Carnivora

## About

Carnivora is a classification of mammals that includes all carnivorous terrestrial placental mammals. Carnivorans are named for their carnivorous diet which only includes meat. the word carnivora itself is derived from the Latin *carō* meaning 'flesh' and *vorāre* meaning 'to devour'. Carnivora is a monophyletic order, meaning it includes the common ancestor of all cat and dog like animals as well as its descendants. Carnivora is the fifth largest mammalian order and includes 279 species. Carnivorans are not limited to a single environment or continent and can be found worldwide in many regions and biomes. The species that are classified under carnivora can be further classified into two suborders, feliformia and caniformia. feliformia includes species classed as cat-like carnivorans. These animals are related more closely to felines than to to canines. Caniformia includes animals classed as dog-like carnivorans and refers to species that are more closely related to canines than to felines. Carnivorans first appeared in the fossil record 60-40mya during the early Paleocene to mid Eocene. Carnivorans were not the first carnivorous mammalian order however, and other groups were established before them. The thylacoleo ***(Thylacoleo carnifex)*** and other various marsupial predators had been abundant before the evolution of carnivorans, throughout the wilderness of Australia. Evolution independent from carnivorans found in Marsupials has been documented many times from Borhyaenidae in South America and members of Dasyuridae in Australia. Much more notably, the order Creodonta served as a major precursor to carnivorans in terms of placental mammals. Creodonts (or Creodontans) were just as diverse as modern carnivorans, having taxa as large as modern day wolves to taxa that closely mirror extant mongooses. Taxa belonging to this order are said to have first appeared in the fossil record during the early tertiary period (65-2.588mya). The similarities between the two order were so close that; Creodonta was at one point said to have been the ancestral order to carnivora and all placental mammals, until this hypothesis was proven incorrect.

## Extinct Families

### Extinct feliformia

#### Nimravidae

Nimravidae is an extinct family of carnivores, commonly known as false sabre-toothed cats that ranged from North America to Eurasia. This nimravids are not actually members of the felidae family unlike true sabre-tooth cats. Though they are in fact included in the suborder feliformia that originated during the middle Eocene to the late Miocene epochs that occurred around 33.2 Mya. The nimravidae family is similar to the sabre-toothed cat subfamily machairodontinae. These cats had very low slung bodies much like other members of the feliform suborder. The nimravidae family diverged from machairodontinae around 50 Mya having a similar but smaller facial structure and smaller canine teeth. These differences were formed through parallel evolution creating two subfamilies with different traits. One of the genera that falls under nimravidae is Dinictis which is comprised only by one species named, D. felina. This cat had a much smaller face structure and bone fragments. The second species in the genus Dinailurictis, was a caracal like feliform that diverged from Quercylurus*,* a much larger 300kg (661lbs) 1m (3.2ft) tall lynx-type build. Those in Dinailurictis were much smaller feliforms that were similar to bobcats, in the sense of its much smaller frame compared to other nimravids. Another genus, the Eofelis diverged and has no living representatives. Both Maofelis and Pogonodon were doth around during the Oligocene of Asia. Dinaelurus existed around 10.2 Mya but had little to no sabre-tooth cat like attributes, with a rounded face and a lack of canines. They were very broad for their size and possessed conical teeth. The last two genera of nimravidae, Hoplophoneus and Nanosmilus who lived around 6 Mya, were not technically true cats, though similar in outward morphology, especially Hoplophoneus with some members being around 160kg (352lbs), mirroring true predatory cats.

#### Palaeogaliidae

The palaeogaliidae family refers to 4 species of early mammals that lived from the late Eocene, early Oligocene to late Miocene in parts of Europe and east Asia. The sole Paleogaliid genus Paleogalie, appeared first around 32 mya living as small mustelid-like mammals. It is comprised of the 4 species: *P. sectoria, P. minuta, P. hyaenoides and P. dorothiae.* All these taxa are related to the oldest member, P. minuta. These species only lasted around 11 Mya before dying out in the late Oligocene. It is currently unclear of the certain anatomy and actual taxonomic evolution of Paleogaliidae.

