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15.12.2015 15:32 - Encyclopedia Largest prehistoric animals Vol.1 Vertebrates part1 Mammals ch.1 Carnivores - Felids,the great forerunners of modern big cats-Tigers and Lions
Автор: valentint Категория: Забавление   
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Felids
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The biological family Felidae is a lineage of carnivorans colloquially referred to as cats. A member of this family is also called a felid or feline.The term "cat" refers both to felids in general and specifically to domestic cats. The characteristic features of cats have evolved to support a carnivorous lifestyle, with adaptations for ambush or stalking and short pursuit hunting. They have gracile and muscular bodies, strong flexible forelimbs and retractable claws for holding prey, dental and cranial adaptations for a strong bite, and often have characteristic striped or spotted coat patterns for camouflage. Cats are obligate carnivores, meaning they are dependent on nutrients in animal flesh for survival, and because of the large proportion of meat in their diet they are sometimes referred to as hypercarnivores. Of the 13 terrestrial families in the order Carnivora, they are the strictest carnivores.
The Felidae comprises two subfamilies, the Pantherinae and the Felinae. The former includes the Panthera species tiger, lion, jaguar, leopard, snow leopard, and Neofelis species clouded leopard and Sunda clouded leopard. All the non-pantherine cats are part of the Felinae, which includes several genera and the majority of cat species.
The first cats emerged during the Oligocene, about 25 million years ago, with the appearance of Proailurus and Pseudaelurus. The latter species complex was ancestral to two main lines of felids, the cats in the extant subfamilies and a third major group of extinct cats, which are assigned to the subfamily Machairodontinae. The machairodonts included the saber-toothed cats such as the Smilodon. The "false sabre toothed cats", the Barbourofelidae and Nimravidae, are not true cats, but are closely related and together with Felidae and other cat-like carnivores (hyaenas, viverrids and mongooses) make up the feliform carnivores.The evolution of the Felidae cat family began about 25 million years ago. These ancient cats evolved into the eight main lineages of the Felidae cat family tree, with most modern cats appearing in the past five million years.
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Felidae Family Tree
Most of the modern cats of today arose due to migrations that occurred during the two major ice ages of the past ten millennia. During these ice ages the sea levels dropped and land bridges formed between continents - enabling animals to migrate to new territories and environments. When the ice sheets melted and sea levels rose again, the land bridges were covered and the migratory animals became isolated from their original populations. The new populations adapted over time to their new environment and eventually become genetically distinct to the extent they evolved into a new species.
Speciation can also occur within continents whenever a group of animals become separated in some way from their founding population. For example snow leopards evolved as they adapted to low temperatures at high altitudes and sand cats evolved as they adapted to the dry and extreme conditions of desert habitats. Inherently wild cats disperse and adapt readily to new environments so this family of animals are likely spread to new territories when the opportunity arises.
The Three Oldest Wild Cat Lineages
The last common ancestor of modern cats was a species of Pseudaelurus that occurred in Asia 9 to 20 million years ago (MYA). Using genetics scientists have established that modern cats diverged from this ancient species in eight groups or lineages of closely related species.
10.8 MYA - Panthera Lineage - Widespread
The oldest cat lineage is the big roaring cats of the Panthera lineage that split from this common ancestor 10.8 MYA. Descendants evolved into seven species which occur across all the continents of Asia, North and South America, Europe and Africa as they migrated to and from Asia over time.
9.4 MYA - Bay Cat Lineage - SE Asia
The second lineage to branch off was the Bay Cat Lineage at 9.4 MYA and three species evolved within South East Asia.
8.5 MYA - Caracal Lineage - Africa
The third Caracal lineage diverged at 8.5 MYA during the first ice age of 8 to 10 MYA, when ancestors crossed the land bridges at the Red Sea from Asia to Africa and into three mid-sized cat species.
The Five Wild Cat Lineages originating in North America
During the same ice age, the Bering Strait land bridge formed between Asia and North America over which cats and other animals migrated spreading through North America and later into South America. These dispersals gave rise to the remaining wild cat lineages, all originating in North America.
8.0 MYA - Ocelot Lineage - North America > South America
The ancestors of the Ocelot or Leopardus lineage, that originated 8.0 MYA, initially evolved into two species in North America. Later during the second ice age of 2 - 3 MYA the Panama Isthmus land bridge between North and South America formed due to lower sea levels as well as continental shifts. Cats migrated to South America and the Ocelot group diversified further to the seven species of today.
7.2 MYA - Lynx Lineage - North America > Eurasia
The Lynx lineage branched off (relatively) soon after the Ocelot lineage at 7.2 MYA and evolved into the distinctive lynx species with short tails and tufted ears. Two species spread through North America and a further two evolved later in Eurasia from ancestors that migrated back over the Bering Strait during the second ice age.
6.7 MYA - Puma Lineage - North America > South America
The third lineage to originate in North America was the Puma lineage which arose 6.7 MYA. Today the group consists of three very diverse cat species - the Cheetah, Puma and Jaguarundi. The Puma and Jaguarundi spread to South America during the second ice age, whereas the Cheetah migrated back into Eurasia and ultimately into Africa.
6.2 MYA - Leopard Cat Lineage - North America > Asia
The last two "youngest"  lineages arose from ancestors that crossed back to Asia from North America during the second ice age. The Leopard Cat lineage split off 6.2 MYA and the resulting five species mainly occupy Southern and Central Asia.
3.4 MYA - Felis Lineage - North America > Asia > Africa
The most recent lineage to diverge at 3.4 MYA is the Felis lineage, comprising mostly smaller cats under 10 kgs which also gave rise to the domestic cat. Some of the ancestral cats that moved back to Asia evolved there, whilst others spread into Europe and some even further into Africa.


