What is the function of the spiracle in dogfish shark?
Many sharks, especially bottom-dwelling species, have paired openings called spiracles located between the eye and the gill slits. Spiracles are used to take in water and ventilate the gills, even while the shark may be feeding or at rest on the bottom.
What are the characteristics of dogfish?
Spiny Dogfish. This long, slender dogfish has a pointed snout, large eyes, and spines in front of its two dorsal fins. It is a brownish slate color, fading to a pale underbelly, with rows of white spots down its upper body that fade with age.
Why is the dogfish important?
These sharp spines serve as a defense mechanism against the dogfish’s predators, such as sixgill sharks and seals. Dogfish are keystone predators, and ecologically important in their niche. Like many sharks, they have been historically misunderstood, as well as overfished.
What did the spiracle evolve from?
Spiracles likely evolved from gill openings. In primitive jawless fish, spiracles were simply the first gill openings behind the mouth. This gill opening eventually separated as the jaw evolved out of the structures between it and the other gill openings.
What is the largest of all fish?
The whale shark (Rhincodon typus) earns the name “whale” solely because of its size. Just as the blue whale (Balaenoptera musculus) is the largest living mammal*, the whale shark is the largest species of any fish, known to reach more than 40 feet in length.
What’s the meaning of Spiracle?
1 : a breathing hole : vent. 2 : a breathing orifice: such as. a : blowhole sense 2. b : an external tracheal aperture of a terrestrial arthropod that in an insect is usually one of a series of small apertures located along each side of the thorax and abdomen — see insect illustration.
Do dogfish sharks bite?
These “dogs” may not bite, but they sure can sting. On the leading edge of their dorsal spine is a big, white, needle-sharp spine, a formidable weapon capable of inflicting agonizing pain.
What’s the meaning of spiracle?
Who use spiracles to breathe?
Insects having spiracles allow air to move their tracheal system. Since insects don’t carry lungs, they use the tracheal system for breathing purposes. Moreover, insect open and close spiracles with the use of muscle contraction. During this process, oxygen molecules travel through the insect’s tracheal system.
Where are the spiracles located in a dogfish?
But in Dogfish (Scoliodon) the spiracles are vestigial pits in the pharynx with no lamellae and external branchial apertures. 1. Inspiration:
How does a dogfish shark bring water to its gills?
The shark can bring water into its pharynx to the gills by way of the spiracle and mouth. Urogenital Anatomy of the Dogfish Shark •Thekidneys are flattened, ribbon-like, darkly colored structures lying dorsally on either side of the midline, along the entire length of the body cavity.
Where is the spiracle located in a shark?
The spiracle is a vestigial first gill slit. It appears as an opening behind the eye, as in the spiny dogfish photo below. It is absent or reduced in many sharks, especially the fast swimming sharks and is usually larger and present in sedentary or bottom dwelling sharks.
How does the superficial constrictor in a dogfish shark work?
The superficial constrictor muscles act as flap-like valves to open and close the external gill slits. The specimen in the photographs was prepared by removing the skin and the ventral musculature over the pericardial cavity. A membrane was removed to expose the heart and some of its major blood vessels.