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
... subconcentric anteriorly , but posteriorly may be subconcentric , strongly oblique , or effaced . Discussion The origins of Rutitrigonia are cryptic . It first appears in the Bathonian of East Africa ( Venzo 1942 ) , and its ancestry ...
... subconcentric anteriorly , but posteriorly may be subconcentric , strongly oblique , or effaced . Discussion The origins of Rutitrigonia are cryptic . It first appears in the Bathonian of East Africa ( Venzo 1942 ) , and its ancestry ...
Page 27
... - PCZ8528 . F. Zulutrigonia krenkeli ( Lange ) . A plastercast of the holotype , in the South African Museum . All × 1 . narrower than the interspaces . They are subconcentric anteriorly but. A NEW GENUS OF RUTITRIGONIINAE 27.
... - PCZ8528 . F. Zulutrigonia krenkeli ( Lange ) . A plastercast of the holotype , in the South African Museum . All × 1 . narrower than the interspaces . They are subconcentric anteriorly but. A NEW GENUS OF RUTITRIGONIINAE 27.
Page 28
... subconcentric anteriorly but curve strongly upwards to the posterior , cutting the growth striae obliquely and approaching the area almost at right angles . In the middle growth stages the ribs terminate at the umbonal ridge but in ...
... subconcentric anteriorly but curve strongly upwards to the posterior , cutting the growth striae obliquely and approaching the area almost at right angles . In the middle growth stages the ribs terminate at the umbonal ridge but in ...
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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