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


Genus Shimodaia MacKinnon, Saito & Endo, 1997
[Type species= Shimodaia pterygiota MacKinnon, Saito & Endo, 1997 (p. 226)]

* Small, red to white color markings, ovate, commissure rectimarginate; beak erect, attrite; foramen submesothyrid; deltidial plates disjunct. Dental plates recessive, pedicle collar long, sessile. Cardinal process inconspicuous; septal pillar arising (in adults) about midvalve, very long and narrow, strongly inclined anteroventrally, sometimes spinose distally, extending posteriorly as low ridge; hinge trough with incipient inner hinge plates; adult loop annular with descending branches attached to septal pillar and ascending branches commonly incomplete; juvenile axial loop phase with well-developed septal flanges.

** Shells small, commonly with red/white markings. Adult loop annular. Dorsal pedicle adjustor muscle scars broad, occupying floor of hinge trough.


* Diagnosis from volume 5 of the Treatise on Invertebrate Paleontology (2006)

** Diagnosis from MacKinnon & Long (2009)

Extant Species of Shimodaia
  • S. pterygiota MacKinnon, Saito & Endo, 1997
  • S. macclesfieldensis MacKinnon & Long, 2009
  • Diagnosis

    Shimodaia pterygiota  MacKinnon, Saito & Endo, 1997

    Type locality: Off Shimoda (Japan)
    Depth range: 37 - 98 m

    Diagnosis (MacKinnon, Saito & Endo, 1997)

    As for genus - [Nota: there is a gap in the diagnosis of this species because the diagnosis of the genus given in 1997 is different from that publishied in 2009]

    Shimodaia macclesfieldensis  MacKinnon & Long, 2009

    Type locality: Macclesfield Bank (China Sea)
    Depth range: 46 - 92 m

    Diagnosis (MacKinnon & Long, 2009)

    A Shimodaia with ascending loop elements forming a complete ring that attains no more than approximately half the width of the descending lamellae.