TABLE 4. Shell comparison of B.aenigma with phylogenetically closely related species (see Figure2). The conchologically dissimilar Ipsa childreni (J. E. GRAY 1825) (see Figure 6 h) is excluded. Nesiocypraea midwayensis not obtained for molecular analyses is included for morphological comparison with Nesiocypraea teramachii.

	Propustularia surinamensis (Figure 5 g)	Bouchetaria aenigma (Figure 4)	Nesiocypraea midwayensis (Figure 6 c-e)	Nesiocypraea teramachii (Figure 6 a-b)
Fossula	flat, weak denticles	projecting,	distinctly denticulate	projecting, smooth
Spire	small, pointed, partly concealed	large, pointed, mostly exposed	small, pointed, mostly concealed	large, flat, exposed, or covered by callus
Col. teeth	coarse, extending	fine, extending	fine, restricted	fine, restricted to the peristome
dental branches	rare, towards tips	present throughout		absent
flanges	faintly pitted	smooth
terminal ridge	short, ribbed, flat	long, sloping	short, sloping	long, less sloping
ring of spots	absent	indicated	distinct,	confluent
dorsal pattern	densely mottled	absent	fine spotting to	fine spotting to confluent blotching
color of base	red	pure white	cream	cream to orange