|
Bayerotrochus Westralis
''Bayerotrochus westralis'', commonly known as "Australia's split shell", is a species of sea snail, a marine gastropod mollusk in the family (biology), family Pleurotomariidae. Description The shell has a turbinate shape with an apical spire angle of approximately 90 degrees, with inflated body whorls that are proportionate in expansion so that the spire profile is straight, a clearly defined suture, and the periphery is oblique and slightly rounded. The base is highly inflated and lacks a columellar callus at the center of the base area. The aperture (mollusc), aperture is oval, the slit is positioned roughly one third of the way between the upper and lower sutures and is relatively long, about 19 percent of the circumference. The shell is lightly sculptured with very numerous fine spiral cords above and below the selenizone (the area where the shell growth filled in the slit), crossed by very numerous fine axial growth lines. The base has very numerous spiral striae which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
The gastropod shell is part of the body of a Gastropoda, gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the Aperture (mollusc), aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columellar
Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the works of Cato the Elder and Marcus Terentius Varro, both of which he occasionally cites. A smaller book on trees, ', is usually attributed to him. In 1794 the Spanish botanists José Antonio Pavón Jiménez and Hipólito Ruiz López named a genus of Peruvian asterid ''Columellia'' in his honour. Personal life Little is known of Columella's life. He was probably born in Gades, Hispania Baetica (modern Cádiz), possibly to Roman parents. After a career in the army (he was tribune in Syria in 35), he turned to farming his estates at Ardea, Carseoli, and Alba in Latium. ''De re rustica'' In ancient times, Columella's work "appears to have been but little read", cited only by Pliny the Elder, Servius, Cassiodorus, and Isidorus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broome, Western Australia
Broome, also known as Rubibi by the Yawuru people, is a coastal pearling and tourist town in the Kimberley region of Western Australia, north of Perth. In the the population was recorded as 14,660. It is the largest town in the Kimberley region. Geography Broome is located on Western Australia's tropical Kimberley coast on the eastern edge of the Indian Ocean. Roebuck Bay Being situated on a north–south peninsula, Broome has water on both sides of the town. On the eastern shore are the waters of Roebuck Bay extending from the main jetty at Port Drive to Sandy Point, west of Thangoo station. Town Beach is part of the shoreline and is popular with visitors on the eastern end of the town. It is the site of the 'Staircase to the Moon', where a receding tide and a rising moon combine to create a stunning natural phenomenon. On "Staircase to the Moon" nights, a food and craft market operates on Town Beach. Roebuck Bay is of international importance for the millions of migratin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
The operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periostracum
The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as ''Allonautilus scrobiculatus''. The periostracum is an integral part of the shell, and it forms as the shell forms, along with the other shell layers. The periostracum is used to protect the organism from corrosion. The periostracum is visible as the outer layer of the shell of many molluscan species from terrestrial, freshwater, and marine habitats, and may be seen in land snails, river mussels, and other kinds of freshwater bivalves, as well as in many kinds of marine shelled molluscs. The word ''periostracum'' means "around the shell", meaning that the periostracum is wrapped around what is usually the more calcareous part of the shell. Technically, the calcareous part of the shel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleoconch
The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the mantle. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as conchiolin. The outermost layer is the periostra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoconch
A protoconch (meaning first or earliest or original shell) 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 whorls of the adult shell, which are formed after the protoconch, are known as the teleoconch. The teleoconch starts forming when the larval gastropod becomes a juvenile, and the protoconch may dissolve. Quite often there is a visible line of demarcation where the protoconch ends and the teleoconch begins, and there may be a noticeable change in sculpture, or a sudden appearance of sculpture at that point. In some gastropod groups (such as the Architectonicidae), the teleoconch whorls spiral in the opposite direction to the protoconch. In those cases, the shell is called heterostrophic. In species which ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenizone
A selenizone (from the Greek "selene" meaning "moon", and "zone" meaning "girdle") is an anatomical structure that exists in the shells of some families of living sea snails: the slit shells, the little slit shells and the abalones, which are marine gastropod mollusks from ancient lineages. It is a spiral band of crescentric growth lines or threads (lunulae) on the shell surface due to the semicircular end of a notch or slit on the outer lip. A structure of the same type exists in several fossil groups of mollusks, including all the fossil families of slit shells, as well as three superfamilies of what may have been gastropods, but may possibly have been monoplacophorans or paragastropods instead. The function of the holes and slits in living sea snails is to allow for exhalant water circulation, which is important for respiration and other functions. It has also been suggested that the selenizone may serve to reinforce the shell against catastrophic breakage during predati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc. The term ''aperture'' is used for the main opening in gastropod shells, scaphopod shells, and also for ''Nautilus'' and ammonite shells. The word is not used to describe bivalve shells, where a natural opening between the two shell valves in the closed position is usually called a ''gape''. Scaphopod shells are tubular, and thus they have two openings: a main anterior aperture and a smaller posterior aperture. As well as the aperture, some gastropod shells have additional openings in their shells for respiration; this is the case in some Fissurellidae (keyhole limpets) where the central smaller opening at the apex of the shell is called an orifice, and in the Haliotidae (abalones) where the row of respiratory openings in the shell are also called orifices. In gastropods In some prosobranch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayerotrochus Westralis 003
''Bayerotrochus'' is a genus of sea snails, marine gastropod mollusks in the family Pleurotomariidae. The generic name ''Bayerotrochus'' is in honor of marine biologist Frederick Bayer.Cairns S. D. (2008). "Frederick M. Bayer – Commissioner 1972-1995, octocoral taxonomist and Smithsonian curator". '' Bulletin of Zoological Nomenclature'' 65(2)86-87 The shells of the snails in this genus show a selenizone. Species Species within the genus ''Bayerotrochus'' include: *''Bayerotrochus africanus'' ( Tomlin, 1948) *''Bayerotrochus boucheti'' (Anseeuw & Poppe, 2001) *''Bayerotrochus charlestonensis'' (Askew, 1988) *''Bayerotrochus diluculum'' (Okutani, 1979) *''Bayerotrochus indicus'' (Anseeuw, 1999) *''Bayerotrochus midas'' (Bayer, 1966) *''Bayerotrochus philpoppei'' Anseeuw, Poppe & Goto, 2006 *''Bayerotrochus poppei'' Anseeuw, 2003 *''Bayerotrochus pyramus'' (Bayer, 1967) *'' Bayerotrochus quiquandoni'' Cossignani, 2018 *''Bayerotrochus tangaroanus'' (Bouchet & Métivier, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
The operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_torquata_002.jpg "Click for more on -> Operculum (gastropod)")
