Evolution at a different pace: distinctive phylogenetic patterns of cone snails from two ancient oceanic archipelagos

Area of Science:

• Marine biology
• Evolutionary biology
• Biogeography

Background:

• Oceanic archipelagos of similar age and habitat are expected to have comparable endemic lineages.
• The Macaronesia region, including Cape Verde and the Canary Islands, shows remarkable differences in marine snail (Conus) diversity.

Purpose of the Study:

• To investigate the contrasting diversification patterns of Conus snails in the Cape Verde and Canary Islands.
• To understand the factors driving the significant disparity in Conus species richness between these archipelagos.

Main Methods:

• Molecular phylogenetic analyses.
• Geometric morphometrics.
• Bathymetric and paleoclimatic reconstructions.
• Random Forests modeling using oceanographic variables.

Main Results:

• Conus species diversity is lower in the Canary Islands than previously thought, with a single species identified from a putative complex.
• Sea level fluctuations did not explain the habitat area disparity between archipelagos.
• Recurrent gene flow with West Africa, volcanic activity, and limited colonization influenced Canarian Conus diversity.
• Sea surface temperature emerged as a key determinant of Conus diversity globally and along the eastern Atlantic coast.

Conclusions:

• Geological age and habitat analogy do not guarantee similar diversification rates in oceanic archipelagos.
• Multiple factors, including gene flow, habitat instability, and oceanographic conditions, shape marine gastropod diversity.
• Sea surface temperature is a critical driver of Conus species richness patterns.