Complex sentence: This taxonomy was published in 2005 in the journal "Malacologia"; it encompasses all families of living slugs and snails, and also of fossil gastropods (including fossils that may or may not have been gastropods).
Split into simpler sentences: This taxonomy was published in 2005 in the journal "Malacologia". The taxonomy attempts to encompass all known living slugs and snails and all fossil gastropods (including fossils that may have been gastropods).