Figure 1.
COI (K2P) distances for the barcode region within species and genera.
Conspecific distances are based on provisional species assignments and congeneric values are between provisional species.
Figure 2.
The effect of sample size on genetic distances.
Linear regression of the number of individuals in each barcode cluster versus mean intraspecific distance (A) and maximum intraspecific distance (B).
Figure 3.
Comparison of COI (K2P) distances between morphologically identified polychaete species (A) and MOTUs (B).
Plotting axes at 2% nearest neighbour divergence (y-axis) and 10× the average intracluster divergence of 3.8% (x-axis) creates four species categories where intraspecific distance and nearest neighbour distance respectively are: I) <3.8%, >2%: typical species; II) >3.8%, >2%: probable species complex; III) <3.8%, <2%: hybridization, young species, synonymy; IV) >3.8%, <2%: possible specimen misidentification.
Table 1.
Species with multiple MOTUs across Atlantic (AT), Arctic (AO), and Pacific (PC) Oceans of North America.
Figure 4.
Morphological versus molecular diversity estimates.
A comparison of rarefaction curves for morphologically identified species and MOTUs (95% confidence intervals are plotted).
Figure 5.
Examples of geographic splits in widespread species.
Neighbour joining (NJ) trees with K2P divergences between amphiboreal species with divergent Pacific and Atlantic lineages (A), between species with divergent Pacific and Atlantic-Arctic lineages (B), and between species with multiple divergent lineages (K2P divergence is averaged among the three lineages) (C). Red, black, and yellow shaded regions correspond with branch colour on the NJ tree and indicate different lineages.
Figure 6.
Faunal connectivity among sampling sites.
The similarity in species composition among seven regions measured by Chao's Abundance-based Sørensen similarity index. Similarity values indicated in boxes (range 0–1, with 1 indicating complete overlap in species composition) are represented by line width between two regions.