Gibbula spurca is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of sea snail

Sea snail

Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

, a marine gastropod mollusk in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Trochidae

Trochidae

The Trochidae, common name top snails, are a taxonomic family of very small to large sea snails, marine gastropod molluscs in the clade Vetigastropoda ....

, the top snails.

Description

The size of an adult shell varies between 8 mm and 12 mm. The small, solid shell is globose-conical, sculptured with fine, shallow, revolving alternate grooves and elevations. The yellowish shell is shining and delicately variegated with oblique zigzag dusky lines. The two colors are about in equal proportions with a series of somewhat conspicuous quadrate dusky and yellow spots just below the suture. There are four or five ventricose whorls

Whorl (mollusc)

A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...

. The suture is deeply impressed. The base is moderately conical, imperforate or minutely umbilicated. The aperture

Aperture (mollusc)

The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

 is very oblique. The rounded columella is arcuate. The outer subnacreous lip is sharp and smooth.

Distribution

This species occurs in the Atlantic Ocean along Madeira

Madeira

Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...

 and the Canary Islands

Canary Islands

The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...

.

External links

• Gastropods.com: Gibbula (Gibbula) spurca; accessed = 3 July 2011