Table 1.

Morphological comparison between Archaeocyclotus Asato and Hirano, gen. nov. and some morphologically similar genera of Cyclophoridae.

Genus	Morphological characters
	Size (mm)	Texture	Shell form	Base	Umbilicus	Aperture	Ornamentations
Cyclotus Swainson, 1840	Small to middle (10–30)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Pterocyclos Benson, 1832	Small to middle (10–31)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Platyrhaphe Möllendorff, 1890	Small (5–10)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Aulopoma Troschel, 1847	Small to middle (10–30)	Thin, glossy	low-turbiniform	Phaneromphalous	Narrow, deep	Circular	Smooth, growth lines
Scabrina Blanford, 1863	Small to middle (10–31)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines with periostracal hairs
Theobaldius Nevill, 1878	Small to middle (10–31)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Lagocheilus Blanford, 1864	Small (5–10)	Thin, solid	Low-trochiform to trochiform	Phaneromphalous	Narrow, deep	Circular	Smooth, growth lines with periostracal hairs
Micraulax Theobald, 1876	Small to middle (10–31)	Thin	low-turbiniform	Phaneromphalous	Narrow, deep	Circular	Smooth, growth lines
Crassopoma Pfeiffer, 1847	Small to middle (10–32)	Thin, glossy	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Ptychopoma Möllendorff, 1885	Small to middle (10–33)	Thin	Discoidal to very low-turbiniform	Phaneromphalous	Wide, shallow	Circular	Smooth, growth lines
Archaeocyclotus Asato and Hirano, gen. nov.	Minute (around 5)	Thin, solid	Discoidal	Phaneromphalous	Wide, shallow	Ovoid to elliptical	Fine growth ribs with short periostracal hairs