Annals of the South African MuseumThe Museum, 1991 - Natural history |
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Page 14
... growth stages with transverse growth striae , later remaining smooth or with coarse , irregular growth rugae , which may extend on to the flanks ; flank costae tend to become crowded ventrally , where they may bend sharply for- wards ...
... growth stages with transverse growth striae , later remaining smooth or with coarse , irregular growth rugae , which may extend on to the flanks ; flank costae tend to become crowded ventrally , where they may bend sharply for- wards ...
Page 15
... growth striae of the area are replaced in maturity by coarse , irregular growth rugae . The earliest genus in the subfamily is Steinmanella itself , which first occurs in Tithonian rocks of South America ( Leanza & Garate 1987 ) ...
... growth striae of the area are replaced in maturity by coarse , irregular growth rugae . The earliest genus in the subfamily is Steinmanella itself , which first occurs in Tithonian rocks of South America ( Leanza & Garate 1987 ) ...
Page 19
South African Museum. growth striae and the median row of tubercles . These are replaced by irregular , transverse growth rugae in maturity . Flank ornament comprises c . 16 distant rows of prominent nodes that curve slightly to the ...
South African Museum. growth striae and the median row of tubercles . These are replaced by irregular , transverse growth rugae in maturity . Flank ornament comprises c . 16 distant rows of prominent nodes that curve slightly to 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