#### Barbourofelidae

Barbourofelidae is an extinct family of false sabre-tooth cats that lived in North America, Eurasia and Africa during the Miocene epoch (16.9—9.0Mya) meaning it existed for around 7.9 million years, before going completely extinct. The family has been described as a sister group of machairodontinae (True sabre-tooth cats). barbourofelidae was originally thought to be a part of nimravidae, another genus of false sabre tooth cats. The family originally appears during the early Miocene in Africa. By the end of the early Miocene era, land bridges to Asia had appeared and the barbourofelids were able to travel and further and become abundant worldwide. The genus Sansanosmilus began to evolve in Europe and by the late Miocene the barbourofelids had reached North America. Ginsburgsmilus was a member of the genus that was endemic to Africa. The only noted species, G. napakensis, lived around 20 - 19 Mya. prosansanosmilus is another barbourofelid genus that lived in Europe during the Miocene epoch (16.9—16.0 Mya), It only lasted around 0.9 million years before the sole species, prosansanosmilus peregrinus, died out. This genus was also originally classified as a member of the nimravidae family. barbourofelis*,* the largest genus in the family, lived around 13.6 to 7.3 Mya and was endemic to North America and Eurasia during the Miocene. Two species in the genus, B. fricki and B. morrisis, were thought to have muscular robust bodies and express similar features to an extant lion. The species measured around 90 cm (2.11 ft) in shoulder height. Like other members of of the superfamily machairodontinae, barbourofelidae was much more similar to a true sabre-tooth cat, with bony extensions on either side of the lower jaw and a bear like build. Albanosmilus was another genus that lived through the Upper Miocene in Europe, Asia, and North America. This genus resembled a bear-like lion and was much stockier than extant big cats.

#### Lophocyonidae

Lophocyonidae is an extinct family of the feliform group that lived during the Miocene in Europe. Much similar to the racoon and coati families of today that fall under the procyonidae genus. The only genus of lophocyonidae is Sivanasua. They ranged from different regions of Europe from Austria to Spain. The adaptive molars indicate that this mammal had an exclusively herbivorous diet, which is unique among carnivorans.

#### Percrocutidae

Percrocutidae is an extinct hyena-like family of feliforms that were endemic to the Old World, including: Asia, Africa and Southern Europe during the mid Miocene epoch, existing for only around 8 million years. There are only 2 genera that belong to this family, being dinocrocuta *and* percrocuta*.* Dinocrocuta was originally identified as a member of the still extant hyaenidae family, but was recently placed percrocutidae. The species within this genus has been found to have had rough shoulder heights of 1.9 m (6.2 ft) and 1.3 m (4.3 ft). The species have also been said to weigh around 380 kg (840 lb). The dinocrocuta species were the apex predators of their time throughout Eurasia, using their large frame to dominate their prey. Chilotherium, a large rhinoceros like herbivore of its time, was often seen as dinocrocuta's prey of choice, as it was dense and offered sustainability for a large predator. Paleontologists know that this was the cause because of dinocrocuta's distinctive bite marks on the rhinos skull, indicating that this large herbivore was likely apart of the predator's diet. The second genus, percrocuta was much like dinocrocuta in its robust body and a length of around 1.50 m (5 ft). This genus much like todays hyaenids had a very powerful torso and skull along with hind legs that were shorter than its front legs, having a plantigrade stance.

### Extinct caniformia

#### Amphicyonidae

Amphicyonidae is an extinct family of terrestrial carnivorans that fall under the sub order caniformia. This family first appeared in North America during the mid Miocene around 45 Mya and slowly started spreading across the globe during the late Eocene. These animals started reducing in numbers during the late Miocene 8 Mya, the last recorded species was found in Pakistan at the end of the Miocene. These were among some of the first carnivorans, evolving a larger and more robust figure/body. Even though they were much larger in comparison their dental and facial structure to other dog-like canines, amphicyonids are often colloquially referred to as "*bear-dogs*". Amphicyonids could range from 5 kg (11 lb) all the way to the larger species which were as large as 100-773 kg (220-1,704 lb) varying lots between species. An earlier species, Daphoenodon, possessed a digitigrade posture and locomotion (walking on their toes). As the the family continued to evolve into the future, many species continued to become a lot larger and more territorial, like other modern day bears. The fall of this family was caused by extensive competition by canids, that were far more adapted to the climate and region. Amphicyonidae was overall outcompeted. Amphicyonidae took the move from North America to a less densely forested region and would take the stage in a more archaic grassland Europe, during the Miocene epoch. Fossils of juvenile agnotherium, ischyrocyon, and magericyon all show an unusual type of tooth eruption indicating that these species emerged into sub adulthood at around 2 to 3 years old.

