Extinct American Cheetah, Miracinonyx inexpectatus
July 2010

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HOW DO WE KNOW THIS? Like living animals, fossil remains of once-living animals are classified and grouped according to their relationships to each other and to their ancestors.

(Barnett et al 2005) (Christiansen & Mazak 2009) (Menotti-Raymond & O'Brien 1993) (Valkenburgh et al 1990) (Johnson et al 2006)

Describer (Date): Cope 1895 for Miracinonyx inexpectatus

Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia
             Order: Carnivora
                Suborder: Feliformia
                    Family: Felidae
                           Genus: Acinonyx Kurtén (EXTINCT) Newly discovered cheetah species
                                        (Christiansen & Mazak 2009)    
                           Genus: Miracinonyx (EXTINCT)
                                  Species: Miracinonyx inexpectatus (EXTINCT) American cheetah
                                  Species: Miracinonyx trumani (EXTINCT)

Taxonomic History and Nomenclature  Phylogeny 


HOW DO WE KNOW THIS? Scientists use knowledge of the earth's rocks, global plate tectonic movements, together with genetic and phylogenetic data to make sense of fossil distribution patterns. Ancient habitats are understood by studies of modern environments where sediments are deposited.

(Hodnett 2010) (Martin et al 1977) (Van Valkenburgh et al 1990)

Prehistoric Distribution  Prehistoric Habitat:


HOW DO WE KNOW THIS? Careful study of fossil bone or tooth anatomy yields much exact information about placement and strength of muscles, tendons, ligaments, nerves, and blood vessels. In rare cases, skin, nail and hair impressions or actual skin, nails, or hair is preserved. Body weight is more difficult to gauge because fat leaves no impression on the skeleton.

(Shaw & Cox 2006) (Turner & Anton 1997) (Van Valkenburgh et al 1990)

Estimated Body Weight: 70 kg (156 lb)
Head/Body Length: 170 cm (5.6 ft)
Height at Shoulder: 85 cm (33 in)
Tail Length: 92 cm (3 ft)

General Teeth


Sexual Dimorphism Other Physical Characteristics


HOW DO WE KNOW THIS? Since direct observation of a fossil animal's behavior isn't possible, paleontologists use comparison and contrast with living animals for guidance. Tracks can reveal clues too. Associated animals and plants found at a fossil site suggest predator/prey dynamics and dietary options. Tooth wear studies may indicate eating habits.

(Hodnett et al 2010) (Shaw & Cox 2006) (Turner & Anton 1997) (Van Valkenburgh et al 1990)

Social Life Locomotion Interspecies Interaction


HOW DO WE KNOW THIS? Clues to fossil mammals' diets come from not only teeth, but also skull shape. Rarely, fossil dung and gut contents can be preserved. Microscopic viewing of wear on teeth offer direct evidence of the diet's impact on tough enamel. Lab analysis of oxygen, carbon, and nitrogen isotopes in bone and teeth yield state-of-the-art insight into the plants and animals ate. Isotopes help describe even the soils and water in a long-gone ecosystem. Diets of similar modern animals may offer further insight.

(Hodnett 2010)

(Martin et al 1979) (Valkenburgh et al 1990)


HOW DO WE KNOW THIS? Abnormalities in fossil bones may show evidence of arthritis, cancer, nutritional stress, fractures (healed ones and unhealed ones at death) and more.

(Rothschild & Martin 2003)

IMPORTANT WEB RESOURCES (and where to find fossils in museums):

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