Conus betulinus, common name the betuline cone, is a species of sea snail, a marine gastropod mollusk in the family Conidae, the cone snails and their allies. These snails are venomous, they are capable of "stinging" humans. The size of the shell varies between 40 mm and 170 mm; the color of the shell is yellow or orange-brown, with revolving series of spots, short lines of chocolate upon narrow white bands. The spire is radiated with chocolate; the base of the shell is grooved. This marine species occurs off Aldabra Chagos Madagascar Mascarene Basin Mauritius Mozambique Seychelles TanzaniaAlso off Indo-China, Indo-Malaysia, New Caledonia, Solomon Islands and Queensland, Australia. Linnaeus, C.. Systema Naturae per regna tria naturae, secundum classes, genera, cum characteribus, synonymis, locis. Editio decima, reformata. Laurentius Salvius: Holmiae. Ii, 824 pp Röding, P. F. 1798. Museum Boltenianum sive. Hamburg: Trappii 199 pp Reeve, L. A. 1843. Monograph of the genus Conus. Pls 1-39 in Reeve, L. A.. Conchologica Iconica.
London: L. Reeve & Co. Vol. 1. Smith, E. A. 1891. On a collection of marine shells from Aden, with some remarks upon the relationship of the Molluscan Fauna of the Red Sea and the Mediterranean. Proceedings of the Zoological Society of London 1891: 390-436 Oostingh, C. H. 1925. Report on a collection of recent shells from Obi and Halmahera, Molluccas. Mededeelingen van de Landbouwhoogeschool te Wageningen 29: 1-362 Dautzenberg, P. 1937. Gastéropodes marins. 3-Famille Conidae'. AA. RR. Le Prince et la Princesse Lé Belgique. Mémoires du Musée Royal d'Histoire Naturelle de Belgique 2: 284 pp, 3 pls Salvat, B. & Rives, C. 1975. Coquillages de Polynésie. Tahiti: Papeete les editions du pacifique, pp. 1–391. Cernohorsky, W. O. 1978. Tropical Pacific marine shells. Sydney: Pacific Publications 352 pp. 68 pls. Petuch, E. J. 1979. Twelve new Indo-Pacific gastropods. Nemouria 23: 1-20 Wilson, B. R. & Gillett, K. 1971. Australian Shells: illustrating and describing 600 species of marine gastropods found in Australian waters. Sydney: Reed Books 168 pp. Wilson, B. 1994.
Australian Marine Shells. Prosobranch Gastropods. Kallaroo, WA: Odyssey Publishing Vol. 2 370 pp. Röckel, D. Korn, W. & Kohn, A. J. 1995. Manual of the Living Conidae. Volume 1: Indo-Pacific Region. Wiesbaden: Hemmen 517 pp. Puillandre N. Duda T. F. Meyer C. Olivera B. M. & Bouchet P.. One, four or 100 genera? A new classification of the cone snails. Journal of Molluscan Studies. 81: 1-23 The Conus Biodiversity website Cone Shells - Knights of the Sea "Dendroconus betulinus". Gastropods.com. Retrieved 15 January 2019
The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In certain groups of carnivorous snails, where the siphon is long, the structure of the shell has been modified in order to house and protect the soft structure of the siphon, thus the siphonal canal is a semi-tubular extension of the aperture of the shell through which the siphon is extended when the animal is active. One gastropod whose shell has an exceptionally long siphonal canal is the Venus comb murex; some gastropods have a simple siphonal notch at the edge of the aperture instead of a canal. Siphonal notch stromboid notch Vermeij G. J. "The ecology of invasion: acquisition and loss of the siphonal canal in gastropods". Paleobiology 33: 469-493. Doi:10.1666/06061.1
The nautilus is a pelagic marine mollusc of the cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of, the genus Nautilus. Though it more refers to species Nautilus pompilius, the name chambered nautilus is used for any of the Nautilidae. All are protected under CITES Appendix II. Nautilidae, both extant and extinct, are characterized by involute or more or less convolute shells that are smooth, with compressed or depressed whorl sections, straight to sinuous sutures, a tubular central siphuncle. Having survived unchanged for millions of years, nautiluses represent the only living members of the subclass nautiloidea, are considered "living fossils"; the word nautilus is derived from the Greek ναυτίλος nautílos and referred to the paper nautiluses of the genus Argonauta, which are octopuses. The word nautílos means "sailor", as paper nautiluses were thought to use two of their arms as sails.
