Sous-embranchement (subphylum) des Rhynchonelliformea
Classe des Rhynchonellata
Ordre des Terebratulida
Sous-Ordre des Terebratellidina
Super-famille des Terebratelloidea


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
Treatise on Invertebrate Paleontology (2006)

Extant Species of Nipponithyris
  • N. nipponensis Yabe et Hatai, 1934
  • N. afra Cooper, 1973
  • N. lauensis Bitner, 2008
  • Diagnosis

    Nipponithyris nipponensis  Yabe et Hatai, 1934

    Type locality: "Soyo-maru, Sta. 412, 418, 425 along the west coast of Kyusyu, and 475 593, 599,600, 601, 602, 649, 653 in the Japan Sea, 31°10'30"-41°39'15"N, 129°13'-140°39'45"E."
    Depth range: 86 - 454 m

    Diagnosis in preparation -

    Nipponithyris afra   Cooper, 1973

    Type locality: "Station 398B, latitude 22° 25' S, longitude 35° 54' E at 740 meters, off Mozambique, off Cabo Sao Sebastiao."
    Depth range: 740 - 960 m

    Nipponithyris afra: Bitner & Logan (2016 - cum syn.).

    Diagnosis - Cooper (1973) -

    Small pentagonal Nipponithyris, with fairly strong anterior sulcation.

    Nipponithyris lauensis   Bitner, 2008

    Type locality: “Fiji Islands, Lau Ridge, BORDAU 1, stn DW 1485, 19°02.69’S, 178°29.80’W, 700-707 m.”
    Depth range: 477 - 1226 m

    Diagnosis - Bitner (2008) -

    Nipponithyris of medium size, strongly unisulcate, posterior part strongly thickened, teeth withswollen bases, no crura, loop trabelacur with long, slender descending branches and broad transverse band.