Mammalogy 4764 Fall 2009

Proboscidea, Sirenea, Hyracoidea Proboscidea Today: 2 genera, 2 species Body mass -- 7500+ kg

ax yr 70 H

ng go 60 Du Phenacodus m riu a he de Eosimias et oi o c m M iu yra er 50 th Fig. 14.1, Vaughn Eosimias H o in De ia Paenungulates ion Ph ut 40 m am ? M 30

n do elo Millions ago years of b Am 20 n do go n te do a s S lo an u e ric im ab s af ax tr u a m s go la ph nt u te ril la o as th 10 S o e od ph u o G im x la m m Pr Lo E am an o M P H 0

Mammuthus primigenius Mammut americanum Loxodonta africana

Elephas maximus

Lister

Proboscidea Proboscidea Functional teeth -- consequences of long life -- Ordinal characteristics (feet and trunk) Single tooth active (may be adjacent one too)

Development of foot -- Tusks -- 2nd upper incisor Pad to distribute weight uniformly Digitigrade Trunk Deinotherium Teeth Deinotherium 40 million years ago Moeritherium Back

20 mya

20 mya

Gomphotherium 1 mya Mammuthus

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4 mya

20 mya

30 mya Phiomia

50 mya

Ambelodon 25 MYA Lister and Bahn 1992

Proboscidea: Elephantidae Proboscidea Asiatic or Indian elephant African elephant Loxodonta africana Social behavior Elephas maximus Possibly 2 species? Female groups -- matriarchal kinship Gestation 22 months Ears smaller 19 pairs of ribs (not 21) Adult females, mothers and offspring 120 kg young Head dome, high point Nurse 3-4 years Males Single “finger” on trunk Bachelor herds or solitary Musth reproductive period 2-3 months High hormone levels Aggressive behavior

Communication -- Low frequency sounds Trumpeting

Sirenia Dusisiren -- Sirenea Stellar sea cow ancestor “Seacows” -- Dugongs, manatees Teeth vary in each genus Tropical, marine “Escalator” as in Elephants 20 mya but more teeth present Dugong: 500 to > 5,000 kg Dugong Dugong: Large, columnar, 60,000 individuals no enamel, worn away Fewest of any order covered in cementum 15 mya Trichechus: indefinite number Enamel covered, no cementum Trichecha: Manatee Nearly hairless (e.g., whales) 5 to 8 functional at a time Valvular nostrils (e.g., beaver, otter) Maintain feeding position: 10 mya Lung orientation Dense bone – ribs as ballast

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1 genus,Sirenea: 3 species Trichechidae

West Indian manatee: Trichechus manatus West African manatee: T. senegalensis Amazonian manatee: T. inunguis

Usually solitary to small group Palate Warm-water discharge areas Sirenea: Dugongidae

Protected in Florida since late 1800’s (legal vs. practical) Steller’s sea cow: Hydrodamalis gigas

Low reproductive potential -- Seasonal food availability -- thin in winter -- 13 month gestation problem faced by northern Sirenian

Skin

Hyracoidea Hyracoidea

1 family, 3 genera Arboreal and terrestrial 6 species (or fewer) species

Hyraxes, Dassies Terrestrial: diurnal, gregarious: family groups Africa and Middle East -- rock badgers in the Bible poor thermoregulators -- -huddle together First fossils 50 mya Arboreal: Elephants/Sirenians or Perissodactyls? nocturnal, solitary, territories maintained Rabbit-sized--1 to 5 kg Feet -- 10+ years in wild Stomach morphology: Suction cup-like arrangement Large cecum at start of large intestine Short, hoof-like nails, 1 claw Paired cecae at end of large intestine

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