Nassarius


Nassarius, common name nassa mud snails or dog whelks, is a genus of minute to medium-sized sea snails, marine gastropod molluscs in the family Nassariidae. They are scavengers.

Etymology

The name is derived from the Latin word "nassa", meaning a wickerbasket with a narrow neck, for catching fish. Nassarius would then mean "someone who uses such a wickerbasket for catching fish".

Ecology

Distribution and habitat

within this genus are found worldwide. These snails usually live on mud flats or sand flats, intertidally or subtidally.

Life habits

Most Nassarius species are very active scavengers, feeding on crabs and carrion as dead fish, etc. They often burrow into marine substrates and then wait with only their siphon protruding, until they smell nearby food.

Shell description

The shells of species in this genus have a relatively high cyrtoconoid spire and a siphonal notch.

Anatomy

The animal has a long siphon.

Human use

Archeology

Several beads made from Nassarius gibbosulus shells are thought to be the earliest known forms of personal adornment, or even jewelry. Two shell beads found in Skhul Cave on the slopes of Mount Carmel, Israel, are thought to be 100,000 years old, whilst another found at Oued Djebbana, Algeria, is believed to be 90,000 years old. A further group of pierced shells, some with red ochre, has been recovered from the Aterian levels at the Taforalt site in Morocco; these Nassarius gibbosulus beads have been securely dated to about 82,000 years ago.
All these examples predate several 75,000-year-old Nassarius kraussianus beads which were found at Blombos Cave, South Africa. These beads had previously been thought to be the oldest examples of jewelry.

Modern uses

Nassarius vibex is a species which is often selected for marine aquaria. It is often confused with Nassarius obsoletus, a cooler water snail less suited to tropical marine aquarium temperatures. In aquaria, the Nassarius is considered nearly indispensable for keeping sand beds clean and healthy, as these snails tend to burrow and plow through the upper layer in a conch-like fashion, keeping algae and detritus from building up visibly on the surface.
The shells of various species of Nassarius are popular with shell collectors, and are sometimes used in jewelry and other forms of decoration.

Taxonomy

The genus Nassarius has traditionally been subdivided into several subgenera, based on differences in shell morphology, especially the sculpture: Aciculina, Alectrion, Allanassa, Nassodonta, Niotha, Plicarcularia, Profundinassa, Pygmaeonassa, Telasco, and Zeuxis. However, this division is difficult to define, resulting in much confusion. Even phylogenetic analysis shows that the division into these subgenera appears to be uncertain and unreliable. There seem to be two groups within the genus Nassarius with the closest relationship between the subgenera Zeuxis and Telasco. Even the species within the subgenus Plicarcularia do not belong to a single clade. In the end, the molecular phylogeny did not match the previous morphological phylogeny.

Gallery

Species

In the course of time, more than 800 names have been allocated to species in the genus Nassarius, most of which have become synonyms.
The following species are accepted names according to the World Register of Marine Species :
Other species in the genus Nassarius include, according to ITIS:
The following species are also mentioned as names in current use by the Indo-Pacific Molluscan Database:
;Subgenus Nassodonta
;Subgenus Plicarcularia
;Subgenus Zeuxis