#### Enaliarctidae

Enaliarctidae is an extinct genus of Pinnipedimorph that include living mammals like seals, sea lions and walruses. This specific family is made up of five species that lived from the Oligocene Epoch (29 Mya) to the Miocene Epoch (23 Mya). These species lived across the west coast of North America through Oregon to California. The oldest species of which were Enaliarctos barnesi and E*.* tedfordi which lived around the Oligocene epoch (29.3 Mya). Britannica states that these two species as well as one other; E*.* mealsi, were found in the Yaquina Formation of Oregon as well as the rocks of central California that were apparent 29 - 23 Mya. The most well known of these species; E. mealsi was thought to look and live a lot like modern day sea lions, however only weighing between 73 to 88 kg (161 to 194 lbs). The enaliarctos genus is thought to have evolved into something very similar to modern pinnipeds. they had hind limbs use as flippers and had become very diverse marine mammal predators and had a very flexible body like modern day seals. Like sea lions, the hind legs were also put to use with the ability of efficiently functioning locomotion on land. Distant relatives of enaliarctos were otter-like semi-aquatic mammals in the genus Puijila, that lived during the Miocene and functioned a lot like a walking seal in a way. This genus was initially placed in the same order as bears, dogs, cats, raccoons, and weasels. Though as these mammals started to spread across the globe due to the upwelling of deep waters off the western coast of North America, the were placed in a separate genus, as their aquatic behaviours were realised.

#### Semantoridae

Semantoridae is an extinct family of stem-pinnipeds that have fossil remains that are observed in France, Kazakhstan and Canada that date back to various times during the Miocene epoch. According to their fossil records, semantorids were not specifically marine specialists as their bodies were much more elongated, had a long tail and powerful robust limbs suggest that they were much closer anatomically to mustelids in the case of semantor and potamotherium. Potamotherium*,* especially was seen as a stem of Puijia, another genus of stem pinniped. Little extra information is known about semantoridae.

#### Desmatophocidae

Desmatophocidae is an extinct family of pinnipeds very closely related to eared seals and walruses. Desmatophoca is a genus in the family and was comprises of earlier pinnipeds that lived much through the Miocene. This genus shared small morphological differences to modern day pinnipeds, though did not survive through the Holocene, it has been debated that there were fossil records of them during the Oligocene. Much of the fossil data found about desmatophoca was found through Washington and Oregon, USA. These seals were seen as smaller seals though had a much more powerful jaw, meaning they had a much more powerful bite force of any pinniped today. This made them great hunters, hunting using sight-based detection. The second genus Allodesmus is another extinct genus of pinniped that lived from the middle to late Miocene of California and Japan. Allodesmus possesed large canines in well-defined growth zones that were likely used for fighting bulls like the modern walruses and elephant seals of today. In order to defend their harem, males would not venture to the sea to feed on marine life. Allodesmus was also around 2.4m (8ft) long and weighed 360kg (800lbs). Atopatarus and Eodesmus are the third and fourth genera, though little is known about the two, appearing to be the most recently discovered of the family.

## Extant Families

### feliformia

As previously discussed, feliformia includes all of the carnivorans classed under the label of "cat-like". Taxa included in this suborder include but are not limited to cats (both wild and domestic), hyenas, civets and mongooses. Not feline feliforms are referred to as cat-like due to their genetic similarities to cats rather than dogs.

#### Nandiniidae

Nandiniidae includes only one member, being the African palm civet ***(Nandinia binotata)***. The species was placed in its own family and genus during 1929, when Reginald Innes Pocock (1843-1947) proposed the family nandiniidae, with the genus nandinia to accommodate the species as its sole member. Pocock argued that, due to the animal's ear canal structure and mastoid part of its temporal bone, the species was distinct from other feliforms.

