Composed of orders Cingulata and Pilosa
Distribution - Neotropics (and Cingulata invading North America)
Position in the Eutherian phylogenetic tree (Murphy et al. 2001)
- General characteristics of both these orders
- A tendency towards rigidity of the spine
- Xenarthran processes on vertebrae (especially lumbar)
- Fusion of vertebrae with pelvic girdle
- Fusion of cervical vertebrae
- Were once very diverse; some interesting ones:
- glyptodonts: had turtle-like shell; most completely armored of all vertebrates
fossil skeleton
artist's rendering
- Megalonyx : giant ground sloth
fossil skeleton
museum reconstruction
artist's rendering
- Order Cingulata - armadillos
- Characteristics
- Carapace
- covers most of the body
- made of dermal bone plates covered by epidermal scales
- varies from a complete protective covering when animals roll
into a ball, to a more loose fitting one that doesn't
completely cover
- attached to axial skeleton by muscles and ligaments (not in direct
contact with the skeleton)
- Order Pilosa - sloths and anteaters
- General characteristics of sloths - specializations for arboreal living and herbivorous diet
- Arboreal (have great difficulty moving on the ground)
- Often move upside-down on the underside of branches
- Long-limbed, with forelimbs longer than hind
- Toes are fused ( syndactyly )
- Cervical vertebrae are variable in number (6-9)
- Teeth
*Lack incisors and canines
*Cylindrical, homodont, rootless teeth
- Rudimentary tail
- Long, coarse hair on which blue-green algae grows
- Herbivorous: eat buds, flowers, fruit
- Very, very low metabolic rate and poor temperature regulation
- General characteristics of anteaters - convergence with other ant and termite eating species
- Very long, tubular rostrum and very small mouths
- Long, sticky tongue that moves in and out rapidly
- No teeth
- Myrmecophagous
- Crush insects with thickened stomach (pyloric portion)
- Have large front claws for opening up termite mounds, tearing
up rotting logs, etc.