HYRACOIDEA & SIRENIA: Remnants of the Subungulate Radiation Mammalogy - EEOB 625: 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

. Character states: Proboscidea Hyracoidea Sirenia Carpal & tarsal bonesx x x Short, hoof-like nails 5/4 or 4/3 4 /3 4/ No clavicle x x x Pectoral mammariesx x x Abdominal testes x x x “Horizontal molariform tooth replacement x x x Similarities among the Subungulates

Horizontal tooth replacement in Sirenia

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

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

Dugong Steller’s Sea Cow ( extinct) Dugongidae Trichechidae W. AfricanAmazonian

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

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 1 st year calves Major causes of mortality Conservation: Recovery Plan & recent issues Current status: n ~ 1900, ~ 8% annual mortality West Indian Manatee

Characteristics of Endangered Species : 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

2-3 meters long, 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 kg/day Reproduction: Polygynous, - 1 st 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? Natural History of Manatees