#### Felidae

Felidae includes all of the species that are more commonly known as cats. Felidae is not limited to domestic cats however, and also includes all species of wild cat. Felids can be further separated in the subfamilies known as felinae and pantherinae. The former, felines, include smaller cats such as cheetahs, cougars/ mountain lions, domestic cats and lesser wild cats. Felines can typically be identified by their retractable claws, -with the exception of cheetahs- which are protected by the cutaneous lobe. The general structure of a feline's body is different to pantherines, as the larynx (voice box) of felines are kept close to the base of the skull via the use of an ossified hyoid. Owing to the shorter vocal cords of felines, measuring only to 6mm (0.24in), felines are able to emit purring sounds, which cannot be found in pantherines. Purring is typically used as a way to express relaxation or contentedness, which is replaced by 'chuffing' in pantherines. pantherines, much more commonly known informally as 'big cats', the second subfamily of feliformia and include; lions, tigers, leopards, snow leopards and clouded leopards. pantherines possess imperfect ossified hyoids which allow mobility in the larynx through the use of elastic tendons. pantherines also possess a single vocal fold with a thick coat of mucousal lining as well as a large cricothyroid muscle and vocalis muscle which have thin and lengthy membranes. A vocal fold that is longer than 19mm (0.75in) enables all pantherines to roar with the exception of the snow leopard ***(Panthera unica)***. The reasoning for this seemingly arbitrary difference is the snow leopard's shorter vocal fold, that measures 9mm (0.35in). This shortened vocal fold provides a vastly lower resistance to low airflow. Due to this reasoning, the snow leopard is often proposed to remain in its own genus of Unica. In physical appearance, pantherines have a much shorter rhinarium (bare skin surrounding the nostrils and base of nose), when compared to felines. The first members of felidae diverged from the common ancestor of feliformia around 35-28.5mya, during the late Eocene - the mid to late Oligocene periods. Due to gaps left in the fossil record, the ancestor of felidae and by extension feliformia, is unknown, making the families in feliformia having 'ghost lineages'.

#### Prionodontidae

Prionodontidae is comprised of the sole genus prionodon, which includes the two species of Asiatic linsangs, the banded linsang ***(P. linsang)*** and the spotted linsang ***(P. pardicolor)***. Prionodontidae and felidae are said to be extremely close, being considered sister groups to one another. It is thought that prionodontidae first diverged from felidae around 35.2-31.9mya (mid Miocene period). This evidence makes Asiatic linsangs the closest relatives to felidae. Despite the molecular similarities between prionodontidae and felidae, Priodonts and viverrids share morphological similarities. After the discovery of the Asiatic linsangs in 1822 by Thomas Horsefield (1773-1859), Horsefield placed the species under the section prionodontidae under the genus felis, due to the linsang's similarities to both genera felids and viverrids. Subsequently, in 1864, John Edward Gray (1800-1875), placed the genera prionodon and Poiana (African linsangs) under the same tribe in the shared family of viverridae. Reginald Innes Pocock had originally agreed with Gray in his hypothesis however, eventually grew skeptical due to the existence of scent glands in Poiana, which lead him to propose that Poiana was a specialised form of Genetta, with its likeness to prionodon being simply an adaptation. The skeletal anatomy of the Asiatic linsangs is said to be a collage of features shared by viverrine animals. For example, the Asiatic linsangs share cranial, post cranial and dental similarities with falanoucs, African palm civets and oyans (African linsangs) respectively. DNA analysis performed on the basis of 29 carnivoran species, comprising 13 species included in viverrinae and the three species of *paradoxurus*, *paguma* and *hemigaliinae*, would go to confirm Pocock's original evaluation of Poiana being a sister group to Genetta. This analysis would also heavily support the idea that prionodontidae was the sister group to felidae, leading to Asiatic linsang being placed in prionodontidae.

