Before going completely to the idea of entirely derived descendants of these primitive tetrapods, is also worth to see a little about the group itself, i.e., frogs and some other normal amphibian. From the Mesozoic to the human age, many members of the Lissamphibia subclass have remained stably as small semiaquatic tetrapods, although most have not emerged as part of the megafauna in much of the Earth's history, as temnospondyl their extinct relative. Still, those details not overshadow the great success that they achieved, not by being different or huge, but surviving two mass extinctions and probably for part of the anurans, that have evolved one of the most derived and most conservative body plans.
Summarizing its story with humans, amphibians suffered one of its greatest harm since the K/Pg event, with hundreds of threatened species; few became a plague and many others extinct, mainly by human activities. Despite the danger they were, they managed to overcome such event until mankind left the planet. During much of the Cenozoic had, as in previous period’s small but important roles in terrestrial ecosystem, being sometimes outstanding for some megafauna’s size specimens.
During the transition of the Cenozoic and therozoic, they again lost much of its biodiversity for the gravity of the mass extinction; however, they remained and survived, becoming for a short period of time in some of the dominant animals in specific environments. At the rests of this era, they managed to expand into new and varied forms, some groups tending to be neotenic. After winning 3 great extinction events, among the transition from the Therozoic to the Phinizoic, was the breaking point for all lissamphibia, which these could not endure against the catastrophic events caused by the supercontinent hysterea as temnospondyls whit Pangea, taking them to a huge reduction in its diversity and reaching a point where they could not recover, become extinct in later periods. Of course, this does not mean the end of all amphibians, as they left some new clades.
The most important of all is the Sperahoda, a singular monophyletic order of neotenic amphibians, which evolved around the end of the Therozoic period in the regions of Australia. After the great mass extinction, these became on one of the most successful groups of amphibians for the rest of the Phinizoic era.
An advice: the specimens shown on the imagen are not to scale, at first this was the intention, but some radical changes in the ecological roles in some species changed that perspective, so the real size are in the descriptions.
1. Hirudophimorphus sp.
This genus of little neotenic caecilian have a length of about 6 cm, is a parasitic form which lives in the gills and in inside the mouth of some big animals in the rivers of the subcontinent Aaru. Because of its living conditions, this preserves the long gills of the larval form which allow it to absorb oxygen from the water. To parasitize large vertebrates, this can cause some long-term damage if kept feeding on these, usually exposed as red sores around the mouth. If they leave the water, the caecilian can be wound on itself and encapsulated in a mucosa cover, while being able to feed on the blood of its host.
2. Ophicharcharias atrox
The great extinction of the Cenozoic finished with a huge lost of species, largely left enough space for many others, at the beginning of the Therozoic, the caecilians were at their peak. With about 5 meters long and a weight of about 50 kg, is one of the biggest caecilian species ever. Is a voracious carnivore, it feeds on a different variety of small and medium sized aquatic animals such as crustaceans, fish, others amphibians and even little crocodilians, birds and mammals; when it have the opportunity, is able to eat the carcasses of big animals that manage to get to the bottom. Something unusual in this species is the way as females keep the eggs while they hatch, as these are adhered in special segments in the middle of the body. A female can usually keep about 3 bags filled with about 5 eggs.
3. Basilodagon pardus
Whit the void of aquatic predators in the time after the extinction caused by the supercontinent around the Klastogeian, some of the frog clades left started to grow quickly, and at a pace that in a few million years, some species began to reach enormous sizes, and there is one of the largest species of Sperahoda, the Basilodagon is an example of how this last lineages has managed to adapt to the lack of competition, with 6 meters long and weighing 150 kg. This heavy monster is one of several residents of the rivers that cross much of central Africa during the period Klastogeian.
4. Amplinascis metaformis
A peculiar frog which inhabit the high mountains formed by the collision of Australia around the period Crescgeon, has a unique lifecycle among many other amphibians, as it remains a larval form for much of its lifespan, living underwater for several years, then they become adults, and for a few weeks , seeking couple, copulate, and after all, die. The tadpole has a length of about 10 cm long, and the adult just 5 cm.
