Shell morphology and color pattern of N. radula and three species of clade B A–C N. radula, RM31904, Omura, Nagasaki (34) D N. radula, RM31902, Omura, Nagasaki (34) E N. radula, RM31899, Nagato, Yamaguchi (31) F–H N. nigrans, RM31892, Nishiku, Fukuoka (32) I N. nigrans, RM31888, Kada, Wakayama (22) J N. nigrans, RM31895, Higashisonogi, Nagasaki (33) K–M N. nigrans, RM31887, Minamiizu, Shizuoka (15) N N. nigrans, RM31886, Minamiizu, Shizuoka (15) O N. nigrans, RM31897, Higashisonogi, Nagasaki (33) P–R N. habei, RM31874, Ishinomaki, Miyagi (12) S N. habei, RM31875, Tateyama, Chiba (13) T N. habei, RM31873, Usujiri, Hokkaido (5) U–W N. teramachii, RM31930, Nishiku, Fukuoka (32) X N. teramachii, RM31925, Sanuki, Kagawa (28) Y N. teramachii, RM31922, Ainancho, Ehime (24). Scale bars: 5 mm.

 
 
  Part of: Teruya S, Setiamarga DHE, Nakano T, Sasaki T (2022) Molecular phylogeny of Nipponacmea (Patellogastropoda, Lottiidae) from Japan: a re-evaluation of species taxonomy and morphological diagnosis. ZooKeys 1087: 163-198. https://doi.org/10.3897/zookeys.1087.78193