The "tentacles" of the nautiluses are cirri, composed of long, flexible appendages which are retractable into corresponding hardened sheaths. Unlike the 8–10 head appendages of coleoid cephalopods, nautiluses have many cirri. In the early embryonic stages of nautilus development a single molluscan foot differentiates into a total of 60–90 cirri, varying within a species. Nautilus cirri differ from the tentacles of some coleoids in that they are non-elastic and lack pads or suckers. Instead, nautilus cirri adhere to prey by means of their ridged surface. Nautiluses have a powerful grip, attempts to take an object grasped by a nautilus may tear away the animal's cirri, which will remain attached to the surface of the object; the main cirri emerge from sheaths. The pair of cirri before the eye and the pair of cirri behind the eye are separate from the others; these are more evidently grooved, with more pronounced ridges. They are believed to serve an olfactory purpose; the radula is wide and distinctively has nine teeth.
The mouth consists of a parrot-like beak made up of two interlocking jaws capable of ripping the animal's food— crustaceans— from the rocks to which they are attached. Males can be superficially differentiated from females by examining the arrangement of tentacles around the buccal cone: males have a spadix organ located on the left side of the cone making the cone look irregular, whereas the buccal cone of the female is bilaterally symmetrical; the crop is the largest portion of the digestive tract, is extensible. From the crop, food passes to the small muscular stomach for crushing, goes past a digestive caecum before entering the brief intestine. Like all cephalopods, the blood of the nautilus contains hemocyanin, blue in its oxygenated state. There are two pairs of gills which are the only remnants of the ancestral metamerism to be visible in extant cephalopods. Oxygenated blood arrives at the heart through four ventricles and flows out to the animal's organs through distinct aortas but returns through veins which are too small and varied to be described.
The one exception to this is the vena cava, a single large vein running along the underside of the crop into which nearly all other vessels containing deoxygenated blood empty. All blood passes through one of the four sets of filtering organs upon leaving the vena cava and before arriving at the gills for re-oxygenation. Blood waste is emptied through a series of corresponding pores into the pallial cavity; the central component of the nautilus nervous system is the oesophageal nerve ring, a collection of ganglia and connectives that together form a ring around the animal's oesophagus. From this ring extend all of the nerves forward to the mouth and funnel; the nerve ring does not constitute what is considered a cephalopod "brain": the upper portion of the nerve ring lacks differentiated lobes, most of the nervous tissue appears to focus on finding and consuming food. Nautiluses tend to have rather short memory spans, the nerve ring is not protected by any form of brain case. Nautiluses are the sole living cephalopods whose bony body structure is externalized as a planispiral shell.
The animal can withdraw into its shell and close the opening with a leathery hood formed from two specially folded tentacles. The shell is coiled, aragonitic and pressure-resistant, imploding at a depth of about 800 m; the nautilus shell is composed of two layers: a matte white outer layer, a striking white iridescent inner layer. The innermost portion of the shell is a pearlescent blue-gray; the osmeña pearl, contrarily to its name, is not a pearl, but a jewellery product derived from this part of the shell. Internally, the shell divides into the chambered section being called the phragmocone; the divisions are defined by septa, each of, pierced in the middle by a duct, the siphuncle. As the nautilus matures, it creates new, larger camerae and moves its growing body into the larger space, sealing the vacated chamber with a new septum; the camerae increase in number from around 4 at the moment of hatching to 30 or more in adults. The shell colouration keeps the animal c
The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods, the body whorl, or last whorl, is the most formed and largest whorl of a spiral or helical shell, terminating in the aperture, it is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is high, the aperture and the body whorl are large, the shell tends to be low spired; the shell of the abalone is a good example of this kind of shell. The opposite tendency can sometimes create a high spire with little whorl increase per revolution. In these instances, e.g. in the shell of Turritella species, both the body whorl and the aperture are small. In mollusc shells where there is no elevation at all to the spire, only moderate whorl expansion, the body whorl can sometimes still represent a large part of the shell, e.g. in some species in the family Planorbidae, such as the genus Segmentina.