#### Viverridae

Viverridae is comprised of 33 species spread across 14 genera. It is estimated that viverridae first emerged 34.29mya, separating from the three subfamilies of Paradoxurinae, Hemigaliinae and viverrinae during the late Oligocene and following the early Miocene. Viverridae is a large family and includes civets, genets, African linsangs and the binturong ***(Arctictis binturong)***. Viverrids share similar features among their family, all having four to five digits on each foot, semi-retractable claws, six incisors on each upper and lower jaw, as well as molars that possess tubercular grinders that are located towards the rear of the upper and lower jaw. Viverrids also share anatomic similarities to felids, with their prickled tongues. A pouch/ gland can be found in viverrids, located beneath the anus of the animal however, it does not possess a cecum (beginning of the large intestine). Despite similarities to felidae, viverrids are far more primitive, being much less specialised. In fact, viverrids are the most primitive of all feliformia families, even having relatively undeveloped carnassial teeth. As a means to distinguish viverrids from felids, the observer should identify the longer muzzle and tufts of vibrissae/ whiskers located between the lower jaw bones. Most viverrids also have a baculum also known less formally as penis bones, which aids in reproduction by remaining stiff during intercourse. This anatomical detail is absent in felids. The largest subfamily in viverridae is viverrinae. viverrinae includes the genera of viverra, Civettictis and viverricula. These genera are comprised of 4 species, 1 species and 1 species respectively, with 5 being present on the Asian continent, whilst the last is found in Africa.

#### Eupleridae

Eupleridae is comprised of seven genera which include all 10 known species of Madagascan carnivorans. Eupleridae probably diverged from a common herpestid ancestor around 24-18mya during the late Oligocene and early Miocene. It is widely believed that euplerids first evolved on Madagascar after their common ancestor arrived from mainland Africa through means of 'rafting'. The largest member of eupleridae is the extinct giant fossa ***(Cryptoprocta spelea)***. The giant fossa would have been the dominant predator but when extinct possibly before the 1400s for unknown reasons. The extinction of the giant fossa, likely caused predation dynamics to shift, as the smaller fossa ***(Cryptoprocta ferox)*** would become the apex predator of Madagascar. Eupleridae is a relatively new family, as every member in the euplerinae subfamily originally belonged to viverridae, while species included in the euplerid subfamily of galiidiinae, were at one point considered to be members of the mongoose family, herpestidae. These placements would eventually be disputed by a molecular analysis performed on each euplerid species, that proved each of the members likely comprised their own family, with the fossa and Malagasy civet ***(Fossa fossana)*** being most genetically and evolutionarily distinct from each other and the other euplerids. Eupleridae and herpestidae remain extremely close, being sister groups and along with hyaenidae these families comprise the herpestoidea superfamily. The evolutionary diverged between the euplerids and herpestids is said to date back to the Oligocene, with many feliforms being similar at the time (in particular, similarities are apparent between felids and viverrids). The modern Malagasy carnivorans are distinctly different from other feliformia families however, the galiidiinae and euplerinae subfamilies retain similarities to civets and mongooses respectively. Members of galiidiinae have similar auditory regions to those of herpestids, while species included in euplerinae have auditory regions that closely mirror viverrids. On this basis, in 1996 Robert M. Hunt Jr. proposed that the similarities entailed that Madagascar was 'colonised' twice by both the viverrids and herpestids however, genetic studies conducted in 2003 concluded that it was more likely that Madagascar was colonised by a single, herpestid ancestor which soon adaptively radiated (diversified into many species).

#### Herpestidae

Herpestidae is composed of 2 subfamilies, 14 genera and all 34 species of mongoose as well as the meerkat ***(Suricata suricatta)***. Furthermore, 10 species of herpestid are classed as extinct, most of which have been placed into subfamilies with extant members however, older extinct species have yet to be categorised. Herpestidae is thought to has diverged from other feliformia groups during the early Miocene around 21.8mya. All herpestids appear similar in appearance, all having long muzzles/ faces, short legs, long bodies, rounded ears, horizontal pupils and tails that taper toward the tip. Some few species have heavily marked coats, which can attribute to a similarity to mustelids (a caniform family). Mongooses are one of four mammalian taxa who are immune to the effects of snake venom due to a mutation in the species' nicotinic acetylcholine receptor. This venom immunity led to herpestids becoming extraordinarily adapted to hunted snakes, to the point where they pioneered a new niche.

