Malevus

Tag: Sarkastodon

  • Patriofelis: The Father of Cats, A Jaguar-Like Prehistoric Animal

    Patriofelis: The Father of Cats, A Jaguar-Like Prehistoric Animal

    The fossils of the extinct Oxyaenodonta mammal Patriofelis (genus Patriofelis) have been discovered in North America, and they existed during the middle Eocene (about 48 to 40 million years ago). Although the resemblances between this predator and a modern jaguar were the consequence of convergent evolution, they were still strikingly similar. Patriofelis was a massive Oxyaenodonta (“sharp hyena”), measuring in at over 100 inches (250 cm) in length (including its tail).

    The Discovery of Patriofelis

    Patriofelis The Father of Cats
    Patriofelis, the “Father of Cats”.

    Joseph Leidy initially defined the genus Patriofelis in 1870 using fossils discovered in Middle Eocene soils in Wyoming; the type species is Patriofelis ulta, which was also discovered in Colorado. Fossils of P. ferox, another well-known species, have been discovered in somewhat older soils in Wyoming and Oregon.

    Patriofelis is typical of the Oxyaenodontas (“sharp tooth hyenas”), a widespread group of animals from the Paleocene and Eocene that exhibited extreme carnivory. Among the Oxyaenodonta, Patriofelis was both huge and highly specialized. The smaller Oxyaena, the related Malfelis genus, and the enormous Sarkastodon were its closest relatives.

    The Lifestyle of This Animal

    Patriofelis ferox by Charles R. Knight.
    Patriofelis ferox by Charles R. Knight.

    A Scavenger

    Despite its small size, Patriofelis was clearly an effective predator because of its robust set of teeth and smaller skull. Patriofelis must have been an active scavenger, since the skeleton seems to be designed to enable the animal to climb trees, despite this trait being more often associated with predators who feed on carrion. Not built for speed, this predator was better adapted to ambush hunting.

    Unique Adaptations

    Right hand of Patriofelis.
    Right hand of Patriofelis.

    Since the fossils of Patriofelis have been discovered at river deoposites and flood zones, this may imply that this animal was suited to walking on soft terrain, like riverbanks. Because of its small legs and widely spaced fingers, several researchers have hypothesized that Patriofelis was a strong swimmer. Given Patriofelis’ massive size, it’s hard to believe that this animal ever engaged in burrowing behavior, as suggested by the morphology of its upper arm bone (humerus) and hand.


    The Distinct Features of Patriofelis

    Powerful Jaw Muscles and a Strong Bite

    The cranium of this prehistoric animal was huge, measuring up to 10 inches (25 cm) in length and as big as a lion’s. It also had a short nose. In contrast to other creodonts (“meat teeth”), Patriofelis had some distinct skull features. For starters, it had special ear bones (ossified tympanic bulla) and passages in its skull that were likely linked to its hearing, sensory perception, facial expressions, etc.

    The depiction of the Patriofelis.
    The depiction of the Patriofelis.

    When we look at its skull, we see large ridges where muscles are attached, showing it had powerful jaw muscles. Its cheekbones were strong, and its lower jaw was sturdy despite being not very long. Interestingly, the teeth of this ancient animal were quite distinct. The upper premolars had sharp internal edges, and their incisors were smaller than their canines. It was also missing its top third molar. Additionally, the upper back teeth were shaped like sharp blades, indicating they likely had a strong bite.

    All these features give us clues about Patriofelis as a prehistoric mammal. It probably had a strong bite and might have been really good at hunting. Thanks to its ear bones and facial structures, it had acute senses like a modern felidae.


    A Shorter Body but a Muscular Tail

    Patriofelis had a somewhat sturdy skeleton. It had a shorter body and a neck of average length compared to other creodonts. The lumbar vertebrae in Patriofelis connected in a way that resembled how some animals with split hooves, like deer or cows, have their spines arranged.


    However, it was on a more complicated scale. A long, muscular tail curled out from the body towards the end.

