Lecture 17 Rodentia Lagomorpha PDF

Lecture 17 Rodentia Lagomorpha Superorder Euarchontoglires Grandorder Archonta Order Primates: lemurs, bushbabies, monkeys, apes Order Dermoptera: colugos Order Scandentia: tree shrews Grandorder Glires Order Lagomorpha: pikas, rabbits, hares Order Rodentia: rodents – 42%...

Lecture 17 Rodentia Lagomorpha Superorder Euarchontoglires Grandorder Archonta Order Primates: lemurs, bushbabies, monkeys, apes Order Dermoptera: colugos Order Scandentia: tree shrews Grandorder Glires Order Lagomorpha: pikas, rabbits, hares Order Rodentia: rodents – 42% of all living mammals  Tree Shrew Colugo Primate Lagomorph Rodent Superorder Euarchontoglires - rodents are the most successful of all mammalian orders. The order contains at least 32 families, more than 476 genera and 2,277 species. - they have a worldwide distribution (excluding Antarctica) and are major components of nearly every fauna. - morphological diversity within the Rodentia is extreme, which makes it very difficult to discern the evolutionary relationships. This also results in a very plastic taxonomy. - lagomorphs on the other hand have not been nearly so successful. The timing of the origin of rodents is also controversial. Fossil evidence indicates a radiation of the rodents 55 MYA, although other studies have suggested 125 MYA. Recent molecular analyses support a major rodent diversification at the transition between Paleocene and Eocene about 55 MYA. The split between rodents and lagomorphs is estimated to be 65 MYA, just at the Cretaceous-Tertiary boundary.  Old World rats and mice 870 species New World mice and Voles 681 species Squirrels 200 species Spiny rats 89 species Madagascar rats and mice 68 species Tuco-tuco 65 species Their success is due to their small size, short breeding cycle, and ability to gnaw and eat a wide variety of foods. Rodents are found in all habitats except oceans and are the only placental order, other than Chiroptera and Pinnipeds, to reach Australia without human introduction (about 5 MYA via rafting). African pygmy mouse (35 g) Capybara (65 kg)  The Order Lagomorpha contains 12 genera and 84 species.  They too have a nearly worldwide distribution. However, they were introduced to Australia and the southern portion of South America by man.  Why do we consider these 2 orders together?  Historically, rodents and lagomorphs were considered to be part of the same order.  There are similarities between the groups.   the pterygoid process in rodents extends back past the palate and nearly touches the auditory bullae. This breaks off easily on museum specimens.  almost no other mammalian group has this feature. Lord Derby's scaly-tailed squirrel Anomalurus derbianus  if you look at the pterygoid processes of lagomorphs, you discover that they also almost reach the auditory bullae.  clearly, there are differences between the 2 groups, but they may be more closely related than we thought.  Order: Rodentia  The taxonomy of the Rodentia remains in flux.  There are 5 suborders of extant rodents:  Anomaluromorpha  Castorimorpha  Sciuromorpha (squirrel-shaped)  Myomorpha (mouse-shaped)  Hystricomorpha (porcupine-shaped)  these suborder names relate to the structure of the skull (specifically the infraorbital foramen and zygomatic arch) and the organization of the masseter muscles.  regardless of their taxonomic utility, these features give us an important clue about the success of the rodents. Infraorbital foramen – a small opening in the skull's upper jawbone that allows blood vessels, nerves and muscles to pass through to the face Protrogomorphous Sciuromorphous – small foramen, no plate – small foramen, large plate Hystricomorphous Myomorphous – huge foramen, no plate – small foramen, small plate  1023  rodent dental formula is usually = 22 1013  the single incisor in each jaw quadrant grows constantly and occludes with the opposite incisor to produce a sharp cutting edge.  there are no canines and they have a diastema.  cheek teeth grow continuously and have open pulp cavities.  premolars and molars have complex occlusal surfaces that are effective at grinding plant material.  cheek teeth are difficult to interpret in terms of the standard tribosphenic tooth model. A: mole rat B: murid C: old world porcupine D: chinchilla E: cuspidate murid F: folded murid  the glenoid fossa of the squamosal is elongate, and allows both anteroposterior movement, and lateral movement of the dentary.  the mandibular symphisis is flexible, allowing the 2 halves of the dentary to move semi-independently. The two rami can be pulled in different directions and the tips of the front incisors can be pointed towards one another. 