#### Hyaenidae

To the uninformed, hyenas may appear dog-like morphological and molecular traits however all hyaenids are closer to cats in both regards. Hyaenidae is comprised of 3 subfamilies, ictitheriinae, hyaeninae and protelinae. Ictitheriinae is the outlier of the subfamilies, including only extinct species. protelinae only includes the aardwolf ***(proteles cristata)***. By far the largest subfamily, hyaeninae includes all 3 species of hyena, all of which are spread through the genera of hyaena, parahyaena and crocuta. Characteristics present in hyaenids include; rounded ears, short hind legs and long front legs that give the animals a hobbling motion while mobile, bushy tails, spotted or stripped patterning (with the exception of one species), massive jaws made for shattering bones (with the exception of the aardwolf) and blunt, non-retractable claws that closely mirror those of a canine's. Hyaenidae is said to date back to the Miocene period and the family is most similar phylogenetically to eupleridae and herpestidae, together comprising the herpestoidea superfamily.

### Caniformia

Caniformia is the parallel to feliformia and includes all of the carnivoran species that are colloquially referred to as 'dog-like' carnivores. Taxa that comprise this suborder include but are not limited to; dogs (wild and domesticated), bears and seals (true and eared).

#### Canidae

Canidae is comprised of the caniform carnivores referred to as canines or dogs. Though canids can greatly vary in size, most species retain a similar appearance, having elongated muzzles, long legs, tapering bushy tails and pointed ears. Uniquely, canids (particularly dogs) were the earliest example of the domestication of a carnivore by humans. Dogs ***(Canis lupus familiaris)*** remain the largest carnivoran to be domesticated to the extent of being considered pets. Canids were domesticated in such a distant past, that it is unknown when and where the domestication occurred however, dates can be estimated. It is believed that modern dogs diverged from a sole ancestral population of wolves 27,000-40,000 years ago, just before the last Ice Age (Last/Late Glacial Maximum). The reason as to why wolves became tame towards humans is thought to be because of a genetic variation that was abundant in the domestic dog's ancestors. This variation compromised the wolf's flight-or-fight response, making them less aggressive and skittish, which led to a greater curiosity and infatuation with humans. This attitude towards would result in the mutually beneficial relationship that domestic dogs and human share in the modern day. Canids occur on every continent excluding Antarctica, they were either brought to these places whilst accompanying humans or through natural means, such as land-bridges. Canids and caniforms in general are believed to have first appeared in the fossil record around 42mya during the Eocene period, predating feliform carnivorans. The first caniforms were arboreal animals that superficially resembled martens ***(Martes)***. Unlike almost all feliforms, canids employ pack hunting tactics, which have greatly improved their hunting success. This pack hunting behaviour would allow dogs to spread across regions and greatly diversify, whilst retaining their pack hunting behaviour, which would in turn increase their survivability.

#### Ursidae

Ursids (bears) comprise the superfamily Ursoidea, being the sole family that is present in the group. Ursidae itself is comprised of 8 extant species which belong to 5 genera and though not diverse, the species can be found on every continent with the exception of Australia, Africa and Antarctica. Interestingly, though Africa is absent of ursids in the present day, a subspecies of brown bear known as the Atlas bear ***(Ursus arctos crowtheri)*** once roamed Northern Africa. The Atlas bear unfortunately was hunted to extinction in 1807, -which similarly to the extinction of the giant fossa-, caused a shift in predator dynamics for the region. Ursids and early bears first appeared during the late Eocene-early Miocene (38-18mya) however, the oldest known animal belonging to the subfamily Hemicyoninae, was the raccoon-sized Cephalogalie, which first appeared in the fossil record during the middle Oligocene in Eurasia around 30mya. The subfamily Hemicyoninae is a direct translation of the Greek *hemi-kyōn,* (ἡμικυων) which means *'Dog-bear',* in reference to how bears in this order mirrored the appearance of dogs. Hemicyoninae includes some of the earliest bears including Phoberocyon and Plithocyon which date back to 20-15mya and 15-7mya respectively. The New World bear order, Tremarctinae, includes all species of New World short-faced bears. Tremarctinae diverged from the main ursid subfamily of ursinae during the mid-Miocene (13mya) following the family's distribution into the North American continent. Despite members of Tremarctinae being exclusively found in North and South America, modern New World bears are not classed in this subfamily, instead being classed in the wider ursinae subfamily. The Tremarctinae genus Plionarctos of North America, is likely the common ancestor of both North and South American short-faced bears, as well as spectacled bears, of which one extant species exists in South America.

