Serendipity and adaptation in New World marsupial evolution

MARTIN, GABRIEL; BRAND, CECILIA; MONJEAU, JORGE ADRIAN

JOURNAL OF MAMMALIAN EVOLUTION

SPRINGER

Lugar: Berlin; Año: 2022 vol. 29

1064-7554

This is the frst study analyzing the distribution of New World marsupials and their relationship to climatic zones on acontinental scale. We describe the distribution at diferent taxonomic categories (order, subfamily, tribe, genus) and theirpresence within climates, and discuss these patterns considering two diferent processes: serendipity or adaptation (i.e.,a serendipitous process afects a taxon older than the climate it inhabits, or afects a taxon younger than the climate itinhabits but without the evolution of new traits; an adaptation process afects a taxon in a climate with the evolution ofnew traits). Living Didelphimorphia included the highest richness and least functional redundancy in Tropical climates atthe four taxonomic categories studied; living Paucituberculata was mostly represented in Temperate climates, and livingMicrobiotheria was exclusively represented in Temperate climates. The most restrictive climates grouped generalized forms(e.g., scansorial animalivores) with a high order richness, but high functional redundancy and low richness for all the othertaxonomic categories (i.e., subfamily, tribe, genus). Also, climates which favor complex habitats (e.g., tropical, subtropicaland temperate forests) have a higher richness and functional redundancy, while simple habitats resulting from drier and/orcolder climates have less specialized forms, albeit taxonomically singular (e.g., Lestodelphys, Chacodelphys, Caenolestes).Highly seasonal climates grouped generalized taxa with high functional redundancy, and convergent adaptations (e.g., caudalfat storage, torpor or hibernation), while stable climates over long periods of time, acted as diversifcation centers for NewWorld marsupials, especially Didelphimorphia.