    The lower extremities, and the forelegs of the Patriofelis in particular, were short and powerful. The shoulder blade of Patriofelis had specific features. It had two equal-sized depressions and large protrusions. Additionally, there was a visible bony projection. These shoulder blade characteristics indicate good mobility and advanced hunting techniques for Patriofelis. These features were generally typical among early meat-eating animals.

    Patriofelis shared similarities in its upper arm bone with its relative, the Oxyaena (“sharp hyena”), but it had more distinctive traits. Notably, it had a highly developed deltoid crest, which is a bony ridge where powerful shoulder muscles attach. Thus, Patriofelis likely had strong chest and shoulder muscles which makes it powerful as a predator.

    Powerful Leg Muscles

    As expected, the size of the olecranon (an elbow bone), along with other features, suggests that Patriofelis was exceptionally adept at walking. Its well-adapted limbs and muscles likely allowed it to move efficiently.

    Patriofelis also had a unique hip and leg structure. Its femur, the thigh bone, could move freely due to its long ilium (a part of the pelvic bone) which provided a sturdy base for attaching powerful gluteal muscles that are crucial for movement. A bony protrusion on the femur was positioned at a higher angle in Patriofelis which indicates robust leg muscles.

    Almost Dull Claws

    The limbs of this animal ended in pentadactyl hands and feet, meaning it had five digits on each. This is still a common trait among mammals after millions of years. However, Patriofelis had small and widely spaced toes with slightly blunt nail phalanges, suggesting that its claws weren’t extremely sharp.

    These features hint at its ability to walk effectively but it might not have been specialized for climbing or grasping prey with its claws because its claws probably weren’t that sharp.

  • Andrewsarchus: One of the Biggest Predatory Land Mammals

    Andrewsarchus: One of the Biggest Predatory Land Mammals

    • Andrewsarchus has one of the largest jaws of any land carnivorous mammal known to date.
    • It has an elongated snout, measuring approximately 20 inches.
    • This animal was one of the biggest known predatory land mammals, with a length between 150–180 inches, and 2,000 lb of weight.

    Extinct huge carnivorous animals known as Andrewsarchus (Andrewsarchus mongoliensis) formerly roamed Central Asia (Inner Mongolia, China) during the Middle Eocene over 41 million years ago. It is known only from a complete skull from Inner Mongolia, where it was discovered in 1923. Originally identified as the largest representative of the Mesonyhids, the systematic position of Andrewsarchus is not clear today, but a close relationship with the cloven-hoofed animals is assumed.

    Two Distinctive Features

    A depiction of Andrewsarchus.
    A depiction of Andrewsarchus.

    One distinctive feature of this prehistoric mammal was the elongated snout, which measured a good 20 inches from the position of the first incisor to the posterior molar, while the posterior skull was correspondingly short and had only around 70% of the length of the snout. Another distinctive feature of this mammal is that it has one of the largest jaws of any land carnivorous mammal known to date.

    The Andrewsarchus was called a “sheep in wolf clothing” in the BBC program Walking with Beasts due to its proximity to ungulates and its potential predatory nature. In this program, it was reconstructed to look like a giant hyena with hooves. This is based on the assumption that this species was not very agile due to its huge body size and that it fed mainly on slow-moving prey and carcasses.

    Andrewsarchus
    (Apokryltaros, cc by sa 3.0)

    It belongs to the order Mesonychia and the family Triisodontidae. These creatures are primordial ungulates, meaning they still have their original five- or four-toed limbs with hooves on the ends.

    Andrewsarchus is the sole member of its genus.

    The Meaning Behind the Naming

    The name of this genus comes from the Greek term for “chief,” “leader,” and “regal,” (άρχος or archos) and the surname of the expedition commander, Roy Chapman Andrews. The species name “mongoliensis” for this species honors Inner Mongolia, the location where the fossils were discovered.

    Discovery of the Andrewsarchus

    Depiction of Andrewsarchus.
    A depiction of Andrewsarchus.