#### Ailuridae

Ailuridae is comprised solely of the red panda ***(Ailurus fulgens)*** and its many extinct relatives. The genus Ailurus -in which the red panda is placed- was in 1825 considered to be a part of the raccoon family of procyonidae, by famous naturalist and zoologist Georges Curvier (1769-1832) however, this placement was made based solely on the shared morphological traits of red pandas and raccoons. Cuvier's placement grew more controversial in the zoology community at the time and was eventually changed to be a part of the ursidae family however, according to the fossil record, red pandas diverged from their closest common ancestor with bears around 40mya, further dismantling the red panda being a member of ursidae. Phylogenic molecular studies conducted concluded that, as the red panda is an ancient member of carnivora, it may be classed under a subfamily or monotypic in procyonidae, as it is quite closely related to the American raccoon ***(Procyon lotor)***. Despite the species' history with classification difficulties, the most recent molecular research into the red panda's DNA concluded that the species is more accurately placed in its own family; ailuridae. Ailuridae now comprises the musteloidea superfamily, which also includes mustelids, procyonids and mephitidae. It is believed that ailurids first evolved during the late Oligocene-early Miocene in Europe and North America and diverged from the last common ancestor with ursidae around 40mya, further dismantling the red panda's association with ursids.

#### Mephitidae

Mephitidae includes skunks and the closely related stink badgers and comprises the musteloidea superfamily along with mustelidae, procyonidae and ailuridae. Mephitidae is comprised itself, out of 4 genera with 12 extant species distributed among them, with the greater of the genera being Conepatus (hog-nosed skunks) and Spilogalie (spotted skunks), which are each made up of 4 species. The lesser genera, Mydaus (stink badgers) and mephitis (hooded and striped skunks) are comprised of 2 species each. Originally, skunks were treated as members of mustelidae however, recent genetic studies provided the adequate data to warrant skunks to become a part of their own family. Similarly, stink badgers were once classed with true badgers however, genetic evidence suggests that their more recent common ancestor is related to skunks, allowing them to be considered mephitids.

#### Mustelidae

Mustelidae is the largest family of carnivora, including 66-70 species and 9 subfamilies, all comprised of weasels and their relatives. Mustelidae is comprised of a range of extremely diverse species which are really unique from one another, from the aggressive wolverine ***(Gulo gulo)*** to the domesticated ferret ***(Mustela putorius furo)***. Mustelid-like creatures likely first appeared coinciding roughly with the appearance of rodents, around 40mya during the Eocene. The first common ancestor of mustelids however, appeared 18mya Miocene. The fossil record largely indicates that mustelids appeared during the late Oligocene period, 33mya. Mustelids live presently on every continent with the exceptions of Australia and Antarctica, having originated in Eurasia, and diverged into the Americas via the Bering land bridge. The oldest known North American mustelid, Corumictis wolsani, can be dated back to the early-late Oligocene.

#### Procyonidae

Procyonidae is an exclusively New World family of carnivorans that includes raccoons and their many relatives. Members of procyonidae all possess facial markings and banded tails, with the exception of the kinkajou ***(Potos flavus)***. Procyonids are often confused with relatives of bears due to morphological similarities as well as European etymology in reference to them however, procyonids are instead much closer to mustelids, ailurids and mephitids, being a part of the musteloidea superfamily. The recent evolutionary developments of procyonidae have all been made in Central America, with most species being native to the region. Procyonids likely became common in South America, following the Great American Interchange about 7.3mya in the late Miocene. The earliest representation of procyonidae from this time is Cyonasua. Genetic studies conducted surrounding procyonidae concluded that kinkajous likely represent a sister group to every other extant procyonid, diverging about 22.6mya. The divergence between coatis and olingos occurred around 10.2mya, similarly to the divergence between raccoons and cacomistles.