4 – mandibular (glenoid) fossa Bringing the incisors together or using them to chisel away at a surface requires muscles that forcefully brings the lower jaw forward. In rodents, this is done primarily by the masseter muscle. Primitively, the masseter was divided into three muscles: the superficial masseter, the lateral masseter, and the medial masseter. The complexity of the 3 masseters and the dentary articulation, allows complicated rotation of the jaw, and excellent ability to masticate plant material. These features, more than any others, are responsible for the evolutionary success of the rodents. By moving the point of origin of the masseter musculature anteriorly, rodents have gained both mechanical advantage and additional range of movement of the lower jaw. The change in origin of this muscle has happened in at least three different ways. Complex jaw structure is associated with rotational movement of the dentary, and maintenance of crushing power. A. Origin and insertion of masseter muscle in different rodent groups has 4 patterns: A. Protrogomorph = primitive shape B. B. Sciuromorph = squirrel shape C. Myomorph = mouse shape D. Hystricomorph = porcupine shape C. D. (A) The primitive protrogomorph form with the origin of the masseter muscle entirely on the zygomatic arch and not anterior on the A. rostrum. (B) Sciuromorphs have a small infraorbital foramen through which no masseter muscles B. pass. Origin of the middle muscle is anterior to the eye, and the deep muscle is beneath the zygomatic arch. (C) A slightly larger infraorbital foramen is found in myomorphs, with the deep portion of the masseter muscle passing through it A. and originating on the rostrum, whereas the middle masseter is anterior to the eye, as in sciuromorphs. (D) In hystricomorphs, the infraorbital B. foramen is very large; the deep masseter muscle passes through it and attaches anterior to the eye, and the middle masseter originates on the zygomatic arch. C. Two additional suborders are now generally recognized: Anomaluromorpha and Castorimorpha. D. A. Protrogomorphous - This is the least derived (most primitive) of the four types. It is similar to the entirely zygomatic origin of the masseters. In living rodents, it is seen only in mountain beavers (Family: Aplodontiidae). mountain beaver Aplodontia rufa  Superficial masseter Lateral masseter Medial masseter B. Sciuromorphous In sciuromorphs, the front of the zygomatic arch is developed into a large, distinctive zygomatic plate. This condition is found in squirrels, beavers, and a number of other families. The lateral masseter moves forward and attaches to the front of the zygomatic plate where it meets the rostrum. The origin of the superficial masseter is also shifted forward, but the origin of the medial masseter does not change much from the primitive condition. B. Sciuromorphous: Families: – Sciuridae (squirrels) (3) – Geomyidae (pocket gophers) – Heteromyidae (kangaroo rats and mice) – Castoridae (beavers) – Anomaluridae (scaly-tailed squirrels) – Pedetidae (springhares) C. Hystricomorphous The infraorbital foramen becomes very large. Through it, a much- expanded medial masseter passes to originate on the side of the rostrum anterior to the zygomatic arch. They can generate a great deal of force because of the efficient right angle attachment of medial masseter on dentary. This corresponds with a shift from less efficient temporal and lateral masseter muscles to medial masseter.  C. Hystricomorphous Family Ctenodactylidae: gundis Family Hydrochoeridae: capybara Family Bathyergidae: African mole rats Family Dasyproctidae: agoutis Family Hystricidae: Old World porcupines Family Cuniculidae: pacas Family Erethizontidae: New World porcupines Family Ctenomyidae: tuco-tucos (6) Family Petromuridae: dassie rat Family Octodontidae: octodonts Family Thryonomyidae: cane rats Family Abrocomidae: chinchilla rats Family Chinchillidae: chinchillas and viscachas Family Echimyidae: spiny rats (4) Family Dinomyidae: pacaranas Family Capromyidae: hutias Family Caviidae: cavies, guinea pigs Family Myocastoridae: nutria D. Myomorphous From a sciuromorphous precursor: this includes development of a small zygomatic plate and anterior shift of the lateral masseter, as in sciuromorphs. The infraorbital foramen is also slightly enlarged, and the medial (deep) masseter passes through it. D. Myomorphous Families – Muridae (Old World rats and mice) (1) – Cricetidae (New World voles and mice) (2) – Nesomyidae (Malagasy rats and mice) (5) – Spalacidae (blind mole rats) – Gliridae (dormice) – Platacanthomyidae (spiny tree mice) – Calomyscidae (mouse-like hamsters) – Dipodidae (jumping mice)  rodent systematics are no longer based on the myomorphous / sciuromorphous / hystricomorphous skull anatomy, but instead we now divide rodents into 2 major clades based on jaw morphology.  all rodents are currently classified as either:  Sciurognathous or Hystricognathous  These terms refer to the structure of the dentary (gnathous refers to jaw). NOTE: this means that all rodent families ultimately have a designation both for skull morphology and jaw morphology Reminder of processes – coronoid and angular  Sciurognathous (C): the angular process, which receives much of the masseter, arises more or less in a line with the rest of the jaw - that is, it originates in the same vertical plane that also includes the alveolus (socket) of the incisors. The coronoid process is obvious. condyloid process arrow points to angular process  Hystricognathous (D): the origin of the angular process is lateral to this plane, and the angular process often appears to be flared laterally. The coronoid process is usually reduced in hystricognathous forms. condyloid process arrow points to angular process ORDER RODENTIA (from Latin, rodere, to gnaw) Suborder: Sciuromorpha Family Aplodontiidae: mountain beaver Family Sciuridae: squirrels, chipmunks, prairie dogs, and marmots (3) Family Gliridae: dormice Suborder: Castorimorpha Family Geomyidae: pocket gophers (true gophers) Family Heteromyidae: kangaroo rats and kangaroo mice Family Castoridae: beavers Suborder: Anomaluromorpha sciurognathous jaw morphology Family Pedetidae: springhares Family