Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 9
... crowded and broader than the interspaces . Posteriorly the ribs terminate against the marginal carina of the right valve , but there is a narrow antecarinal sulcus to the left . Discussion Rennie ( 1947 ) compared material from the ...
... crowded and broader than the interspaces . Posteriorly the ribs terminate against the marginal carina of the right valve , but there is a narrow antecarinal sulcus to the left . Discussion Rennie ( 1947 ) compared material from the ...
Page 29
... crowded , simple , subconcentric ribs running from the anterior commissure to the marginal carina , where they flex strongly forwards , forming an acute angle with the flank costae , to cross the area obliquely and pass weakly on to the ...
... crowded , simple , subconcentric ribs running from the anterior commissure to the marginal carina , where they flex strongly forwards , forming an acute angle with the flank costae , to cross the area obliquely and pass weakly on to the ...
Page 39
... crowded posterior set . The anterior costae are as wide as or narrower than the interspaces ; those closest to the umbo are coarsely tuberculate throughout . Posteriorly , however , the coarse rounded tuberculation is increasingly ...
... crowded posterior set . The anterior costae are as wide as or narrower than the interspaces ; those closest to the umbo are coarsely tuberculate throughout . Posteriorly , however , the coarse rounded tuberculation is increasingly ...
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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