Figure 1

(a) Geographical range of each species in the Phocoenidae family. Map generated using ArcGIS 10.3 software using the open source data from the ETOPO1 Global Relief Model²³ (https://www.ngdc.noaa.gov/mgg/global/) and adapted from Gaskin¹⁸ and Berta et al.²⁴. (b) Maximum-likelihood mitochondrial phylogeny. The external branches and the tip labels are colored by species. The tree is rooted with eight sequences from four closely related Odontoceti species (in black). Numbers at the nodes are discussed in the text. The nodes indicated in red and green represent nodes with bootstrap support ≥ 90% and ≥ 70%, respectively. The red star indicates a node with a 63% bootstrap support in the Neighbor-joining tree (Fig. S1b). The lineage code includes the vaquita (P. sinus, V), Burmeister’s porpoise (P. spinipinnis, BP), spectacled porpoise (P. dioptrica, SP), Dall’s porpoise (P. dalli, DP), harbor porpoise (P. phocoena, HP) and finless porpoise (N. phocaenoides + N. asiaeorientalis, FP). Some species have been also further subdivided into distinct groups: harbor porpoises are divided into North Pacific (NP) and North Atlantic (NA), and within each of these groups, further subdivisions are recognized. Four groups are recognized within NA: NAT (North Atlantic), IB (Iberian), MA (Mauritanian), BS (Black Sea). NP is divided into two subgroups: NP1 and NP2. Three sub-species or species are also recognized among the finless porpoises: Indo-Pacific (IPF), Yangtze finless (YFP) and East Asia finless (EAF). Spectacled porpoise subgroups are designated as SP1 and SP2. Dall's porpoise subgroups as DP1 and DP2. The scale bar unit is in substitution per site.