Tigers
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The tiger"s closest living relatives were previously thought to be the Panthera species lion, leopard and jaguar. Results of genetic analysis indicate that about 2.88 million years ago, the tiger and the snow leopard lineages diverged from the other Panthera species, and that both may be more closely related to each other than to the lion, leopard and jaguar.P. t. palaeosinensis from the Early Pleistocene of northern China is the most primitive known tiger to date.Fossil remains of Panthera zdanskyi were excavated in Gansu province of northwestern China. This species lived at the beginning of the Pleistocene about two million years ago, and is considered to be a sister taxon of the modern tiger. It was about the size of a jaguar and probably had a different coat pattern. Despite being considered more "primitive", it was functionally and possibly also ecologically similar to the modern tiger. Northwestern China is thought to be the origin of the tiger lineage. Tigers grew in size, possibly in response to adaptive radiations of prey species like deer and bovids, which may have occurred in Southeast Asia during the early Pleistocene.
Panthera tigris trinilensis lived about 1.2 million years ago and is known from fossils excavated near Trinil in Java.The Wanhsien, Ngandong, Trinil and Japanese tigers became extinct in prehistoric times.Tigers reached India and northern Asia in the late Pleistocene, reaching eastern Beringia, Japan, and Sakhalin. Some fossil skulls are morphologically distinct from lion skulls, which could indicate tiger presence in Alaska during the last glacial period, about 100,000 years ago.
Tiger fossils found in the island of Palawan were smaller than mainland tiger fossils, possibly due to insular dwarfism.Fossil remains of tigers were also excavated in Sri Lanka, China, Japan, Sarawak dating to the late Pliocene, Pleistocene and Early Holocene.The Bornean tiger was apparently present in Borneo between the Late Pleistocene and the Holocene, but may have gone extinct in prehistoric times.
The potential tiger range during the Late Pleistocene and Holocene was predicted applying ecological niche modelling based on more than 500 tiger locality records combined with bioclimatic data. The resulting model shows a contiguous tiger range from southern India to Siberia at the Last Glacial Maximum, indicating an unobstructed gene flow between tiger populations in mainland Asia throughout the Late Pleistocene and Holocene. The tiger populations on the Sunda Islands and mainland Asia were possibly separated during interglacial periods.
Results of a phylogeographic study indicate that all living tigers had a common ancestor 72,000–108,000 years ago.
The tiger"s full genome sequence was published in 2013. It was found to have similar repeat composition to other cat genomes and an appreciably conserved synteny.


The heaviest felid ever was the Ngangdong tiger (Panthera tigris soloensis) with the largest specimen weighing in at 470 kg
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The Ngandong tiger (Panthera tigris soloensis), is an extinct subspecies of tiger which lived in what is now the Sundaland region of Indonesia in the Pleistocene epoch.
Fossils of P. t. soloensis have been found primarily in the village of
Ngandong, hence the common name. Only seven fossils are known, making study of the animal difficult. 
The few remains of P. t. soloensis known suggest that the animal would have been about the size of a modern-day Bengal tiger. However, other specimens suggest an animal larger than any of the modern tigers in Indonesia. Heltler and Volmer (2007) estimated that a large male could potentially weigh up to 480 kilograms, heavier than the Siberian tiger, one of the largest extant cats.
Other than the remains of P. t. soloensis, many other fossils from the same era have been discovered in Ngandong, like the proboscideansStegodon trigonocephalus and Elephas hysudrindicus, the bovines Bubalus palaeokerabau and Bos paleosondaicus, the extant perissodactylsTapirus indicus and Rhinoceros sondaicus, and a great variety of cervine species.Homo erectus fossils are also known from the area.

