The most ancient reptiles. The oldest reptile is the three-eyed lizard, the tuatara (sphenodon punctatus)
Task 1. Write down the numbers of correct statements.
Assertions:
1. The most ancient animal among modern scaly ones is the tuatara.
2. All reptiles eat animal food.
3. All reptiles swallow food whole.
4. Snakes are non-venomous snakes.
5. The ancestors of snakes had limbs.
6. The shell of turtles is fused with the spine and ribs.
7. All extinct ancient reptiles were gigantic in size.
8. Crocodiles have mixed blood, although their heart is four-chambered.
9. Lungs in reptiles are large-meshed, like in amphibians.
10. Inhalation and exhalation in reptiles leads to the raising and lowering of the wall of the floor of the oral cavity.
11. Lizards and snakes belong to the Scaly order.
Correct statements: 1, 4, 5, 6, 8, 11.
Task 2. Why it is necessary to protect all the snakes. Why are reserves and sanctuaries organized to protect crocodiles? Provide reasonable answers.
Snakes kill insects and small rodents.
They protect and grow snakes for the sake of poison, which is used in medicine, many vaccines are made, the skin of some snakes is used for the manufacture of various products.
Task 3. The ancestors of crocodiles were land animals. Confirm or refute this statement.
Pulmonary respiration, keratinized skin, almost complete septum in the heart, reproduction on land.
Task 4. Name the animals - the probable ancestors of reptiles and the periods when ancient reptiles dominated.
The first mammals appeared in the Triassic period. The ancestors were reptiles with teeth planted in separate alveoli (recesses in which the teeth were planted). After the death of dinorsaurs, they dominated.
Task 5. Write what features distinguish modern reptiles from their ancient ancestors.
1) Dimensions,
2) External structure - many dinosaurs had devices for defense and attack: spines (stegosaurus), bone growths (ankylosaurus), a strong bone skull or growth (pachycephalosaurus), horns and lumpy growths (protoceratops, triceratops and), some had sail-shaped outgrowths to maintain the required body temperature (Uranosaurus, Stegosaurus, Spinosaurus). Species such as the parasavralof had a hollow outgrowth on the voice - breathing, running, communicating.
3) The structure of the bones of the foot, leg and thigh - in dinosaurs, the legs are directed straight down the body, so they act like columns, supporting the large weight of the animal. Also, this structure of the legs allowed them to move long distances with minimal energy consumption. In most reptiles, the limbs are directed towards the sides of the body, which does not allow the animal to run quickly and reach large body sizes.
THE MOST ANCIENT LIVING REPRESENTATIVE - GATTERIA
This is the only modern representative of the order of beak-headed reptiles. Outwardly it looks like a lizard. A ridge of triangular scales along the back and tail. Lives in burrows up to 1 m deep. Before the arrival of the Maori and Europeans, it inhabited the North and South Islands of New Zealand, but by the end of the 19th century it was exterminated there; survived only on nearby islands in a special reserve. It is listed in the Red Book of the International Union for Conservation of Nature and Natural Resources (IUCN). Successfully bred at Sydney Zoo.
Animals similar to the tuatara - homeosaurs - lived 140 million years ago in the part of our planet that has become Europe today.
From the famous English navigator James Cook, the Europeans learned that New Zealand is home to "a gigantic lizard up to two and a half meters long and as thick as a man." She seems to "sometimes even attack people and devour them." I must say that Cook's story contains some exaggeration. The length of the tuatara with the tail (male) is at most 75 cm (weight about a kilogram), and the tuatara does not hunt for humans, but is content with more modest prey - insects, earthworms, and sometimes lizards.
The Europeans, who followed Cook's footsteps to New Zealand, almost put an end to the history of beakheads, which is more than 200 million years old. More precisely, not they themselves, but the rats, pigs and dogs that arrived with the people. These animals exterminated the juveniles of the tuatara and ate its eggs. As a result, the tuatara almost disappeared. Now the tuatara is taken under strict protection: whoever caught or killed this animal runs the risk of ending up in prison. Few zoos in the world can boast of a tuatara in their collections. The famous English naturalist Gerald Durrell managed to get the offspring of the tuatara in his zoo, which was presented to him by the New Zealand government. Thanks to environmental measures by the end of the 70s. XX century, the number of tuataras increased slightly and reached 14 thousand specimens, which brought these animals out of the threat of extinction.
