Sous-embranchement (subphylum) des Rhynchonelliformea  
Classe des Rhynchonellata 
Ordre des Terebratulida 

Sous-ordre des Terebratulidina 
Super-famille des Dyscolioidae 

Genus Dyscolia Fischer & Œl;hlert, 1890
[Type species = Terebratulina wyvillei Davidson, 1878 (p. 436)]

Medium to very large, subtrigonal to elongate oval; ventribiconvex; surface smooth or with fine, zigzag capillae; beak short, suberect, often truncated or labiate; foramen large, epithyrid to submesothyrid; symphytium almost concealed; pedicle collar long, anteriorly excavated; cardinal process not developed, diductor muscles attached to apical pit; outer hinge plates very weakly developed; crural processes weak, blunt; loop small (less than 0.3 dorsal valve length), thin, with rounded, anterolateral extremities; lophophore small, modified schizolophe; spicules very abundant; four main mantle canals in each valve, branching pattern pinnate.

Pliocene - Present

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

Extant Species of Dyscolia
  • D. wyvillei (Davidson, 1878)
  • D. subquadrata (Jeffreys, 1878)
  • D. johannisdavisi (Alcock, 1894)
  • D. radiata Cooper, 1981
  • D. sp

    Dyscolia radiata   Cooper, 1981

    Type locality: st. MD.08: 6, DC 47: 33°11.4'S, 44°00.4'E, Walters Bank, at 620-635 m.
    Depth range: 263 - 635 m.

    Diagnosis (Cooper, 1981)

    Subtriangular, loop narrow, crural processes obtuse, surface covered by fine irregular capillae.

    Copper (1981, p. 24) states: “Dyscolia? radiata most resembles Dyscolia ewingi Cooper from off South America in south Atlantic waters. There is also resemblance to Liothyrella? neozelanica.”

    Dyscolia sp.

    References and Depth: Foster (1974): 915-1153 m, 1887-1894 m; Foster (1989): 4118 m; Hiller (1994): 680-715; Zezina (1980): 580 m.

    See Antarctic - sub-Antarctic map