File:Emergence of traits along the mammalian lineage.jpg

Emergence of traits along the mammalian lineage

Amniotes split into the sauropsids (leading to birds and reptiles) and synapsids (leading to mammal-like reptiles).

These small early mammals developed hair, homeothermy and lactation (red lines).

Monotremes diverged from the therian mammal lineage 166 Myr ago2 and developed a unique suite of characters (dark-red text). Therian mammals with common characters split into marsupials and eutherians around 148 Myr ago2 (dark-red text).

Geological eras and periods with relative times (Myr ago) are indicated on the left. Mammal lineages are in red; diapsid reptiles, shown as archosaurs (birds, crocodilians and dinosaurs), are in blue; and lepidosaurs (snakes, lizards and relatives) are in green.

Original file name: Figure 1 Nature06936-f1.2.jpg http://www.nature.com/nature/journal/v453/n7192/fig_tab/nature06936_F1.html

Reference

<pubmed>18464734</pubmed>| PMC2803040 | Nature

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