians decided to leave Earth in order to escape the disaster. Boarding the Silurian Ark, a spaceship carrying Silurians and several species of dinosaur, they placed themselves in suspended animation, with the ship programmed to bring them back to Earth long after the effects of the upcoming disaster had dissipated. (TV: Dinosaurs on a Spaceship)

Twelve years before the large planet came dangerously close to Earth, the Silurians were divided on the matter of a mating between the land castes and aquatic castes. Normally, such matings were forbidden, and any offspring were killed along with their parents. However, facing the threat of a global cataclysm, they allowed a colony of such hybrids to remain in their Shelter near Smallmarshes. With the rest of the Silurian race, they took part in the Great Hibernation. (PROSE: The Scales of Injustice)

The panicked Silurians sealed themselves in their underground hibernation units, (TV: Doctor Who and the Silurians) along with a male and female of all the more useful reptile animals, (PROSE: Doctor Who and the Cave-Monsters) and planned to suspend their lives until the atmosphere returned, (TV: Doctor Who and the Silurians) by using a device on the ground above each shelter containing the hibernation units which would automatically trigger a massive amount of electricity to wake the Silurians once the atmosphere returned to normal. (PROSE: Doctor Who and the Cave-Monsters) However, they were unaware the dangerous planetoid that they predicted would draw away the atmosphere was instead drawn into Earth's and became the Moon. As a result, the Silurians were never revived, as the atmosphere was not drawn away for it to return to the planet. (TV: Doctor Who and the Silurians) Although the atmosphere was never completely drawn off and the creatures on the surface did not suffocate, many mammalian life forms perished, while others survived, due to the great forces caused by the Moon's appearance creating cyclones and tidal waves. (PROSE: Doctor Who and the Cave-Monsters) During millions of years of hibernation, the reactivation machinery of the hibernation units deteriorated. (TV: The Sea Devils)

Despite their intentions to punish Tulok, the renegade Silurian scientist instead sabotaged a number of the hibernation chambers and destroyed them. (AUDIO: Bloodtide)

The Arkive tried to attract the Silurians to Saturn in order to repair itself. Though the Silurians noticed one of Saturn's moons being destroyed, they were too busy preparing for the disaster to investigate. (PROSE: The Wheel of Ice)


 * The time of this rule has never been consistently dated.

Awakenings
Over the millions of years since their rule, many of the Silurians' prominent structures such as the Hall of Heroes were lost to erosion and plate movement which erased any traces of their ancient civilisation. (PROSE: The Scales of Injustice) After millions of years, some of the Silurian hibernation units were activated and opened.

In 102, a number of Silurians were part of the Alliance of the Doctor's worst enemies that imprisoned the Eleventh Doctor in the Pandorica. (TV: The Pandorica Opens)

Charles Darwin and the HMS Beagle expedition, along with the Sixth Doctor and Evelyn Smythe, encountered a rogue Silurian group in the Galapagos Islands. The leader of this group was Tulok, responsible for creating humanity's prehistoric ancestors via a forbidden breeding program. (AUDIO: Bloodtide)

Prior to 1888, a group of Silurians was awoken by the digging of the London Underground. This led to the death of several navvies. Vastra, a skilled Silurian warrior who had been awoken by their digging, wanted revenge. The Doctor convinced her to live peacefully in London. In 1888 she resided with her human partner Jenny, although she fed on human criminals. Then, she and several of her soldiers were called up by the the Doctor to fight at the Battle of Demon's Run. (TV: A Good Man Goes to War)

In 1892, the Silurians led by their leader Vekkis found a piece of the Eternity Clock to reclaim Earth. They planned to use the power of the Clock to pump toxin to wipe out the human race. The Eleventh Doctor and River Song destroyed the toxin and took the Eternity Clock. (GAME: The Eternity Clock)

Jules Verne and the Doctor once encountered Silurians and a giant squid. This incident was worked into 20,000 Leagues Under the Sea, though the Doctor had some difficulties convincing Jules to remove the parts with the Silurians. (PROSE: Peacemaker)

In 1903, after receiving a wealth of information from the future, Grigori Rasputin saw beings which lived beneath the surface of the Earth. (AUDIO: The Wanderer)

