Scorched mussels (BIVALVIA: MYTILIDAE: BRACHIDONTINAE) from the temperate coasts of South America: phylogenetic relationships, trans-Pacific connections and the footprints of Quaternary glaciations.

摘要: Abstract This study addresses aspects of the phylogeny and phylogeography scorched mussels (BIVALVIA: MYTILIDAE: BRACHIDONTINAE) from southern South America (Argentina Chile), as well their ecophylogenetic implications. Relationships were inferred sequences two nuclear (28S 18S) one mitochondrial (COI) genes, using Bayesian maximum likelihood analyses. Our results indicate that monophyletic BRACHIDONTINAE include three supported clades: [i] Brachidontes Swainson (=Hormomya Morch), [ii] Ischadium Jukes-Browne + Geukensia van de Poel, [iii] Austromytilus Laseron + Mytilisepta Habe (usually considered a member SEPTIFERINAE) + Perumytilus Olsson. Species clade are distributed along temperate coasts Pacific Ocean. Available evidence supports divergence between (Australia) Perumytilus (South American) following breakup Australian, Antarctic American shelves. Four brachidontins occur in America: rodriguezii (d’Orbigny), B. granulatus (Hanley), genetically distinct clades Perumytilus. The latter confined to Chile-Peru (North Clade) Magellanic Biogeographic Provinces, respectively warm- cold-temperate. Clade is only brachidontin restricted cold-temperate waters. considerations fossil record prompted hypothesis originated North by incipient peripatric differentiation, followed isolation during Quaternary glaciations, genetic differentiation non-glaciated eastern Patagonia, back-expansion over Chile post-LGM de-glaciation, development secondary contact zone south-central Chile. Evidence upper Pleistocene expansion parallels similar on other organisms have colonized coastal ecosystems Patagonia since LGM, apparently occupying free ecological space. We emphasize assembly communities cannot be explained solely terms environmental drivers, history also matters.