Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . (30 CRETACEOUS FAUNAS FROM SOUTH AFRICA 319 Yabeiceras crassiornatum sp. 50A-B Holotype BMNH C81501, from locality 145 in the Morrisvale area, north of Ngweni,Zululand, St. Lucia Formation, Coniacian II. Refers to the coarse ornament. Dimensions D c 137,00(100)ic Wb52,5(38,3)50,5(36,9) Wh 44,0(32,1)44,0(32,1) Wb: Wh1,191,15 U 61,7(45,0) Description The coiling is very evolute, serpenticone, with a broad, rather shallowumbilicus that comprises 45 per cent of the diameter. The whorls are slightlydepressed (whor
Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . (30 CRETACEOUS FAUNAS FROM SOUTH AFRICA 319 Yabeiceras crassiornatum sp. 50A-B Holotype BMNH C81501, from locality 145 in the Morrisvale area, north of Ngweni,Zululand, St. Lucia Formation, Coniacian II. Refers to the coarse ornament. Dimensions D c 137,00(100)ic Wb52,5(38,3)50,5(36,9) Wh 44,0(32,1)44,0(32,1) Wb: Wh1,191,15 U 61,7(45,0) Description The coiling is very evolute, serpenticone, with a broad, rather shallowumbilicus that comprises 45 per cent of the diameter. The whorls are slightlydepressed (whorl breadth to height ratio is 1,19 costally and 1,15 intercostally),the greatest breadth being well below midflank. The inner flanks are stronglyrounded, the outer flanks flattened, converging to the broad venter. The innerwhorls bear fifteen strong, broad, coarse primary ribs per whorl. These bearstrong clavate tubercles that migrate progressively outward from an umbilico-lateral to lower lateral position. At the smallest diameter visible, the beginningof the outer whorl,
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