5. Matercaudus cosmetodermus
This particular frog species is characterized by an unusual sexual dimorphism, because the females during the breeding season, is able to develop a tail on which embeds the eggs through special foam. The amount of eggs that can spawn and maintain ranges from 20 to 30. While the female is dark brown, males have greenish colors, with some bluish spots on the back, and lines of light blue and white head. Males tend to gather in muddy places, where they create small burrows in the ground, which the females can use to live during the incubation of eggs lasts for weeks. Are inhabitants of the East Asia forests, extending from India, Indonesia and China during the period Agresti.
6. Ciclodorsu dermipilosus
Around the rivers and lakes of Australia, a very particular group of amphibians appeared developing a complete dependence of water, which is called Selenopoda, characterized by the shape of their bodies resembled the shape of a crescent moon. This birth of this group is around 30 to 60 million years after humanity, when Australia passed between Ecuador and part of its climate change, becoming a tropical continent and covered with forests. The Ciclodorsu is the precursor of this kind, being a flat frog of about 9 cm long; it lives around the Agresti period.
7. Deltaphysis pterynicha
A more derived form of Selenopoda, it have reduced its frontal limbs, and hypertrophied its hind limbs, which uses to propel in the water. It is an active predator, always hidden near the seabed. When it can identify their potential prey, he is able to use his long legs to propel, together with its aerodynamic body, allowing you to achieve a very great speed; it has a body length of about 20 cm, but with a width of 50 cm including the legs.
8. Electrogyrus takinosis
A long salamander species of about 1 meter long is one of the variants of large amphibians evolved during the Early Therozoic in the Haemonova period. This species is characterized by its ability to generate strong electrical shock which can become lethal to as large as 2 meters animals in a short discharge.
9. Kallipleura sp.
This Indonesian frog genus from the Therozoic era, is notorious for its modified vocal sacs, which inflates, take a deltoid shape, colored with differences patterns which use for different purposes, depending of the species, and both defensive as ornamental. At the same time, they are able to produce loud call, which whit the shape of the vocal sacs; these can have a variety of tones and frequencies. Most species of this clade have an approximate length of 5 to 12 cm.
10. Tenubatrus cladimorphus
This species of frog, endemic of the African subcontinent, evolved around the period Crescgeon, being part of a lineage of long thin frogs adapting to live among the dense forests. Its main feature is its method of camouflage, which is pretending to be a branch. This is quite longs and light, with a length of 25-35 cm but with a lower weight of about 200 g.
11. Giraffospondilus megalocolla
This little forest salamander of about 8 cm long, is characterized in that the males have excessively elongated and thin necks, this elongated shape of their cervical spines. This male is used primarily to fight with other males. Its range only covers Southeast Asia, during the period Crescgeon.
12. Anatorhiny macrosuchus
This a great carnivorous salamander of about 1.8 meters long, which lives around north America water bodies during the early Haemonova, just a few million years after the great Cenozoic mass extinction. Its name is due to the structure of the front of its head, which is reminiscent of a duck, however, this is not a beak, is an extension of the head which has several electroreceptors that allows to detect a possible prey under the river floor.
13. Bovibatrus camarogastrus
At one point of the life cycle in various types of frogs, tadpoles are able to eat and digest plant material with the help of their digestive systems that are able to deal with this kind of food; however, this capability is lost by becoming in adults, which are predominantly carnivores. In the jungles south of the subcontinent Aaru in the Haemonova period, a particular group of amphibians preserved this unique feature in their adult forms, at first, turning herbivores, and later, few specimens became completely herbivorous, and between these, there is the Bovibatrus.
14. Micefiges barbatus
After the great Klastogeian extinction event caused by the supercontinent hysterea, only few clades of amphibians managed to survive, and less were able to recover so quickly as the Micefiges. This little Sperahoda is a nocturnal dweller with a size of about 12 cm, spends most of which time in burrows, and comes out at night to feed, is characterized by long "whiskers" around the mouth, which they are remnants of its digging ancestors, which they are still quite useful to perceive the vibrations in the air.
15. Scandognathus phiranoides
This is a strange species of gregorial scavenger Sperahoda, which like piranhas, it is capable of congregating in large groups of dozens around the corpses of animals and eat them up just leave them in the bones. It has a length of about 15 cm long, and its distribution is global by the situation of the Supercontinent around the Klastogeian.
