Nautilus shells are ancient creatures associated with squid and octopus and appeared in the ocean long before the first dinosaurs. This is known as “living fossils” because it remains relatively unchanged in the last 450 million years.
Nautilus lives in a beautiful spiral shell divided into greater space. When its first hatched from the egg, it had formed 4 rooms. When growing, it moved to the next biggest room in the shell and built a wall to close the old room.
Nautilus is known to exceed and build up to 30 rooms in their adult life. It is interesting to note that these rooms are not in vain, because nature does not waste anything – Nautilus keeping the inner space filled with gas to help control the buoyancy. When they want to dive, it adds water to the room.
Seeing the cross-section of the nautilus chamber in real life is the sight that must be seen. It is shaped like an elegant spiral and coated with bright pearls.
Anatomy of the nautilus shells
The anatomy of Nautilus follows the basic molluscan plan. However, because the Nautilus line diverges from the main cephalopod line (which then raises cephalopods current) so far in the past which is far from many modern nautilus anatomy features that are quite unique.
This includes, but is not limited to,
1) external difference;
- Clear shell.
- A number of tentacles.
- Tentacles don’t have suckers.
- Eye structure,
2) internal differences;
- Nautili has four gills (not two).
- They also have four (not two) ‘kidneys’.
- They don’t have an ink bag.
- They don’t have chromophores.
Visible from the side, the nautilus that lives can be seen as a circular shell with the largest part. The body parts that are seen are hoods, eyes, and various extending tentacles in the future. Judging from the front of the Nautilus body, the part of it looks outside the shell, it can be seen having a dorsal hood, hypernome ventral, two eyes, and mass of tentacles.
Dorsal hoods are difficult rough organs that evolved from tentacles and which closed the shell when the animal was completely drawn. The opposite is called Siphon and consists of two, the lobe that is not used, it is very flexible and is the nautilus of movement. The eyes are large and have many tentacles.
In the first space of the shell, the main visceral mass of the animal’s body is detained, and attached to the shell, with strong muscles on both sides of the body. The coat cavity is open to the sea, water flows in, and is pumped through hypernome. In Nautilus, the mantle cavity extends completely around the body. It’s the deepest ventrally (bottom part of the body) and shallow on the side (lateral); Dorsally (the top part of the body) is only about a third of the ventrally.
Gills (Ctenidia) are located at the bottom of the mantle cavity. In addition, the kidneys and ovaries have ducts open to the ventral space of the mantle cavity and digestive tract, like the anus, ending there.
While the most extinct cephalopods are fully shelled, Nautilus is the only cephalopods that live today, it is still growing, and living in shells. In the remaining majority of Cephalopods, the shell is internalized, reduced, and in many cases does not exist. The Shell of Nautilus is made of calcium carbonate form called Aragonite. It has two layers, the outer layer is white and the layer in the pearlescent gives a beautiful sheen
The nature of the Nautilus shell steps forward for its far nautiloid ancestors. It gives them buoyancy, the ability to rise in the water column. While we bring animals swimming on the surface of the seabed just like that, 500 million years ago it was radical innovation that gave the ancestors of Nautilus a big advantage over other predators at the time.
In modern Nautili, the shell can be divided into two parts. The front room, where the animal lives and has 99% of his body only called “living space ‘. The remaining space, which is sealed from each by the wall called’ Septa ‘is called collectively as’ phragmocone’. A small central hole exists In each Septa that crossed the ‘siphuncle’ animal. A siphuncle is a thin strap of nerves and blood vessels that stretch back through the spiral to the first room of the original cell.
Every phragmocone room was once a ‘living room’ of animals. When animals live grow and slowly enlarge the living space. Finally, it became too big and animals sealed from the back to make another room.
Buoyancy and movement
Just like Nautilus, submarines use a ballast tank to control their floating by filling them with air (to the surface) or water (to sink). Nautilus’s unique strategy uses osmosis gradients to move water and modulate floating can have applications for new types of underwater vehicles for transportation, supervision, and research. Smart buoys can also feel the traffic that comes in and soak until the boat cleared them.
Ecology Of Nautilus Shells
Apart from the historical resistance of the Nautilus species, it proved their survival through the five major mass extinctions, marine conservationists fear that they would not be tariffs and also through the sixth global extinction episode. The non-regulated and poorly managed shell harvest industry is thinning the Pacific population at a worry and consequential level, further worsening the biotic threat caused by excessive exploitation.
Their typical shells and patterned internationally as souvenirs, pieces of jewelry, and home décor items, to mention only a few uses. Because there is no evidence or an indication that Nautilus fishing is part of cultural practice or comes from historical relevance, it seems that the demand for these shells is excessive. While the destruction of habitat and climate change has been used as part of the construct argument to explain the decline in the nautilus population, the shell harvest industry, the most prominent in the Philippines and West Indonesia, has proven to be the most influential culprit.
