Atlanta brunnea
Encyclopedia
Atlanta brunnea is a species
of sea snail
, a holoplankton
ic marine
gastropod mollusk in the family
Atlantidae
.
diameter to 2.0 mm) that is darkly pigmented (brown to reddish-and golden-brown). The keel is tall and colorless, and inserts between the last and penultimate shell whorls in animals larger than 1.5 mm. The spire
is tall and conical, consisting of 4 whorls and possessing a complex pattern of spiral sculpture
that ends on the protoconch and is replaced by spiral rows of small punctae on the teleoconch. Coloration ranges from brown to amber and reddish-brown.
Juveniles of this species are easily recognised by their shape and ornament. The protoconch
is rather high conical and has 3½ - 3¾ whorls
, slowly increasing in diameter. On the first whorl, in front of the nucleus, an ornament is seen of some nine or ten irregular spirals. Two stronger spirals from the second whorl on delimit a subsutural zone and the base of the shell. On these spirals the whorl profile is slightly angular. The whole surface of the protoconch is furthermore covered with numerous finer spirals in an irregular zigzag shape, also on the base and within the umbilicus. The boundary with the teleoconch is made distinct by the sudden disappearance of these spirals. From that point on the whorl diameter increases rapidly, by which the shape of the shell becomes lenticular. Somewhat more than one teleoconch whorl is present in the largest specimens. The periphery of the body whorl
is angular and bears a distinct flange-like keel. The protoconch is visible in an apertural view.
Eyes aretype a, operculum is type a, and radula type I.
Description overview:
of Anda, Pangasinan
, Luzon, Philippines.
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 holoplankton
Holoplankton
Holoplankton are organisms that are planktonic for their entire life cycle. Examples of holoplankton include some diatoms, radiolarians, some dinoflagellates, foraminifera, amphipods, krill, copepods, and salps.-Sources:Asexual Holoplankton:...
ic marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
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...
Atlantidae
Atlantidae
Atlantidae is a family of sea snails, holoplanktonic gastropod molluscs in the clade Littorinimorpha.According to taxonomy of the Gastropoda by Bouchet & Rocroi the family Atlantidae has no subfamilies.- Description :...
.
Description
Atlanta brunnea is a small species (shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
diameter to 2.0 mm) that is darkly pigmented (brown to reddish-and golden-brown). The keel is tall and colorless, and inserts between the last and penultimate shell whorls in animals larger than 1.5 mm. The spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
is tall and conical, consisting of 4 whorls and possessing a complex pattern of spiral sculpture
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
that ends on the protoconch and is replaced by spiral rows of small punctae on the teleoconch. Coloration ranges from brown to amber and reddish-brown.
Juveniles of this species are easily recognised by their shape and ornament. The protoconch
Protoconch
A protoconch is an embryonic or larval shell of some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod...
is rather high conical and has 3½ - 3¾ 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...
, slowly increasing in diameter. On the first whorl, in front of the nucleus, an ornament is seen of some nine or ten irregular spirals. Two stronger spirals from the second whorl on delimit a subsutural zone and the base of the shell. On these spirals the whorl profile is slightly angular. The whole surface of the protoconch is furthermore covered with numerous finer spirals in an irregular zigzag shape, also on the base and within the umbilicus. The boundary with the teleoconch is made distinct by the sudden disappearance of these spirals. From that point on the whorl diameter increases rapidly, by which the shape of the shell becomes lenticular. Somewhat more than one teleoconch whorl is present in the largest specimens. The periphery of the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
is angular and bears a distinct flange-like keel. The protoconch is visible in an apertural view.
Eyes aretype a, operculum is type a, and radula type I.
Description overview:
- The maximum recorded shellGastropod shellThe gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
length is 1.7 mm. / Maximal shell diameter is 2.0 mm. - Keel tall and colorless, and inserts between last and penultimate whorls in shells > 1.5 mm diameter
- Spire tall and conical, with ornate, complex sculpture
- Coloration brown to amber and reddish-brown
- Eyes type a; operculum type a; radula type I
Distribution
Atlanta brunnea has an almost worldwide tropical and subtropical distribution pattern.Fossil distribution
Atlanta brunnea is known from the PliocenePliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
of Anda, Pangasinan
Anda, Pangasinan
Anda is a 4th class island-municipality in the province of Pangasinan, Philippines. The people of Anda generally speak Bolinao. The island is near the Hundred Islands, a popular tourist destination for its caves and beaches....
, Luzon, Philippines.