Evolution, 4th Edition

458 CHAPTER 17

Futuyma Kirkpatrick Evolution, 4e

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Evolution4e_17.27.ai Date 02-16-2017

Morganucodonts

Docodonts

Australosphenidans–

monotremes

Eutriconodonts

Multituberculates

Spalacotheroids

Cladotherians

Boreosphenidans

Placental

mammals

Marsupials

252 201 145 66 23 Present

Time (Mya)

Tr J K Pg Ng

FIGURE 17.27 Phylogenetic relationships

and temporal distribution of major groups

of mammals. The morganucodonts, arising

in the Jurassic, are important intermediates

between mammal-like reptiles and true

mammals (see Chapter 20). The only groups

that survive to the present are monotremes,

placentals, and marsupials. The coloration of

the reconstructed figures of morganucodont

and multituberculate are based on supposi-

tion, not data. The changing width of each

branch represents changes in the diversity of

known species in that group. (After [56].)

Futuyma Kirkpatrick Evolution, 4e

Sinauer Associates

Troutt Visual Services

Evolution4e_17.28.ai Date 01-16-2017

Jurassic

Modern

Early Cretaceous

Volaticotherium

Sugar

glider

Flying

squirrel

Gliding

Henkelotherium

Sinodelphys

Eomaia

Tree shrew

Climbing

Fruitafossor

Armadillo

Aardvark

Digging

Haldanodon

Castorocauda

Beaver

Otter

Swimming

FIGURE 17.28 The lower (black) figures

are reconstructions of the likely form

of diverse Mesozoic mammals that are

inferred, from their anatomy, to have had

different ecological features. The upper

figures portray living mammals that are

ecologically similar to the Mesozoic forms

below, a result of convergent evolution.

Swimming, digging, climbing, and glid-

ing forms are shown. (After [56].)

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