Anomaluridae: scaly-tailed squirrels Suborder: Myomorpha Family Muridae: true mice and rats, gerbils, spiny mice, crested rat (1) Family Cricetidae: hamsters, New World rats and mice, voles (2) Family Platacanthomyidae: spiny dormice Family Spalacidae: mole rats, bamboo rats, and zokors Family Nesomyidae: climbing mice, Malagasy rats and mice (5) Family Calomyscidae: mouse-like hamsters Family Dipodidae: jerboas Family Zapodidae: jumping mice Suborder: Hystricomorpha Family Ctenodactylidae: gundis Family Bathyergidae: African mole rats Family Hystricidae: Old World porcupines Family Erethizontidae: New World porcupines Family Petromuridae: dassie rat Family Thryonomyidae: cane rats Family Chinchillidae: chinchillas and viscachas Family Dinomyidae: pacaranas Family Caviidae: cavies, including guinea pigs Family Hydrochoeridae: capybara Family Dasyproctidae: agoutis hystricognathous jaw morphology Family Cuniculidae: pacas Family Ctenomyidae: tuco-tucos (6) Family Octodontidae: octodonts Family Abrocomidae: chinchilla rats Family Echimyidae: spiny rats (4) Family Capromyidae: hutias Family Myocastoridae: nutria Suborder: Sciuromorpha Family: Aplodontiidae (1, 1) The mountain beaver is the most primitive extant rodent. It lives in forested areas of western North America. mountain beaver Aplodontia rufa Adults weigh 500–900 g and are 30–50 cm long with a short tail. Mountain beavers build elaborate burrow systems with chambers devoted to fecal and food caches. They exhibit coprophagy. Hard fecal pellets are transferred to fecal storage chambers using their incisors. Strict herbivores. Altricial young. mountain beaver Aplodontia rufa Suborder: Sciuromorpha Family: Sciuridae (51, 200) squirrels, chipmunks, prairie dogs, and marmots  This Family was historically divided into the Sciurinae (tree and ground squirrels) and the Petauristinae (flying squirrels).  Now divided into 5 subfamilies. Indian giant squirrel Ratufa indica (2 kg) neotropical pygmy squirrel Sciurillus pusillus (35 g) The family includes tree squirrels, ground squirrels, flying squirrels, chipmunks, marmots, woodchucks, and prairie dogs. Squirrels are found in the Americas, Eurasia, and Africa and were introduced to Australia. Squirrels are most closely related to the mountain beaver and to dormice among living species. Flying squirrels are convergent with the Anomaluridae (scaly-tailed flying squirrels), Cynocephalidae (colugos), Petauridae (gliding possums), Pseudocheiridae (ring-tailed possums), and Acrobatidae (feathertail gliders). Flying squirrels have gliding membranes between the forearms and hind limbs. northern flying squirrel , Glaucomys sabrinus Typically, squirrels have bushy tails as long as the body, smooth coats, and pointed ears. In some species, the fur coat is coarse and spiny, and in others, the ears have long hairs extending from the points. eastern gray squirrel Sciurus carolinensis Most squirrels have cheek pouches for temporary food storage. Arboreal squirrels have double- jointed hind limbs, with four toes and a vestigial thumb that allows them to climb trees quickly. eastern chipmunk Tamias striatus Squirrels live in almost every habitat from tropical rainforest to semiarid desert, avoiding only the high polar regions and the driest of deserts. They are predominantly herbivorous, eating seeds and nuts, but will eat insects and even small vertebrates. Some tropical species have shifted almost entirely to a diet of insects. Squirrels cannot digest cellulose. Cape ground squirrel Xerus inauris Suborder: Sciuromorpha Family: Gliridae (9, 28) (dormice) Found in Asia, Europe, and Africa. They are known for their long periods of hibernation. They are small (< 20 cm) and mouse-like, but with furred, rather than scaly, tails. They are largely arboreal and nocturnal. Dormice have excellent hearing and signal each other with a range of vocalizations. African dormouse Graphiurus sp. Dormice can hibernate for up to six months, if the weather remains sufficiently cool, sometimes waking for brief periods to eat food they had stored nearby. During the summer, they accumulate large fat reserves. Suborder: Castorimorpha Family: Geomyidae (6, 40) Pocket gophers are found in North and Central America. They are convergent with talpids and marsupial moles. Large claws, heavy pectoral girdle, small eyes/pinna. Incisors extend anteriorly so the lips can be closed while digging. southeastern pocket gopher Geomys pinetis Pocket gophers are heavily built and range from 12 to 30 cm and weigh a few hundred grams. Males are always larger than the females and can be nearly double their weight. They have small eyes and a short, hairy tail which they use to feel around tunnels when they walk backwards. northern pocket gopher Thomomys talpoides  northern pocket gopher Thomomys talpoides The distinguishing feature are the large cheek pouches, or “pockets”. These pouches are fur-lined, can be turned inside out, and extend from the side of the mouth back to the shoulders. Pocket gophers are burrowers and larder hoarders. Their presence can be determined by the appearance of mounds of fresh dirt about 20 cm (7.9 in) in diameter. Pocket gophers are solitary, during non- breeding season, and aggressively maintain territories that vary in size depending on the resources available. Males and females may share some burrows and nesting chambers if their territories border each other, but in general, each pocket gopher inhabits