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 25
... Broad 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 ...
... Broad 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
... area only in the nepionic stages when it is ornamented . Marginal and inner carinae are lacking , but an umbonal ridge marks the position of the marginal carina . The broad subtrigonal area is weakly concave , almost flat , and with an ...
... area only in the nepionic stages when it is ornamented . Marginal and inner carinae are lacking , but an umbonal ridge marks the position of the marginal carina . The broad subtrigonal area is weakly concave , almost flat , and with an ...
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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 comprises coarse concentric costae curve strongly upwards described Haughton Diagnosis Shell 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