Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 5
... beaks prosogyrous ; 4 = area with concentric ornament ; 5 = antecarinal sulcus very broad , shallow ; 6 = area very broad , flanks wholly or partly with radial costae ; 7 marginal carina and ornament to area restricted to nepionic ...
... beaks prosogyrous ; 4 = area with concentric ornament ; 5 = antecarinal sulcus very broad , shallow ; 6 = area very broad , flanks wholly or partly with radial costae ; 7 marginal carina and ornament to area restricted to nepionic ...
Page 33
... beaks . The straight , subvertical anterior margin passes evenly into the almost straight ventral margin . The posterodorsal margin is broadly concave and the respiratory margin seems to have been narrowly rounded . The oval , flattened ...
... beaks . The straight , subvertical anterior margin passes evenly into the almost straight ventral margin . The posterodorsal margin is broadly concave and the respiratory margin seems to have been narrowly rounded . The oval , flattened ...
Page 37
... beaks . Anterior margin broadly convex , flattish , passing into the very broad , gently convex ventral margin . The ... beak . A beaded marginal carina may extend for the same dis- tance , becoming rounded thereafter . The area is ...
... beaks . Anterior margin broadly convex , flattish , passing into the very broad , gently convex ventral margin . The ... beak . A beaded marginal carina may extend for the same dis- tance , becoming rounded thereafter . The area is ...
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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