Pachymerus fracticollis Schilling, 1829: 82. ST(S): Poland, Silesia; lost.
Pachymerus insectus Boheman, 1851: 250 (syn. Baerensprung, 1858b: 80). STS: male, female, Sweden, Gotland, Westerby; lost.
Plociomerus collaris Baerensprung, 1859: 329, 332 (syn. Fieber, 1861a: 172). LT (Péricart, 1998c: 6): male, Italy, Piemonte; ZMHB.
Pachybrachius fracticollis var. tridens Roubal, 1959b: 30. HT: Czech Republic, Moravia, Moravoany; SNMC?