Suborder Hystricomorpha: 1) Angular process of jaw not in same plane as most of dentary (hystricognathous; “gnath” = “jaw”) 2) Coronoid process more reduced than in sciurognaths 3) Often has prominent shelf projecting outwards from near base of last molar 4) Hystricomorphous musculature means medial masseter muscle passes through often enlarged infraorbital foramen 5) 18 families! Mostly African, South American, Caribbean, now in tropical N Am, some in SE Asia (but you only need to know 9) Family Bathyergidae (African mole rats) • 6 genera, 17 species Bathyergus • Sub-Saharan Africa • Small, fossorial; reduced eyes and external ears, loose skin, robust skull • Dig using mostly incisors; incisors procumbent, protrude from mouth even when mouth is closed, roots extend behind molars; cheek teeth are ring or 8-shaped • Herbivorous, eat primarily underground storage organs of plants; elaborate burrows systems, some solitary, some eusocial Heterocephalus Family Hystricidae (Old World porcupines) • 3 genera, 11 species Brush-tailed porcupine; • Africa, Italy, southern and SE Asia Atherurus • Large (up to 27 kg), plantigrade, terrestrial; covered in spines (which lack barbs), inflated rostrum in some African species • Nocturnal, herbivorous, dig burrows • Give birth once a year in an underground chamber, young born fully developed, but with soft spines which harden after a couple of hours Crested porcupine; Hystrix Family Erethizontidae (New World porcupines) • 5 genera, 16 species • Forests in N. America & northern S. America • Large (900 g-16 kg), terrestrial and arboreal; covered in spines (with barbs) mixed with hairs • Herbivorous (esp. cambium in winter), nocturnal, solitarily or in pairs (will share Coendou winter dens) Erethizon Family Chinchillidae (chinchillas & viscachas) • Southern S. America, high country of Chinchilla Peru and Bolivia, through Argentina • Medium to large (500 g-8 kg), 4 toes on front feet, 3-4 on hind feet; dense fur; long, well-furred tails Mountain • Burrows & rock crevices; good jumpers; viscacha; Lagostomus highly cursorial Lagidium • Very vocal, vocalizations used in social interactions, live in colonies; herbivorous; diurnal Plains • Breed year round, usually twins, young viscacha born fully furred with eyes open • Hunted & farmed for fur Lagostomus Family Caviidae (capybaras, maras, & guinea pigs) • 6 genera, 18 species Capybara • S. America in diverse habitats • 400 g-79 kg, even larger forms (200 kg giant capybara) existed during the Pliocene • Diurnal, nocturnal, or crepuscular (varies by species), herbivorous, rows of cheek teeth Hydrochoerus converge anteriorly • Mating & social systems vary: maras can be Mara; monogomous, but most cavies are Dolichotis promiscuous or live in groups dominated by a top male Cavy; Cavia Family Dasyproctidae (agoutis & acouchis) • 2 genera, 13 species Agouti • Southern Mexico through the Amazon Basin, mostly in tropical forest • Up to 2 kg; digitigrade, slim legs, many cursorial adaptations; toes are thick & hoof- like, short tail Dasyprocta • Premaxillae & nasals extend past thin incisors • Herbivorous, scatterhoard fruits and nuts; Agouti important seed dispersers • Largely diurnal; solitary, but will group around food resources • Young born fully developed • Fast runners & good swimmers Acouchi; Myoprocta Family Cuniculidae (Pacas) • 1 genus, 2 species Paca; Cuniculus • Central Mexico to southern Brazil in tropical forests along streams, rivers • Up to 12 kg; nearly tailless; conspicuous white stripes and spots; short legs and blunt heads • 4 digits on front feet, 5 on hind feet (most others we discussed so far have 3 Good to eat toes on hind) • Resonating chambers formed by maxillaries and greatly broadened zygomatic arches • Herbivorous, including fruit; single young; hunted as food Family Ctenomyidae (tuco-tucos) • 1 genus, 60 species • Sandy/loamy soils in southern 2/3 of S. America • Up to 700 g; fringe of stiff hairs on feet (used for Ctenomys moving soil); long claws, procumbent stout incisors, small external ears and other typical fossorial adaptations; kidney-shaped cheek teeth (3rd molar vestigial) • Fossorial, herbivorous (esp. underground plant parts), usually live in “colonies” of solitary individuals, but at least 1 species social • Same ecological role as gophers in N. America (but no external cheek pouches) Family Myocastoridae (nutrias) • 1 genus, 1 species Nutria; Myocastor • S. & Central America, introduced to Europe & the U.S. in fur farms • Up to 8 kg; webbed hind feet, long & bare tail; dense underfur • Excellent swimmers (stay under water up to 5 min), live in burrows in river banks, eat vegetation on land & in shallow water • Breed year round & are prolific • Nipples are high on females sides so young can nurse while mother is in water • Live in groups up to 10 individuals Family Echimyidae (spiny rats) • 21 genera, 87 species • Tropical regions of S. & Central America (also West Indies until 1880s) • Long tail which can break off (but doesn’t regenerate), bristly hairs on back & rump of most • Nocturnal, can be fossorial, terrestrial, or arboreal, most species are solitary Family Capromyidae (hutias) • Of 8 genera and 20 species, at least 8 species recently extinct • Found in West Indies, most diverse in Cuba • Up to 7 kg, plantigrade, 5 toes on each foot with strong curved claws • Tail varies- vestigial to prehensile • Mostly terrestrial, but some are partially arboreal, nest in trees & rock crevices • Primarily herbivorous, but will eat insects & even lizards Order Lagomorpha (rabbits, hares, & pikas) • Unlike rodents, males have no baculum • Like marsupials, testes are in front of penis • Born with 3 pairs of upper incisors (evergrowing), but lose outer pair with age • 2nd pair of incisors found behind first pair & lack sharp edge • Form 2 types of fecal pellets- 1 is re-ingested to extract nutrition Family Ochotonidae (pikas) • 1 genus, 30 species Ochotona • Holarctic: N. America, eastern Europe, & northern Asia • N Am: rocky outcrops and talus; Eurasia: variety of habitats, including steppe or plains as well as rocky outcroppings • 100-150 g; stocky bodies, short, round ears; short limbs; hairy soles of feet; no external tail; males lack scrotum • Diurnal, herbivorous; steppe-dwelling pikas prolific breeders like rabbits, but N Am talus-dwellers only 1 litter per year • Lay out vegetation to dry & store for use as food & bedding in winter • Social systems vary- solitary to large colonies, communicate with loud whistles Family Leporidae (rabbits & hares) • 11 genera, 61 species • Found worldwide, but introduced in S. America, Australia, New Zealand, Indonesia, Pygmy rabbit; & Madagascar Brachylagus • 300 g-5 kg (females larger than males); elongated hind legs, short tail, ears longer than wide • Rabbits dig burrows for shelters, hares typically do not; rabbits born naked/blind, hares born fully formed • Variety of habitats; herbivorous Jackrabbit; Sumatran striped Lepus rabbit; Nesolagus .