Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 15
... coarse growth rugae of the posterior part of the area ; flank costae generally weakly curved , uninterrupted , and coarsely nodate . Age : Tithonian - Neocomian . Steinmanella holubi ( Kitchin , 1908 ) Trigonia sp . LOWER CRETACEOUS ...
... coarse growth rugae of the posterior part of the area ; flank costae generally weakly curved , uninterrupted , and coarsely nodate . Age : Tithonian - Neocomian . Steinmanella holubi ( Kitchin , 1908 ) Trigonia sp . LOWER CRETACEOUS ...
Page 24
... coarse , irregular , growth rugae . The concentric flank costae of the nepionic stages pass on to the area , whereas the longitudinal furrow persists almost to maturity and is situated closer to the escutcheon than the flank . The ...
... coarse , irregular , growth rugae . The concentric flank costae of the nepionic stages pass on to the area , whereas the longitudinal furrow persists almost to maturity and is situated closer to the escutcheon than the flank . The ...
Page 39
... coarse rounded tuberculation is increasingly restricted to the ventral part of the costa , leaving the dorsal extension as a thin , wavy , vertical , finely crenulated costella . It is with final loss of coarse tuberculation that the ...
... coarse rounded tuberculation is increasingly restricted to the ventral part of the costa , leaving the dorsal extension as a thin , wavy , vertical , finely crenulated costella . It is with final loss of coarse tuberculation that the ...
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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