its own individual tunnel system. Suborder: Castorimorpha Family: Heteromyidae (6, 60) (kangaroo rats, kangaroo mice, and pocket mice) Primarily in the SW-USA, as well as Mexico, Central America, and South America. Although they’re very different in physical appearance, the closest relatives of the heteromyids are pocket gophers in the Geomyidae family. Kangaroo rats are saltatorial/bipedal, while pocket mice are quadrupedal. Bailey's pocket mouse kangaroo rat Chaetodipus baileyi Dipodomys deserti Kangaroo rats and mice have inflated auditory bullae and extremely sensitive hearing in the low to mid-frequency ranges. They are apparently able to hear the faint sounds made by the usually silent flight of owls as the owl brakes to seize its prey during an attack. Most heteromyids live in complex burrows within the deserts and grasslands of western North America, though some species are also found in forests and extend down as far as northern South America. They feed mostly on seeds and other plant parts, which they carry in their cheek pouches to their burrows. Trinidad spiny pocket mouse Heteromys anomalus Suborder: Castorimorpha Family: Castoridae (1, 2) (beavers) Beavers are the 2nd largest rodent in the world (30 kg) (after the North American beaver capybara). Castor canadensis They are semiaquatic, with sleek bodies, nictitating membranes, and webbed hind feet. Their tails are flattened and scaly, adaptations that help them maneuver in the water. Beavers are known for building dams, canals, and lodges. Their colonies create one or more dams to provide still, deep water to protect against predators, and to float food and building material. They eat the cambium, bark, leaves and roots and store sections of trees underwater for winter use. Suborder: Anomaluromorpha Family: Pedetidae (1, 2) (springhares) These are highly saltatorial. Springhares live in SE Africa, feeding South African springhare on plants and insects. They have four Pedetes capensis toes on their hind feet with claws that look like small hoofs. They have a thick muscular neck supporting their short head. They also have large eyes and ears with a tragus that prevents sand from entering when they are digging. Springhares are mostly nocturnal but are sometimes active in the day. During the day, they live in tunnels where they plug the entrance with soil from the inside of the tunnel. The springhare jumps like a kangaroo on its hind legs, retreating to its burrow when frightened. Seem to be most closely related to the Anomaluridae - scaly-tailed flying squirrels (see next slide). South African springhare Pedetes capensis  Suborder: Anomaluromorpha Family: Anomaluridae (3, 7) (scaly-tailed flying squirrels) Restricted to equatorial western and central Africa. Most species roost during the day in hollow trees, with up to several dozen animals per tree. They give birth to litters of up to three precocial young. Pel's scaly-tailed squirrel - Anomalurus pelli Almost all species can glide and have a well formed patagium that encloses fore and hind-limbs as well as the tail. They are arboreal, nocturnal and herbivorous and may form colonies of up to 100 individuals. They generally consume leaves, flowers, or fruit, although they also eat a small amount of insects. Pel's scaly-tailed squirrel - Anomalurus pelli Pel's scaly-tailed squirrel - Anomalurus pelli Suborder: Myomorpha Family: Muridae (150, 870) (Old World rats and mice) (1) This family used to have 7 subfamilies and almost 2000 species, but taxonomic revisions have resulted in splitting this group into several other families: - Cricetidae (2) - Nesomyidae (5) - Platacanthomyidae - Spalacidae - Calomyscidae Collectively in the Superfamily: Muroidea Suborder: Myomorpha Family: Muridae (150, 870) (Old World rats and mice) (1) Murids are small ranging from 4.5 cm in the pygmy mouse to 48 cm in Cuming's slender-tailed cloud rat. They typically have a slender body with a scaled tail and pointed snouts with prominent whiskers. However, there is a wide degree of variation. brown rat , Rattus norvegicus Many murids have long legs and feet allowing them to hop. Others have broad feet and prehensile tails to improve their climbing ability. Murids have excellent senses of hearing and smell. They live in a wide range of habitats from forest to grassland, and mountain ranges. Several species, especially gerbils, are adapted to arid desert conditions, and can survive for a long time with minimal water. They are either herbivores or omnivores, eating a wide range of foods. Mongolian jird or gerbil Meriones unguiculatus black rat Rattus rattus The African crested rat chews the roots and bark of a highly toxic tree, the poison arrow tree, and then anoints the lethal mixture on its specially adapted fur. It is not clear how they survive a dose of the toxin. Traditionally, this poison has been used by hunters to kill elephants. African crested rat Lophiomys imhausi Microscopy reveals that the hair could "wick up" the poison When it is under attack, it doesn’t run. Instead, it freezes and exposes a black-and- white-striped tract of hairs that run down its flank - it is this fur that is covered in poison. African crested rat Lophiomys imhausi The only other mammal that uses a similar trick is the hedgehog. Microscopy reveals that the hair could "wick up" the poison Suborder: Myomorpha Family: Cricetidae (140, 681) (hamsters, voles, New World rats and mice) (2) Includes true hamsters, voles, lemmings, and New World rats and mice. It is the 2nd largest family of mammals, and is found throughout the New World, Asia, Africa and Europe. Most are terrestrial but there are fossorial, arboreal, aquatic and semi- aquatic members. Cricetids are small, ranging from just 5 cm and 7 g in the New World pygmy mouse up to 62 cm and 1 kg in the muskrat. Tail length varies greatly in relation to the body and may be either furred or sparsely haired.  