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HYRACOIDEA & SIRENIA: Remnants of the Subungulate Radiation

HYRACOIDEA & SIRENIA: Remnants of the Subungulate Radiation. Mammalogy - EEOB 625: 10-12 March 2004 Taxon Quiz III: Friday, 12 March, in lecture

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HYRACOIDEA & SIRENIA: Remnants of the Subungulate Radiation

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  1. HYRACOIDEA & SIRENIA:Remnants of the Subungulate Radiation Mammalogy - EEOB 625: 10-12 March 2004 Taxon Quiz III: Friday, 12 March, in lecture Will cover 25 families (posted on website) of Carnivora, Cetacea, Proboscidea, Hyracoidea, Sirenia, Perissodactyla, and Artiodactyla

  2. Similarities among the Subungulates . Character states: ProboscideaHyracoideaSirenia Carpal & tarsal bones x x x Short, hoof-like nails 5/4 or 4/3 4 /3 4/ No clavicle x x x Pectoral mammaries x x x Abdominal testes x x x “Horizontal molariform tooth replacement x x x

  3. Horizontal tooth replacement in Sirenia

  4. Hyracoidea of the Ethiopian • One family with 6 species in Ethiopian & Palearctic • Locomotion: mesaxonic but climbers more than runners Adaptive radiation - Extinction of a diverse group, some as large as tapirs - Body size? Gestation length (8 months) a clue? • Convergent with rodents and lagomorphs: “rodent-like” “lagomorph-like” dentition? : 1/2, 0/0, 4/4, 3/3 li • Colonial herbivores - rocky desert areas to forests ‑ low mortality

  5. SIRENIA: Unique among all orders? • Habitat and diet ________ & _________ • A mere remnant of a once diverse group (20 genera) of the Miocene • Distribution: Dugongidae & Trichechidae • Four extant & one recently extinct species

  6. Trichechidae Amazonian W. African Dugong Dugongidae Steller’s Sea Cow (extinct)

  7. SIRENIA: Unique among all orders? • Habitat and diet ________ & _________ • A mere remnant of a once diverse group (20 genera) of the Miocene • Dugongidae & Trichechidae compared • Dugongidae (with forked tails): one species Dugong of Indonesia (Stellar’s sea cow: extinct) • Trichechidae: Distribution of 3 species: W. African, Amazonian, and West Indian or Florida Manatee

  8. West Indian Manatee • One of four species in a declining, endangered (?) order • Characteristics of endangered species • Physical characteristics and distribution • Habitat requirements & Feeding behavior • Reproduction: 5-15% of population in 1st year calves • Major causes of mortality • Conservation: Recovery Plan & recent issues • Current status: n ~ 1900, ~ 8% annual mortality

  9. Characteristics of Endangered Species : • Adapted to stable, undisturbed communities • Low natality and low natural mortality • Specialized, narrow habitat or environmental requirements • Historically restricted in distribution, on periphery of range or low in density

  10. Natural History of Manatees • 2-3 meters long, 350-450 kg, no hind limbs • Former range reduced to Florida & Puerto Rico • Habitat: Shallow, warm fresh to marine waters with abundant aquatic vegetation • Feed 4-6 hrs/day, consuming 25-35 kg/day • Reproduction: Polygynous, - 1st breed at 4-6 yrs, every 3-4 years thereafter - single calf, 390 day gestation, nurse ~1 year • Is this characteristic of an endangered species?

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