role of physical geography and habitat type in shaping the biogeographical history of a recent radiation of Neotropical marsupials (Thylamys: Didelphidae)

• Published in: Journal of biogeography Vol. 41; no. 8; pp. 1547 - 1558
• Main Authors: Giarla, Thomas C, Jansa, Sharon A, Ladle, Richard
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Scientific Publications 01.08.2014; Blackwell Publishing Ltd; John Wiley & Sons Ltd; Blackwell; Wiley Subscription Services, Inc
• Subjects: Andes; Animal and plant ecology; Animal, plant and microbial ecology; biogeographical area coding; Biogeography; Biological and medical sciences; Biomes; Didelphidae; diversification; Ecosystems; Evolutionary histories; fauna; Fundamental and applied biological sciences. Psychology; General aspects; Geography; grasslands; Habitats; historical biogeography; Lestodelphys; loci; Lowlands; Mammalia; Marsupials; mountains; Natural history; open habitats; Physical geography; riverine barrier hypothesis; Riverine habitats; rivers; Savannas; South America; sowing; Synecology; Taxa; Thylamys; trees; tropics; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; South America; Andes; America; Geography; South America; Lestodelphys; Andes; Didelphidae; Biogeography; Thylamys; biogeographical area coding; Barrier; Diversification; open habitats; Case history; Vertebrata; Mammalia; Mountain; Marsupialia; historical biogeography; riverine barrier hypothesis; Habitat; Neotropical Region
• ISSN: 0305-0270; 1365-2699
• DOI: 10.1111/jbi.12320

AIM: In this study, we reconstructed the biogeographical history of species within the sister‐genera Thylamys and Lestodelphys, Neotropical marsupials that primarily inhabit open biomes. We used this reconstruction to test the extent to which physical geography (e.g. mountains and rivers) and habitat type (e.g. biomes) shaped patterns of diversification. LOCATION: Central and southern South America. METHODS: A fossil‐calibrated ultrametric tree for all species within Thylamys and Lestodelphys, along with relevant marsupial outgroups, was reconstructed using sequences from 23 nuclear loci and three mitochondrial loci. Using two biogeographical area schemes (based on biomes and physical barriers, respectively), the biogeographical history of this clade was reconstructed using Lagrange, a maximum‐likelihood approach. RESULTS: Thylamys and Lestodelphys originated during the Pliocene in the lowland areas east of the Andes and later expanded their range into and across the Andes. Rivers are implicated in speciation events that occurred in the lowlands, whereas differentiation among habitat types may have led to increased in situ speciation within the Andes. MAIN CONCLUSIONS: Biogeographical area schemes based on biomes and physical geographical barriers offered largely complementary results, supporting the hypothesis that both physical geography and ecological differences among habitats drive speciation in continental fauna. Invasion of high‐elevation grasslands may have been the impetus for further diversification in montane habitats, eventually seeding the adjacent lowland areas with additional species.