Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 9
... shell length , and is ornamented with radial rows of fine tubercles that , on D1876 , curve inward to meet the commissure . The trigonal area is relatively narrow and almost flat . It is ornamented by finely beaded radial costellae ...
... shell length , and is ornamented with radial rows of fine tubercles that , on D1876 , curve inward to meet the commissure . The trigonal area is relatively narrow and almost flat . It is ornamented by finely beaded radial costellae ...
Page 24
... shell . It is ornamented by irregular oblique rows of elongate tubercles that vary in size and follow the growth striae . Posteriorly these tubercles are continuous with the growth rugae of the area . There is a very narrow lunule ...
... shell . It is ornamented by irregular oblique rows of elongate tubercles that vary in size and follow the growth striae . Posteriorly these tubercles are continuous with the growth rugae of the area . There is a very narrow lunule ...
Page 29
... Shell very large ( maximum length about 165 mm ) , massive , pyriform , inequilateral , strongly produced posteriorly ( H / L = 0,50-0,61 ) . Umbones fairly prominent , rounded , situated about 30 per cent of the shell length from the ...
... Shell very large ( maximum length about 165 mm ) , massive , pyriform , inequilateral , strongly produced posteriorly ( H / L = 0,50-0,61 ) . Umbones fairly prominent , rounded , situated about 30 per cent of the shell length from 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