Annals of the South African Museum: Annale Van Die Suid-Afrikaanse MuseumWest, Newman & Company for the trustees of the Museum, 1990 - Natural history |
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Page 24
... subtrigonal and subtrapezoidal . Typically with inner and marginal carina lacking , resulting in poor discrimination between the smooth escutcheon and area . The latter is ornamented only in the nepionic stages and may be weakly ...
... subtrigonal and subtrapezoidal . Typically with inner and marginal carina lacking , resulting in poor discrimination between the smooth escutcheon and area . The latter is ornamented only in the nepionic stages and may be weakly ...
Page 25
... subtrigonal area essentially flat , meeting the posterodorsal commissure in an acute angle , so that the shell is fastigiate ( roof - shaped ) posteriorly . Ornament comprises coarse , robust , relatively sparse costae that are ...
... subtrigonal area essentially flat , meeting the posterodorsal commissure in an acute angle , so that the shell is fastigiate ( roof - shaped ) posteriorly . Ornament comprises coarse , robust , relatively sparse costae that are ...
Page 26
... subtrigonal area is weakly concave , almost flat , and with an indistinct longitudinal groove . It forms an acute angle with the opposing area at the posterodorsal commissure so that the posterodorsal part of the shell is fastigiate ...
... subtrigonal area is weakly concave , almost flat , and with an indistinct longitudinal groove . It forms an acute angle with the opposing area at the posterodorsal commissure so that the posterodorsal part of the shell is fastigiate ...
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Common terms and phrases
abbreviated according to chronology acute angle Aitken ANNALS antecarinal sulcus bicuspidata Gould Broad subtrigonal area Cape Town comma separates comprises coarse concentric costae curve strongly upwards described Haughton escutcheon fastigiate roof-shaped flank costae Gastropoda GENUS OF RUTITRIGONIINAE Hoepen holotype Kobayashi krenkeli Lamarck Lange Later flank Leda LOWER CRETACEOUS APTIAN margin and obliquely marginal carina Megatrigonia middle growth stages Nakano namacolus nepionic stages noteworthy similarities Nucula obliquely truncate opisthogyrous beaks ornament comprises paratypes parentheses posterodorsal commissure punctuation reduction or enlargement references registration number respiratory margin ribbing Roman numerals RUTITRIGONIINAE BIVALVIA scientific name separate author's name shell is fastigiate Shell medium sized shouldered italics Smith South African Museum species straight posterodorsal margin strongly upwards posteriorly subconcentric subheadings are shouldered subterminal umbones subtrapezoidal Synonymy arrangement Syrotrigonia taxa Trigonia Rutitrigonia TRIGONIACEA umbonal ridge V-shaped costae ventral margin VOLUME 99 volume number Von Huene weakly ZULULAND Zulutrigonia gen Zulutrigonia pongolensis Rennie