Figure 1.
Sampling locations and the number of specimens examined in this study. Only specimens that generated a sequence are shown. Twenty-three sequences obtained from GenBank are not included as they lack locality information.
Figure 2.
Maximum intraspecific divergence (% K2P) in the barcode region of cytochrome c oxidase subunit I plotted against nearest neighbour distance (% K2P) for the 227 morphospecies examined in this study. Points above the line indicate species with a barcode gap.
Figure 3.
The relationship between COI distance and sample size within species.
Maximum and mean intraspecific divergences (% K2P) at COI plotted against the number of individuals analyzed for 147 species of Canadian marine molluscs. The regression between sample size and mean divergence is insignificant (P = 0.38; R2 = 0.005) as well as the regression between sample size and maximum divergence (P = 0.72; R2 = 0.0009).
Figure 4.
The relationship between COI distance and sample size within genera.
Mean nearest neighbour distance (% K2P) at COI plotted against the number of species sampled from each genus of marine mollusc with ≥2 species (N = 50). The regression was insignificant (P = 0.052; R2 = 0.08). Morphospecies lacking a generic identification were excluded from analysis.
Figure 5.
The relationship between COI distance and sampling completeness within genera.
Mean nearest neighbour distance (% K2P) at COI plotted against sampling completeness (%) of each genus of marine mollusc with ≥2 species (N = 50). The ANOVA was insignificant (P = 0.77). Morphospecies lacking a generic identification were excluded from analysis.
Figure 6.
Deep divergences at COI within species of gastropod.
Neighbour-joining trees (K2P) with locality information for four gastropod species showing more than 2% sequence divergence at COI. Triangles on the NJ tree represent compressed clades, with sample size provided in brackets.
Figure 7.
Deep divergences at COI within species of bivalve.
Neighbour-joining trees (K2P) with locality information for four bivalve species showing more than 2% sequence divergence at COI. Triangles on the NJ tree represent compressed clades, with sample size provided in brackets. *(Layton 2012)
Figure 8.
The relationship between GC content and genetic distance across genera.
Mean nearest neighbour distance (% K2P) at COI plotted against mean GC content (%) for congeneric species in the 138 genera of molluscs analyzed in this study. The correlation was significant (P<0.001; R = 0.29).
Figure 9.
Mapping insertions and deletions in COI.
Secondary structure of COI marked with insertions and deletions A) gastropods and B) bivalves. Insertions are marked with a blue circle, while deletions are marked with a red circle.