Robert FeranecCurator of Vertebrate Paleontology, NYSM

TOTALLY AWESOME: Extreme Evolution in Mammals—YEAH!! (with fist pump)

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Who’s the Biggest?

Who’s the Smallest?

Who’s the Baddest?

Best Common Name?

Best Scientific Name?

Who’s the Biggest?:Paraceratherium

•Age: 30 million years ago•Height: upto 23 feet tall (15 feet at shoulder)•Weight: upto 20 tons

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Who’s the Smallest?:Batodonoides

•Age: 53 million years ago•Height: small•Weight: 1.3 grams

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Best Scientific Name?:Sunkahetanka pahinsintewakpa

•Age: 28 million years ago•Weight: 20 kgs

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Hesperocyonidae (distant canid relative)

Best Common Name?:Gunther’s Dik Dik

•Age: Modern•Height: upto 40 cm•Weight: upto 5 kgs

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EXTREME?

Head Gear

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Why Head Gear?

Defense:

Combat:

Mate Recognition:

Ornamentation:

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Differential survival and reproduction

Sexual SelectionCertain evolutionary traits are the result of

intraspecific competition

Intrasexual Competition: Generally Male-Male competition, female mates with the “winner”

Intersexual Competition: Female Choice

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Types of Head Gear?

Ossicones:

Horns:

Antlers:

Pronghorns:

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Head Gear: Ossicones

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Head Gear: OssiconesFossils

Sivatherium~8,000 years ago

Samotherium~4 million years ago

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Head Gear: Horns

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Head Gear: HornsFossils

Hoplitomeryx

Syndoceras Synthetoceras

Bison latifrons

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Cranioceras

Head Gear: HornsFossils

Arsinoitherium (from Egypt)Age: 35 Ma

Height: ~7 feet at shoulder

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Head Gear: HornsFossils

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Head Gear: HornsFossils: Brontotheriidae

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Mylagaulid rodentsWhy do they have those crazy horns?

30-5 MaNorth America

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Mylagaulid Ecology• Herbivorous• Body size:

~ 0.5-5 kg.• Fossorial

(burrowing), but how?

• One of the only fossorial animals with horns

Mill

ions

of y

ears

ago

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Fossorial adaptation in rodents

Figure from Stein 2000

Scratch digging

Chisel tooth digging

Head lift digging

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Head digging in mylagaulids

Features consistent with head-digging:

• Thickened, projecting nasal bones

• Tall, forward-tilted occipital plate

• Shortened skull

• Powerful forelimbs

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Likely evolved from head-lift diggers

Why horns?

Possible uses of horns:

• Species recognition

• Digging

• Sexual display/combat

• Defense

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Horns : digging implement

In favor:• Higher occipital plate with

taller hornsAgainst:• Position, orientation of

horns• Change in horns through

time• Increases force needed to

dig• CONCLUSION: unlikely

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Horns : sexual display/combat

• Not sexually dimorphic

• Lack of visual ability

• Display useless underground

• Orientation of horns

• CONCLUSION: unlikely

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Horns : defense

• Passive or active defense

• Predator diversity: mustelids (weasels and stoats), snakes?

• CONCLUSION: Likely, consistent with available evidence.

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Horns…or Not Horns

CoelodontaLate Pleistocene (~20,000 years ago)

Europe

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NOT “true” horns

CoelodontaLate Pleistocene (~20,000 years ago)

Europe

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Horns…or Not Horns

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Horns

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Horns…or Not Horns

Narwhal (modern)

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NOT Horns

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Head Gear: Pronghorns

Antilocapra americana

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Head Gear: PronghornsFossils

Merycodus15 Mya

Ramoceros12 Mya

Ilingoceros8 Mya

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Head Gear: Antlers

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Head Gear: Antlers

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Head Gear: AntlersFossils

Megaloceros giganteus~10000 years ago

•Each antler is 6ft long

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Antlers and…

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Antlers and…Saberteeth!!!

MoschusModern

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Why Head Gear?

Defense:

Combat:

Mate Recognition:

Ornamentation:

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Evolution of saberteeth

Thylacosmilus

SmilodonEusmilus

Machaerodus

Machaeroides

Homotherium

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From Akersten 1985

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Homotherium Smilodon

Is the evolution of the sabertooth convergent evolution or parallel evolution?

