TASMANIAN TIGER

The thylacine was the largest known carnivorous marsupial of modern times. It is commonly known as the Tasmanian tiger (because of its striped back) or the Tasmanian wolf. Native to continental Australia, Tasmania and New Guinea, it is thought to have become extinct in the 20th century. It was the last extant member of its family, Thylacinidae, although several related species have been found in the fossil record dating back to the early Miocene.
The thylacine had become extremely rare or extinct on the Australian mainland before European settlement of the continent, but it survived on the island of Tasmania along with several other endemic species, including the Tasmanian devil. Intensive hunting encouraged by bounties is generally blamed for its extinction, but other contributing factors may have been disease, the introduction of dogs, and human encroachment into its habitat. Despite its official classification as extinct, sightings are still reported, though none has been conclusively proven.
Like the tigers and wolves of the Northern Hemisphere, from which it obtained two of its common names, the thylacine was an apex predator. As a marsupial, it was not closely related to these placental mammals, but because of convergent evolution it displayed the same general form and adaptations. Its closest living relative is thought to be either the Tasmanian devil or numbat. The thylacine was one of only two marsupials to have a pouch in both sexes (the other being the water opossum). The male thylacine had a pouch that acted as a protective sheath, covering the male's external reproductive organs while he ran through thick brush. It has been described as a formidable predator because of its ability to survive and hunt prey in extremely sparsely populated areas.

The modern thylacine first appeared about 4 million years ago. Species of the family Thylacinidae date back to the beginning of the Miocene; since the early 1990s, at least seven fossil species have been uncovered at Riversleigh, part of Lawn Hill National Park in northwest Queensland.[9][10] Dickson's Thylacine (Nimbacinus dicksoni) is the oldest of the seven discovered fossil species, dating back to 23 million years ago. This thylacinid was much smaller than its more recent relatives. The largest species, the powerful thylacine (Thylacinus potens) which grew to the size of a wolf, was the only species to survive into the late MioceneIn late Pleistocene and early Holocene times, the modern thylacine was widespread (although never numerous) throughout Australia and New Guinea.

An example of convergent evolution, the thylacine showed many similarities to the members of the dog family, Canidae, of the Northern Hemisphere: sharp teeth, powerful jaws, raised heels and the same general body form. Since the thylacine filled the same ecological niche in Australia as the dog family did elsewhere it developed many of the same features. Despite this, it is unrelated to any of the Northern Hemisphere predators.

Descriptions of the thylacine vary, as evidence is restricted to preserved joey specimens, fossil records, skins and skeletal remains, black and white photographs and film of the animal in captivity, and accounts from the field.

The thylacine resembled a large, short-haired dog with a stiff tail which smoothly extended from the body in a way similar to that of a kangaroo. Many European settlers drew direct comparisons with the hyena, because of its unusual stance and general demeanour. Its yellow-brown coat featured 13 to 21 distinctive dark stripes across its back, rump and the base of its tail, which earned the animal the nickname, "Tiger". The stripes were more marked in younger specimens, fading as the animal got older.One of the stripes extended down the outside of the rear thigh. Its body hair was dense and soft, up to 15 mm (0.6 in) in length; in juveniles the tip of the tail had a crest. Its rounded, erect ears were about 8 cm (3.1 in) long and covered with short fur. Colouration varied from light fawn to a dark brown; the belly was cream-coloured.

The mature thylacine ranged from 100 to 130 cm (39 to 51 in) long, plus a tail of around 50 to 65 cm (20 to 26 in).The largest measured specimen was 290 cm (9.5 ft) from nose to tail. Adults stood about 60 cm (24 in) at the shoulder and weighed 20 to 30 kg (40 to 70 lb).There was slight sexual dimorphism with the males being larger than females on average.

The female thylacine had a pouch with four teats, but unlike many other marsupials, the pouch opened to the rear of its body. Males had a scrotal pouch, unique amongst the Australian marsupials, into which they could withdraw their scrotal sac

The thylacine was able to open its jaws to an unusual extent: up to 120 degrees. This capability can be seen in part in David Fleay's short black-and-white film sequence of a captive thylacine from 1933. The jaws were muscular but weak and had 46 teeth.

