Bull. nat. Hist. Mus. Lond. (Zool.) 61(1): 11-90 Issued 29 June 1995 



Studies on the deep-sea Protobranchia 

 (Bivalvia); the Subfamily Yoldiellinae 



J.A. ALLEN 



University Marine Biological Station, Millport, Scotland KA28 OEG 



H.L. SANDERS 



Woods Hole Oceanographic Institution, Woods Hole, Mass., 02543, U.S.A. 



F. HANNAH 



University Marine Biological Station, Millport, Scotland KA28 OEG 



CONTENTS 



Synopsis 12 



Introduction 12 



Subfamily Yoldiellinae Allen & Hannah, 1986 13 



Genus Yoldiella Verrill & Bush, 1897 13 



Yoldiella lucida (Loven, 1846) 13 



Yoldiella obesa obesa (Stimpson, 185 1 ) 15 



Yoldiella obesa incala ( new subspecies) 19 



Yoldiella similiris (new species) 20 



Yoldiella hanna (new species) 22 



Yoldiella capensis (new species) 23 



Yoldiella bilanta (new species) 24 



Yoldiella artipica (new species) 25 



Yoldiella similis (new species) 26 



Yoldiella sinuosa (new species) 27 



Yoldiella blanda (new species) 29 



Yoldiella biscayensis (new species) 30 



Yoldiella lata (Jeffreys, 1876) 32 



Yoldiella frigida (Torrell, 1859) 36 



Yoldiella robusta (new species) 39 



Yoldiella extensa (new species) 41 



Yoldiella inconspicua inconspicua Verrill & Bush, 1898 41 



Yoldiella inconspicua africana ( new subspecies) 44 



Yoldiella inconspicua profundorum (new subspecies) 45 



Yoldiella argentinensis (new species) 46 



Yoldiella curta Verrill & Bush, 1898 47 



Yoldiella perplexa (new species) 51 



Yoldiella americana (new species) 52 



Yoldiella subcircularis (Odhner, 1960) 54 



Yoldiella biguttata (new species) 57 



Yoldiella ovata (new species) 59 



Yoldiella insculpta (Jeffreys, 1879) 60 



Yoldiella Jeffrey si (Hidalgo, 1877) 63 



Yoldiella enata (new species) 68 



Yoldiella ella (new species) 70 



Yoldiella fabula (new species) 73 



Yoldiella veletta (new species) 76 



Genus Portlandia (Morch, 1857) 77 



Portlandia lenticula (Moller, 1842) 77 



Portlandia fora (new species) 78 



Portlandia minuta (new species) 80 



Portlandia abyssorum (Knudsen, 1970) 81 



Discussion 82 



References 90 



) The Natural History Museum, 1995 



