Broad geographic dispersal is not a diversification driver for Emberizoidea

Area of Science:

• Evolutionary Biology
• Biogeography
• Ornithology

Background:

• Dispersal is often considered a primary driver of speciation and explains variations in species richness among avian clades.
• The Emberizoidea, a diverse New World Oscine bird superfamily, exhibit widespread ecological and geographical distributions, making them an ideal model for studying dispersal's role in speciation.

Purpose of the Study:

• To investigate the relationship between dispersal rates and speciation rates within Emberizoidea families.
• To determine if biogeographical dispersal promotes or hinders speciation in this diverse avian group.

Main Methods:

• Bioregionalization analysis to delineate geographical areas.
• Ancestral area reconstruction to infer historical distributions.
• Speciation rate estimation methods to quantify diversification dynamics.

Main Results:

• The Emberizoidea superfamily originated from a widespread New World ancestor, with range evolution dominated by contractions.
• Major cladogenetic events occurred within bioregions, not primarily driven by dispersal between them.
• Dispersal rates between bioregions showed no correlation with speciation rates.

Conclusions:

• Biogeographical dispersal is not a significant driver of speciation for Emberizoidea families.
• Range stability and cladogenetic events within bioregions are crucial for broad-scale speciation in this group.