Another,much bigger than modern prehistoric tiger - Panthera tigris acutidens

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The Wanhsien tiger (Panthera tigris acutidens), is an extinct subspecies of tiger that lived in Asia from the late Pliocene until the middle Pleistocene. They were driven to extinction in the islands of Indonesia by another tiger subspecies, the Trinil tiger (P. t. trinilensis) and in Asia by yet another subspecies, the South China tiger (P. t. amoyensis)
The Wanhsien tiger is the earliest known extinct tiger subspecies, and populated a huge majority of Asia. It is larger than Siberian tigers, it grew to sizes of 2.8 metres (8 ft) in length, 120 centimetres (47 in) in height, and 250 kilograms (580 lb) to 400 + kilograms (900 + lb) in weight.


Lions
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The earliest fossils recognisible as from lions were excavated in Olduvai Gorge in Tanzania and date to between 1.4 and 1.2 million years ago.From East Africa, lions would spread throughout the continent and into the Holarctic and the Indian subcontinent with the expansions of open habitats.
The earliest fossil record in Europe was found near Pakefield in the United Kingdom and is about 680,000 years old.Fossil remains found in the Cromer Forest Bed suggest that it was of a gigantic size and represented a lineage that was genetically isolated and highly distinct from lions in Africa and Asia.It was distributed throughout Europe, across Siberia and into western Alaska via the Beringian landmass.The gradual formation of dense forest likely caused the decline of its geographic range near the end of the Late Pleistocene. Lion bones are frequently encountered in cave deposits from Eemian times, suggesting the cave lion survived in the Balkans and Asia Minor. There was probably a continuous population extending into India.Fossil lion remains were found in Pleistocene deposits in West Bengal.
The American lion arose when a population of Beringian lions became isolated south of the North American continental ice sheet about 370,000 years ago. This lion spread throughout North America,but was absent from the northeast, perhaps due to the presence of dense boreal forests in the region.It was formerly believed to have colonised northwestern South America as part of the Great American Interchange. However, the fossil remains found in the tar pits of Talara, Peru were later identified as unusually large jaguars.On the other hand, fossils of a large felid from late Pleistocene localities in southern Patagonia traditionally identified as an extinct subspecies of jaguar, Panthera onca mesembrina, have been reported to be remains of a lion.Eurasian cave lions and American lions both became extinct at the end of the last glacial period without mitochondrial descendants on other continents


Giant ancestor of modern lions
- Panthera leo fossilis image

Panthera leo fossilis, also known as the Early Middle Pleistocene European cave lion, is an extinct feline of the Pleistoceneepoch. It is generally considered to be an early subspecies of the lion (Panthera leo).
With a maximum head and body length of 2.40 meters, which is about half a meter longer than today"s African lions, Panthera leo fossilis was almost as big as the American lion from the Upper Pleistocene.
Many bone-fragments of this cat are known from Mosbach in Germany, a small village, which is now included in the town of Wiesbaden. A nearly complete skull was found at Mauer, near Heidelberg (Germany). In the same sediment as the lion-skull was a 550,000-year-old lower jaw from the early hominid Homo heidelbergensis. The oldest records of Panthera leo fossilis in Europe are from Isernia at Italy and are about 700,000 years old. A 1.75-million-year-old lion-jaw from
Olduvai in Kenya shows a striking similarity to those of Europe.
From Panthera leo fossilis derived the Upper Pleistocene European cave lion (Panthera leo spelaea), which is recorded for the first time about 300,000 years ago.


