Table 3.

Sampling sites and number of specimens in the morphometric study.

Number	Sampling Site	N (Genotyped)	N (Genotypic Classes)
1	Stream Broel between Broel and Winterscheidt, North Rhine-Westphalia, Germany; 50°47'N 7°20'E	48	48 Stream Broel sculpins
2	Stream Broel south of Broel, North Rhine-Westphalia, Germany; 50°47'N 7°19'E	48	42 Stream Broel sculpins; 1 BI Hybrid
3	Stream Broel at Mueschmuehle, 200 m above outlet into River Sieg, North Rhine-Westphalia, Germany; 50°47'N 7°18'E	130	26 Stream Broel Sculpins; 45 BI Hybrids; 13 Invasive Sculpins
4	River Sieg at Allner, below outlet of Stream Bröl, North Rhine-Westphalia, Germany; 50°46'N 7°18'E	36	2 Stream Broel Sculpins; 16 BI Hybrids; 2 Invasive Sculpin
5	Stream Wahnbach, Outlet into River Sieg at Seligenthal, North Rhine-Westphalia, Germany; 50°47'N 7°16'E	4	1 Invasive sculpin
6	Stream Pleis, outlet into the River Sieg at Niederpleis, North Rhine-Westphalia, Germany; 50°46'N 7°12'E	5	5 Invasive sculpin
7	River Sieg at Muehlenbach, North Rhine-Westphalia, Germany; 50°47'N 7°10'E	35	19 Invasive sculpin
8	Stream Naaf, Outlet into River Agger, North Rhine-Westphalia, Germany; 50°51'N 7°14'E	48	1 Stream Naaf sculpins;
9	Stream Naaf at Kreuznaaf, 200 m above outlet into River Agger, North Rhine-Westphalia, Germany; 50°51'N 7°14'E	48	30 Stream Naaf sculpins
10	Stream Naaf southeast of Hausdorp, North Rhine-Westphalia, Germany; 50°52'N 7°16'E	48	45 Stream Naaf sculpins

Sampling Sites, total number of genotyped specimens and numbers in genotypic classes used for this study. The individual genotypic classes were inferred from microsatellite data and served to group specimens for morphometric analyses. Specimens excluded from the analysis include later generation backcrosses or those for which morphometric data could not be obtained. Note that there are sampling sites at which all genotypic classes occur syntopically.