Besla convexa | |
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Apertural view of the shell of Besla convexa | |
Scientific classification ![]() | |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Clade: | Heterobranchia |
Clade: | Euthyneura |
Order: | Panpulmonata |
Family: | Pyramidellidae |
Genus: | Besla |
Species: | B. convexa |
Binomial name | |
Besla convexa (Carpenter, 1857) [1] | |
Synonyms | |
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Besla convexa is a species of sea snail, a marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies. [2] [3]
In biology, a species ( ) is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies.
Sea snail is a common name for snails that normally live in salt water, in other words marine gastropods. The taxonomic class Gastropoda also includes snails that live in other habitats, such as land snails and freshwater snails. Many species of sea snails are edible and exploited as food sources by humans.
Family is one of the eight major hierarcical taxonomic ranks in Linnaean taxonomy; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as being the "walnut family".
The small, slender shell is elongate-conic. It measures 2.4 mm. The two and one-half whorls of the protoconch form a moderately elevated helicoid spire, whose axis is at right angles to that of the succeeding turns, in the first of which it is about one-fifth immersed. The six whorls of the teleoconch overhang and are strongly contracted at the sutures, appressed at the summit, angulated at the posterior extremity of the anterior third. They are marked, between the sutures, strong, rounded, sinuous, almost vertical axial ribs, of which 16 occur upon the second and third, 18 upon the fourth, and 22 upon the penultimate turn. The intercostal spaces are a little more than twice as wide as the ribs, crossed by three equal and equally spaced cords, which are about one-half as strong as the ribs. The first of these cords is at the periphery, the third at the posterior termination of the anterior third between the sutures, which it renders strongly angulated. The sutures are constricted. The periphery and the base of the body whorl are well rounded, marked by the continuation of the axial ribs, and about eight slender spiral lirations. The aperture is broadly oval. The posterior angle is acute. The outer lip is thin, showing the external sculpture within. The columella is slender, slightly curved, decidedly oblique and revolute, and is provided with a slender fold at its insertion. The parietal wall is covered with a strong callus. [4]
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 ammonites.
A protoconch is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called "nucleus". The protoconch may sometimes consist of several whorls, but when this is the case, the whorls show no growth lines.
The body whorl is part of the morphology of the 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.
The type specimen of this marine species was found in the Pacific Ocean off the coast of Mazatlán, Mexico.
The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west and the Americas in the east.
Mazatlán is a city in the Mexican state of Sinaloa. The city serves as the municipal seat for the surrounding municipio, known as the Mazatlán Municipality. It is located at 23°13′N106°25′W on the Pacific coast, across from the southernmost tip of the Baja California Peninsula.
Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
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