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

Sous-ordre des Terebratulidina 
Super-famille des Terebratuloidae 
Super-famille des Dyscolioidae 
Super-famille des Cancellothyroidea 

Genus Acrobrochus Cooper, 1983

[Type species= Liothyrella? vema Cooper, 1973 (p. 17)]

Medium to large, oval to subpentagonal; anterior commissure rectimarginate to uniplicate, smooth; beak suberect, short, labiate; foramen moderately large, permesothyrid; symphytium partly visible; pedicle collar short, excavate; cardinal process is a transverse semiellipse; outer hinge plates taper onto posteroventral edges of crural processes; loop narrow with broad, transverse band.


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

Extant Species of Acrobrochus
  • A. blochmanni (Jackson, 1912)
  • A. vema (Cooper, 1973)
  • A. marotiriensis Bitner, 2007
  • Diagnosis

    Acrobrochus vema   (Cooper, 1973)

    Type locality: “V-17-61. Latitude 54°44'S, longitude 55°39'W, at 1814-1919 meters, off east end of Burdwood Bank, east of south end of Argentina.”
    Depth range: 732 - 2578 m

    Liothyrella? vema Cooper, 1982
    Liothyris vema Zezina, 1976
    Acrobrochus hendleri Cooper, 1982

    Diagnosis - (Cooper, 1973)

    Large, nearly equivalved Liothyrella?, with stout loop and broadly uniplicate anterior margin.


    Acrobrochus blochmanni   (Jackson, 1912)

    Type locality: “Station 417; lat. 71°22'S., long. 16°34'W. (off Coasts Land). Depth, 1410 fathoms. March 18, 1904” [depth 2579 m].
    Depth range: 103 - ? 3697 m

    Liothyrina blochmanni Jackson, 1912
    Liothyrella blochmanni Thomson, 1918
    ?Liothyrella multiporosa Foster, 1974
    ?Liothyrella scotti Foster, 1974
    Liothyris blochmanni Zezina, 1976

    Diagnosis - (Jackson, 1912) - in preparation


    Should be added:
  • Muscle disposition: see Fig. in front - the posterior accessory diductor scars sometimes with several separate units.
  • ML

    Muscle attachment (modified, from Foster, 1974 - with absence of separate posterior accessory diductor muscles base, the pair of ventral adductor muscle bases in &a single unit)


    Acrobrochus marotiriensis   Bitner, 2007

    Type locality: Station DW 1886; 27°51.27’S, 143°32.39’W, Marotiti island, Australes archipelago (French Polynesia). Depth, 620-1000 m.
    Depth range: 360 - 1000 m

    Diagnosis - Bitner (2007)

    Acrobrochus of medium size, strongly biconvex, loop with subparallel descending branches and very broad, gently folded transverse band.

    (modified, from Bitner, 2007)