In the late 20th century a group of Silurians were awakened from hibernation by the energy from the nearby nuclear power research centre at Wenley Moor. After disagreement between Okdel and Morka over a course of action, Morka won out, killing Okdel, and the Silurians tried to reclaim the planet from humanity by releasing a deadly virus. This plan was prevented by Dr Liz Shaw of UNIT and the Third Doctor, when they had the cure mass produced. After this plan was thwarted, they tried using their molecular disperser to destroy Earth's van Allen belt, so that the sun's radiation would burn the humans to death while allowing the cold-blooded Silurians to survive, but Liz and the Doctor stopped them again when they overloaded the disperser and the facility's reactor. Despite the Doctor's best efforts to broker a peaceful solution, the Silurian base was bombed by UNIT by order of Brigadier Lethbridge-Stewart. (TV: Doctor Who and the Silurians) Shortly afterwards, a second base was awoken in Oregon, and was likewise dealt with by UNIT. (PROSE: The Devil Goblins from Neptune) A different base of Silurians was found in the Smallmarshes. This group consisting of hybrids born of unions between Silurians and Sea Devils. They too wanted to take back the Earth. There was a power struggle until The Third Doctor managed to ensure that this shelter was left in peace and there was an end to the fighting. (PROSE: The Scales of Injustice)

In 1983, Sarah Jane Smith and K9, while visiting Warren Martyn's archaeological expedition in Egypt, discovered an underground city of Silurians and Sea Devils. Sarah Jane opened diplomatic relations with them. On her return to England, she contacted the Brigadier, who wished to make amends for his earlier mistakes. (COMIC: City of Devils)

By 2003 there were Silurians serving as part of UNIT, in particular Imorkal, who worked with Liz Shaw at Tranquillity Moonbase located on Earth's Moon. (PROSE: Eternity Weeps) Some years later, Sir Alistair helped the Silurians try to finally make peace with the humans, though the general public believed it to be a stunt involving men in rubber suits. (AUDIO: The Coup) Later, the Silurians aided UNIT in finding a cure for a plague. (AUDIO: The Wasting)

In late 2010, a fossilised Silurian egg was discovered by the Pharos Institute. Sarah Jane went to the institute to take a look at it. (TV: Sarah Jane's Alien Files episode 6)

In the 2010s, a Silurian was a resident of the hidden trap street in London which housed lost aliens on Earth under the protection of Mayor Me. As with the rest of the inhabitants it appeared cloaked in human form through use of the lurkworms. (TV: Face the Raven)

In 2020, a Silurian city in Wales was awoken by a mining trial led by Nasreen Chaudhry and Tony Mack. The Silurians took corpses from a graveyard for study, as well as Mo Northover and later Amy Pond as living subjects. Eventually they contained the village in a force field and captured Elliot Northover. Alaya came to the surface and was captured. While the Eleventh Doctor and Nasreen travelled to the Silurian city to negotiate her return for Mo, Elliot and Amy, Alaya was guarded by Tony, Rory Williams and Ambrose Northover. The Eleventh Doctor and Nasreen were captured, while Amy and Mo escaped. After an abortive rescue attempt, the Doctor was able to convince the Silurian leader, Eldane, to negotiate with Amy and Nasreen for the future of both their races. Back on the surface, Ambrose tried to help her family and threatened Alaya, accidentally killing her just as the group were summoned to the city. Alaya's death was received badly, especially by her sister, Restac, who tried to kill all the humans in retribution. Eldane managed to lead the Doctor and his friends to a laboratory. He released a deadly gas into the city, forcing Restac's troops to return to their hibernation. The timer was set for a thousand years, to permit a second chance at negotiation. (TV: The Hungry Earth/Cold Blood)

Circa 2084, a group of Silurians allied themselves with the Sea Devils to invade Sea Base 4. They attempted to launch nuclear weapons to provoke a war between the two major power blocs. They were killed when the Fifth Doctor, perceiving no more peaceful option, flooded hexachromite gas in order to kill them. (TV: Warriors of the Deep)

