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Order XENARTHRA (formerly Edentata)

anteaters, sloths and armadillos

Traits

  1. xenarthrous vertebrae [fig 14.2]
  2. incorporation of caudal vertebrae into sacrum
  3. reduced to absent dentition, without enamel;
  4. low metabolic rates and low body temperatures [Fig. 14.1]

Families

Tardigrada (sloths)

  1. Neotropical
  2. no tail, blocky skull
  3. arboreal; hang upside down in trees
  4. folivores
  5. variable body temperature,  bask to warm
  6. form symbiotic relationships with red or green algae on the surface of hair making green appearance to pelage
  7. gestation unusually long--11.5 months

Bradypodidae

  1. Bradypus (three-toed tree sloths, ais) [Fig. 14.4B]
  2. 3 toes on front [Fig. 14.3A, B] and hind limb
  3. 8 or 9 cervical vertebrae give neck greater flexibility
  4. photographs of Bradypus tridactylus left by Dr. Lloyd Glenn Ingles, California Academy of Sciences. Copyright © 2001 California Academy of Sciences.  Right by Ben Hernandez,  © 2001 used with permission 

 

Megalonychidae

  1. Choloepus  (two-toed tree sloths) [fig 14.4A] is currently recognized to be more closely related to the extinct, giant ground sloth Megalonyx
  2. two toes on the front foot [Fig. 14.5C], three on the hind
  3. anterior-most cheektooth is caniniform

  4. 5 to 8 cervical vertebrae

  5. more active than three-toed sloths

  6. broader range of food habits than Bradypus
  7. Good information from the Singapore Zoo

 


Image courtesy Biodidac
 Myrmecophagidae--anteaters [fig 14.6]
  1. Neotropical
  2. feed on ants and termites (myrmecophagy)
  3. long tapered skull [Fig. 6.3]
  4. no teeth
  5. very long vermiform tongue [Fig. 6.3] extending to posterior portion of sternum
  6. large salivary glands 
  7. powerful clawed forelimbs with 3 toes
  8. range in size from Cyclopes (250 gms) to Myrmecophaga (30+ kg)
  9. Tamandua and Cyclopes are arboreal


  Myrmecophaga - image courtesy Zoonet

Dasypodidae--armadillos [Fig. 14.8]
  1. Neotropical, Nearctic
  2. Dasypus novemcinctus  has expanded its range into the Southeastern U.S. [Fig. 14.7]
  3. body covered with bony scutes, which are overlain by epidermal, keratinized scales, connected by flexible skin, and are attached to body by connective tissue [Fig. 14.9]
  4. homodont dentition
  5. diet is insects, invertebrates, carrion, plant material
  6. powerful diggers
  7. delayed implantation [Fig. 9.7D, pp. 158-159]
  8. birth of 1 to 12 young from a single ovum (monozygotic polyembryony).  D. novemcinctus produces four young of the same sex. [pp. 158-159]

Dasypus novemcinctus -- nine banded armadillo photograph © 2001by Dr. Allan H. Chaney,
 used with permission

the Texas Small Mammal

 

Order PHOLIDOTA--pangolins or scaly anteaters

 

  • learn more about pangolins from
  1. the University of Michigan Animal Diversity web
  2. or the University of California Museum of Paleontology
  • Oriental and Ethiopian (tropical)
  • monotypic order (1 genus, 7 species)
  • molecular evidence place pangolins in the Laurasiatheria

Manidae

  1. pangolins: "scaly anteaters" (fig 14.10)
  2. covered dorsally in overlapping, keratinous scales 
  3. belly is furred
  4. nocturnal, arboreal or terrestrial
  5. arboreal forms with prehensile tail
  6. Diet of ants and termites
  7. edentate
  8. extremely long tongue (longer than head and body length) passes over sternum and is anchored to long processes of the pelvis

 


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