To an uninitiated person, the tuatara (Sphenodon punctatus) is simply a large, imposing species of lizard. And in fact, this animal has greenish-gray scaly skin, short strong legs with claws, a ridge on the back, consisting of flat triangular scales, like in agamas and iguanas (the local name of the tuatara - tuatara - comes from the Maori word meaning "prickly "), And a long tail.
However, the tuatara is not a lizard at all. The features of its structure are so unusual that a special detachment was established for it in the class of reptiles - Rhynchocephalia, which means "beak-headed" (from the Greek "rhynhos" - beak and "kefalon" - head; an indication of the premaxillary bone curving downward).
True, this did not happen immediately. In 1831, the famous zoologist Gray, having only the skull of this animal, gave it the name Sphenodon. 11 years later, a whole specimen of the tuatara fell into his hands, which he described as another reptile, giving it the name Hatteria punctata and referring to lizards from the agama family. It was only 30 years later that Gray established that Sphenodon and Hatteria are one and the same. But even before that, in 1867, it was shown that the similarity of the tuatara with lizards is purely external, and in terms of the internal structure (first of all, the structure of the skull) Tuatara stands completely apart from all modern reptiles.
And then it turned out that the tuatara, now living exclusively on the islands of New Zealand, is a "living fossil", the last representative of the once widespread group of reptiles that lived in Asia, Africa, North America and even Europe. But all other beakheads became extinct in the early Jurassic period, and the tuatara managed to survive for almost 200 million years. It's amazing how little has changed over this huge span of time, while lizards and snakes have achieved such a variety.
A very interesting feature of the tuatara is the presence of a parietal (or third) eye, located on the crown of the head between two real eyes. Its function has not yet been clarified. This organ has a lens and a retina with nerve endings, but lacks muscles and any adaptations for accommodation, or focusing. In a tuatara calf, just hatched from an egg, the parietal eye is clearly visible - like a bare speck surrounded by scales that are arranged like flower petals. Over time, the "third eye" becomes overgrown with scales, and in adult Tuatars it can no longer be seen. Experiments have shown that the tuatara cannot see with this eye, but it is sensitive to light and heat, which helps the animal regulate body temperature, dosing the time spent in the sun and in the shade.
However, a similar formation in the upper part of the brain is present in all vertebrates, only it is hidden under the cranium.
As the excavations show, not so long ago, tuataras were found in abundance on the main islands of New Zealand - North and South. But the Maori tribes who settled in these places in the XIV century, significantly reduced the number of Tuatars. An important role in this was played by animals that arrived with people, which are not characteristic of the fauna of New Zealand. True, some scientists believe that the tuatara died due to changes in climatic conditions. Until 1870, it was still found on the North Island, but at the beginning of the 20th century it survived only on 20 small islands, of which 3 are in the Cook Strait, and the rest are off the northeastern coast of the North Island.
The view from these islands is gloomy - cold lead waves break on the fog-shrouded rocky shores. The already sparse vegetation was badly damaged by sheep, goats, pigs and other wild animals. Now, every single pig, cats and dogs have been removed from the islands where the tuatara populations have survived, and the rodents have been destroyed. All these animals caused great damage to the tuatars, eating their eggs and juveniles. Of the vertebrates on the islands, only reptiles and numerous seabirds remained, settling their colonies here.
Females of tuatara are smaller in size and almost twice as lighter as males. These reptiles feed on insects, spiders, earthworms and snails. They love water, often lie in it for a long time and swim well. But Tuatara runs badly.
The tuatara is a nocturnal animal, and, unlike many other reptiles, it is active at relatively low temperatures - + 6 ° ... + 8 ° C - this is another of the interesting features of its biology. All life processes in the tuatara are slowed down, the metabolism is low. It usually takes about 7 seconds between two breaths, but the tuatara can remain alive without taking a single breath for an hour.
In winter, from mid-March to mid-August, the tuataras spend in burrows, hibernating. In spring, females dig special small burrows, where, with the help of their paws and mouths, they transfer a clutch of 8-15 eggs, each of which is about 3 cm in diameter and enclosed in a soft shell. From above, the masonry is covered with earth, grass, leaves or moss. The incubation period lasts about 15 months, which is significantly longer than that of other reptiles.
Tuatara grows slowly and reaches sexual maturity no earlier than 20 years. That is why it can be assumed that she is one of the outstanding centenarians of the animal world. It is possible that some males are over 100 years old.
What else is this animal famous for? The tuatara is one of the few reptiles with a real voice. Her sad, hoarse screams can be heard on foggy nights or when someone bothers her.