    In 1924, Henry Osborn wrote a description of Andrewsarchus based on a single, roughly 33-inch-long skull that Roy Chapman Andrews (1884–1960) discovered in Inner Mongolia. An assistant paleontologist named Kan Chuen Pao discovered the skull in the spring of 1923 in the Eocene deposits of the Irdin Manha Formation, which dates back to the late middle Eocene. Also, a sarkastodon bone was found in the same place.

    This skull was discovered during the Third Central Asiatic Expedition of the American Museum of Natural History in the Inner Mongolian part of the Gobi Desert. The skull was found by expedition member George Olsen in the Erlian Basin. It was located in the Irdin-Manha Formation, a rock formation with more than 200 inches of grayish-white to grayish-yellow sandstones and sandy gravels, as well as numerous cylindrical calcareous concretions. The formation dates to the Middle Eocene, 46 to 40 million years ago, which gives a clue to the age of Andrewsarchus.

    The skull can be inspected right now at New York’s American Museum of Natural History.

    An Andrewsarchus model
    An Andrewsarchus model. This wolf-like appearance is disputed. (Boris Dimitrov, cc by sa 3.0, cropped)

    What Did Andrewsarchus Look Like?

    2,000 Pounds of Weight

    Andrewsarchus is one of the biggest known predatory land mammals (the polar bear is now the greatest land predator). The skull measured 32.8 inches in length (the greatest length of a contemporary brown bear’s head is 22 inches) and 22 inches in width at the zygomatic arches. Thus, the skull is about twice the size of an adult grizzly bear.

    Reconstructions put the whole length of the Andrewsarchus at about 150 inches; other calculations put it at around 180 inches, including a tail that might be as long as 60 inches. Andrewsarchus might reach up to 63 inches in height at the withers. 2,000 pounds of weight was possible for this big predatory land mammal.

    Strong Bites and Enormous Fangs

    The animal’s large nose and broad zygomatic arches contributed to its low head. Large canines and incisors were paired with blunt molars. The brain cavity was tiny, as it usually is in most mesonychids. At the same time, the mandibular condyle was placed low, the temporal foramen was broad, and there was a prominent sagittal crest.

    Andrewsarchus mongoliensis skull cast, British Museum (Natural History).
    Andrewsarchus mongoliensis skull cast, British Museum (Natural History). (Alexei Kouprianov cc by sa 3.0, cropped)

    In English, all of these point to the existence of a well-developed temporal muscle and a strong bite in Andrewsarchus. If the size of the dental alveoli or the sockets in the jaws is any indication, Henry Osborn’s original description of the species draws attention to the “enormous size” of the fangs of the Andrewsarchus. Since the initial reconstruction of Andrewsarchus relied on a comparison to a smaller mesonychid, Synoplotherium (Dromocyon), it resembled a wolf and had relatively long legs and an extended skull.

    The reconstruction was based on the fact that this mammal was long thought to be a close cousin of predators belonging to the group Mesonychidae, which were mostly rebuilt as wolf-like creatures despite having emerged much before the advent of actual wolves.

    Long Torso, Small Legs, and a Huge Head

    The current conception of Andrewsarchus posits that it had a long torso, small legs, and an extended, disproportionately huge head. In accordance with the nature of the mesonychids for which skeletons are available, the Andrewsarchus is often represented as toe-walking, resting on four toes. It’s possible that, like ancient Mesonychids, it still had five toes on each paw. Similar to other mesonychids, it probably had hooves on each toe. Its limbs ended in split phalanges, similar to those found in condylarth mammals.

    Habits and Behaviour of Andrewsarchus

    Wide Variety of Foods

    The details regarding the daily existence of this prehistoric animal are mostly unknown. The animal’s low sagittal crest and tuberous cheek teeth indicate its ability to eat a wide variety of foods. Its premolar teeth measured 2.3 inches while the biggest molar was 2.6 inches wide.

    Carnivorous Diet

    An Andrewsarchus skull
    An Andrewsarchus skull. (MikSed cc by sa 4.0)

    Additionally, their packed row of teeth could grind through bone. The Andrewsarchus’ large pharynx and fang-like second set of incisors point to its carnivorous diet. The incisors likely improved the animal’s grip on the skin, making it easier to break off chunks of meat.

