Cross barred venus
Encyclopedia
Chione cancellata, is a species
of medium-sized saltwater clam
, a marine
bivalve mollusc in the family Veneridae
, the venus clams.
This species is now understood to be strictly Caribbean
in distribution. The more northern species which resembles this, which is usually called the "cross-barred venus" and which was considered to be C. cancellata for many years is now known to be Chione elevata.
The interior of the shell possesses crenulations on its bottom edge, and like most Veneridae it has well-developed lateral and cardinal teeth on the hinge line.
The shell of C. cancellata sensu stricto is quite brightly colored and patterned. (This is in contrast to the species C. elevata which usually has a grayish yellow-white exterior, occasionally with a few lavender radial stripes. The shell interior of C. elevata is usually purple.)
to Brazil
. It is now known that the Caribbean Chione is in fact C. cancellata and the more northern clam is a different species, C. elevata.
status of the common tropical western Atlantic venerid bivalve, Chione cancellata, was radically revised in 2000. What had previously been thought to be one species was discovered to be a "cryptic species pair" and as such it was divided into two separate species, on the basis of morphological, morphometric and phylogenetic analyses.
The more colorful Caribbean species is still called C. cancellata. However, specimens inhabiting waters off the United States
and Central America
south to Belize
, are in fact a different species. This species was described originally by Thomas Say
as Chione elevata. Examination of specimens of both species supported the separation, including difference in shell sculpture
, hinge morphology, and size of the pallial cavity.
A phylogenetic analysis of extant species failed to define the exact evolutionary history of C. cancellata and C. elevata. Separation of the two species suggests an ancient faunal division in the western Atlantic between the northern Caloosahatchian Province and the southern Atlantic Gatunian Province. This hypothetical division has been dated back to the Early Pliocene
.
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 medium-sized saltwater clam
Clam
The word "clam" can be applied to freshwater mussels, and other freshwater bivalves, as well as marine bivalves.In the United States, "clam" can be used in several different ways: one, as a general term covering all bivalve molluscs...
, a 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...
bivalve mollusc in the family Veneridae
Veneridae
The Veneridae or venerids, also known as the Venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. There are over 500 living species of venerid bivalves, most of which are edible, and many of which are exploited as a food source.Many of the most...
, the venus clams.
This species is now understood to be strictly Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
in distribution. The more northern species which resembles this, which is usually called the "cross-barred venus" and which was considered to be C. cancellata for many years is now known to be Chione elevata.
Shell description
This species grows to be 1 3/4 inches across, and has a rounded, triangular shell with both strong concentric ridges and strong radial ribbing, which together form a raised crisscross pattern of ridges, hence the specific name, cancellata or cancellate.The interior of the shell possesses crenulations on its bottom edge, and like most Veneridae it has well-developed lateral and cardinal teeth on the hinge line.
The shell of C. cancellata sensu stricto is quite brightly colored and patterned. (This is in contrast to the species C. elevata which usually has a grayish yellow-white exterior, occasionally with a few lavender radial stripes. The shell interior of C. elevata is usually purple.)
Habitat
The species commonly lives on sandy bottoms of sounds and shallow offshore waters, and the shells are commonly found washed ashore on sound and ocean beaches.Distribution
This species was, until recently, thought to range from New JerseyNew Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. It is now known that the Caribbean Chione is in fact C. cancellata and the more northern clam is a different species, C. elevata.
Human use
Although this clam is sweeter in taste than the northern quahog, Mercenaria mercenaria, it is a lot smaller, and is rarely eaten.Genetic evolution and anatomy
The taxonomicTaxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
status of the common tropical western Atlantic venerid bivalve, Chione cancellata, was radically revised in 2000. What had previously been thought to be one species was discovered to be a "cryptic species pair" and as such it was divided into two separate species, on the basis of morphological, morphometric and phylogenetic analyses.
The more colorful Caribbean species is still called C. cancellata. However, specimens inhabiting waters off the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
south to Belize
Belize
Belize is a constitutional monarchy and the northernmost country in Central America. Belize has a diverse society, comprising many cultures and languages. Even though Kriol and Spanish are spoken among the population, Belize is the only country in Central America where English is the official...
, are in fact a different species. This species was described originally by Thomas Say
Thomas Say
Thomas Say was an American naturalist, entomologist, malacologist, herpetologist and carcinologist. A taxonomist, he is often considered to be the father of descriptive entomology in the United States. He described more than 1,000 new species of beetles and over 400 species of insects of other...
as Chione elevata. Examination of specimens of both species supported the separation, including difference in shell 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...
, hinge morphology, and size of the pallial cavity.
A phylogenetic analysis of extant species failed to define the exact evolutionary history of C. cancellata and C. elevata. Separation of the two species suggests an ancient faunal division in the western Atlantic between the northern Caloosahatchian Province and the southern Atlantic Gatunian Province. This hypothetical division has been dated back to the Early Pliocene
Pliocene
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...
.