Another amazing feature of the Tuatara is its cohabitation with gray petrels, which nest on the islands in self-dug burrows. The tuatara often settles in these burrows, despite the presence of birds there, and sometimes, apparently, ruins their nests - judging by the finds of chicks with bitten off heads. So such a neighborhood, apparently, does not give the petrels much joy, although usually birds and reptiles coexist quite peacefully - the tuatara prefers other prey, in search of which it goes at night, and in the daytime the petrels fly into the sea for fish. When the birds migrate, the tuatara hibernates.
The total number of living tuataras is now about 100,000 individuals. The largest colony is located on Stephens Island in the Cook Strait - there on an area of 3 sq. km 50,000 Tuatars live - an average of 480 individuals per hectare. On small islands - less than 10 hectares - the population of tuatara does not exceed 5000 individuals. The New Zealand government has long recognized the value of the amazing reptile for science, and the islands have had a strict conservation regime for about 100 years. They can only be visited with special permission, and there is strict liability for violators.
They are not eaten and their hides are not commercially available. They live on remote islands, where there are no people or predators, and are well adapted to the conditions existing there. So, apparently, the survival of these unique reptiles is currently not threatened. They can quietly while away their days on secluded islands to the delight of biologists, who, among other things, are trying to figure out the reasons why the tuatara did not disappear in those distant times when all of its relatives died out.
Perhaps we should learn from New Zealanders on how to conserve our natural resources. As Gerald Durrell wrote, “Ask any New Zealander why they are guarding the tuatara. And they will consider your question simply inappropriate and will say that, firstly, this is a one-of-a-kind creature, secondly, zoologists are not indifferent to it and, thirdly, if it disappears, it will disappear forever. "
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The same age as the dinosaurs. 10 most ancient modern animals
Horseshoe crabs - aquatic chelicerae from the merostomaceous class - are considered the most ancient animals living on Earth today. At the moment, four modern species of these arthropods are known. They inhabit the shallow waters of the tropical seas of Southeast Asia and the Atlantic coast of North America. Horseshoe crabs appeared on our planet about 450 million years ago.
Neopilin cephalopods originated on Earth 355-400 million years ago. They live in the Pacific, Indian and Atlantic oceans at depths from 1800 to 6500 meters. These creatures were discovered only in 1957.
Coelacanths are the only modern genus of cross-finned fish and in our time are considered living fossils. Now there are only two species of coelacanths - one lives off the eastern and southern coasts of Africa, and the second was first described only in 1997-1999. near the island of Sulawesi in Indonesia.
Interestingly, at the moment, scientists do not know what a young individual of coelacanth looks like and where young fish live for the first few years of their life - not a single young individual was found during diving. It is believed that coelacanth originated on Earth 300-400 million years ago.
Cockroaches appeared on our planet about 320 million years ago and since then have been actively spreading - at the moment, scientists know more than 200 genera and 4500 species.
The remains of cockroaches are, along with the remains of cockroach crickets, the most numerous traces of insects in the sediments of the Paleozoic.
The oldest surviving large predator is the crocodile. At the same time, it is considered the only surviving species of crurotars, a group that also included a number of dinosaurs and pterosaurs. It is believed that crocodiles appeared on Earth approximately 250 million years ago.
Crocodiles are common in all tropical countries, living in a variety of freshwater bodies; relatively few species tolerate salt water and are found in the coastal part of the seas (Nile crocodile, salted crocodile, African narrow-necked crocodile).
The first crocodiles lived mainly on land and only later moved on to life in the water. All modern crocodiles are adapted to a semi-aquatic lifestyle - living in water, they, however, lay their eggs on land.
Small crustaceans of the gill-legged class appeared on Earth 220-230 million years ago, when dinosaurs still lived on the planet. Shields are small creatures and are rarely longer than 12 cm, nevertheless, due to a unique survival system, they managed to survive.
The fact is that shields live in stagnant water of temporary fresh reservoirs, due to which they are freed from natural enemies and in their niche are at the top of the ecological pyramid.
The tuatara, a species of reptile, is the only modern member of the ancient beak-headed order. They inhabit only a few islands of New Zealand, while the tuataras are already extinct on the North and South Islands.
These reptiles grow up to 50 years old, and the average life expectancy is 100 years. It is believed that they originated on the planet 220 million years ago, and now the tuatara are included in the IUCN Red List and have a protected status of a vulnerable species.
The Nephila spider is not only considered the oldest on the planet - scientists believe that this genus originated about 165 million years ago, but it is also the largest spider weaving webs. These spiders live in Australia, Asia, Africa, America and the island of Madagascar.
