Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 9
... produced , with subterminal umbones ; marginal and inner carinae prominently nodate , generally persisting to maturity ; area broad , typically with transverse ornament and longitudinal groove LOWER CRETACEOUS TRIGONIOIDA FROM THE ALGOA ...
... produced , with subterminal umbones ; marginal and inner carinae prominently nodate , generally persisting to maturity ; area broad , typically with transverse ornament and longitudinal groove LOWER CRETACEOUS TRIGONIOIDA FROM THE ALGOA ...
Page 13
... produced posteriorly . Umbones subterminal , elevated , with moderately inturned , opistho- gyrous beaks . Posterodorsal margin shallowly concave , anterior and ventral margins broadly rounded forming a semi - circle , respiratory ...
... produced posteriorly . Umbones subterminal , elevated , with moderately inturned , opistho- gyrous beaks . Posterodorsal margin shallowly concave , anterior and ventral margins broadly rounded forming a semi - circle , respiratory ...
Page 25
... produced so that umbones are generally not subterminal , area rela- tively narrow with concentric ornament in nepionic stages later smooth , flank costae subconcentric ; 2 beyond nepionic stages flank costae V - shaped , with tendency ...
... produced so that umbones are generally not subterminal , area rela- tively narrow with concentric ornament in nepionic stages later smooth , flank costae subconcentric ; 2 beyond nepionic stages flank costae V - shaped , with tendency ...
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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