Diet is variable, with herbivorous, omnivorous, and insectivorous species. muskrat Ondatra zibethicus field vole Microtus agrestis deer mouse Peromyscus maniculatus Mongolian hamster Allocricetulus curtatus hispid cotton rat Sigmodon hispidus  The grasshopper mouse is the only completely carnivorous rodent eating insects, worms, scorpions, snakes, and even other mice. They will even eat Arizona bark scorpions whose sting causes a searing pain in its victim, but in grasshopper mice, the venom turns off pain receptors instead of activating them. northern grasshopper mouse Onychomys leucogaster Suborder: Myomorpha Family: Spalacidae: (6, 36) (blind mole rats, bamboo rats, root rats, and zokors) Spalacids are native to eastern Asia, Steppe zokor Myospalax aspalax Africa, Middle East, and south-eastern Europe. Spalacids are mouse to rat sized rodents, adapted to burrowing and living underground. They have short limbs, wedge- shaped skulls, strong neck muscles, large incisor teeth, and small eyes/pinna. Steppe zokor Myospalax aspalax In zokors, which dig primarily with their feet, rather than their teeth, the front claws are also enlarged. These features are less extreme in bamboo rats, which spend at least some of their time above ground, foraging for food. These digging features are most highly developed in the blind mole rats, whose eyes are completely covered by skin, and entirely lack external ears or tails. lesser bamboo rat Cannomys badius Spalax mole rats are blind. Unlike many other fossorial rodents, Spalax mole rats don’t have enlarged front claws and don’t use their forearms for digging. Digging is conducted using their powerful front teeth, which are separated from the rest of the mouth by a flap of skin. When a Spalax mole rat closes its mouth, its incisors are still on the outside. Palestine mole rat Spalax ehrenbergi  Suborder: Myomorpha Family: Platacanthomyidae (2, 2) (spiny dormice) These are about the size of a brown rat and live in tree holes in colonies. They have spiny fur, clawless hallux, a bushy tail and prominent ears. They are herbivores. Malabar spiny dormouse Platacanthomys lasiurus  Suborder: Myomorpha Family: Nesomyidae (21, 68) (pouched rats and mice) Nesomyids are small to medium African rodents, with the largest being the size of a rat. Physically, they resemble mice, rats, voles, or hamsters, depending on the species and subfamily. Malagasy giant rat Hypogeomys antimena Sometimes thrown back into the Muridae. Their diet varies from strict herbivory to nearly pure insectivory, with everything in between. Their habits are similarly variable, with some species climbing trees, and others burrowing in the ground. Malagasy giant rat Hypogeomys antimena  Gambian pouched rat Cricetomys gambianus These have been introduced into the Florida Keys (Grassy Key) after a private breeder allowed the animals to escape. Females are capable of producing up to 10 litters of up to 5 young each year (gestation is about 30 days). Suborder: Myomorpha Family: Dipodidae (16, 51) (jumping mice, birch mice, and jerboas) Found across the northern hemisphere, in grassland, deserts, and forests. They are all capable of saltation, especially in jerboas. Most are omnivorous, seeds and insects, but some species of jerboa are entirely insectivorous. meadow jumping mouse woodland jumping mouse Zapus hudsonius Napaeozapus insignis Jerboas have very long hind legs which include cannon bones. The metatarsal bones are fused into one long bone, called the cannon bone. Jumping mice have long feet, but lack the extreme adaptations of the jerboas, so that they move by crawling or making short hops, rather than long leaps. Both jerboas and jumping mice have very long tails to aid their balance. thick-tailed pygmy jerboa Salpingotus crassicauda Jerboas and birch mice nest in burrows, which, in the case of jerboas, may be complex, with side-chambers for food storage. In contrast, jumping mice take over burrows of other species, and usually don’t dig their own. Most hibernate for at least half the year. thick-tailed pygmy jerboa Salpingotus crassicauda Suborder: Hystricomorpha Family Ctenodactylidae: gundis Family Bathyergidae: African mole rats Family Hystricidae: Old World porcupines Family Erethizontidae: New World porcupines Family Petromuridae: dassie rat Family Thryonomyidae: cane rats Family Chinchillidae: chinchillas and vscachas Family Dinomyidae: pacaranas Family Caviidae: cavies, including guinea pigs and capybara Family Dasyproctidae: agoutis Family Cuniculidae: pacas Family Ctenomyidae: tuco-tucos (6) Family Octodontidae: octodonts Family Abrocomidae: chinchilla rats Family Echimyidae: spiny rats (4) Family Capromyidae: hutias Family Myocastoridae: nutria Suborder: Hystricomorpha Family: Ctenodactylidae (4, 5) (gundis) Look like pikas - found in semi-arid northern Africa. Gundis are 17-18 cm long, with compact bodies covered in soft fur, short legs, and large eyes. They have short tails covered in a large fan of hair