Figure 20-2

FIGURE 01: One phylogenetic hypothesis of the evolutionary relationships among the Afrotheria Adapted from Nishihara, H., et al., Mol Biol Evol. 22 (2005): and Seiffert, E.R., BMC Evol Biol. 7 (2007): 1-13.

Macroscelidea Long, mobile snout Long, slender legs adapted for running Large eyes and prominent ears Complete auditory bulla Complete zygoma

Family Macroscelididae (elephant-shrews) Subclass Theria Infraclass Eutheria Order Macroscelidea (elephant-shrews)Macroscelidea 4 genera / 19 species (4/16) Fossils date to Eocene of northern Afri New species discovered in Tanzania in 2007 Africa Some with 3 digits on hind foot Short fleshy proboscis, large ears and eyes 1-3/3, 1/1, 4/4, 2/2-3 = 36-42

Macroscelidea Inhabit open plains to tropical forests Largely insectivorous Some species strikingly colored Territorial—may maintain intricate trail system Scent marking and foot drumming Some species use behavioral thermoregulation (basking)

Tenrecidae Tenrecidae (tenrecs) Subclass Theria Infraclass Eutheria Order Afrosoricida (tenrecs and golden moles)Afrosoricida 10 genera / 24 species west-central Africa & Madagascar P1  absent, M usually 3/3 one with stridulating organ (Hemicentetes)

Chrysochloridae Chrysochloridae (golden moles) Subclass Theria Infraclass Eutheria Order Afrosoricida (tenrecs and golden moles) Afrosoricida 7 genera / 18 species southern Africa 3/3 1/1 3/3 3/3 = 40 No “W-shaped” ectolophs 3/3 1/1 3/3 3/3 = 40

Family Orycteropodidae (aardvark) Subclass Theria Infraclass Eutheria Order Tubulidentata (aardvark)Tubulidentata 1 genus / 1 species African savannahs Fossils appear in Miocene of southern Europe, Middle East, and Africa Termite eaters, thick skinned, strong claws Long protrusible tongue 0/0 0/0 2-3/2 3/3 = 20-22

Tubulidentata Skull elongate Dentary bone long and slender Adults lack incisors and canines Cheekteeth are rootless, columnar, and lack enamel Teeth made of hexagonal prisms of dentine Tongue is long and protrusible

Tubulidentata Dismantle termite mounds with powerful forelimbs Burrow rapidly for protection Aardvark burrows used as retreats by many other mammals Also eat fruits of cucurbit plant (Cucumis) or “aardvark cucumber”—may be symbiotic

Tubulidentata Olfaction well- developed Fleshy tentacles on nasal septum Adapted from Kingdon, J. The Kingdon Field Guide to African Mammals. Princeton University Press, FIGURE 13: The complex nose of an aardvark (Orycteropus afer)

Tubulidentata Courtesy of A. Taylor FIGURE 11: An aardvark (Orycteropus afer, Orycteropodidae)

Tubulidentata FIGURE 12: The skull of the aardvark Adapted from Hatt, R. T., Bull. Amer. Mus. Nat. Hist. 66 (1934):

FIGURE 01: One phylogenetic hypothesis of the evolutionary relationships among the Afrotheria Adapted from Nishihara, H., et al., Mol Biol Evol. 22 (2005): and Seiffert, E.R., BMC Evol Biol. 7 (2007): 1-13.

Paenungulata Order Proboscidea—Elephants Order Sirenia—Manatees and sea cows Order Hyracoidea—Hyraxes

Paenungulata Adapted from Seiffert, E.R., BMC Evol Biol. 7 (2007): 224 and Nishihara, H., et al., Mol Biol Evol. 22 (2005): FIGURE 01: Two possible phylogenies of the Paenungulata

Order Proboscidea Elephants Fossil record begins in Eocene of North Africa Diverse in late Eocene Large size Columnar limbs and graviportal locomotion Expanded out of Africa in late Oligocene Reached North America in Miocene

Proboscidea Major trends in evolution: Columnar limbs Enlarged skull and reduced neck Elongate proboscis or trunk Incisors become tusk-like Numerous cross lophs on cheek teeth Anterior replacement of cheek teeth

Adapted from Shoshani, J., Natural History 106 (1997): FIGURE 02: One family tree of probocideans from the Eocene to the present

Family Elephantidae (elephants) Subclass Theria Infraclass Eutheria Order Proboscidea (elephants)Proboscidea 2 genera / 2 species Sub-Saharan Africa, India, Nepal, & SE Asia Tusks from upper incissors long fleshy proboscis 3/3 Mammoths extinct

Family Elephantidae Feed on trees, shrubs, and grasses Highly social Matriarchal kinship groups Matriarch plus related females and young Communicate using infrasound over long distances Audible, tactile, and visual communication at short range

Family Elephantidae Adult male elephants form bachelor herds or are solitary Musth—periods of heightened aggression and sexual activity

Family Elephantidae Largest living land mammals (up to 6,000 kg) Long, muscular trunk Large ears (smaller in Elephas) Digitigrade posture with dense heel pad FIGURE 06: The bone of the right hind foot of Mammut, a late Tertiary and Pleistocene proboscidean Modified from Romer, A.S. Vertebrate Paleontology. University of Chicago Press, 1966.