The body chamber or living chamber in shelled cephalopod mollusks is an equivalent space, is sometimes called the body whorl. It is the last chamber in the shell of a nautiloid or ammonoid; the body of the animal occupies the living chamber, apart from the siphuncle which extends through the rest of the septa to provide buoyancy
The mollusc shell is a calcareous exoskeleton which encloses and protects the soft parts of an animal in the phylum Mollusca, which includes snails, tusk shells, several other classes. Not all shelled; the ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid and some smaller groups such as the caudofoveata and solenogastres, the derived Xenoturbella. Today, over 100,000 living species bear a shell. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, this is called conchology—although these terms used to be, to a minor extent still are, used interchangeably by scientists. Within some species of molluscs, there is a wide degree of variation in the exact shape, pattern and color of the shell. A mollusc shell is formed and maintained by a part of the anatomy called the mantle. Any injuries to or abnormal conditions of the mantle are reflected in the shape and form and color of the shell.
When the animal encounters harsh conditions that limit its food supply, or otherwise cause it to become dormant for a while, the mantle ceases to produce the shell substance. When conditions improve again and the mantle resumes its task, a "growth line" is produced; the mantle edge secretes a shell. The organic constituent is made up of polysaccharides and glycoproteins; this organic framework controls the formation of calcium carbonate crystals, dictates when and where crystals start and stop growing, how fast they expand. The shell formation requires certain biological machinery; the shell is deposited within a small compartment, the extrapallial space, sealed from the environment by the periostracum, a leathery outer layer around the rim of the shell, where growth occurs. This caps off the extrapallial space, bounded on its other surfaces by the existing shell and the mantle; the periostracum acts as a framework from which the outer layer of carbonate can be suspended, but in sealing the compartment, allows the accumulation of ions in concentrations sufficient for crystallization to occur.
The accumulation of ions is driven by ion pumps packed within the calcifying epithelium. Calcium ions are obtained from the organism's environment through the gills and epithelium, transported by the haemolymph to the calcifying epithelium, stored as granules within or in-between cells ready to be dissolved and pumped into the extrapallial space when they are required; the organic matrix forms the scaffold that directs crystallization, the deposition and rate of crystals is controlled by hormones produced by the mollusc. Because the extrapallial space is supersaturated, the matrix could be thought of as impeding, rather than encouraging, carbonate deposition. Nucleation is endoepithelial in Neopilina and Nautilus, but exoepithelial in the bivalves and gastropods; the formation of the shell involves a number of genes and transcription factors. On the whole, the transcription factors and signalling genes are conserved, but the proteins in the secretome are derived and evolving. Engrailed serves to demark the edge of the shell field.
In gastropod embryos, Hox1 is expressed. Perlucin increases the rate at which calcium carbonate precipitates to form a shell when in saturated seawater. Perlucin operates in association with Perlustrin, a smaller relative of lustrin A, a protein responsible for the elasticity of organic layers that makes nacre so resistant to cracking. Lustrin A bears remarkable structural similarity to the proteins involved in mineralization in diatoms – though diatoms use silica, not calcite, to form their tests! The shell-secreting area is differentiated early in embryonic development. An area of the ectoderm thickens invaginates to become a "shell gland"; the shape of this gland is tied to the form of the adult shell. The gland subsequently evaginates in molluscs. Whilst invaginated, a periostracum - which will form a scaffold for the developing shell - is formed around the opening of the invagination, allowing the deposition of the shell when the gland
A plait is an anatomical feature, present the shells of some snails, or gastropods. This sculpture occurs in the shells of marine gastropod mollusks in the clade Neogastropoda, but it is found in some pulmonate land snails. Plaits are folds on the columella at the center of the shell; the columella is the central structure around which the whorls of a coiled gastropod shell are coiled. The presence or absence of plaits, the number of plaits, are characteristics used in the description of many gastropod molluscs enabling similar species to be separated and identified correctly. Powell A W B, New Zealand Mollusca, William Collins Publishers Ltd, New Zealand 1979 ISBN 0-00-216906-1