Post-contact
At some point after the 2084 incident, a human colony faced a devastating war against the Earth Reptiles. Humans developed a doomsday device which they placed in a base around the moon colony, designed to scour the surface of the satellite. To combat this, the Earth Reptiles dispatched Quarra to infiltrate the base and take it over. However, she was unaware of an entertainer called Jen Yates who was not on the crew count, and this last survivor managed to activate the weapon, killing everyone in the colony. Though Quarra killed Jen, the shock of the event led to Quarra taking on the entertainer's personality to shield her from the truth. She believed that she was now human and that she was guarding the weapon alone in case the Earth Reptiles won the war. After a visit by the Seventh Doctor, Quarra remembered the past and killed herself by walking onto the surface of the moon without a spacesuit. (PROSE: Cold War)

Around the 24th century, Solomon sent a distress signal to the Silurian Ark. Realising that there were valuable dinosaurs on board, he and his robots killed the Silurians on board. Unable to pilot the ship to his destination, the ark headed back to Earth. (TV: Dinosaurs on a Spaceship)

By the 26th century, the inter-species conflicts appeared to have come to an end. Silurians and Sea Devils were accepted into Earth society, and the term "Earth Reptile" was apparently popularised among humans. (PROSE: Love and War)

During the 29th century, when solar flares were threatening to engulf the Earth, the Silurians built a spacecraft, surreptitiously attaching it to the bottom of the humans' own. After takeoff, a Dalek attack caused the Silurian ship to break away from the humans. (GAME: Evacuation Earth)

In the 30th century, the Earth Reptiles were part of the Earth Empire, considered full members of the government as an Earthborn species. (PROSE: So Vile a Sin)

In the year 3020, one thousand years after the encounter at Cwmtaff, Eldane's clan were scheduled to reawaken and unite with humanity and their Earth Reptile cousins. (TV: Cold Blood)

In the 32nd century, it became illegal to trade in Earth Reptile pituitary analogue extract on the planet Dramos. (PROSE: Burning Heart)

In 3110, a Silurian was running the Musée d'Orsay when the Eleventh Doctor visited it. (PROSE: The War of Art)

Around the 52nd century, a group of armed Silurian warriors resembling those from Wales were called upon by the Eleventh Doctor to help him in the Battle of Demon's Run to rescue Amy Pond. Many of these Silurians were killed by the Headless Monks. (TV: A Good Man Goes to War)

In the 91st century, a Silurian actor starred as the protagonist of a film adaptation of H. G. Wells' The Time Machine spoken in haiku. (PROSE: Synthespians™)

In the 101st century, the Earth Reptiles were part of the Union. (PROSE: The Crystal Bucephalus)

Undated events

 * At least one Silurian (similar to the Welsh tribe) was abducted and sent to face their fear in the Minotaur's Prison Ship. (TV: The God Complex)
 * attempted to kill the Doctor's ally the Graak with a group of Silurians. (GAME: Destiny of the Doctors)
 * Silurian Arks were present above Trenzalore when they were drawn there by the First Question. They retreated or burned during the Siege of Trenzalore when the Daleks broke through the planetary force field of the Papal Mainframe and intense fighting began. (TV: The Time of the Doctor)
 * The Silurians were once part of the Alliance of Races led by Rassilon in a war against the Hyperion and Count D'if of the Cybock Imperium. (COMIC: Terrorformer, Gangland)
 * A Silurian was at Florana when the Eleventh Doctor, Amy, and Rory went there for their summer holiday. (COMIC: Summer Wholiday)
 * A dead Silurian was seen on a battlefield. A Corvid fed on its mind. (COMIC: The Highgate Horror)

Alternative histories

 * In one alternative version of the 1970s, the Third Doctor having died during the Wenley Moor incident, the Silurians ruled Earth unchecked. They reintroduced dinosaurs into Earth's ecosystem and reduced the surviving humans into powerless scavengers. (PROSE: Blood Heat)
 * Another alternative history branched out from the same incident. In this timeline, the Third Doctor and the Brigadier died during the same incident. However the Silurians, Sea Devils and humans now lived in peace under the URIC or United Races Intelligence Command, formerly known as UNIT. (COMIC: Final Genesis)
 * In an alternate timeline created by the Black Guardian where the First Doctor never left Gallifrey, and became Lord President, the Silurians and the Sea Devils fought over Earth with a number of alien invaders such as the Zygons, the Ice Warriors and the Sontarans. This timeline was destroyed when the Seventh Doctor retrieved the Key to Time. (COMIC: Time & Time Again)
 * In a world where all of history occured at once, Silurians lived alongside humans. Malokeh served as physician to the Holy Roman Emperor, Winston Churchill. (TV: The Wedding of River Song)