Convergent Evolution vs. Parallel Evolution?

Convergent Evolution: describes the acquisition of the same biological trait in unrelated lineages.

Parallel Evolution: the development of a similar trait in different not closely related species (that is in species of a different clade), but descending from the same ancestor.

Question: How do we distinguish how closely an organism is related?

How to Solve this?

Hall (2003) Biological Reviews

Question: How do we distinguish how closely an organism is related?

How to Solve this?

Convergence: Similarity arising through independent evolution having different developmental pathways

Parallelism: A feature present in closely related organisms but not present continuously in all members of the lineage, and uses similar developmental pathways.

Hall (2003) Biological Reviews

Evolution of saberteeth

How do they develop?

Thylacosmilus Machaerodus

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You are what you eat…and drink

Isotopes in modern precipitation

18O

SM

OW

AugustJanuary January

FLAGSTAFF, AZ 1961-1963

From IAEA GNIP Database

+18O

-18O

Oxygen Isotopes(Isotope: same # of P, E- but different # of N)

+18O

-18O

Summer Summer

Winter

Predicted cyclicity in oxygen isotope values of enamel carbonate

TipBase

+18O

-18O

TipBase

12 months

Predicted cyclicity in oxygen isotope values of enamel carbonate

25mm 85mm

60 mm

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

0 10 20 30 40 50 60 70 80 90 100

18 O

val

ue

-10

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

0 10 20 30 40 50 60 70 80 90 100

18 O

val

ue

Isotope values for

S. fatalis

Distance from enamel-root contact (mm)

Average: 66 mm / 12 months =

5.5 mm per month

Feranec, in prep

Panthera tigris2

Panthera leo1

Smilodon gracilis ~12 months

18 months

9-14 months

6.7 mm/month

3 mm/month

9 mm/month

Comparison in Felid canine development

1. Smuts et al., 1978

2. Mazak, 1981

Smilodon fatalis ~18 months5-7 mm/month

Homotherium serum ~15 months2.5 mm/month

Panthera leo >18 months2.8 mm/month

Panthera atrox >18 months2.9 mm/month

TAXONDURATION

OF GROWTHRATE

Feranec. 2004, 2005, 2008

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Convergent Evolution

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Who’s the Biggest?

Who’s the Smallest?

Who’s the Baddest?

Best Common Name?

Best Scientific Name?

Who’s the Baddest?:2010 Championship

Winner

4. Smilodon populator

1. Ursus maritimus tyrannus

2. Andrewsarchus mongoliensis

3. Daeodon hollandi

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Who’s the Baddest?:

V.

6 ft. tall at shoulderWeighs up to 2000 lbs

4ft. tall at shoulderWeighs up to 1300 lbs

4. Smilodon populator1. Ursus maritimus tyrannusEX

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Who’s the Baddest?:

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Who’s the Baddest?:

Polar Bear Wins!!EXTREM

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Who’s the Baddest?:

2. Andrewsarchus mongoliensis 3. Daeodon hollandi

Height: up to 8 ft at shoulderLength: 11 feet longWeight: up to 2200 lbs.Age: 40 Ma

Height: up to 7 ft at shoulderLength: 12 feet longWeight: up to 2200 lbs.Age: 25 Ma

V.

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Who’s the Baddest?:

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Andrewsarchus mongoliensis Daeodon hollandi

Who’s the Baddest?:

Andrewsarchus Wins!!EXTREM

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Who’s the Baddest?:

Winner

1. Ursus maritimus tyrannicus

4. Smilodon fatalis

1. Ursus maritimus tyrannicus

2. Andrewsarchus mongoliensis

2. Andrewsarchus mongoliensis

2. Daeodon hollandi

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Who’s the Baddest?:

V.

6 ft. tall at shoulderWeighs up to 2000 lbs

Can stand up to 11 feet tall

1. Ursus maritimus tyrannus 2. Andrewsarchus mongoliensis

Height: up to 8 ft at shoulderLength: 11 feet longWeight: up to 2200 lbs.

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Who’s the Baddest?:

Size ComparisonEXTREM

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Who’s the Baddest?:

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Ursus maritimus tyrannus!!!

Thank you

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