The thylacine's footprint is easy to distinguish from those of native and introduced species.

Thylacine footprints could be distinguished from other native or introduced animals; unlike foxes, cats, dogs, wombats or Tasmanian devils, thylacines had a very large rear pad and four obvious front pads, arranged in almost a straight line. The hindfeet were similar to the forefeet but had four digits rather than five. Their claws were non-retractable.

The early scientific studies suggested it possessed an acute sense of smell which enabled it to track prey,but analysis of its brain structure revealed that its olfactory bulbs were not well developed. It is likely to have relied on sight and sound when hunting instead. Some observers described it having a strong and distinctive smell, others described a faint, clean, animal odour, and some no odour at all. It is possible that the thylacine, like its relative, the Tasmanian devil, gave off an odour when agitated.

The thylacine was noted as having a stiff and somewhat awkward gait, making it unable to run at high speed. It could also perform a bipedal hop, in a fashion similar to a kangaroo—demonstrated at various times by captive specimens.Guiler speculates that this was used as an accelerated form of motion when the animal became alarmed. The animal was also able to balance on its hind legs and stand upright for brief periods.

Observers of the animal in the wild and in captivity noted that it would growl and hiss when agitated, often accompanied by a threat-yawn. During hunting it would emit a series of rapidly repeated guttural cough-like barks (described as "yip-yap", "cay-yip" or "hop-hop-hop"), probably for communication between the family pack members. It also had a long whining cry, probably for identification at distance, and a low snuffling noise used for communication between family members.

The thylacine was exclusively carnivorous. Its stomach was muscular with an ability to distend to allow the animal to eat large amounts of food at one time, probably an adaptation to compensate for long periods when hunting was unsuccessful and food scarce.Analysis of the skeletal frame and observations of it in captivity suggest that it preferred to single out a target animal and pursue that animal until it was exhausted. Some studies conclude that the animal may have hunted in small family groups, with the main group herding prey in the general direction of an individual waiting in ambush. Trappers reported it as an ambush predator.

Little is known of the thylacine's diet and feeding behaviour. Prey is believed to have included kangaroos, wallabies and wombats, birds and small animals such as potoroos and possums. One prey animal may have been the once common Tasmanian emu. The emu was a large, flightless bird which shared the habitat of the thylacine and was hunted to extinction around 1850, possibly coinciding with the decline in thylacine numbers. Both dingoes and foxes have been noted to hunt the emu on the mainland. European settlers believed the thylacine to prey upon farmers' sheep and poultry.Throughout the twentieth century, the thylacine was often characterised as primarily a blood drinker; according to Robert Paddle, the story's popularity seems to have originated from a single second-hand account heard by Geoffrey Smith in a shepherd's hut. In captivity, thylacines were fed a wide variety of foods, including dead rabbits and wallabies as well as beef, mutton, horse, and occasionally poultry. Tasmania's leading naturalist Michael Sharland published an article in 1957 stating that a captive thylacine refused to eat either dead wallaby flesh or to kill and eat a live wallaby offered to it, but "ultimately it was persuaded to eat by having the smell of blood from a freshly killed wallaby put before its nose."

 A 2011 study by the University of New South Wales using advanced computer modelling indicated that the thylacine had surprisingly feeble jaws. Animals usually take prey close to their own body size, but an adult thylacine of around 30 kilograms (66 lb) was found to be incapable of handling prey much larger than 5 kilograms (11 lb). Researchers believe thylacines only ate small animals such as bandicoots and possums, putting them into direct competition with the Tasmanian devil and the Tiger Quoll. Such specialisation probably made the thylacine susceptible to small disturbances to the ecosystem.

SEBECUS: THE GOD CROCODILE

Sebecus (meaning "Sebek" in Latin) is an extinct genus of sebecid crocodylomorph from the Eocene of South America. Fossils have been found in Patagonia. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by a single species, the type S. icaeorhinus. Several other species have been referred to Sebecus, but were later reclassified as their own genera.

