. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. PLEISTOCENE MOLLUSCS FROM THE NAMAQUALAND COAST 209 the most anterior 4 or 5 being oblique. Median teeth reduced and almost absent in some. 10 or 11 posterior teeth, almost all oblique. Inner surface of valves with fine radiating lines. Inner margin of shell crenulate. Named from the location—'Brak', Afrikaans —'brack' river. Material Holotype: K1448 L. 26 mm A. 15 mm Other specimens: 23 mm 11 mm 21 mm 12 mm 16 mm 8 mm Remarks These shells are placed in the subgenus Acar as defined by Thiele (
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. PLEISTOCENE MOLLUSCS FROM THE NAMAQUALAND COAST 209 the most anterior 4 or 5 being oblique. Median teeth reduced and almost absent in some. 10 or 11 posterior teeth, almost all oblique. Inner surface of valves with fine radiating lines. Inner margin of shell crenulate. Named from the location—'Brak', Afrikaans —'brack' river. Material Holotype: K1448 L. 26 mm A. 15 mm Other specimens: 23 mm 11 mm 21 mm 12 mm 16 mm 8 mm Remarks These shells are placed in the subgenus Acar as defined by Thiele (1929), as there is a posterior ridge present, the sculpture being knobbed, the umbo anterior to the midline of the shell, the dorsal plane small, the median hinge teeth weak/rudimentary and the outer teeth oblique. The present species differs from Area [Acar) plicata Dillwyn, which it most strongly resembles, in the following respects: the present shell is flatter than A. {A.) plicata and has well-developed anterior and posterior radiating, nodulose ribs which A. {A.) plicata lacks. In the region of the posterior ridge, A. {A.) plicata usually has prominent squamae instead of the nodules of the present species. In the hinge area, the dorsal plane of ^. [A.) plicata, which is wider than in the present species, has 10 or more oblique/elongate grooves, the more medial ones extend- ing the entire length of the hinge area; A. {A.) halmyrus however, has only about 5 oblique grooves, none extending beyond the umbo. The angle of the posterior ribs radiating from the umbo differs considerably in these species. Family Gondylocardiidae Carditella calipsamma Fig. 4 Location i. 45-50 m Transgression complex. Back-beach Fig. 4. Carditella calipsamma Holotype. a. Right valve in external view. b. Right valve in internal view. c. Hinge of left Please note that these images are extracted from scanned page images that may have been digitally enhanced for read
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