Elephant Tooth Replacement Adapted from Kingdon, J. The Kingdon Field Guide to African Mammals. Princeton University Press, FIGURE 07A: The occlusal surface of a molar of the Asian elephant (Elephas maximus)

Family Elephantidae Skull foreshortened Skull contains large air sinuses Modified from Romer, A.S. Vertebrate Paleontology. University of Chicago Press, FIGURE 04: The skull of Mammuthus, a Pleistocene elephantid

Order Sirenia Dugongs and manatees Completely aquatic herbivores 2 genera and 4 species 5 th species, Steller’s sea cow (Hydrodamalis gigas), became extinct in 1768 Fossils date to early Eocene of Jamaica Still capable of terrestrial locomotion

Order Sirenia Weights above 1,500 kilograms Nearly hairless, thick skin Nostrils valvular Thick dentary bone Middle ear bones are massive Dense, heavy bones provide ballast

Order Sirenia Five-toes manus enclosed in flipper Pelvis vestigial, hind limbs absent Tail is horizontal fluke Cheekteeth large, columnar, and covered with cementum (dugongs) or covered with enamel (manatees) Tooth replacement similar to elephants

Order Sirenia FIGURE T01: Comparison of Characteristics of Two Sirenian Families

Family Dugongidae (dugong & sea cow) Subclass Theria Infraclass Eutheria Order Sirenia (dugongs, manatees, and sea cows)Sirenia 1 genus / 2 species Coasts of E Africa, Asia Phillipines, & Australia Lack vestigal nails on flippers Notched flukes 2/3, 0/1, 3/3, 3/3 = 36 Up to 3.5 m Stellar’s Sea Cow lived in Bering Sea

Family Trichechidae (manatees) Subclass Theria Infraclass Eutheria Order Sirenia (dugongs, manatees, and sea cows)Sirenia 1 genus / 3 species Coasts of SE US, West Indies, South America (Orinoco & Amazon) vestigal nails on flippers rounded flukes 6 present at any time, indefinite number Up to 4 m

Order Sirenia FIGURE 11: The skull of a manatee; length of skull 360 millimeters Adapted from E. Raymond and Kelson Keith Hall. Mammals of North America, Volume 2. John Wiley & Sons Ltd., 1959.

Family Procaviidae (hyraxes) Subclass Theria Infraclass Eutheria Order Hyracoidea (hyraxes)Hyracoidea 3 genera / 7 species (3/4) Sub-Saharan Africa & Middle East Earliest fossils from Eocene of Morocco Weird 3 digits (hind) with almost hoof-like nails Pads of feet moistened by sweat glands 1/2, 0/0, 4/4, 3/3 = 34

Order Hyracoidea FIGURE 15A: Two Procavia capensis (above) and two Heterohyrax brucei (below) basking with their bodies broadside to the early morning sun Courtesy of Dr. Hendrik Hoeck FIGURE 15B: Hyraxes of both species huddled together on a cool day Courtesy of Dr. Hendrik Hoeck

Order Hyracoidea Rabbit-sized Deep mandible Incisors ever-growing Diastema present Four toes on forefeet; three toes on hind feet Feet mesaxonic Digits of pes bear flattened nails (except clawed second digit) Adapted from Hatt, R. T., Bull. Amer. Mus. Nat. Hist. 72 (1936):

Order Hyracoidea Herbivorous (caecal fermentation) Prefer rocky outcrops (trees for Dendrohyrax) Diurnal with polygynous family groups Heterohyrax and Procavia share rock outcrops and share nurseries (mixed groups of young) Use behavioral thermoregulation (basking)

Order Hyracoidea Both photos courtesy of Dr. Hendrik Hoeck FIGURE 14: The sole (A) and dorsum (B) of the hind foot of a tree hyrax (Dendrohyrax sp.)

Figure 20-2

Megalonychidae (two-toed sloths) Subclass Theria Infraclass Eutheria Order Pilosa (edentates)Pilosa 1 genus / 2 species Central America & N South America 0/0 0/0 PM 5/4- 5 = syndactylus

Bradypodidae (three-toed sloths) Subclass Theria Infraclass Eutheria Order Pilosa (edentates)Pilosa 1 genus / 3 species Cantral America & N South America 0/0 0/0 PM 5/4- 5 = 18-20, no enamel Zygomatic arch incomplete

Family Cyclopedidae (silky anteaters) Subclass Theria Infraclass Eutheria Order Pilosa (edentates)Pilosa 1 genus / 1 species S Mexico to Bolivia arboreal

Family Myrmecophagidae (anteaters) Subclass Theria Infraclass Eutheria Order Pilosa (edentates)Pilosa 3 genera / 4 species Central & South America terrestrial

Family Dasypodidae (armadillos)Dasypodidae Subclass Theria Infraclass Eutheria Order Cingulata (armadillos)Cingulata 8 genera / 20 species North, Central & N South America homodont, 7/7 to 18/19 4 identical quadruplets