Fig. 4

Auximetric grid for comparison of OGP between D. exoleta and other venerid species worldwide. Diagonal lines denote OGP isolines, symbols and numbers refer to the species listed in Table 3 (multiplication symbol, Dosinia spp.; filled circle symbol, Ameghinomya sp.; open circle symbol, Amiantis sp.; filled square symbol, Callista spp.; open square symbol, Chamelea spp.; filled diamond symbol, Eurhomalea sp.; open diamond symbol, Mercenaria sp.; plus symbol, Tawera sp., filled triangle symbol, Venerupis sp.; open triangle symbol, Venus sp.). Shadow circles denote D. exoleta populations from the Portuguese coast (Aveiro, Setúbal and Faro)