The name Sebecus is a Latinisation of Sebek (also called Sobek), the crocodile god of ancient Egypt. Sebek was considered an alternative to the Greek χάμψαι, or "champsa" in crocodilian nomenclature (the Greek historian Herodotus claimed that champsa was the Egyptian word for crocodile).The specific name icaeorhinus of the type species is derived from the Greek words εικαίοs and ρύγχος. Εικαίοs means "random" or "not according to plan" and ρύγχος means "snout", in reference to the animal's unusually deep snout

Named by American paleontologist George Gaylord Simpson in 1937, Sebecus was one of the first known sebecosuchians. Simpson described the type species, S. icaeorhinus, from a fragmented skull and lower jaw. The specimen was discovered by the American Museum of Natural History's First Scarritt Expedition to Patagonia.[2] Teeth had been known since 1906 when Argentine paleontologist Florentino Ameghino associated them with carnivorous dinosaurs. The more complete material found by Simpson firmly established that the new animal was a crocodyliform. Although Simpson's fossil was considered one of the best finds of the expedition, Simpson described the genus only briefly in 1937. He noted its unusual ziphodont dentition in which the teeth were laterally compressed and serrated. Simpson was preparing a more detailed monograph on the genus, but entered the United States Army before its completion. Another American paleontologist, Edwin Harris Colbert, completed Simpson's work, thoroughly describing the genus and placing it in a new family, Sebecidae. Colbert placed Sebecus and the Cretaceous baurusuchid Baurusuchus (also from South America) in the suborder Sebecosuchia (erected by Simpson for all ziphodont crocodylomorphs), as both had deep snouts and ziphodont teeth.

In 1965, American paleontologist Wann Langston, Jr. named a second species, S. huilensis, from the Miocene La Venta Formation in Columbia.S. huilensis was named on the basis of skull fragments.The deposits are Friasian in age (about 15 million years old), extending the range of the genus into the Neogene by around 40 million years. In 1977, remains were described from the Miocene of Peru.

A third species of Sebecus, S. querejazus, was named in 1991 from the early Paleocene Santa Lucia Formation in Bolivia. This extended the range of Sebecus back to the beginning of the Paleogene, soon after the Cretaceous–Paleogene extinction event. In 1993, Gasparini et al. described Sebecus carajazus. This was not a fourth species but a misspelling, or lapsus calami, of Sebecus querejazus.

A 2007 study of sebecids reclassified several species. The two species S. huilensis and S. querejazus were given their own genera, Zulmasuchus and Langstonia, respectively. Langstonia huilensis, named after Langston, was distinguished from Sebecus by its narrower snout and widely spaced teeth. Zulmasuchus querejazus, named after Zulma Gasparini, one of the authors of the study, differs from Sebecus in its wider snout..

The postcranial skeleton of S. icaeorhinus was virtually unknown until Pol et al. (2012) described postcranial remains of several individuals of this species, including a partially articulated specimen MPEF-PV 1776 with anterior region of the dentary (allowing the identification of this individual as representing S. icaeorhinus) and most of the postcranial skeleton preserved. Estimates of total body length and mass of MPEF-PV 1776 vary from 2.2 to 3.1 m, and from 52.2 to 113.5 kg, respectively. The postcranial skeleton of Sebecus provides additional evidence of its terrestriality. Its limbs, especially femora, were proportionally longer than limbs of living crocodilians; the shoulder-to-hip length of its body can be estimated at 2.3 times the length of the femur - similar to another, unrelated terrestrial crocodylomorph, Pristichampsus, while American alligators have proportionally shorter femora.

Unusual among crocodyliforms, Sebecus has a deep, narrow snout. The nares, or nostrils, open anteriorly at the tip of the snout. While most crocodilians have flat skulls that are raised near the eyes and postorbital region behind the eyes, the skull of Sebecus is essentially level. The great depth of the snout makes most of the length of its upper margin level with the margin of the orbits, or eye sockets. The supratemporal fenestrae, two holes on the skull table, are relatively small.

