![]() ![]() The stem of the Old World clade diverged from Neotropical ancestors around 27 Ma, in the Oligocene. Our divergence date estimates using the plastid dataset and fossil calibration points in Salicaceae indicate that the Casearia crown group started to diversify during the late Eocene, approximately 39 Ma. ![]() Another clade, which includes all Palaeotropical species, is nested among Neotropical lineages. Casearia is constituted by several major clades, mostly being entirely Neotrop-ical, one of which exclusively comprises species endemic to the Caribbean islands. Our phylogenetic analyses based on four combined rapidly evolving plastid regions (petD, rpl16, rps4-trnT-L-F, trnK-matK-psbA) as well as nuclear ITS revealed Casearia as monophyletic with high support, including not only the former members of Laetia, Samyda and Zuelania but also Euceraea and Neoptychocarpus. We further put a focus on the Neotropical taxa since Casearia and allies are speciose both on the Caribbean islands and adjacent mainlands, thus providing an interesting group to address the origin of the Caribbean and Cuban flora. We tested the monophyly of Casearia and examined the relationships of its species to other taxa of the tribe Samydeae, including Laetia, Samyda and Zuelania, which recently have been sunk into Casearia, as well as Euceraea, Lunania, Neo-ptychocarpus, Ryania and Tetrathylacium. Despite the availability of phylogenetic studies that suggest that Casearia sensu Sleumer is not monophyletic, a strong phylogenetic framework was still lacking for this genus. The history of the Andean flora is complex and plantdiversification has been driven by a variety of processes, including environmental change,adaptation, and biotic interactionsĬasearia (Salicaceae) is a pantropical genus of circa 200 species, around half of which dwell in the Neotropics. Direct biogeographical relationships between the Andes and otherdisjunct regions have also been shown in phylogenetic studies, especially with the easternBrazilian highlands and North America. The Andes are biogeographically related to allneighbouring areas, especially Central America, with floristic interchanges in both directionssince Early Miocene times. Divergence time estimates of plant groupsoutside the Andes encompass a wider range of ages, indicating that the Andes may not benecessarily the cause of these diversifications. Dispersal along the Andes has been shown to occur ineither direction, mostly dated after the Andean uplift. This isinterpreted as evidence of vicariance. ![]() Mostclades with disjunct distribution on both sides of the Andes diverged during Andean uplift.Inner-Andean clades also tend to have divergence time during or after Andean uplift. Asexpected, Andean mid-elevation lineages tend to be older than high-elevation groups. ![]() Divergence timeestimates indicate that high-elevation lineages originated and diversified during or after the majorphases of Andean uplift (Mid-Miocene to Pliocene), although there are some exceptions. Biogeographicalrelationships between the Andes and other regions are also considered. PELLUCID HAWK MOTH VS HUMMING BIRD GENERATORThe influence of the Andes on plant diversification is separated into four major groups:The Andes as source of new high-elevation habitats, as a vicariant barrier, as a North-Southcorridor and as generator of new environmental conditions outside the Andes. We compare available phylogenetic studies anddivergence time estimates for plant lineages that may have diversified in response to Andeanorogeny. Andean orogeny is considered as one of the most important events for the developmentof current plant diversity in South America. ![]()
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