Interestingly, fishermen collect Nephila's web, form a ball out of it, which they then throw into the water to catch fish.
What animals of antiquity have survived to this day, and what do we know about them? On the pages of our site, it has already been said about dinosaurs and other prehistoric animals that once inhabited our planet, but have now become extinct.
Are among the contemporaries of dinosaurs there are those who could survive to this day ?! Today we will present to your attention 25 of the most real "living fossils".
Shield
A freshwater crustacean that looks like a small horseshoe crabs. Over the past 70 million years, its prehistoric morphology has hardly undergone any changes, almost not differing from the ancestors of the shield, who inhabited the earth about 220 million years ago.
24. Lamprey
Jawless fish. Has a funnel-like suction cup mouth. Occasionally they burrow their teeth into the bodies of other fish, sucking blood, but the bulk of 38 species of this fish do not.
The oldest remains of this fish date back 360 million years ago.
23. Sandhill Crane
Endemic to North-Eastern Siberia and North America, a heavy and large bird, weighing up to 4.5 kilograms. Presumably the oldest representative of this species, fossils of which could be found, lived 10 million years ago in Nebraska.
22. Sturgeon
The subarctic, temperate and subtropical sturgeon inhabiting lakes, rivers and coastal waters is sometimes called "primitive fish". The reason for this is that the morphological characteristics of the sturgeon remained practically unchanged. In any case, the most ancient sturgeon fossils are practically indistinguishable from its modern descendants, despite the past 220 million years.
True, as it is regrettable, but pollution of the environment, overfishing put these unique fish on the earliest of complete extinction, and some species of sturgeon can hardly be restored.
21. Giant Chinese Salamander
The largest amphibian, the length of which can reach 1.8 m. It is a family of hidden gibers that appeared 170 million years ago. Like the sturgeon, it is on the verge of extinction.
The reason is loss of habitat, overfishing and pollution. Like many other rare species, it is used by the Chinese for food and is used for the dubious needs of Chinese medicine.
20. Martian ant
It lives in the rainforests of Brazil and the Amazon. It belongs to the oldest ant genus and is about 120 million years old.
19. Goblin shark
The body length of this fish can reach 4 meters. A very rare and poorly studied species of deep-sea shark. Eerie and unusual appearance indicates prehistoric roots. Apparently, her first ancestors lived on Earth 125 million years ago. Despite its frightening appearance and size, it is absolutely safe for people.
18. Horseshoe crabs
A marine arthropod that lives primarily in shallow ocean waters on a soft muddy or sandy bottom. It is considered the closest relative of the trilobite and is one of the most famous living fossils, practically unchanged over 450 million years.
17. Echidna
Like the platypus, the echidna remains the only oviparous mammal. Her ancestors split off from the platypus about 48-19 million years ago. The common ancestor of both of them led an aquatic lifestyle, but the vipers adapted to life on land. Due to its appearance, it was named after the "Mother of Monsters" from ancient Greek mythology.
16. Hatteria
The endemic tuataras from New Zealand can reach a length of 80 cm, with a spiny ridge along the back, which is especially pronounced in males. However, despite the clear similarity with modern reptiles and lizards, the body structure of the tuatara has remained unchanged for two hundred million years. In this regard, tuataras are extremely important for science, since they can help in the study of evolution, both snakes and lizards.
15. Frilled shark
Frilled sharks live in the Pacific and Atlantic oceans at depths of fifty to two hundred meters. Like the brownie shark, the frilled shark has an extremely frightening appearance.
This line has existed for at least 95 million years (from the end of the Cretaceous). It is possible that the age of frilled sharks may be 150 million years (late Jurassic).
The frilled shark is a living fossil that belongs to one of the oldest surviving shark lines. 14. Vulture turtle
The vulture turtle lives mostly in the waters adjacent to the southeastern territories of the United States. Belongs to one of the two surviving families of the Cayman turtles.
This prehistoric turtle family has a centuries-old fossil record dating back to the Maastricht stage of the Late Cretaceous (72-66 million years ago). The vulture turtle can weigh up to 180 kilograms, making it the heaviest freshwater turtle in the world.
13. Coelacanth
A genus of fish endemic to the coastal waters of Indonesia, which includes two living species of the coelacanth family. Until 1938, coelacanths were considered extinct until they were rediscovered.
Oddly enough, coelacanths are more closely associated with mammals, reptiles and lungfish than with other ray-finned fish. Presumably, coelacanth acquired its present appearance about 400 million years ago.
