| Abstract | Across Annelida, accessing the water column drives morphological and lifestyle modifications--yet in the primarily "benthic" scale worms, the ecological significance of swimming has largely been ignored. We investigated genetic, morphological and behavioural adaptations associated with swimming across Polynoidae, using mitogenomics and comparative methods. Mitochondrial genomes from cave and pelagic polynoids were highly similar, with non-significant rearrangements only present in cave Gesiella. Gene orders of the new mitogenomes were highly similar to shallow water species, suggestive of an underlying polynoid ground pattern. Being the first phylogenetic analyses to include the holopelagic Drieschia, we recovered this species nested among shallow water terminals, suggesting a shallow water ancestry. Based on these results, our phylogenetic reconstructions showed that swimming evolved independently three times in Polynoidae, involving convergent adaptations in morphology and motility patterns across the deep sea (Branchipolynoe), midwater (Drieschia) and anchialine caves (Pelagomacellicephala and Gesiella). Phylogenetic generalized least-squares (PGLS) analyses showed that holopelagic and anchialine cave species exhibit hypertrophy of the dorsal cirri, yet, these morphological modifications are achieved along different evolutionary pathways, i.e., elongation of the cirrophore versus style. Together, these findings suggest that a water column lifestyle elicits similar morphological adaptations, favouring bodies designed for drifting and sensing. |
| Text | 468803 2021 10.1038/s41598 021 89459 y Scopus 2 s2.0 85106575018 Annelida adaptation comparative analyses phylogenetics Morphological convergence and adaptation in cave and pelagic scale worms Polynoidae, Annelida Gonzalez B.C.; Martinez A.; Worsaae K.; Osborn K.J. Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, Washington, DC, Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, Washington, DC, USA, , , United States; Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, Washington, DC, Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012, Washington, DC, USA, , , United States; Molecular Ecology Group MEG , Water Research Institute IRSA , National Research Council of Italy CNR , Largo Tonolli, 50, Pallanza, Molecular Ecology Group MEG , Water Research Institute IRSA , National Research Council of Italy CNR , Largo Tonolli, 50, Pallanza, Italy, , , Italy; Molecular Ecology Group MEG , Water Research Institute IRSA , National Research Council of Italy CNR , Largo Tonolli, 50, Pallanza, Molecular Ecology Group MEG , Water Research Institute IRSA , National Research Council of Italy CNR , Largo Tonolli, 50, Pallanza, Italy, , , Italy; Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, Copenhagen Ø, Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, Copenhagen Ø, Denmark, , Denmark; Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA, Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA, USA, , United States Across Annelida, accessing the water column drives morphological and lifestyle modifications yet in the primarily benthic scale worms, the ecological significance of swimming has largely been ignored. We investigated genetic, morphological and behavioural adaptations associated with swimming across Polynoidae, using mitogenomics and comparative methods. Mitochondrial genomes from cave and pelagic polynoids were highly similar, with non significant rearrangements only present in cave Gesiella. Gene orders of the new mitogenomes were highly similar to shallow water species, suggestive of an underlying polynoid ground pattern. Being the first phylogenetic analyses to include the holopelagic Drieschia, we recovered this species nested among shallow water terminals, suggesting a shallow water ancestry. Based on these results, our phylogenetic reconstructions showed that swimming evolved independently three times in Polynoidae, involving convergent adaptations in morphology and motility patterns across the deep sea Branchipolynoe , midwater Drieschia and anchialine caves Pelagomacellicephala and Gesiella . Phylogenetic generalized least squares PGLS analyses showed that holopelagic and anchialine cave species exhibit hypertrophy of the dorsal cirri, yet, these morphological modifications are achieved along different evolutionary pathways, i.e., elongation of the cirrophore versus style. Together, these findings suggest that a water column lifestyle elicits similar morphological adaptations, favouring bodies designed for drifting and sensing. 11 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85106575018 origin=inward Articolo in rivista Nature Publishing Group 2045 2322 Scientific reports Nature Publishing Group Scientific reports Nature Publishing Group Scientific reports Nature Publishing Group alejandro.martinezgarcia MARTINEZ GARCIA ALEJANDRO |
