1. PROBOSCIDEA and the Subungulate Radiation Mammalogy EEOB 625 8 March 2004

2. The Subungulate Radiation Orders Proboscidea, Hyracoidea, & Sirenia Descendants of a common ancestor: Condylartha, but does this make them close all that closely related? Morphology & agreement in cladistic analyses Hyracoidea as a sister group to Proboscidea & Sirenia, or Perhaps more closely related to Perissodactyla

3. Colbert 1955

4. . 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

5. Range of Body Mass in Mammals 3 g in Sorex hoyi to 7500 kg in elephants Most mammals – 10 to 100 g (0.001 – 0.1 kg) Relatively few (10 orders) > 10 kg Orders with species > 100 kg? (5-7) The largest: Bovidae: 1000 kg Rhinocerotidae: 2000 kg Hippopotamidae: 4500 kg Elephantidae: 7500 kg Advantages & Disadvantages of large body size

6. Origin & Evolution of Proboscidea I Subungulate descendants of Condylartha - First fossils in Eocene, Elephantidae Miocene - Moeritherium of Oligocene ‑ pig ‑ like - Dinotherium & Primelephas (Trilophodon): ancestral? Morphological trends in divergent forms Rapid evolution of three genera of “modern” elephants during the Pliocene & Pleistocene Elephas: greatest in adaptive radiation?

7. Vaughan ‘00

8. Fig. 143, Colbert ‘55 Moeritherium Dinotherium Mastodons Elephants from the Oligocene to Pleistocene

9. Fig. 18.5, Feldhamer Recent Radiation of Elephantidae: since the Pliocene

10. Origin & Evolution of Proboscidea II Morphological trends in divergent forms - increased body size: graviportal locomotion - shortening of the skull & mandible - upper or lower incisors as tusks - lengthening of legs Special features of modern elephants - graviportal adaptations of legs & feet - proboscis with hydrostatic muscle, - dental formula: - 1/0, 0/0, 3/3, 3/3 - sequential replacement of cheek teeth

11. Fig. 18.2, Feldhamer

12. Diphyodonty: modified for diet and long life Fig. 18.4, Feldhamer 45-60 years

13. Rapid Evolution of Modern Elephants During the Pleistocene Similar to the time scale for humans Mastodons & Mammoths of Ohio Elephant Fossils & Ohio Historical Society Differences in molars & feeding habits (?) mastodons: with cusps (bunodont) mammoths: lophodont ( vertical plates)

14. Ohio Historical Society

15. Rapid evolution Pliocene + - similar time scale to humans - elephants in Ohio Dental morphology and feeding habits of mastodons & mammoths: bunodont vs. lophodont Ohio Historical Society

16. Elephas maximus 2 species, 6 subspecies forest savanna I C M S Loxodonta africana