Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 17
... persists to maturity , and is closer to the escutcheon than the flank . The broad trigonal area is essentially flat ; in the nepionic stages it is crossed by sub- concentric flank costae but in the middle growth stages is ornamented ...
... persists to maturity , and is closer to the escutcheon than the flank . The broad trigonal area is essentially flat ; in the nepionic stages it is crossed by sub- concentric flank costae but in the middle growth stages is ornamented ...
Page 24
... persists almost to maturity and is situated closer to the escutcheon than the flank . The flanks are ornamented with coarse nodes that form almost straight rows directed posteroventrally over much of the shell surface . Anteriorly the ...
... persists almost to maturity and is situated closer to the escutcheon than the flank . The flanks are ornamented with coarse nodes that form almost straight rows directed posteroventrally over much of the shell surface . Anteriorly the ...
Page 43
... persists into the Maastrichtian of New Zealand ( Fleming 1964 , 1987 ) it is an important phy- letic line that ... persist to large size but may become effaced in maturity when they are replaced by concentric growth rugae . Discussion ...
... persists into the Maastrichtian of New Zealand ( Fleming 1964 , 1987 ) it is an important phy- letic line that ... persist to large size but may become effaced in maturity when they are replaced by concentric growth rugae . Discussion ...
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Common terms and phrases
Algoa Basin Anditrigonia antecarinal sulcus anterior commissure anterolateral shoulder anteroventrally Apiotrigoniinae Bivalvia broad chevrons coarse commissure comprises convex Cooper Cretaceous Description Shell Diagnosis elongate escutcheon carina faunas finely crenulated flank costae flank ornament genus growth rugae growth striae Hauterivian Hoepen holotype inflated anteriorly interspaces Iotrigonia irregular Kobayashi kraussi Kitchin lanceolate large maximum length Lateral view lectotype left valve longitudinal groove Megatrigoniacea moderately Myophorella Myophoriidae Nakano neotype nepionic stages Neumayr nodate Nototrigoniinae opisthogyrous beaks Paranditrigonia paratypes persisting to maturity phyletic Port Elizabeth Museum posterior set posterodorsal margin Poulton Pterotrigonia radial costellae radial ornament Rennie respiratory margin Reyes ribs right valve rostrate shallowly concave shell length Skwarko smooth South African Museum Steinmanella herzogi Goldfuss straight strongly oblique subconcentric subfamily Sundays River Superfamily synonymy Tashiro Tithonian transverse costellae transverse ornament Trigonia Trigoniacea Trigoniinae trigonioid tubercles Type species Upper Valanginian V-shaped Valanginian vau Sharpe ventral margin ventricosa Krauss Yaadia