Summary of Nature Article 06277 Essay
.Ecological diversification: is lineage splitting of early mammals decoupled from, or correlated with ecological diversification?
.Morphological transformation: are originations of key mammalian characters singular evolutionary events, or iterative convergences despite their complexity?
Temporal pattern of early mammal evolution
The evolution of early mammals occurred in successive diversifications or episodes of quick splitting of relatively short-lived …show more content…
Fossorial behaviour was documented by taphonomic evidence or some premammaliaform cynodonts, but only recently did the fossorial skeletal specializations (such as scratch digging) become known for mammaliaform lineages.
The hypertrophied digging-limb features and the unique columnar and enamel-less teeth were developed in the Late Jurassic Fruitafossor 150 million years (Myr) ago, 100 Myr before a similar character complex evolved convergently in armadillos and aardvarks, among placentals.
New skeletal fossils suggest that some (although not all) Mesozoic eutherians and metatherians and their near kin also developed such adaptations(climb on uneven terrain) , as shown by the elongate intermediate phalanges and convex profiles of manual and pedal distal phalanges, and in the tarsus, among other skeletal features.
They unveiled a new picture in which ecological diversification is not unique to the Early Cenozoic mammalian radiation, and that many dead-end Mesozoic mammal clades