 In many cases researchers established new generic names because they thought this was necessary or did not know that others had previously established another genus for the same group of species.An example is the genus "Pomatia" Beck, 1837, which was established for a group of terrestrial snails containing as its type species the Burgundy or Roman snail "Helix pomatia"—since "Helix pomatia" was already the type species for the genus "Helix" Linnaeus, 1758, the genus "Pomatia" was an objective synonym (and useless).At the same occasion "Helix" is also a synonym of "Pomatia", but it is older and so it has precedence.