that aids in balancing as they move about their rocky and uneven environment. They are herbivorous and do not drink. common gundi , Ctenodactylus gundi Suborder: Hystricomorpha Family: Ctenodactylidae (4, 5) (gundis) Look like pikas - found in semi-arid northern Africa. Gundis are 17- 18 cm long, with compact bodies covered in soft fur, short legs, and large eyes. They have short tails covered in a large fan of hair that aids in balancing as they move about their rocky and uneven environment. They are herbivorous and do not drink. Common gundi , Ctenodactylus gundi  Suborder: Hystricomorpha Family: Bathyergidae (5, 16) (blesmols and mole rats) Convergent with Geomyidae (pocket gophers), Ctenomyidae (tuco- tucos), and Spalacidae (blind mole rats). Blesmols have greatly reduced eyes and pinnae, a relatively short tail, loose skin, and (aside from the hairless naked mole rat) velvety fur. Cape dune mole rat Bathyergus suillus Blesmols are blind, although they may use the surfaces of their eyes for sensing air currents. Despite their small or absent pinnae, they have a good sense of hearing, although their most important sense appears to be that of touch and have an excellent sense of smell. They are able to close their nostrils during digging. silky mole rat Heliophobius argenteocinereus Naked mole rats feed primarily on the underground parts of plants, particularly the succulent tubers formed by many of the plant species that grow in arid areas. They obtain all the water they need through their food; they do not drink, and they are coprophagic. A single tuber can provide a colony with a long-term source of food—lasting months or even years. They eat the inside but leave the outside, allowing the tuber to regenerate. Symbiotic bacteria in their intestines ferment the fibers, allowing cellulose to be used. naked mole rat Heterocephalus glaber  Naked mole rats are one of two species of eusocial mammals (the other is the Damaraland mole rat). Both species have a complex social structure in which only one female (the queen) and one to three males reproduce, while the rest of the colony are workers. They lack pain sensation in the skin and have a very low metabolism – can deal with low oxygen levels. naked mole rat Heterocephalus glaber  Their eyes are small and visual acuity is poor. Their legs are thin and short. Their large, protruding teeth are used to dig, and their lips are sealed just behind the teeth to prevent soil from filling their mouths while digging. They have little hair and wrinkled pink or yellowish skin. naked mole rat Heterocephalus glaber Suborder: Hystricomorpha Family: Hystricidae (3, 11) (Old World porcupines) (without barbed quills) SE Asia, Africa, and Middle East. (introduced to Italy) Herbivorous, but occasionally consume insects, small vertebrates and carrion. They often gnaw on bones to get calcium and sharpen incisors. They have a cecum and enlarged anterior large intestine where fermentation occurs. crested porcupine Hystrix cristata Suborder: Hystricomorpha Family: Erethizontidae (5, 16) (New World porcupines) (with reverse barbs) New World porcupines are large (up to 16 kg) arboreal rodents inhabiting forests and wooded regions across North America, and into northern South America. North American porcupine Erethizon dorsatum They are less strictly nocturnal than Old World species and some live entirely in trees while others have dens on the ground. They have long powerful prehensile tails. They eat mainly bark, leaves and conifer needles, but can also eat roots, stems, berries, fruits, seeds, nuts, grasses and flowers. Some species also eat insects and small reptiles. 1,347 quills were removed Suborder: Hystricomorpha Family: Petromuridae (1, 1) (Dassie rats) Angola, Namibia, and South Africa. Dassie rats are squirrel-like with hairy tails, soles of feet are bare with pads, flattened heads and no underfur. The teats are located on the sides of the torso, which allows the young to feed from the side when crammed in a narrow rock crevice. Feed primarily on grasses but also fruits, seeds and leaves. Dassie rat Petromus typicus Suborder: Hystricomorpha Family: Thryonomyidae (1, 2) (African cane rats) Thryonomys swinderianus, cane rat Cane rats range in length from 35-60 cm and weigh 10 kg. They live in marshy areas and along river and lake banks, and are herbivores, feeding on aquatic grasses in the wild. In agricultural areas they will also feed on crops in cane plantations, making them a significant pest. Suborder: Hystricomorpha Family: Thryonomyidae (1, 2) (African cane rats) Thryonomys swinderianus, cane rat Cane rats range in length from 35-60 cm and weigh 10 kg. They live in marshy areas and along river and lake banks, and are herbivores, feeding on aquatic grasses in the wild. In agricultural areas they will also feed on crops in cane plantations, making them a significant pest. Suborder: Hystricomorpha Family: Chinchillidae (3, 6) (chinchillas and visachas) Restricted to southern and western South America, often in association with the Andes. They are large, weighing from 800 g to 8 kg with strong hind legs and large ears. Chinchillas live in burrows or crevices in rocks. Plains viscacha Lagostomus maximus They are agile jumpers and can jump very high, up to 6 ft (1.8 m). Chinchillas have a variety of defensive tactics including spraying urine and releasing fur if bitten. In the wild, chinchillas have been observed eating plants, fruits, seeds, and