    The structure of the jaw joint enabled this prehistoric animal to extend its mouth widely, exposing the cheek teeth for grabbing huge prey. The muzzles (snouts) of highly specialized predators like this are often shorter, and they have fewer teeth overall than those of generalist predators.

    An Adapted Scavenger

    Because of its enormous size, the animal was unusual in its movements. The short, somewhat obliquely oriented eyes, the long, narrow face, and the relatively deep nasal depression all suggest that Andrewsarchus may have been an adapted scavenger. Apparently, it could also scare away lesser predators (such as the huge bear-sized Harpagolestes mesonychid) from its prey. Andrewsarchus may also be capable of hunting live prey.

    A Semi-Aquatic Animal

    Its large head suggests it may have had a semi-aquatic existence and eaten fish (similar to other reptiles that do so, such as crocodiles, gharials, and phytosaurus). The rounded shape of the cheek teeth, however, refutes the theory of a fish-only diet.

    One cannot rule out the possibility of Andrewsarchus meeting on the shores, where it gathered up washed-up carrion or possibly hunted small animals. However, present paleontological concepts suggest that the known areas of findings in the Eocene were relatively distant from the seas; therefore, it is plausible that the beast’s habitat was on the seashores.

    A diet that included carrion, young, and small animals, as well as scaring away smaller predators from its prey, suggests that Andrewsarchus was an omnivore like contemporary bears. The skull, which is similar in form to the skulls of entelodonts, suggests as much.

    Categorizing the Andrewsarchus

    A head model of Andrewsarchus. This model is dog-like and considered outdated.
    A head model of the animal. This model is dog-like and it is disputed. (Ben Sutherland, cc by sa 2.0)

    Formerly classified with the family Mesonychidae or the family Arctocyonidae, Andrewsarchus is now the only member of its own family, Andrewsarchidae.

    The systematic position of Andrewsarchus, a genus of ancient mammals, remains uncertain. Initially thought to be a huge porcupine of the Entelodon genus, it was later considered a mesonychid, related to Mesonyx and Harpalogestes. Mesonychids, extinct ungulates from the Paleogene of North America and Asia, were primarily carnivorous or omnivorous with five-toed limbs.

    Modern studies propose the classification of Andrewsarchus in Cetartiodactyla, although their exact placement is debated, either as a stem group or in Cetancodontamorpha.

    Andrewsarchus, once in the Triisodontidae family, is now seen as a sister taxon to even-toed ungulates, closely related to entelodonts, whales, hippos, and certain anthracotheres. Only one established species, Andrewsarchus mongoliensis, exists; reports suggest two more species, A. crassum and Paratriisodon henanensis, though the latter’s classification is uncertain.

    Fragmentary remains of Andrewsarchus found in China indicate its presence in Dongjun, Hetaoyuan, and Lushi. There is still debate about whether Andrewsarchus crassum is a separate species. In 1959, a piece from the Lushi Formation in Henan Province, China, was used to describe a possible synonym called Paratriisodon.

    In Popular Culture

    Andrewsarchus in ARK: Survival Evolved (2015).
    Andrewsarchus in ARK: Survival Evolved (2015).
    • Walking with Beasts, a 2001 TV series, prominently featured Andrewsarchus, although in its antiquated mesonychid form.
    • Andrewsarchus is also featured in popular a video game called ARK: Survival Evolved (2015).

    References

    1. PDF. Thewissen et al. reply (nature.com)
    2. Morphological Support for a Close Relationship between Hippos and Whales on JSTOR
    3. (PDF) Chapter 10 – Ecomorphological analysis of carnivore guilds in the Eocene through Miocene of Laurasia. (researchgate.net)
  • Sarkastodon: A Giant Wolverine or a Bear Cat with a Long Tail

    Sarkastodon: A Giant Wolverine or a Bear Cat with a Long Tail

    • Ancient Asian predator of the Eocene era.
    • Skull discovered in 1930s China, revealing massive size and unique features.
    • Carnivorous diet, possibly scavenging carrion and hunting prehistoric animals.