Top view of a cast of the skull of Sebecus icaeorhinus (AMNH 3160)

Laterally compressed, or ziphodont teeth, are characteristic of Sebecus and other sebecosuchians. Although the teeth vary in size, they are homodont, having a similar shape throughout the jaw. At the tips of the upper and lower jaws, the teeth are rounder in cross-section. The fourth dentary tooth is raised in the lower jaw to form an effective canine. The foremost teeth of the lower jaw are much smaller and lower than the fourth tooth. At the tip of the jaw the first dentary tooth is procumbent, or directed forward. The teeth of the upper and lower jaws form an alternate pattern to allow the jaw to close tightly. A notch is present between the maxilla and premaxilla bones of the upper jaw, accommodating the fourth dentary tooth when the jaw is closed. The procumbent first dentary teeth fit between the first and second premaxillary teeth. This close fit allows the serrated edges of the teeth shear with one another.

The articulation between the articular and quadrate bones at the jaw joint is well developed. Along with the broad downturned "wings" formed by the pterygoid and ectopterygoid bones at the bottom of the skull, this articulation restricts the jaw to up-and-down movement. The jaw movement and close shearing of the teeth suggest that Sebecus was carnivorous. Its compressed, blade-like teeth would have been well-suited for cutting meat. In contrast, living crocodilians have circular, widely spaced teeth and usually consume their food in large pieces. Sebecus likely consumed food in a manner more similar to theropod dinosaurs than living crocodilians. In particular, the teeth of tyrannosaurids bear the closest resemblance to those of Sebecus..Both animals have serrated teeth with rounded projections called denticles, and sharp clefts between the denticles called diaphyses. These diaphyses compress meat fibers between the serrations and rip them apart. Ultrastructural analyses using electron microscopes have revealed microwear scratches on the teeth that are suggestive of this form of cutting.

A cast of the skull roof and jaws of Sebecus icaeorhinus (AMNH 3160)

Colbert's monograph on Sebecus included a description of the brain, Eustachian tubes, and jaw musculature. Details of these soft tissues were inferred from characteristics of the skull and endocasts, or molds of its interior. The deep snout of Sebecus makes the shape of its brain somewhat different from those of living crocodiles, although its structure is the same. The olfactory bulb is elongate and makes up a significant portion of the brain. The cerebrum is narrow and long in comparison to crocodilians, and tapers toward the olfactory bulb. The temporal lobes are somewhat smaller than those of living crocodilians. Colbert interpreted the smaller cerebrum of Sebecus as a sign of primitiveness, with an evolutionary trend toward larger brain size in crocodilians. Hans C. E. Larsson performed a 2001 study of the endocranial anatomy of the dinosaur Carcharodontosaurus saharicus, comparing the ratio of its cerebrum to its total brain volume to the ratios of other prehistoric reptiles. Larsson found that Sebecus and Allosaurus fragilis had similar ratios to C. saharicus, falling within the 95% confidence range characterizing living reptile species.

 The Eustachian tubes, passages that connect the middle ear with the pharynx, are very complex in crocodilians. Unlike those of other vertebrates, the tubes are made of several interconnected branches. This branching is fully developed in Sebecus, and probably appeared much earlier in crocodylomorphs.

The jaw muscles of Sebecus were likely similar to those of living crocodilians, but the distinctively deep skull of Sebecus indicates that the muscles were longer. In Sebecus, the shape of the skull and jaws provides more room for adductor muscles, or muscles that close the jaws. The supratemporal fenestrae at the top of the skull are relatively wide, allowing for the passage of large muscles. In crocodilians, the depressor muscle that opens the jaws originates near the top of the skull and inserts into a projection at the back of the jaw called the retroarticular process. Living crocodilians have a straight retroarticular process at the back of the jaw and a low point of origin for the depressor muscle. Sebecus, with its deeper skull, has a higher point of origin for the depressor, but the retroarticular process curves upward to make the length of the depressor about the same as it is in crocodilians. Like living crocodilians, the depressor muscle of Sebecus was relatively underdeveloped. Therefore, while the closure of the jaws would have been very strong, the ability to open the jaws would be much weaker.