small insects. Chinchilla - Chinchilla brevicaudata Suborder: Hystricomorpha Family: Hydrochoeridae (capybaras) Capybaras are semi-aquatic and are the largest extant rodent (134 cm and 65 kg). The Capybara was formerly a subfamily of Caviidae. capybara They live in densely forested Hydrochoerus hydrochaeris areas near bodies of water, such as lakes, rivers, swamps, ponds, and marshes, as well as flooded savannah and along rivers in the tropical rainforest. They are superb swimmers and can hold their breath underwater for up to five minutes at a time. Capybaras live in groups of up to 10, but sometimes many more, with a dominant male and a number of females, subordinate males, and juveniles. Suborder: Hystricomorpha Family: Dinomyidae (1, 1) (pacarana) This family was once a very large group of South American rodents. The Dinomyidae included the largest rodent ever known, the extinct bison-sized Josephoartigasia monesi (1000 kg). They occupied niches usually associated with large grazing mammals and were outcompeted by ungulates after connection to North America. The modern pacarana is modest sized (100 cm and 8 kg). Eat fruits, leaves and plant stems. pacarana Dinomys branickii Reconstruction of the head of (a) Josephoartigasia monesi in comparison with (b) the living pakarana Suborder: Hystricomorpha Family: Caviidae (6, 18) (guinea pigs, mara) South America, in open areas from savanna to thorn forests or scrub desert. Except for maras, which are more rabbit-like, caviids have short, heavy bodies, and large heads, with no visible tail. They range in size from cavies (300 g) to maras (9 kg – 4th largest rodent). [aside: beavers (30 kg) and porcupines (16 kg) are 2nd and 3rd largest rodents] guinea pig Cavia porcellus These are herbivores, eating tough grasses or softer leaves, depending on species. Social organization varies widely. Many cavies are promiscuous, forming no long-lasting social groups, although, in some species, males maintain harems of two or more females. Maras are monogamous and form temporary colonial creches to care for the young of multiple mothers. mara Dolichotis patagonum Suborder: Hystricomorpha Family: Dasyproctidae (2, 13) (agoutis and acouchis) The Dasyproctidae are a family of large herbivores, often feeding on ripe fruit that falls from trees. They live in burrows but will bury some of their food for later use. Agoutis have five front and three hind toes; the first toe is very small. The tail is very short, or non-existent and hairless. Brazilian agouti Dasyprocta leporina Agoutis are found in forest and wooded areas in Middle and South America. They conceal themselves at night in hollow tree-trunks or in burrows among roots. Their pace is either a kind of trot or a series of springs following one another so rapidly as to look like a gallop. They take readily to water and swim well. When feeding, agoutis sit on their hind legs and hold food between their forepaws. They may gather in groups of up to 100 to feed. They will hoard food in small buried stores. Suborder: Hystricomorpha Family: Cuniculidae (1, 2) (pacas) These are large (10 kg) burrow-dwelling rodents (tied for 4th largest) inhabiting high altitude South American forests. Pacas are nocturnal, sedentary, and solitary animals with territorial tendencies. They eat mostly fruits and seeds. lowland paca - Cuniculus paca They have thick strong legs, with four digits on the forefeet and five on the hind feet; the nails function as hooves. The tail is short and hairless. The zygomatic arch is expanded laterally and dorsally and is used as a resonating chamber - a unique feature among mammals. Suborder: Hystricomorpha Family: Ctenomyidae (1, 65) (tuco-tucos) Tuco-tucos are heavily built with short legs, skin is loose, they have long forefeet for burrowing and bristled hind feet for grooming. They have large heads, small ears, and hairy tails; body length ranges from 15–25 cm, and they weigh up to 700 g. tiny tuco-tuco Ctenomys minutus  Closest relatives are degus and other octodontids. They are found in South America where they are ecologically equivalent to pocket gophers or mole rats. tawny tuco-tuco Ctenomys fulvus Suborder: Hystricomorpha Family: Octodontidae (8, 13) (viscacha rats, degus) Found in south-western South America. Octodontids are medium sized, 12 to 20 cm. The name derives from the wear pattern of their teeth, which resembles a figure 8. Most are nocturnal, social, burrowing herbivores, though the degu is largely diurnal. It has a long, thin tail with a tufted black tip, dark sparsely-furred ears, and pale grey toes. degu Octodon degus Degus are highly social, living in burrows, and, by digging communally, are able to construct larger and more elaborate burrows. Degus form digging chains. Females living in the same group nurse one another's young. They spend a large amount of time on the surface, where they forage for food. When foraging, their ability to detect predators is increased in larger groups. Degus are strict herbivores feeding on grasses and browsing leaves. They will also take seeds and are coprophagic. degu Octodon degus Suborder: Hystricomorpha Family: Abrocomidae (2, 9) (chinchilla rats) They resemble chinchillas in appearance but have a body-structure more like a short-tailed rat. They are social, tunnel-dwelling animals, and live in the Andes. They are medium sized with stiff hairs projecting over the three middle digits of the rear feet. Their