Parallel dimensions
When Avalon was created as a shelter for the Catuvellauni, some Silurians were unintentionally brought there as well. Their descendants were known as the Fair Folk. (PROSE: The Shadows of Avalon)

The Silurians of Mondas
There were believed to be Silurians and Sea Devils on Mondas as well as Earth (much as humans and the Mondasians were identical). These Lizard Kings worshipped Golgoth, a primordial god-figure, who resembled a gigantic Silurian crossed with a Sea Devil. (COMIC: The Cybermen: The Dead Heart)

Dating issue
The era of the Silurians have never been consistently or clearly dated.
 * In the television story Doctor Who and the Silurians, the Silurians were seen to have a globe from some point before the of 200 million years ago, which was the late . In the same scene, the Third Doctor discovered calculations about the age of the Earth inside Dr Quinn's office with particular reference to the  (roughly 440 million to 415 million years ago).
 * Narration in the novelisation Doctor Who and the Cave-Monsters mentions that the sunset Okdel sees before going into hibernation was "the last time he was to see the sun for a hundred million years".
 * The Third Doctor mused in the television story The Sea Devils that the (roughly 55 million to 35 million years ago) would have been a more accurate dating, although this was after the dinosaurs (which the Silurians were shown using) were believed to have become extinct.
 * In the television story The Hungry Earth, the Eleventh Doctor told Alaya that she was "300 million years outside of your comfort zone," which would place them around the late, although later in the same episode he referenced that they were sometimes called Eocenes.
 * In the television story Dinosaurs on a Spaceship, the dinosaurs in the Silurian Ark are native to the . On the other hand, the novel Blood Heat shows the Silurians bringing back extinct species from numerous time periods.
 * Silurians tended to make references to early apes, which are believed to have evolved at some point between 40 to 15 million years ago, or the late Eocene to the . Mammalian pets of the Silurians, which eventually evolved into humans, are also depicted in the prologue of the Doctor Who and the Cave-Monsters novelisation.
 * The novel The Quantum Archangel suggests that the Moon was orbiting the Earth before 150 million years ago, which means the Silurians ruled before the.
 * The novel The Wheel of Ice states that the Silurians were preparing for the disaster 50 million years ago, again placing them in the Eocene.
 * However, the television story Kill the Moon (set in 2049) has the Twelfth Doctor describe the Moon as a "little planetoid that's been tagging along beside [the human race] for a hundred million years", which would mean the Silurians placed themselves into suspended animation during the Cretaceous period.
 * The television story The Crimson Horror has a species from the same era, the red leech. Madame Vastra states that she last saw one 65 million years before 1893, while the Eleventh Doctor plans to return it to the Jurassic period.
 * In the comic story The Crystal Throne, Madame Vastra tells Lady Cornelia Basildon-Stone that she learnt to fight while the human race "still had tails".
 * The bookazine TEDW 5 claims the Silurians ruled during the late Cretaceous era, and the planetoid that approached the Earth caused the Silurian Ark to leave Earth, and the Silurians that were left behind to hide to go into hibernation, "circa 65,000,000 BC".

Naming issue
Another name given in Blood Heat, Psionosauropodamorphae, translates as psychic lizard-foot shaped. This may be intended to suggest a connection between the Silurians and the sauropod family of dinosaurs, though this seems unlikely given the near-total lack of physical resemblance and the comparatively small cerebral capacity of most sauropod dinosaurs. Homo reptilia, one of the suggested names used in Doctor Who and the Cave-Monsters, City of Devils, The Hungry Earth / Cold Blood and Dinosaurs on a Spaceship, cannot be a scientific term. The rules governing the use of prevent any two separate groups within a kingdom (i.e. animals) from using the same genus.

References in other media

 * The Alan Moore graphic novel series refers to lizard-men called Silurians and Sea Devils and retcons  as one of the latter.
 * The Sea Devils and Silurians are shown as the original inhabitants of Earth in the steampunk graphic novel, which takes place in a world in which H.G. Wells' The War of the Worlds actually occurred.

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