16. Gelirana glaucodermis
During the transition of the Klastogeian period to the Bathovician had begun a series of short ice ages caused by blockage of ocean currents in the north, leading to the temporary creation of some similar complete cold ecosystems that once existed during the Cenozoic Ice ages. One of these was the isolation of lakes under the ice, causing an interesting path for those animals which were able to survive there. The Gelirana is a polar Sperahoda of about 35 cm long, being one of the few types of vertebrates which survived the insulation under meters of ice in one of the large lakes around the pole that due to low light conditions; it is practically blind, feeling the world through a series of electroreceptors around the head.
17. Limosirenus anguillus
And eel like form of Sperahoda, is a great filter feeder of about 2 meters long which lives in the rivers of the northwest hemisphere of the continent Ruamoku, during the period Bathovician. After the separation of the supercontinent and a minor mass extinction, the diversity of the aquatic Sperahoda began to decline in great amount in most of the continents, leaving very few survivors in some parts.
18. Ballohydrus toxus
After the end of the Cenozoic and the new diversification of anurans, some unusual new morphological features evolved among some groups, especially from one special clade of African frogs, called Siphobucallae or just Siphojaws, which changed the structure of the mouth to a specialized siphon-like jaw, which for the ancestral forms that served them to devour small organisms through suction, however, other forms later managed to take new niches, using these derived structures. The Ballohydrus is one of these forms, one because of its lifestyle have presented a relative degree of neoteny, retaining the tail. It has an unusual method of hunting, something similar to the archerfishes, are capable of throwing a water jet to shoot down its prey, this accumulating in its modified vocal sacs.
19. Cyclopardus globulosa
This is a specialized desert frog which lives around the center of the great north plains of Beringia during the Crescgeon. It is able to catch the air dew in sudden mists that form in the morning, using its rugose skin and its spherical form. It is quite small, being about 3 cm long, feeds small arthropods and small beetles and spiders.
20. Allochromatus hallucinus
This hallucinating frog is a poisonous species of approximately 10 cm in length; it is characterized by its strange arrangement of colors and skin texture, has a number of large and colored glands which are able to produce strong toxins, which can throw a liquid white-red terrible flavor and can kill animals as large as human.
21. Gnatithanus aviphaga
This is an interesting and rare species of predatory frog, because it is able to kill their prey by injecting toxins through spines distributed around the long jaw. It specializes in hunting animals such as birds, mammals and other amniotes. Its head has a triangular shape, being very narrow in the front and forming 2/3 of its length. In total, it size is about 20 cm, with a head of about 15 cm. It lives in the ground of the forests of South America, around the period Haemonova.
22. Irascosarcus chloribatra
This is a relative of the Bovibatrus, which although it’s relative, is not a complete herbivore, is an omnivore of great size, with about 70 cm and a weight of 20 kg, making it the biggest anuran of the Haemonova period. These are more active and ferocious, being quite territorial and easy to provoke.
23. Vitamathus deltocephalus
This is another desert dweller frog, but unlike other forms, this one of the last species of true anuran alive in the far future, being a survivor of the great mass extinction caused by hysterea. It lives around the beginning of the period Klastogeian, around the north of the supercontinent where was South Africa, being a little insectivorous species, it resembles the ancient horned frogs.
24. Ophthalmospela leucus
This cave dweller species is an inhabitant of the cave systems of the eroded Himalaya Mountains, around the Metamonus period. It is characterized by its huge eye orbits, which keep two huge eyes that allow them to see in the darkness of the poor lighting caverns.
25. Haploductus sp.
This is the most common species of Siphojaws around the therozoic in the Eurafrica regions. Unlike other of its family, the skin of most of these is thick, leathery, wrinkled and is adapted to retain largely the water in its bodies, so when are adult, these can remain permanently on land and only return to the water to lay.
26. Macrosiphonus mata
This aquatic ambush predator is one of the largest species of the Siphojaws, with about 40 cm long, inhabits the rivers in central Africa during the Agerogene period. Its method house is quite simple, it remains stuck to the bottom, blending with the surrounding environment, until a potential prey approaches, then opens its huge tubular mouth, causing a current that allows catching its prey.
27. Luxirana talassinus
This is another troglodyte species of frog of about 10 cm long, which inhabit of a deep and isolated group of cave systems below of what was the Andes, which is capable of producing bioluminescence. This feature allows attracting different types of arthropods, which follow the bright spots that produce in the skin.