Remarks. Euconulinae was monophyletic in all our analyses, supported by the presence of radial ribs on the protoconch. Hausdorf (1998) did not recognise Euconulinae and Microcystinae as separate taxa in his analysis, including them both under the family Euconulidae; however, he pointed out that there are no known synapomorphies for Euconulinae and that it might be paraphyletic.

Based on our analysis the Euconulinae is supported by the following key characters:

Shell not reduced; sculptured with fine spiral and radial ribs. Genital system oviparous (rarely ovoviviparous); bursa copulatrix inserted on vagina; vestigial penial stimulator present in some taxa; epiphallic retractor caecum and flagellum absent.

The spermatophore is unknown for this group and may be absent.

Description. Shell present, not reduced. Protoconch and teleoconch sculptured with fine spiral and radial ribs. Whorl profile flattened above and below evenly convex periphery. Internal walls of early whorls complete; umbilicus closed. Mantle laps and lobes absent. Sole of foot tripartite; caudal apparatus formed from curled up sole (Muratov’s 1999 helicarionid type); caudal apparatus very small to moderately large; caudal foss horizontal slit in tail. Kidney unilobed; mantle with no visible minor blood vessels, pigmentation absent or present, mantle gland absent or present. Genital system oviparous (rarely ovoviviparous; Hausdorf 1998); oviduct glandular. Neither carrefour nor talon embedded in albumen gland. Bursa copulatrix short, inserted on vagina; duct of bursa copulatrix wide, not distinguishable from bursa copulatrix. Vagina short. Stimulator absent, or vestiges of stimulator present as diverticulum on base of penis. Epiphallus enters penis through a simple pore (Coneuplecta) or a verge (Nevelasta Iredale, 1937); interior of penis smooth or with diagonal ridges. Penial sheath present. Epiphallic retractor caecum absent; epiphallic flagellum absent. Spermatophore not present in any dissected specimens.