HAAST'S EAGLE

Haast's Eagle (Harpagornis moorei) was a species of massive eagle that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles, which at times reached 80 km/h (50 mph). The Eagle's massive size may have been an evolutionary response to the size of its prey, as both would have been much smaller when they first came to the island, and would have grown larger over time due to lack of competition (see Island gigantism). The Haast's Eagle became extinct around the year 1400, when its major food sources, the moa, were hunted to extinction by Maori living on the island and much of its dense-forest habitat was cleared.

DNA analysis has shown that this raptor is related most closely to the much smaller Little Eagle as well as the Booted Eagle (both of these two species were recently reclassified as belonging to the genus Aquila ) and not, as previously thought, to the large Wedge-tailed Eagle.Thus, Harpagornis moorei may be reclassified as Aquila moorei, pending confirmation. H. moorei may have diverged from these smaller eagles as recently as 700,000 to 1.8 million years ago. Its increase in weight by ten to fifteen times over that period is the greatest and quickest evolutionary increase in weight of any known vertebrate. This was made possible in part by the presence of large prey and the absence of competition from other large predatorsHaast's Eagle was first classified by Julius von Haast in the 1870s who named it Harpagornis moorei after George Henry Moore, the owner of the Glenmark Estate where bones of the bird had been found.

The genus name is a compound crassis word of the Greek word "harpax", meaning 'grappling hook', and the Greek "ornis", meaning 'bird'.

Haast's Eagles were the largest known true raptors, slightly larger even than the largest living vultures. Female eagles are significantly larger than males. Females of the Haast species are believed to have weighed 10–15 kg (22–33 lb) and males 9–12 kg (20–26 lb). They had a relatively short wingspan, measuring roughly 2.6–3 m (8 ft 6 in–9 ft 10 in). This wingspan is similar to that of some extant eagles (the wingspan now reported in large specimens of Golden Eagles and Steller's Sea Eagles). Even the largest extant eagles, however, are about forty percent smaller in body size than the size of Haast's Eagles.

Short wings may have aided Haast's Eagles when hunting in the dense scrubland and forests of New Zealand. Haast's Eagle sometimes is portrayed incorrectly as having evolved toward flightlessness, but this is not so; rather it represents a departure from the mode of its ancestors' soaring flight, toward higher wing loading. Two of the largest extant eagles, the Harpy Eagle and the Philippine Eagle, also have similarly reduced relative wing-length in adaptation to forest-dwelling.

The strong legs and massive flight muscles of these eagles would have enabled the birds to take off with a jumping start from the ground, despite their great weight. The tail was almost certainly long, up to 50 cm (20 inches) in female specimens, and very broad. This characteristic would compensate for the reduction in wing area by providing additional lift. Total length is estimated to have been up to 1.4 m (4 ft 7 in) in females, with a standing height of approximately 90 cm (2 ft 11 in) tall or perhaps slightly greater.

Haast's Eagles preyed on large, flightless bird species, including the moa, which was up to fifteen times the weight of the eagle. It is estimated to have attacked at speeds up to 80 km/h (50 mph), often seizing its prey's pelvis with the talons of one foot and killing with a blow to the head or neck with the other.[citation needed] Its size and weight indicate a bodily striking force equivalent to a cinder block falling from the top of an eight-story building. Its large beak also could be used to rip into the internal organs of its prey and death then would have been caused by blood loss.[citation needed] In the absence of other large predators or scavengers, a Haast's Eagle easily could have monopolised a single large kill over a number of days

Early human settlers in New Zealand (the Māori arrived around the year 1280) preyed heavily on large flightless birds, including all moa species, eventually hunting them to extinction. The loss of its natural prey caused the Haast's Eagle to become extinct as well around the year 1400, when the last of its natural food sources were depleted.

