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
... concentric ribbing of the neanic stage is of such a character in both these ... costae , referring it instead to Megatrigonia . Subsequently , he identified ... concentric costae that pass uninterrupted on to the area where they weaken ...
... concentric ribbing of the neanic stage is of such a character in both these ... costae , referring it instead to Megatrigonia . Subsequently , he identified ... concentric costae that pass uninterrupted on to the area where they weaken ...
Page 25
... costae that are subconcentric anteriorly and curve strongly upwards ... concentric ornament of the nepionic and middle growth stages is identical ... costae of the adult . Significantly , however , the V - shaped costae are far from ...
... costae that are subconcentric anteriorly and curve strongly upwards ... concentric ornament of the nepionic and middle growth stages is identical ... costae of the adult . Significantly , however , the V - shaped costae are far from ...
Page 26
... costae in the early to middle growth stages , an internally crenulated postero- ventral margin and transverse ... concentric costae , broader than the interspaces , which flex slightly at the umbonal ridge before crossing onto the area ...
... costae in the early to middle growth stages , an internally crenulated postero- ventral margin and transverse ... concentric costae , broader than the interspaces , which flex slightly at the umbonal ridge before crossing onto the area ...
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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