RESUMEN
While grasslands, one of Earth's major biomes, are known for their close evolutionary ties with ungulate grazers, these habitats are also paramount to the origins and diversification of other animals. Within the primarily South American spider subfamily Amaurobioidinae (Anyphaenidae), several species are found living in the continent's grasslands, with some displaying putative morphological adaptations to dwelling unnoticed in the grass blades. Herein, a dated molecular phylogeny provides the backbone for analyses revealing the ecological and morphological processes behind these spiders' grassland adaptations. The multiple switches from Patagonian forests to open habitats coincide with the expansion of South America's grasslands during the Miocene, while the specialized morphology of several grass-dwelling spiders originated at least three independent times and is best described as the result of different selective regimes operating on macroevolutionary timescales. Although grass-adapted lineages evolved towards different peaks in adaptive landscape, they all share one characteristic: an anterior narrowing of the prosoma allowing spiders to extend the first two pairs of legs, thus maintaining a slender resting posture in the grass blade. By combining phylogenetic, morphological, and biogeographic perspectives we disentangle multiple factors determining the evolution of a clade of terrestrial invertebrate predators alongside their biomes.
Asunto(s)
Adaptación Fisiológica/fisiología , Pradera , Filogenia , Arañas/anatomía & histología , Arañas/genética , Adaptación Fisiológica/genética , Animales , Evolución Biológica , Ecosistema , América del Sur , Arañas/clasificaciónRESUMEN
We present evidence from the standard cytochrome c oxidase subunit I (COI) barcoding marker and from new collections, showing that the males and females of C. ecotono Werenkraut & Ramírez were mismatched, and describe the female of that species for the first time. An undescribed male from Chile is assigned to the new species Coptoprepes laudani, together with the female that was previously thought as C. ecotono. The matching of sexes is justified after a dual cladistics analysis of morphological and sequence data in combination. New locality data and barcoding sequences are provided for other species of Coptoprepes, all endemic of the temperate forests of Chile and adjacent Argentina. Although morphology and sequences are not conclusive on the relationships of Coptoprepes species, the sequence data suggests that the species without a retrolateral tibial apophysis may belong to an independent lineage.