#### Odobenidae

Odobenidae is a Pinniped family that is comprised of the sole extant genus of odobenus, which inclludes only the walrus ***(Odobenus rosmarus)*** however, the family has an extremely diverse array of 16 extinct genera and 20 species. Most odobenids existed around the Miocene and Pliocene (8-2mya), Though most conspicuous features of modern walruses are the large tusks which males possess however, some extinct walrus species did not possess this now famous feature. Most notably, an odobenid discovered in Hokkaido, Japan, possessed a much more slender body, more narrow skull and cone-shaped teeth which were not long enough to be considered tusks and measured 86.3mm (almost 3.5in). The species was named Archaeodobenus akamatsui, translated from the Greek 'archaios' meaning ancient, in reference to the fossil's great age, dating back to 10-9.5mya.

#### Otariidae

Otariidae includes all species of eared seal spread across 7 genera. Eared seals (also known as otaries) along with odobenids and phocids comprise the larger Pinnipedia group. Otaries can be differentiated from phocids by their small but visible external ears, which are a very prevalent characteristic of otaries. The most apparent difference between otaries and their true seal counterparts, is the morphology that differentiates the two groups. Aside from the otariid namesake of visible external ears, Otaries also have rotary hind flippers, which are much more capable of terrestrial movement when compared to the stiff out-stretch hind flippers of true seals. The maneuverability of otaries is large way of differentiating the two families, as otaries move much more capably on land, even running/ galiloping when on shore. Otaries first appeared during the Miocene (15-17mya) in the North Pacific Ocean, before further diversifying into the Southern hemisphere, where most species are extant. Eotaria crypta is the earliest species that is included in the family, and evolved on the Southern coast of California, whereas the Northern fur seal ***(Callorhinus ursinus)*** has the most extended fossil record, dating back to the middle Pliocene, likely arising from the extinct otariid genus of Thalassoleon. Otariidae was previously split into two subfamilies, being otariinae (sea lions) and Arctocephalinae (fur seals). Arctocephalus was comprised of 2 genera, being Callorhinus having the Northern fur seal as its sole member and Arctocephalus is comprised of 8 species of fur seal native to the Southern Hemisphere. The sea lions of otariinae are comprised of 5 species spread across 5 genera. Recent analysis of genetic evidence suggested that the Northern fur seal is more closely related to several species of sea lion. This analysis also provided evidence towards otaries being much more diverse phylogenetically than previously thought, for example; the Japanese sea lion ***(Zapholus japonicus)*** is now considered an independent species, rather than a subspecies of the California sea lion ***(Zapholus californius)***. Through this new evidence, the subfamilies of otariidae have been discontinued, now otariidae is comprised of 7 genera including 16 species and 2 subspecies. Despite the subfamilies of otariidae being now outdated, they are still used often to differentiate sea lions from fur seals.

#### Phocidae

Phocidae, more commonly known as the true seals includes all the species of true seals. The term true seal refers to not only members of this family, but less specifically, species that have no visible ears and less maneuverability on land. True seals move much differently to otaries on land, sliding on their underbelly in a caterpillar-like motion. This method of movement is due to the lesser dexterity of the true seals. the hind flippers of true seals are stiff on land, facing out stretched from the seal's body, only being able to rotate beneath the seal's body. Unlike otariids, true seals are confined to the polar regions (with the exception of tropical monk seals). phocidae also includes lake and freshwater species, unlike otariids. The earliest known species of fossil true seal, known as Noriphoca gaudini, was dated back to the early Oligocene or Miocene of archaic Italy. Other early fossil species date back to the mid Miocene (15mya) in the Northern Atlantic. Up until recently phocids were believed to have evolved separately from other pinnipeds, (odobenidae and otariidae), evolving from primordial otter-like mammals that inhabited European lakes. Recent evidence strongly supports that all Pinnipeds have a monophyletic origin, having a common ancestor, likely enaliarctos, a mustelid and ursid relative. This hypothesis was confirmed by a recent phylogenetic analysis, proving that true seals and all Pinnipeds are a part of a monophyly.

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