Olives and ancillids
family Olividae consists of two subfamilies.
The species of the Olivinae are the glossy, attractive shells well known to
collectors and treated in a number of monographs.
These are primarily inhabitants of tropical seas, and only a few
species are found very rarely in northern NSW. The other subfamily,
the Ancillinae, has species which are smaller, and most occur only subtidally, so are less
well known and less collected. Of
this subfamily, seven species occur in NSW, all endemic to
Ancillids are sand dwelling carnivores and scavengers. The animal has a large flat foot that may extend twice the length of the shell, completely covering the shell. In some species the foot provides a limited swimming capability, probably used to escape predators. The construction of the shells is unusual in that a glaze or callus is applied over the spire, usually obscuring the suture on the spire, and forming a spiral band below the suture on the body whorl.
tropical olive shells have received much taxonomic attention, but there
is no overall review of the ancillids.
The Australian ancillids are in urgent need of revision, as many
have been named from specimens available in one state, without
investigating the variation throughout the range from
All NSW members of the family are figured, with the exception of
the following species.
Identification Notes: In ancillids the spire is covered with a glaze (also referred to as ‘callus’ if it is thick) applied after the creation of the normal spiral shell. There may be two layers of callus, applied at different times, over different parts of the shell. The callus on the spire may be smooth or spirally ribbed. The subsutural callus is a spiral band of callus below the suture. Below the centre of the body whorl there is a groove known as the ancillid groove, which may be weak or strong. Below the ancillid groove is the ancillid band, and below that the anterior fasciole, or fasciolar band. The fasciolar band usually has a ridge in the centre, which again may be weak or strong. The columellar pillar may be smooth or with plaits, varying in number and strength.