Annals of the South African MuseumThe Museum, 1991 - Natural history |
From inside the book
Results 1-3 of 13
Page 9
South African Museum. one - quarter of the shell length from the anterior and weakly inturned , opistho- gyrous beaks . The valves are moderately weakly inflated ( W / H = 0,28–0,33 ) , with an almost straight posterodorsal margin at ...
South African Museum. one - quarter of the shell length from the anterior and weakly inturned , opistho- gyrous beaks . The valves are moderately weakly inflated ( W / H = 0,28–0,33 ) , with an almost straight posterodorsal margin at ...
Page 24
... weakly curved anterior margins form an acute angle , with terminal umbones and weakly inturned , orthogyrous to slightly opisthogyrous beaks . The ventral margin is very long , weakly convex , and the broad respiratory margin ...
... weakly curved anterior margins form an acute angle , with terminal umbones and weakly inturned , orthogyrous to slightly opisthogyrous beaks . The ventral margin is very long , weakly convex , and the broad respiratory margin ...
Page 25
... weakly inflated anteriorly ; carinae lacking or generally restricted to the nepionic stages ; escutcheon smooth or with transverse costellae ; area smooth or with transverse or radial costellae ; flank costae V - shaped or oblique , weakly ...
... weakly inflated anteriorly ; carinae lacking or generally restricted to the nepionic stages ; escutcheon smooth or with transverse costellae ; area smooth or with transverse or radial costellae ; flank costae V - shaped or oblique , weakly ...
Other editions - View all
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