Table 1.

Shell morphometry characteristics of Cristaria herculea from the upper Amur River basin. L – shell length; H – maximal shell height; h – shell height measured from umbo; h₁ – shell height measured from middle lateral tooth to ventral margin; l₁ – the distance from umbo to posterior end of the lateral tooth; B – maximal shell inflation (width); R₁ = B/l₁, R₂ = B/h₁; n – number of measured shells; * – living mollusks dissected for the anatomical study and (n₁) – their number.

Characteristics	Kharanorsky reservoir	Onon River	Nercha River	Shilka River	Buyr-Nur Lake
L, mm	128.7–290.0 258.0*	147.6–238.0 167.2*	120.2–174.0	152.0	148.9–151.0
H, mm	93.8–212.3 187.5*	94.9–124.8 102.0*	73.3–112.9	92.1	99.9–102.0
h, mm	65.3–148 130.6*	66.5–112.0 74.9*	51.6–80.0	66.3	69.2–71.1
h1, mm	75.0–161.2 152.5*	82.1–134.0 88.9*	68.7–98.1	82.3	63.1–64.9
l1 , mm	52.5–113.0 104.9*	58.0–99.4 66.9*	50.0–74.0	58.2	83.0–84.8
B, mm	41.2–88.0 79.4*	44.3–76.1 50.7*	39.0–53.9	47.1	46.0–48.0
B/L	0.316 ± 0.0055 0.308*	0.294 ± 0.0169 0.289*	0.317 ± 0.007	0.309	0.312 ± 0.0065
R1	0.760 ± 0.0311 0.756*	0.763 ± 0.0039 0.758*	0.768 ± 0.033	0.807	0.736 ± 0.0053
R2	0.540 ± 0.0119 0.521*	0.552 ± 0.0192 0.570*	0.561 ±0.0087	0.571	0.558 ± 0.0052
n (n1)	5 (1)	4 (1)	3	1	3