What Structure Is Unique To Dogfish?

A feature peculiar to our specimen, the spiny dogfish, is the presence of two spines, one immediately anterior to each dorsal fin. When captured, these sharks will arch their backs and attempt to pierce their captor with these long sharp spines.

What type of body shape does a dogfish have?

The spiny dogfish has a slender, elongate body and a moderately flattened head. The snout is narrow, tapering to a pointed tip. The eyes of this dogfish are moderately large.

What external structures can be used to determine the gender of a dogfish?

Examine the pelvic fins to determine its sex. A male has a long, rigid structure called a clasper on the inside edge of each pelvic fin. The clasper is inserted into the female’s cloaca to transfer sperm during reproduction. Locate the cloaca between the pelvic fins.

What are the characteristics of a dogfish shark?

Spiny dogfish are slim, with a narrow, pointed snout and characteristic white spots. They are gray above and white below. They have two dorsal fins with ungrooved large spines. Males grow up to 3.3 feet, and females grow up to 4 feet.

What is the structure that a baby dogfish shark is attached to?

Fertilization in the dogfish shark is internal, usually taking place within the shell gland of the oviduct. The fertilized eggs continue to move posteriorly to the uterus. As they grow the pups are attached to the egg, now known as the yolk sac, by means of a stalk.

Is dogfish a bony fish?

Cartilaginous fishes are jawed fish with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone. Shark fish are called dogfish because they travel and hunt in packs. Shark is a cartilaginous fish. Thus, the correct answer is option A.

What sensory organs do dogfish sharks have and what are their functions?

The patches of pores on the head in the areas of the eyes, snout, and nostrils are the openings of the ampullae of Lorenzini. These sense organs are sensitive to changes in temperature, water pressure, electrical fields, and salinity.

How does the external anatomy of a male shark differ from a female?

Male sharks tend to be smaller than females. But the easiest way to tell them apart is to look for claspers. Males have a pair of claspers, which are used for mating. This is like a pair of extra roll-up fins under their body.

What have you learned about the dogfish shark in terms of physical characteristics?

The spiny dogfish shark is a small shark that is deep gray with some white spots; the belly is off-white. It had two dorsal fins, each preceded by a mildly poisonous spin. It has a short snout, large eyes and no anal fin. The smooth teeth are located in rows which rotate into use as needed.

How many gill slits does a dogfish have?

five gill slits
Gas exchange also takes place in the skin, but primarily in the gills. Look at the diagrams and follow in your shark the passage of water in the mouth and spiracles (which have a one way valve) and through the five gill slits. The gill slits close and the pharyngeal chamber expands to suck in water.

What kind of symmetry does dogfish shark have?

Radial symmetry. How does a sea star feed?

Why is it called a dogfish?

The name “dogfish” stems from their habit of feeding in packs — sometimes numbering in the hundreds or thousands. Gathered together, they sweep an area, eating the fishes in front of them. They’ll eat almost anything they can get their strong jaws and teeth on.

What type of teeth do dogfish sharks have?

Dentition of the smooth dogfish differs greatly from other sharks which have sharp blade-like teeth. The small teeth of the smooth dogfish are flat and blunt, similar in both the upper and lower jaws. They are asymmetrical with a rounded apex or cusp.

What is the structure of a shark?

Shark skeletons are made of cartilage. This is strong and durable, yet much more flexible and lighter than bone. Being lighter helps a shark to stay afloat and reduces the amount of energy they need to move about. The flexibility of cartilage also allows them to make tight turns quickly.

Do sharks pee?

Sharks urinate continuously
Their urine is actually absorbed by their flesh, where the urea is used to keep their scale-like dermal denticles nice and moist. The rest is simply expelled back into the water through their ‘skin’.

Do dogfish have large intestines?

The straight stomach has internal rugae and ends with a muscular pyloric sphincter. The small intestine is the duodenum anteriorly, and then a long coiled portion with internal small folds called plicae, which increase the surface area. There is a short large intestine, which enters the cloaca via the anus.

Is dog fish bony or cartilaginous?

cartilaginous fish
dogfish A cartilaginous fish, Scilliorinus caniculum, or Squalis acanthias, a small shark; sometimes called rock salmon or rock eel.

What are the key distinguishing features between the bony fish and the cartilaginous fish?

However, the most obvious disparity between the two types of fish is the composition of their skeleton. As the name suggests, “bony fish” have a skeleton composed of only bones while a cartilaginous fish has a skeleton made entirely of cartilage.

What is the difference between cartilaginous and bony fish?

Both types of fish have an endoskeleton. The main difference between bony fish and cartilaginous fish is that bony fish have an endoskeleton completely made up of bones whereas cartilaginous fish have an endoskeleton primarily made up of cartilages.

What special abilities do sharks have?

Read on to discover five weird and wonderful shark powers that would put Superman to shame.

• Superpower #5: Super sensitivity to electricity.
• Superpower #4: Highly accurate long-distance navigation.
• Superpower #3: Sperm storage and virgin births.
• Superpower #2: Ninja-like stealth.

Do dogfish have good eyesight?

The fact that its refractive index is high (1.66) suggests that the static optical system of this eye is very similar to that of the teleosts.