“…Their shells vary dramatically in size, shape, sculpture (Goodfriend, 1986), and colour and banding pattern (Jones, Leith & Rawlings, 1977; Johnson, Murray & Clarke, 1993), both within and among species. Although shell variation can provide useful taxonomic characters (Schander & Sundberg, 2001; Jordaens et al ., 2009), levels of within‐species variation may in some cases exceed those between species or even within entire genera (Gould & Woodruff, 1978; Teshima et al ., 2003). In addition to highlighting the potential complexity of reproductive relationships among species distinguished by their shells, detailed studies of closely‐related groups of land snails, including Partula (Murray & Clarke, 1980), Cerion (Gould & Paull, 1977; Gould & Woodruff, 1978), and Ainohelix (Teshima et al ., 2003), have demonstrated the fine‐scale sampling required to distinguish among‐population variation from that distributed among reproductively isolated species.…”