lip expanded and flaring, slightly reflected and not strongly incrassate.
Bulla placement may have functioned as apertural
covering, possibly for protection.
lip little expanded, thin, hardly reflected.
Shell: Medium to large, depressed-discoidal to planorboid, spire very low with little other than embryonic whorls projecting in apertural
view; final part of last adult whorl descending gently prior to aperture; whorls more or less evenly rounded, suture indented; umbilicus very wide, its margin evenly rounded; underside of embryonic whorls clearly visible.
views show the right-hand lopha overlapping above the left (Fig.
Nucella kill and consume their prey by either drilling through the shell or wedging open the prey item's shell margin with their apertural
edge (Barnett 1979, Perry 1987).
Key to genera of Chilodontidae in the south-western Indian Ocean (applies only to specimens with mature apertural
zones are present on both sides of the apertural
providentiae is easily distinguished from the other southern African chilodontid taxa by its rounded whorl profile, very strong, complex apertural
dentition and patent, callus lined umbilicus.
40 mm; smallest specimen with mature apertural
dentition, length 2.
The columella lamella is poorly defined in Pfeiffer's figure, but the Latin description, although not detailed in terms of apertural
tooth morphology, stated that the second tooth (what is now termed the columella lamella--he worked anticlockwise, starting with the parietal lamella) is 'excavata profunde ad columellam' [deeply excavated at/toward the columella].
The possible link between pollinators and sexine ornamentation, habitat and apertural
configuration, and flower morphology and pollen size also provide exciting research topics in several groups of Rubiaceae.
In addition there was a juvenile shell without any apertural
stn--station; h--height, w--greater diameter (both measured in standard, apertural
Shell height and diameter measurements were made with the shell held in apertural
view with the axis of coiling vertical, as shown in Fig.