Xenarthra anteaters, sloths, & armadillos Pholidota pangolins ____________is from the Greek, meaning “________________.” With minor exceptions Xenarthrans are and have always been South American animals. _____________ means “______________.” Pangolins are scaly _____- and termite-eaters of Africa and Southeast Asia.

The Living Xenarthra 65MYA 55MYA

Probable patterns of xenarthran evolution: Earliest types: –Ancestral form was probably a _________________________________________.

______________________________ ____________is highly flexible, but in 1 dimension only. Teeth (if present) lack enamel and are simple & single-rooted. _______ is emphasized over other senses. All exploit “difficult” food resources (armadillos less so than sloths and anteaters). All survivors (except armadillos) are extreme __________. All try to save thermoregulatory energy: –By low body temps and/or ____________. –By behavior. –By choice of habitat and/or microhabitat.

Some Representative Living Xenarthrans

Sloths in general –______________________once much greater; 60 fossil genera are known –2-toed & 3-toed varieties ______________ similarity among living sloths. The problems of a leaf-diet: –____________________- & detoxifying leaves… –Digesting cellulose & energetics 

Giant ground sloths (extinct) Ground sloths are placed in the Family Megalonychidae. The ancestor of the extant sloths. Think 200kg- 3000kg!

Adaptations (?) that are probably related to “sloth energetics”: ____________________in compartmented stomach –Cost of microbial symbiants –Month-long throughput ____________ –About 1-2 times per week (500ml urine!) –Climb down from the tree; why? Slow movement __________________ –28 o C-35 o C (system-failure possible at 18 o ambient) –Range-restriction to tropical rainforest Adaptations to save energy: –Move slowly (hence the name…) –Insulate well & have low body temperatures (must therefore live in tropics)

________________ (Bradypodidae) Bradypus variegatus cm; kg. Much slower than 2-toed sloth. Eats from one tree for very long time. “Green” fur (longitudinal slits and specific algae). 11+ month gestation; extensive maternal care….

______________ (count on front feet) Choloepus hoffmanni More active, fiercer, and more catholic of diet than 3-toed variety cm, 5-8.5kg. Highly variable body temps (24 o C-35 o C). Female-biased sex ratio (reportedly 11 to 1) in wild. (Why?) Animal is long-lived (often > 20 years).

Sloth status and conservation They usually dominate Amazonian-mammal biomass: –2-toed: 2.7/a –3-toed: 7/a The prefer __________over other trees: –This genus thrives in second-growth forest. –So habitat is not endangered.

Anteaters (3 basic types) In the Neotropics, much of the zoomass is concentrated in colonial insects; anteaters eat nothing else. Front legs are powerful; each has a single, greatly _____________ (3 rd digit). Guess why. Teeth are absent, but rostra are elongated & ridged. Tongues are long & sticky. Pyloric region of stomach is thickened and may serve as a “__________” for grinding chitinous exoskeletons (and as a protection against concentrated formic acid).

_____________ Cyclopes didactylus 350g, <50cm head-body. Entirely nocturnal. One author estimated ants/day (former is much too low). Only xenarthran for which paternal care reported (but is it true?). “Male-overlap” territorial pattern.

_________________ _________________ _________________ The genus Tamandua (> 2 species) enters North America in southern Mexico. 2-7kg, 60cm head-body. Eats ants & termites (about 9000/day). “Tripod” defense. 1 baby (rarely twins), extensive maternal care for up to about 1 year. Most common anteater.

_________________ Myrmecophaga tridactyla kg, 180cm total length. Female bears one young per year, nurses for 6mo., carries on back for about one year. Often diurnal where not molested by people. Male-overlap territory. Most endangered by conversion of habitat for cattle ranching.

Ecology of M. tridactyla: How do they manage??? –_____________________ _____________________ ____________________ Termites seldom eaten? –Termites dominate diet? Taking so many from a single colony would destroy resource piecemeal. Native to:

_______________________________ __________________________ Roughly _____________, mostly South American (one species  USA). ______ (bone & horn-like substance) is arranged in bands & plates connected by flexible skin. (Shoulder & hip shields, armored head & legs, rings around body, underside soft….) _________ is mostly invertebrates though small vertebrates & considerable plant matter are also consumed. Respiration often anaerobic; low metabolic rate.

Dasypus novemcinctus: successful invader of USA from the South Total length about 75cm; mass c. 5kg (XX) & 6.5kg (XY). Range is probably constrained by…well, who knows? (Dramatic range extensions in twentieth century.) In USA, > 90% of diet is invertebrates..

How did they get there? How far can they go? US range extensions: –Natural movements plus… –Introductions –Hitch-hiking Limits (& non-limits) to range: –Physiological constraints perhaps not primary Vasoconstriction, shivering, increased metabolism… (Look at Mo, Ok, Tx, Ks.) –Food-supply may be more critical –Global Warming & the Armadillos that ate Manhattan?

Priodontes maximus 100cm h-b, 70kg (? still, largest living xenarthran). Once widespread across _________________. Digs shelters, often in active termite mounds. Main food is ________ (+ a few ______; feeding strategy not like giant anteater). Highly endangered by habitat modification and direct exploitation.

Cabassosus tatouay 20-45cm h-b, 5kg. Main food is _______ (mostly _____ & termites?); sticky tongue. Middle claw greatly enlarged (root-cutting). Usually produces 1 baby/litter. Endangered by habitat destruction.

Tolypeutes matacus 30cm h-b, kg. Probably eats mostly ants & termites. Bears single young. ____________________ ____genus that can roll into a complete ______.

Chaetophractus: ______________ This variable genus includes at least 3 species of small (c. 25cm) armadillos. Thermoregulatory strategy includes burrows several meters long. Chaetophractus includes much plant material in diet. It is known for burrowing under carcasses to obtain maggots.

Euphractus sexcinctus 40cm h-b, 3-7kg. South American dry & seasonally inundated prairies. Spends most of day in burrow.

Zaedyus:_______ Head-body length is 25-35cm. Insect food is typical of armadillos though pichis are said to include a fair amount of plant material in diet. These armadillos inhabit sandy soils in southern South America. Litter is 1-3 young; weaning occurs at about 6 months.

Family Glyptodontidae (extinct) ________________ were distant relatives of armadillos. –More completely armored. –Larger; grazers. Once, successful invaders of the North (including South Carolina). Possible causes of extinction: –Competition? –Climate? –People?

Order Pholidota (____________) Taxonomic position unclear; No teeth. Long, sticky tongues. Bodies covered with scales derived from agglutinated hairs. Pangolins can be highly selective in diet, often moving great distances (at night) and scraping in soil only lightly for preferred ant type. Pangolins play role in traditional medicine and folklore (& are heavily exploited in some areas).

_____________ __________ Manis tetradactyla (top) M. temmincki (bottom) 60cm, 7-15kg. Burrow well and climb OK. Eat mostly ________ (plus some ants). Mother carries single young on back or curled in tail. Can ball up completely.

Manis javanica: an________________ Total length 80-90cm. –Males are larger and are known to fight violently over females. Less armored than African species. An __________________ estimated (uh, by whom?) to take about 70 million insects per year.