Annals of the South African MuseumThe Museum, 1989 - Natural history |
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Page 250
... dimorphism was mainly restricted to pre - Cretaceous ammonites ( e.g. Makowski 1962 ; Callomon 1963 , 1981 ) , the notable exception being the Late Cretaceous scaphitids ( Cobban 1969 ) . Only in recent years has dimorphism been ...
... dimorphism was mainly restricted to pre - Cretaceous ammonites ( e.g. Makowski 1962 ; Callomon 1963 , 1981 ) , the notable exception being the Late Cretaceous scaphitids ( Cobban 1969 ) . Only in recent years has dimorphism been ...
Page 253
... dimorphic pairs , macroconchs retaining weaker ornament to greater diameters than the strongly ornamented microconchs . However , distinct dimorphic pairs that differ only in terms of relative size also occur . Thus dimorphism in itself ...
... dimorphic pairs , macroconchs retaining weaker ornament to greater diameters than the strongly ornamented microconchs . However , distinct dimorphic pairs that differ only in terms of relative size also occur . Thus dimorphism in itself ...
Page 258
... dimorphism gave way to ornament- and size - related dimorphism . In any case , the transition is gradual and cannot be used as a basis for generic and subgeneric division of the groups . VARIATION IN RELATIVE PROPORTIONS Intraspecific ...
... dimorphism gave way to ornament- and size - related dimorphism . In any case , the transition is gradual and cannot be used as a basis for generic and subgeneric division of the groups . VARIATION IN RELATIVE PROPORTIONS Intraspecific ...
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Common terms and phrases
adult adventive lobe Albian ammonites Atlantic Benson body chamber bottom depth Campanian Cape Town catch rates Cenomanian Central Asia Chiplonkar & Ghare compressed Coniacian continental diameter Diaphus dimorphism distribution Engonoceratidae fauna flanks genus Group holotype Hoplitoplacenticeras Hulley Hyatt Hypengonoceras decaryi Collignon Iljin intraspecific variation isobath Karamaites Kennedy & Wright Klinger Lampanyctodes hectoris lanternfish lateral lobe lateral ornament lateral tubercles Maastrichtian Macroconch Madagascar Marine Metaplacenticeras Michailova Microconch with type myctophid oceanic ontogenetic changes ontogeny Orange Shelf ostracod Parengonoceras Paulcke pelagic phragmocone Placenticeras kaffrarium Etheridge Placenticeras polyopsis Placenticeratidae polyopsis Dujardin Proplacenticeras pseudoceanic ribs saddle Santonian separated Shannon shell smooth South African Museum south-western Africa southern Benguela region Spath specimens specimens.h¹ stage stations subkaffrarium sutural ontogeny suture suture line SW Cape temperature text-fig Turonian Type species umbilical tubercles umbilicus umkwelanense Upper Albian Upper Campanian Upper Cretaceous upwelling venter ventral clavi Whatley whorl section Wiedmann Zululand