Dallina

Small to large, triangular to subquadrangular in outline; rectimarginate to paraplicate; beak erect, without beak ridges; foramen small to large, mesothyrid, attrite, symphytium concave. Hinge teeth small, weak; pedicle collar very short. Cardinalia lamellar with excavate inner and outer hinge plates separated by narrow crural bases; inner hinge plates converging on median septum to form V-shaped septalium; cardinal process not differentiated; median septum low anteriorly, extending beyond midvalve; adult loop teloform.^[2]

• 
  Dallina septigera, brachial valve, 24mm long, near the Philippines
• 
  pedicle valve
• 
  anterior view
• 
  interior view
• 
  lateral view

Nine extant species are recognized (though one has recently been synonymized),^[3] these are listed below:

• Dallina septigera (Lovén, 1845), Type species of genus, from northeastern Atlantic.^[4]
• Dallina elongata Hatai, 1940, recorded from Sea of Japan.^[4]
• Dallina eltanini Foster, 1974, southern Pacific, near Antarctica.^[4]
• Dallina floridana (Pourtalès, 1867), recorded from the Gulf of Mexico and Bahamas.^[4]
• Dallina obessa Yabe & Hatai, 1934, recorded from Sea of Japan.^[4]
• Dallina parva Cooper, 1981, recorded from northeast Atlantic (Bay of Biscay).^[4][5]
• Dallina profundis Konjukova, 1957 (junior synonym of Glaciarcula spitzbergensis^[6])
• Dallina raphaelis (Dall, 1970), recorded from off Japan.^[4]
• Dallina tasmaniaensis Verhoeff, 2023, southeastern Australia.^[6]
• Dallina triangularis Yabe & Hatai, 1934, recorded from off Japan and possibly Lau Ridge.^[4][6]