Panthera leo atrox

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 The American lion is an extinct animal that originated in North America and is believed to have colonized northwestern South America as part of the Great American Interchange. (However, the fossil remains found in Peru may actually correspond to large jaguars. The head-body length of the American lion is estimated to have been 1.6–2.5 m (5 ft 3 in–8 ft 2 in) and it would have stood 1.2 m (4 ft) at the shoulder. Thus, it was smaller than its contemporary competitor for prey, the giant short-faced bear, which was the largest carnivoran of North America at the time. The American lion was not as heavily built as the saber-toothed cat Smilodon populator, which may have weighed up to 400 kg (880 lb). Sorkin (2008) estimated the American lion to weigh roughly 420 kg (930 lb), but a more recent study showed an average weight for males of 256 kg (564 lb) and 351 kg (774 lb) for the largest specimen analyzed.
Around 100 specimens of American lions have been recovered from the La Brea Tar Pits, in Los Angeles, so their body structure is well known. The features and teeth of the extinct American lion strongly resemble modern lions, but they were considerably larger. The American lion is believed to be the largest subspecies of lion.
The American lion was initially considered a distinct species of Pantherinae, with the scientific name Panthera atrox (which means "cruel" or "fearsome panther" in Latin).Overall, the skull of this cat was most like that of the jaguar (P. onca). Some later authors accepted this view, but other experts considered the American lion most closely related to the African lion (P. leo) and its extinct Eurasian relative, the cave lion (P. leo spelaea or P. spelaea). Later paleontologists assigned the extinct American cat as a subspecies of P. leo (P. leo atrox) rather than as a separate species.
Cladistic studies using morphological characteristics have been unable to resolve the phylogenetic position of the American lion. At least one authority considers the American lion (along with the cave lion), to be more closely related to the tiger, P. tigris, citing a comparison of skull shapes; the braincase, in particular, appears to be especially similar to the braincase of a tiger. The American lion and Eurasian cave lion were also suggested to be successive offshoots of a lineage leading to an extant lion-leopard clade.A more recent study comparing the skull, jaw, and teeth of the American lion with other pantherines concluded it was not a lion and was distinct from all extant species. The authors suggested it may have arisen from pantherines that migrated into North America in the mid-Pleistocene epoch and gave rise to both American lions and jaguars (P. onca). Another morphological study grouped the American lion with P. leo and P. tigris, and ascribed similarities to P. onca to convergent evolution.
However, mitochondrial DNA sequence data from remains of the American lion from Wyoming and Alberta show it is a sister lineage to the cave lion, and likely arose when an early cave lion population became isolated south of the North American continental ice sheet. The most recent common ancestor of the two populations apparently lived about 340,000 (194,000–489,000) years ago The most recent common ancestor of the P. atrox lineage is estimated to have lived about 200,000 (118,000–246,000) years ago. The dates imply that genetic isolation from P. spelaea had begun by the time of the Illinoian glaciation, about 300,000–130,000 years ago (a spelaea population is known to have been present in eastern Beringia by that period, where it persisted until at least 11,925 ± 70 years ago. This separation was maintained during the Sangamon interglacial, about 130,000–110,000 years ago, as well as during later interstadials of the earlier glaciation and those of the following Wisconsinan glaciation, about 110,000–10,000 years ago. Boreal forest may have contributed to the separation during warmer intervals; alternatively, a species barrier may have existed. The study also indicates the present-day lion is the closest extant relative of P. atrox and P. spelaea (The same study shows Eurasian and Beringian cave lions to be genetically indistinguishable.
The earliest lions known in the Americas south of Alaska are from the Sangamonian Stage (the last interglacial). After that, the American lion spread widely from Alberta to Maryland to Peru. In North America, it has been found in more locations in the west than in the east, and as far south as Chiapas, Mexico. It was generally not present in the same areas as the jaguar, as the latter favored forests, while American lions preferred open habitats. Like many other large mammals, it went extinct at the end of the Pleistocene. The most recent fossil, from Edmonton, dates to 11,355 ± 55 years ago. By then, the American lion was one of the abundant Pleistocene megafauna, a wide variety of very large mammals that lived during the Pleistocene. The most abundant remains have come from the La Brea Tar Pits.
In some areas of its range, the American lion lived under cold climatic conditions. They probably used caves or fissures for shelter from the cold weather. They may have lined their dens with grass or leaves, as the Siberian tiger does, another great cat that currently lives in the north.
Fewer American lions are in the La Brea tar pits than other predators such as saber-toothed cats (Smilodon fatalis) or dire wolves (Canis dirus), which suggests they may have been smart enough to avoid the hazard.American lions likely preyed on North American deer, horses (now extinct), camels, and tapirs, and American bison, mammoths, and other large, herbivorous animals. This species disappeared about the same time as other megafaunal species during the Quaternary extinction event, which wiped out many of the species on which the American lion would have preyed. Lion bones have been found in the trash heaps of PaleolithicAmerican Indians, suggesting human predation may have contributed to its extinction.
A replica of the jaw of the first specimen of American lion discovered can be seen in the hand of a statue of paleontologistJoseph Leidy, which is currently standing outside the Academy of Natural Sciences in Philadelphia.






 




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Автор: valentint
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