title: The life and adventures of an eight-legged castaway: Colonization and diversification of Philisca ghost spiders on Robinson Crusoe Island (Araneae, Anyphaenidae).
abstract: Oceanic archipelagoes, by their young origin and isolation, provide privileged settings to study the origin and diversification of species. Here, we study the anyphaenid spider genus Philisca, endemic to the Valdivian temperate rainforest, which includes species living both on the mainland as well as on the Robison Crusoe Island in the Juan Fernández archipelago. Anyphaenids, as many spiders, are potentially good colonizers due their ability for ballooning, an airborne dispersal mediated by strands of silk that are caught in the wind. We use a molecular approach to estimate both the phylogenetic relationships and the timeframe of species diversification of Philisca, with the aim to infer its evolutionary history. We further estimate the rates of speciation on both the insular and continental Philisca species and score the microhabitat used by each species and their sizes as a proxy to evaluate ecological niche diversification within the island. Most analyses support the monophyly of Philisca, with the exclusion of Philisca tripunctata. Our results reveal colonization from a single lineage that postdated the origin of the island, followed by rapid (∼2Ma) diversification. The ancestral microhabitat was most likely leaf-dwelling but we identify two independent microhabitat shifts. Our data provides evidence that Philisca has undergone an adaptive radiation on the Robison Crusoe Island.
authors: Departamento de Ecología, Genética y Evolución, IEGEBA (CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II (C1428 EHA), Buenos Aires, Argentina; Division of Arachnology, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina. Electronic address: edusoto@ege.fcen.uba.ar.
authors: Eduardo M
authors: EM
authors: Soto
authors: Laboratório Especial de Coleções Zoológicas (LECZ), Instituto Butantan, Av. Vital Brasil, 1500, 05503-900 São Paulo, SP, Brazil; Division of Arachnology, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina.
authors: Facundo M
authors: FM
authors: Labarque
authors: Division of Arachnology, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina.
authors: F Sara
authors: FS
authors: Ceccarelli
authors: Departament de Biologia Animal & Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Av. Diagonal 645, E-8028 Barcelona, Spain.
authors: Miquel A
authors: MA
authors: Arnedo
authors: Laboratorio de Entomología Ecológica, Depto. de Biología, Facultad de Ciencias, Universidad de La Serena, Casilla 599, La Serena, Chile.
authors: Jaime
authors: J
authors: Pizarro-Araya
authors: Division of Arachnology, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina.
authors: Martín J
authors: MJ
authors: Ramírez
mesh_terms: D000818:Animals; D017753:Ecosystem; D005843:Geography; D062312:Islands; D016013:Likelihood Functions; D010802:Phylogeny; D013112:Spiders / Q000145:classification*
keywords: Biogeography; Phylogenetic; Rapid diversification; Robinson Crusoe Island; Spiders