A noted explorer, Charles Edward Douglas, claims in his journals that he had an encounter with two raptors of immense size in Landsborough River valley (probably during the 1870s), and that he shot and ate them. These birds might have been a last remnant of the species, but some might argue that there had not been suitable prey for a population of Haast's Eagle to maintain itself for about five hundred years before that date,[citation needed] and 19th century Māori lore was adamant that the pouakai was a bird not seen in living memory. Still, Douglas' observations on wildlife generally are trustworthy; a more probable explanation, given that the alleged three-metre wingspan described by Douglas is likely to have been a rough estimate, is that the birds were Eyles' Harriers. This was the largest known harrier (the size of a small eagle) — and a generalist predator — and although it also is assumed to have become extinct in prehistoric times, its dietary habits alone make it a more likely candidate for late survival.

Until recent human colonisation that introduced rodents and cats, the only mammals found on the islands of New Zealand were three species of bat, one of which recently has become extinct. Free from terrestrial mammalian competition and predatory threat, birds occupied or dominated all major niches in the New Zealand animal ecology because there were no threats to their eggs and chicks by small terrestrial animals. Moa were grazers, functionally similar to deer or cattle in other habitats, and Haast's Eagles were the hunters who filled the same niche as top-niche mammalian predators, such as tigers or lions.

GORGONOPS

 Gorgonops is an extinct genus of therapsid which lived about 255-250 million years ago, during the latest part of the Permian Period. It was a typical representative of the suborder Gorgonopsia, the dominant predators of their day, which in the largest forms grew to over four metres long. Gorgonops possessed highly developed, 12-cm long "sabre" canine teeth, similar to those found in sabre-toothed cats in the Cenozoic. Arguments have even been made for therapsids of its time being endothermic, though no strong evidence exists either way. All of the gorgonopsids are believed to have died out in the Permian extinction.
Gorgonops itself was a medium to large-sized representative of the group, with a skull length of twenty to thirty-five centimetres, depending on the species. It ranged from 1.5 to 3 metres long from nose to tail. Gorgonops derived superior speed from long legs held beneath its body.
The holotype of the type species, Gorgonops torvus, was in 1876 one of the first therapsids described, by Richard Owen, who also coined the name "Dinosauria" on the basis of the first known dinosaur fossils. It was also used as the type for which Richard Lydekker described the family in 1890. Five years later, in 1895, Harry Govier Seeley used this genus to establish the group as a whole. In later years, a large number of further species and genera were designated, but some of these turned out to be synonyms

The following list of species follows the list provided Sigogneau-Russell, 1989. The type species is listed first, then others in alphabetical order.

Since the publication of the work cited above, the dating of the Karoo Basin (Beaufort Group) has been revised. According to Smith and Keyser 1995, Gorgonops is known from the Tropidostoma and most of the Cistecephalus Assemblage Zones, and this has been taken into account when compiling the following list.
Gorgonops torvus (Owen, 1876) The type species. The holotype is an incomplete and flattened skull found at Mildenhalls, Fort Beaufort, South Africa. A number of other specimens have been found since, all from the Tropidostoma and/or Cistecephalus Assemblage Zone(s). This was a medium-sized therapsid, with a skull about twenty cm in length. It is distinguished from other species by a longer snout, and other details of the bones of the skull. Originally considered rather simple, it is actually (according to Sigogneau-Russell) a rather specialised member of the group.
Gorgonops longifrons (Haughton 1915) A large specimen known from an incomplete and flattened skull about thirty-five cm long. Orbit larger and snout longer than G. whaitsi, from which it may have descended. Beaufort West, Tropidostoma/Cistecephalus Assemblage Zone. Synonyms: Gorgonognathus longifrons Haughton 1915

