Transcript Edentates
Edentates, Pholidotes, and Tubulidentates. An hodge-podge of ant eaters Xenarthra The edentates (without teeth) include 4 families: armadillos, sloths, and vermilinguas (ant-eaters). Verm – worm, lingua – tongue. All are new world. Only the 9-banded armadillo gets into the north. Xenathra Have relatively low body temperatures (34°C) compared to other eutherians. In spite of this, 9-bandeds have been extending their range northward. Xenarthra Old name edentata is inappropriate because only the anteaters are without teeth. New name, xenarthra, refers to accessory zygapophyses on the lumbar vertebrae. These ‘extra’ articulations increase the rigidity of the axial skeleton. 9-banded armadillo 9-banded armadillo 9-banded armadillo Xenarthra Incisors and canines are lost. Molars and premolars lack enamel and are single-rooted. In anteaters and armadillos, the acromion and coracoid are unfused and substantial, aiding powerful digging. Anterior caudal vertebrae have transverse processes fused to Ischium. Aardvark ventral skull: note lack of incisors. Aardvark molars: note lack of enamel. Xenarthrans Group was once much more diverse than today, with some extinctions occuring within recorded history. Glyptodon was huge: 2m total length. Note what happens to the vertebral column. Megalonychidae 2 species of arboreal 2-toed sloths and ground sloths†. Choloepus hoffmani occurs from Nicaragua to Peru and Brazil, while C. didactylus occurs only in S. America, east of the Andes. Lack incisors and canines. First upper premolar is caniniform, and separated from other cheek teeth by a diastema. 2-toed sloth utr: note diastema and caniniform premolar, and articular surface. 3-toed sloth utr 2 and 3 toed sloths. Both have incomplete zygomatic arches, and the jugal forms a flat plate. Extinct xenarthrans: Glyptodon and Paramylodon. Our extinct ground sloth: Nothrotheriops: survived in N. America until about 11,000 years ago. Right pes of Nothrotheriops, and the right manus of Paramylodon. Megalonychidae 2-toed sloths have “SURPRISE” 2 claws on forefeet, and 3 on the rear, while 3-toed sloths have 3 claws on the fore-feet. 2-toed sloths hang upside down almost all the time, except to defecate. Exclusive arboreal folivores. Symbiotic algae in the pelage. Body temp varies from 24-33C. Number of cervical vert. Varies from 5-8! Collared anteater claw: corresponds to ‘D’ on previous slide. Bradypodidae 3-toed sloths. Bradypus tridactylus is distributed from Honduras to Brazil. B. variegatus? Less active than 2-toed sloths, using only a single tree each day. Segmented stomach w/ microflora. Active day and night: Arboreal folivory is tough. 8-9 cervical vert: 270 degree rotation. Myrmecophagidae 4 species, with no teeth. Distributed from S. Mexico to Paraguay. Giant anteaters tongue is 13mm wide, but extendable to 600mm! It is anchored to the base of the sternum, is covered by submaxillary secretion, and has posteriorly directed barbs to trap ants. Collared anteater palate Collare d anteater basicranium Dasypodidae 8 genera and 20 species. 9-banded is only xenarthran in N. America. They have extended their range dramatically since the early 1800’s. Northern limit is probably defined by temperature. High thermal conductance, and an inability to enter torpor. Dadypodidae Excellent diggers … it is almost impossible to fence them in. Opportunistic feeders: invertebrates, plant material, and carion. Defensive behaviors: roll into a ball or jump. Dasypodidae Vertebrae modified for attachment of carapace to lumbar vertebrae via ‘metapophyses.’ Size varies from ‘pink fairy armadillo’ at 100g to giant armadillo at 60kg. Open rooter, homodont molariform teeth w/o enamel. Dasypodidae Dasypus has delayed implantation. Monozygotic polyembryony in some. In Dasypus novemcinctus there are 4 young of same sex, all from a single fertilized egg. They are used as models for medical models for leprosy research. Giant and 9-banded armadillos. 9-banded armadillo utr 3band ed armadillo basicran -ium 3 banded armadillo 3-banded armadillo 3-banded armadillo 3 banded armadillo 6-banded armadillo 6-banded armadillo 6-banded armadillo 6-banded armadillo Pholidota These are the pangolins. There are 4 species in sub-saharan Africa, and 3 species in India, Pakistan, China, Sri Lanka, southeast Asia, and Indonesia. They are ant-termite specialists w/ powerful digging abilities – sometimes semi-arboreal w/ semi-prehensile tails. Pholidota Poor vision and hearing, but olfaction is good. Scent marking – anal scent glands may be used in defense. Response to predation is to roll up in a ball like many other mammals. Scales are soft at birth. African species do not have external ears, but asian species do. Manis pentadactyla (pangolin) palate Manis pentadactyla basicranium Pholidota Truly edentate w/ long, sticky tongue (salivary gland is large and located in chest). Tongue is enclosed in a sheath, passes over the sternum, and is anchored on the pelvis. Incomplete zygomatic arch, and slender dentary (reduced musculature for chewing). Gizzard like pyloric region in stomach for grinding up ants and termites. Pholidota Mid-Eocene pangolin, Eomanis, is found in Europe. Oligocene pangolin, Patriomanis, is found in N. America. Tubulidentata Order is monotypic, contains only Orycteropus afer of Africa. Ant – termite specialist. Note: there are lots of ants and termites in Africa, and lots of lizards specialize on ants and termites as well. Acute olfaction and auditory senses. Travel as far as 30km/night. Orycteropus afer Tubulidentata Aardvark is Afrikaans for ‘earth pig.’ Nostrils are protected from dirt and ants during digging by hairs. Tubulidentata Extensive turbinate bones – good olfaction. Reduced eyes – characteristic of myrmecophagus species, but has erect ears – unusual. Strong clawlike nail for digging out ant/termite mounds. Tubule-teeth: fetal stage has incisors and canines. Ontogeny recapitulates phylogeny? Aardvark utr Tubulidentata Teeth are open-rooted w/o enamel, and covered w/ cementum. Ants and termites are ground up in muscular pyloric region of stomach. Miocene fossil Myorycteropus is from E. Africa. Orycteropus gaudryi is Miocene, and Leptorycteropus is from mid-pliocene. Pleistocene fossils are from France, Greece, Turkey, india, and Madagascar. FIELD TRIP There will be outhouses. Make sure your food group is ready: Stove Utensiles Food Water Fuel etc. Field Trip Make sure you have enough food and drink. If you want a fire at night, make sure you bring wood, matches, and kindling. Bring 1 change of clothes in case it rains. Bring your field notebook, and your skin and stuff kit. You will bust your but in the field, so be prepared. NO BITCHING! Tent and bag? No hunting. Bring an orange vest/hat. Field Trip Water. Be prepared for cold wet weather. Wool is better than down when its wet. Dry feet are important. A tooth brush will chase away the xactlys. Nobody cares what you look like in the field – we will all be ugly together. If you don’t bring your rap music, I won’t bring my Miles Davis. No Radios.