common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...
the southern olive, is a medium-sized
sea snail
Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...
, a
gastropod
Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, freshwater, and fro ...
mollusc
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
of the
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Ancillariidae
The Ancillariidae is a taxonomic family of sea snails, marine gastropod mollusc
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, ...
.Sartori, A.; Rosenberg, G. (2014). Amalda australis (G.B. Sowerby I, 1830). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=409967 on 2014-01-30
Description
The length of the shell attains 52 mm, its diameter 23 mm.
The shell is elongate and fusiform, with a smooth, glossy surface. The
spire
A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...
is relatively short compared to the large
body whorl
The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk ...
, and the overall shape is sleek and streamlined, allowing the snail to easily burrow into sand. The coloration of the shell varies from creamy white to light brown, often with subtle darker bands or streaks. The
aperture
In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...
is long and narrow, with a thin outer
lip
The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Mammal lips are soft, movable and serve to facilitate the ingestion of food (e.g. sucklin ...
. The inner lip and
columella
Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire.
His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...
are typically coated with a thin callus.
Habitat
These predatory snails live in the intertidal sand, an environment that lends itself to high probability of fossilization. ''Amalda australis'' fossils date back to the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58
This marine species is
endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
. and occurs off
North Island
The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...
and northern part of
South Island
The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...
down to
Banks Peninsula
Banks Peninsula () is a rocky peninsula on the east coast of the South Island of New Zealand that was formed by two now-extinct volcanoes. It has an area of approximately . It includes two large deep-water harbours — Lyttelton Harbour a ...