Fig 1.
Map of the collection sites of smooth-shelled blue mussels (Mytilus spp.) in South America, including Chile, Argentina, the Falkland Islands and Uruguay.
Table 1.
Collection site information in Argentina, Chile, the Falkland Islands and Uruguay, including habitat (subtidal or intertidal), geographical coordinates, number of mussels (Mytilus spp.) collected (N), and date of collection (DD.MM.YYYY).
Table 2.
GenBank accession numbers and sample locations of sequences used for this study for COI, 16S and 18S DNA sequence variation (for Figs 2 and 3).
Fig 2.
To the left is the maximum clade credibility tree from the Bayesian analyses based on cytochrome oxidase subunit 1 (COI) sequences with results of the single threshold GMYC model (blue vertical lines), bGMYC (red vertical lines), PTP (purple vertical lines) and bPTP (green vertical lines). Values above tree branches are Bayesian posterior probabilities/maximum likelihood bootstrap values. To the right the heat-map represents a sequence-by-sequence matrix where cells are coloured by the posterior probability that the corresponding sequences are conspecific, allowing for the visualisation of uncertainty in species limits returned by the bGMYC method. The letters correspond to clades a = Mytilus californianus from USA (Monterrey Bay); b = Mytilus coruscus from China (Zhouhan); c = Mytilus trossulus from USA (Damariscotta and Penn Cove) and Canada (Mahome Bay and Bras d’Or Lake); d = Mytilus chilensis from Chile (Maullín, Quillaipe Puerto Saavedra, Caleta Pescadores, Huildad, Estero Fanny, Isla London, Chaihuín, San Gregorio and Puerto Cisne), Argentina (Mar del Plata and Punta Peña), Uruguay (Punta del Este) and Kerguelen island; e = Mytilus spp. from Australia (Tura Head and Green Cape) and Tasmania (Cloudy Bay, Hobart, Simpson’s Bay and Snug); f = Mytilus spp. from New Zealand (Auckland Islands, Dunedin and Wellington), g = Mytilus spp from N/A and Finland (Hanko); h = Mytilus galloprovincialis from Italy (Chioggia), Greece (Samos), Australia (Green Cape, Nedlands, Tura Head), South Africa (Paternoster), Chile (Dichato, Lota); i = Mytilus edulis from Sweden (Tjárno), USA (Beaufort), Canada (Antigonish), Argentina (Punta Cueva) and the Falkland Islands (Bense Island); j = outgroup Choromytilus chorus from Chile (Colún).
Fig 3.
Bayesian tree using the concatenated matrix data set (COI+16S+18S).
The numbers above branches represent the posterior probability/bootstrap support values. Bar on the right of the tree indicate the species limits as proposed by BPP (multilocus analysis). M. edulis = (1) Canada, (2) Sweden, (3) Cornwall, UK, (4) Punta Cueva, Argentina; M. galloprovincialis = (1) Moaña-Pontevedra, Spain, (2) Lota, Chile, (3) South Africa; Mytilus sp. clade = (1) Auckland Islands, New Zealand, (2–3) Quillaipe, Chile, (4) Maullin, Chile, (5) Punta del Este, Uruguay, (6) Maullín, Chile, (7–8) Puerto Cisne, Chile; M. trossulus clade = (1) Penn Cove, USA, (2) Bras d’Or lake, Canada. Sequence details are provided in Table 2.
Fig 4.
Geneland results for K = 3 groups using the spatial model with correlated allele frequencies (based on COI).
(A) Map of estimated posterior probability of population membership (by posterior mode)–different colours represent distinct genetic groups; plots representing the assignment of pixels to: B) introduced Mytilus galloprovincialis in Chile, (C) mussels from the Atlantic coast of South America, and (D) M. chilensis mussels from the Pacific and southern Atlantic coasts of South America. The highest membership values are in white and light yellow and the contour lines indicate the spatial position of genetic discontinuities between populations.