Gorgonops whaitsi (Broom, 1912) Larger than G. torvus, with the rear of the skull wider, and other details of proportion. Originally the type species of Scymnognathus. Despite being known from a large number of specimens from the Karoo Basin, Beaufort West (Tropidostoma/Cistecephalus Assemblage Zone), the species remains poorly known. Watson and Romer placed Gorgonops and Scymnognathus in two different families, while Sigogneau-Russell 1989 placed the two species in the same genus, and considers G. whaitsi a more primitive (less derived) form. Synonyms: Scymnognathus whaitsi Broom, 1912
The following are more problematic species (either synonyms or uncertain placement):
Gorgonops? dixeyi (Haughton, 1926) A large, incomplete and flattened skull, from Chiweta Beds, Nyassaland. Placement uncertain. Probably Low Cistecephalus Assemblage Zone equivalent (= middle of the Wuchiapingian Stage). See Jacobs et al. 2005 for more on this species discussion on its age. Synonyms: Chiwetasaurus dixeyi Haughton, 1926
Gorgonops? kaiseri (Broili & Schroeder, 1934). A large (estimated total length about 35 cm long), incomplete skull, with a high snout and narrower in the rear than other species, from the "High Tapinocephalus zone" (i.e. earlier than the other species, most probably Pristerognathus Assemblage Zone) Synonyms: Pachyrhinos kaiseri Broili & Schroeder, 1934
Gorgonops? eupachygnathus (Watson, 1921) A flattened, incomplete, medium-sized skull, probably a juvenile of either G. torvus or G. whaitsi Synonyms: Scymnosuchus whaitsi Watson, 1921, Scymnognathus whaitsi (Watson, 1921), Leptotrachelus eupachygnathus WATSON, 1921, Leptotracheliscops eupachygnathus (Watson, 1921)

ENTELODONTS:THE TERMINATOR PIGS

Entelodonts, sometimes nicknamed hell pigs or terminator pigs,are an extinct family of pig-like omnivores endemic to forests and plains of North America, Europe, and Asia from the middle Eocene to early Miocene epochs (37.2—16.3 mya), existing for approximately 20.9 million years.

Entelodontidae was named by Richard Lydekker and assigned to Nonruminantia by Gregory (1910). Then assigned to Artiodactyla by Lucas et al.[4] (1998); and to Entelodontoidea by Carroll (1988) and Boisserie et al. (2005). While entelodonts have long been classified as members of the Suina, Spaulding et al. have found them to be closer to whales and hippos than to pigs.

[edit]ntelodonts are an extinct group of rather pig-like omnivorous mammals with bulky bodies but short, slender legs, and long muzzles. The largest were the North American Daeodon shoshonensis, the Entelodon and the Eurasian Paraentelodon intermedium, standing up to 2.1 metres (6.9 ft) tall at-shoulder, with brains the size of an orange.

A single specimen was recorded by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass and was estimated to have a weight of 421 kg (930 lb).

Entelodonts had a full set of teeth, including large canines, heavy incisors, and relatively simple, yet powerful, molars. These features suggest an omnivorous diet, similar to that of modern pigs. Like many other artiodactyls, they had cloven hooves, with two toes touching the ground, and the remaining two being vestigial.

The most distinguishing characteristic of the animals, however, would have been the heavy, bony lumps on either side of their heads which are similar to a warthog's. Some of these may have been attachment points for powerful jaw muscles, but some were larger in males, suggesting that they may also have had a role in competition for mates.Entelodonts lived in the forests and plains where they were the apex predators of North America's Early Miocene and Oligocene, consuming carrion and live animals and rounding off their diet with plants and tubers. They would have hunted large animals, like the cow-sized artiodactyl Eporeodon major and the sheep-sized cameloid Poebrotherium wilsoni, dispatching them with a blow from their jaws. Some fossil remains of these other animals have been found with the bite marks of entelodonts on them. Like modern day pigs, they were omnivores, eating both meat and plants, but their adaptations show a bias towards live prey and carrion. They were most likely opportunists, mainly eating live animals, but not sneering at carrion and roots and tubers in times of drought. Some entelodonts even exhibited cacheing behavior, as an Archaeotherium's cache has been discovered, made up of the remains of several early camels.

Entelodonts appear in the third episode of the popular BBC documentary Walking with Beasts, where in the program, the narrator always refers to the creatures as "Entelodonts," rather than a more specific genus, such as Entelodon or Archaeotherium. The same creatures appear in another BBC production the 2001 remake of The Lost World. Entelodonts were also the main focus of Episode 4 of National Geographic Channels show Prehistoric Predators in an episode titled Killer Pig. The episode featured Archaeotherium (identified as "Entelodont") as being the top predator of the American Badlands, and how it evolved into the even larger Daeodon (aka "Dinohyus").