|
||||
Genus Nipponithyris Yabe et Hatai, 1934 |
[Type species= N. nipponensis Yabe et Hatai, 1934] [= Miyakothyris Hatai, 1938, p. 237 (type: Nipponithyris subovata Hatai, 1936, p. 321); Isumithyris Hatai, 1948, p. 498 (type: I. kazusaensis); Dicrosia Cooper, 1978, p. 12 (type: Abyssothyris fijiensis Elliott, 1960, p. 526)] |
Small to medium, rounded pentagonal, rectimarginate to strongly unisulcate, beak erect to suberect, foramen small, mesothyrid, deltidial plates conjunct, both valves thickened posteriorly. Hinge teeth stout, ventral muscle scars deeply impressed, partly lodged in narrow delthyrial cavity. Cardinal process small, semielliptical to triangular, confined to apex; inner socket ridges strong, sockets deep; inner hinge plates forming a V-shaped trough, median septum extending anteriorly as low ridge well past midvalve; loop diploform to trabecular. |
Neogene (Miocene) - Present
Diagnosis from volume 5 of the
|
Extant Species of Nipponithyris |
|
Diagnosis Diagnosis Diagnosis |
|