Geometric morphometrics A, C, E nMDS based on Procrustes coordinates of landmarks. Euclidean index. Concentration ellipses 90%. B, D, E shape comparisons of superimposed outlines of all individuals of the two species E. sibiricus sp. nov. and E. speratus. A nMDS based on P4 Enp3, stress 0.1804 B shape of P4 Enp3 C nMDS based on P4 Exp3, stress 0.1555 D shape of P4 Exp3 E nMDS based on the P4 inner side of basis, stress 0.1804 F P4 inner side of basis. Symbols: empty circle – North/Central Yakutia; filled dots – Lena River Delta; triangles – Anabar/Putorana Plateau; squares – Udmurtia/Tatarstan; crosses – Saint Petersburg.