massive skulls narrow in the facial areas. They may be closely related to octodontids. Bennett's chinchilla rat Abrocoma bennettii Suborder: Hystricomorpha Family: Echimyidae (21, 89) (spiny rats, brush-tailed rats) Found in Central and South America, most spiny rats resemble rats, although they are more closely related to guinea pigs and chinchillas. Most species have stiff pointed hairs, or spines, that allow for protection. Echimyids can break off their tails when attacked, but this technique can obviously be used only once in each individual's lifetime. Tome's spiny rat Proechimys semispinosus Spiny rats are rare and poorly known, but a few species are extremely abundant. Terrestrial, arboreal, and fossorial members of this family exist. In general, arboreal forms are most rat-like in appearance, burrowing species are more gopher-like, with stocky bodies and short tails. Most species don’t do well in high heat and aridity and are restricted to regions with an abundant source of water. They are almost exclusively herbivorous, although some eat fruit, seeds, fungi, and insects. plain brush-tailed rat Isothrix pagurus Suborder: Hystricomorpha Family: Capromyidae (8, 20) (hutias) Hutias are moderately large rodents that inhabit the Caribbean Islands. They can weigh up to 7 kg. Twenty species of hutia have been identified, but half may be extinct. (Their larger relatives, the giant hutias (>200 kg) of the Family Heptaxodontidae, are extinct.) They resemble nutria in some respects. Tails are present, varying from vestiges to prehensile. They are herbivores, though some consume small animals. They nest in trees or rock crevices. Cuban hutia Capromys pilorides Suborder: Hystricomorpha Family: Myocastoridae (1, 1) (nutria) The nutria is a large, herbivorous, semiaquatic rodent, originally native to temperate South America, it was introduced to North America, Europe, Asia, and Africa, by fur ranchers. They feed on river plants and live in burrows alongside stretches of water. nutria - Myocastor coypus Adults are 5-9 kg and 40-60 cm, with a 30-45 cm tail. Distinguishing marks include a white patch on the muzzle, webbed hind feet and bright orange-yellow incisor teeth (unlike rats, which have brownish yellow incisors). The nipples of female coypu are high on her flanks. This allows their young to feed while the female is in the water. Nutria can be confused with muskrat, but the latter is smaller with a laterally flattened tail, whereas the tail of a nutria is round. It can also be mistaken for a small beaver but is differentiated by the tail. nutria - Myocastor coypus Order: Lagomorpha Family: Ochotonidae (pikas) (1, 30) Family: Leporidae (rabbits and hares) (11, 54) Lagomorphs differ from rodents in that: they have four incisors in the upper jaw (rodents have 2) they are almost wholly herbivorous (rodents are variable) male's scrotum is in front of the penis (unlike rodents) penis contains no baculum (unlike rodents) They resemble rodents in that all teeth grow continuously, and they lack canines, but they have more cheek teeth than rodents do. pika rabbit mara Family: Leporidae (rabbits and hares) (11, 54)  Leporids  rabbits and hares are not the same  rabbits build fur lined nests and give birth to altricial young  hares make shallow depressions and give birth to precocial young  rabbits have an interparietal bone, hares do not Leporids are small to moderately sized and adapted for rapid movement and include rabbits and hares. They have long hind legs, with four toes on each foot, and shorter fore legs, with five toes each. Soles of the feet are hairy, to improve grip while running, and they have strong claws on all of their toes. Leporids also have, elongated and mobile ears, and an excellent sense of hearing. Their eyes are large, and their night vision is good. Arctic hare Lepus arcticus Leporids range in size from the pygmy rabbit, with a head and body length of 25–29 cm, and a weight of around 300 g, to the European hare, which is 50–76 cm in head-body length, and weighs from 2.5 to 5 kg. European hare Lepus europaeus pygmy rabbit Brachylagus idahoensis This is a “German gray giant” named "Robert" who weighed 23 lbs (10.4 kg) Rabbits and hares are almost exclusively herbivorous (with exceptions among the members of Lepus), feeding primarily on low quality grasses and herbs, although they will also eat leaves, fruit, and seeds. They are coprophagic. marsh rabbit Sylvilagus palustris Family: Ochotonidae (pikas) (1, 30) Pikas are native to cold climates, mostly in Asia, North America and parts of eastern Europe. Most species live on rocky mountain sides, where there are numerous crevices to shelter in, although some also construct crude burrows. Pikas are small hamster-like animals, with short limbs, rounded ears, and short tails. They are about 18-20 cm, with a tail less than 2 cm long, and weigh 75 - 290 g, depending on species. Like rabbits, they are coprophagic. American pika Ochotona princeps Skull and molars of pika. As with other lagomorphs, pikas have gnawing incisors and no canines, although they have fewer premolars than rabbits. They are herbivores, and feed on a wide variety of plant matter such as grasses, sedges, shrub twigs, mosses, and lichen. Pikas do not hibernate, so they rely on collected hay for bedding and food. Pikas gather fresh grasses and lay them in stacks to dry. Once the grasses dry out, the pikas take this hay back to the burrows for storage.