Celacanth is endemic to Indonesian waters. 12. Giant freshwater ray
The giant freshwater stingray is one of the largest freshwater fish in the world, growing up to almost two meters in diameter. Its weight can be up to six hundred kilograms. According to research, its oval disc of the pectoral fin formed about 100 million years ago.
Like most of the animals mentioned in this article, the giant freshwater stingray is on the verge of complete extinction due to overfishing for display in aquariums, selling for meat, and due to pollution of the living conditions of this animal.
11. Nautilus
Pelagic mollusk that lives in the Central-West Pacific and Indian Ocean.
Prefers deep coral slopes. Judging by the fossil remains, the Nautilus managed to survive five hundred million years, during which several eras on earth changed and several mass extinctions occurred. Of course, the Nautilus, too, having existed for half a billion years and having survived the most severe cataclysms, may not withstand the most terrible (and this is not an exaggeration) of the evils that our planet has ever faced - man. It is on the verge of extinction due to overfishing and human pollution.
10. Medusa
They live in all oceans from the depths of the sea to the surface. Presumably, they appeared in the seas about 700 million years ago. In view of this, jellyfish can be called the most ancient multiorgan animals. Probably, this is the only animal among those included in this list, the number of which can increase significantly due to excessive catching of natural enemies of jellyfish. At the same time, some types of jellyfish are also on the verge of extinction.
9. Platypus
Oviparous mammal with otter legs, beaver tail and duck beak. It is often called the most bizarre animal in the world. In light of this, it is not surprising that the roots of the platypus go into prehistoric jungle.
On the one hand, the age of the oldest platypus fossil is only 100 thousand years old, but the first ancestor of the platypus roamed the expanses of the supercontinent Gondwana about 170 million years ago.
8. Long-eared hopper
This small four-legged mammal is widespread throughout the African continent and looks like opossums or some small rodents. However, oddly enough, they are much closer to elephants than to possums. The first ancestors of the long-eared jumper lived on earth already in the Paleogene period (about 66-23 million years ago).
7. Pelican
Oddly enough, this large waterfowl with a long, heavy beak is one of the living fossils that have practically not changed since the prehistoric period. The genus of these birds has existed for at least 30 million years.
The oldest fossilized pelican skeleton was found in early Oligocene sediments in France. Outwardly, it is almost indistinguishable from modern pelicans, and its beak is morphologically identical to that of modern birds of this genus.
Pelicans are one of the few birds that have not undergone any changes since prehistoric times. 6. Mississippi carapace
One of the largest North American freshwater fish. It is often called a living fossil or "primitive fish" due to the preservation of a number of morphological characteristics of its most ancient ancestors. In particular, among these characteristics can be mentioned the ability to breathe in water and air, as well as a spiral valve. Paleontologists trace the existence of the carapace for 100 million years back centuries.
Mississippi carapace is a primitive fish. 5. Sponge
The duration of the existence of sea sponges on our planet is rather difficult to trace, since estimates of their age have rather large discrepancies, but today the most ancient fossil is about 60 million years old.
4. Scratch tooth
Poisonous nocturnal mammal burrowing into holes. It is endemic to several countries in the Caribbean and is often called a living fossil, which is not at all surprising, since over the past 76 million years it has practically not undergone any changes.
3. Crocodiles
Unlike most of the animals on this list, the crocodile really looks like a dinosaur. In addition to crocodiles, mention should be made of gavial crocodiles, gharials, caimans and alligators. This group appeared on our planet about 250 million years ago. This happened in the early Triassic period, and the descendants of these creatures to this day carry a lot of morphological features that were formed even in their distant ancestors.
2. Dwarf whale
Until 2012, the dwarf whale was considered an extinct animal, but since it nevertheless survived, so far it is considered the smallest representative of baleen whales. Since this animal is very rare, very little is known about its population and about its social behavior. But it is known for sure that the dwarf whale is a descendant of the Cetotherium family, which is part of the suborder of baleen whales and which existed from the late Oligocene up to the late Pleistocene (28-1 million years ago).
1 black-bellied disc-speaking frog
As it turned out, living fossils can be found among, it would seem, such a completely prosaic creature as a frog. Like the aforementioned dwarf whale, this black-bellied frog was considered extinct, but was rediscovered in 2011.
At first, it was believed that the black-bellied disc-tongued frog had existed for only 15 millennia, but using phylogenetic analysis, scientists were able to calculate that the last direct ancestor of this unique animal jumped on the earth's surface about 32 million years ago. This makes the black-bellied disc-speaking frog not just a living fossil, but also the only representative of its kind that has survived to this day.
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