    During the Eocene, Asia (Mongolia and Inner Mongolia) was home to a genus of predatory animals known as Sarkastodon (“meaty tooth,” from the Greek σαρκάζω – to rip flesh and ὀδούς – tooth), which belong to the family Oxyaenidae of the Creodonts. This is one of the few Asian members of the mostly American family Oxyaenidae.

    The Discovery of Sarkastodon

    Skull of Sarkastodon mongolensis
    Skull of Sarkastodon mongolensis.

    In 1930, the Central Asian Expedition of the American Museum of Natural History uncovered the skull of a Sarkastodon mongoliensis that had been substantially damaged. The discovery was made in the Irdin-Manha Formation, which is located near the town of Iren-Dabasu in China and contains Eocene strata (the skull of the famous Andrewsarchus was also discovered in these levels). A right mandibular branch was discovered in the same age sediments two years before the skull was unearthed in the Ulan-Shireb region (about 100 miles away). There were no bones beyond the skull.

    Sarkastodon
    Sarkastodon

    In 1938, Walter Granger provided the first description of the Sarkastodon species.

    A huge oxyaenid (perhaps a Sarkastodon) molar tooth was discovered in Hetaoyuan, China, in the 1970s. S. henanensis, a species of questionable legitimacy, was described based on this discovery. The discovered tooth has a chance of being from the type species as well.

    A Sarkastodon Compared to a Patriofelis

    Patriofelis ferox.
    Patriofelis ferox.

    Sarkastodon was a typical oxyaenid, with a head shape like that of the famous Patriofelis (“father of cats”) who lived in the middle Eocene Wyoming.

    Short, wide, and heavy, with a prominent jaw, characterized the skull of this creature. A Sarkastodon had a short muzzle. Its lower incisors were quite small and tucked in between the molars, making them invisible from the side.

    However, the massive canines and the molars could be seen clearly. Its lower incisors were drastically smaller, but the lower premolars were much larger than a Patriofelis, whereas the incisor of the first molar was significantly more developed. When compared to that of Patriofelis, the skull of a Sarkastodon was noticeably shorter.

    Sarkastodon
    Sarkastodon

    The Appearance and Size of This Animal

    The dimensions of the Sarkastodon skull, as determined by Walter Granger, are about 21 inches (53 cm) in length and 15 inches (38 cm) in width (at the cheekbones). Sarkastodon’s body and head length were around 102 inches (260 cm) (excluding the tail length of 67 inches or 170 cm), its pelvis height was 49 inches (125 cm), and its mass was 1300 to 1750 pounds (600–800 kg), making a Sarkastodon about the size of the biggest polar bear today. It measured 10 feet (3 m) in length.

    The Sarkastodon has traditionally been portrayed as looking like a giant wolverine or a bear with a long, fluffy tail. This animal was related to Patriofelis; therefore, it probably looked like a big cat with short yet strong legs. It probably didn’t use its paws while hunting. Skull shape suggests that, like other oxyaenids, they had a cat-like snout.

    What Did a Sarkastodon Hunt?

    It is hypothesized that Patriofelis, Sarkastodon’s closest living cousin, had a strictly predatory lifestyle. Some have speculated that it consumed turtles and crocodiles (in keeping with its presumed semi-aquatic existence).

    The snout and teeth of a Sarkastodon were worn down, as if the animal were an active predator, although the skull and teeth of hyenas are otherwise comparable.

    It’s possible that this bear-cat, like other ancient carnivores, relied heavily on carrion for sustenance. Prehistoric rhinoceroses, for instance, might have made good dinner for it.

    Competitors to the Sarkastodon might have included huge hyaenodons and Andrewsarchus. One counterargument is that Andrewsarchus and Sarkastodon did not share the same environment. The larger Andrewsarchus, for instance, was well-suited to broad plains, while the more arboreal and mountainous Sarkastodon was more suited to forests.

    References