Southern sawtail catshark facts for kids
Quick facts for kids Southern sawtail catshark |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Galeus
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| Species: |
mincaronei
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| Range of the southern sawtail catshark | |
The southern sawtail catshark (Galeus mincaronei) is a type of catshark. It belongs to the Scyliorhinidae family. This shark lives only in southern Brazil. It lives deep in the ocean, on reefs found on the upper part of the continental slope. This is usually between 236 and 600 meters (774 to 1,969 feet) deep.
This shark can grow to at least 43 centimeters (17 inches) long. It has a slim body and looks a lot like the Antilles catshark (G. antillensis). A special feature is a noticeable ridge of large, tough scales along the top edge of its tail fin. It also has a unique pattern of dark oval spots on its back, each outlined in white.
The southern sawtail catshark lays eggs. Females produce reddish egg capsules. The International Union for Conservation of Nature (IUCN) says this shark is a Vulnerable species. This means it is at risk. It often gets caught by accident when people are fishing for other things, like squid.
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About the Southern Sawtail Catshark
The first known southern sawtail catsharks were caught in 1988. They were found in special fish traps off the coast of Rio Grande do Sul, Brazil. At first, scientists thought they were Galeus antillensis.
But in 2001, a scientist named Jules Soto described it as a new species. He published his findings in the science magazine Mare Magnum. He named it after Michael Maia Mincarone. This was to honor Michael's help at the Museu Oceanográfico do Vale do Itajaí. The first official specimen studied was an adult male, about 40 centimeters (16 inches) long.
The southern sawtail catshark looks very similar to G. antillensis. Both are part of a group of similar sharks called the G. arae species complex. This group also includes G. arae, G. cadenati, and G. springeri. In 2006, scientists Getulio Rincon and Carolus Vooren found that this shark can vary a lot in its body shape. This made it harder to tell it apart from G. antillensis. They suggested more studies were needed to understand the differences between these two species.
Where It Lives and Its Home
The southern sawtail catshark is the only Galeus species found in the southwestern Atlantic Ocean. It lives off the southern Brazilian states of Rio Grande do Sul and Santa Catarina. It might even live as far north as São Paulo. Scientists believe its total home area is less than 20,000 square kilometers (7,700 square miles).
This shark has been found at depths between 236 and 600 meters (774 and 1,969 feet). However, it is most often seen below 400 meters (1,300 feet). It is a bottom-dwelling shark. It prefers deepwater reefs on the upper continental shelf. These reefs are rich in sea fans, hard corals, sponges, crinoids, and brittle stars.
What It Looks Like
The biggest southern sawtail catshark found was 43 centimeters (17 inches) long. This shark has a thin body. Its head is quite short and flat, with a pointy snout. Its eyes are shaped like horizontal ovals. They have small, protective third eyelids called nictitating membranes. Behind the eyes are tiny breathing holes called spiracles.
The front edges of its nostrils have triangular skin flaps. Its mouth is large and forms a wide arch. There are long, deep grooves around the corners of its mouth. Male sharks have a slightly longer, narrower mouth and bigger teeth than females. This shark has about 57 to 71 rows of teeth on its upper jaw. It has 56 to 63 rows on its lower jaw. Each tooth has a narrow main point. It also has one or two smaller points on each side. It has five pairs of gill slits. The fourth and fifth pairs are above the bases of its pectoral fins.
The first dorsal fin is above the back part of its pelvic fins. The second dorsal fin is above the back part of its anal fin. Both dorsal fins are small and have rounded tips. The first dorsal fin is a little smaller than the second. Its pectoral fins are fairly large with rounded corners. The pelvic fins are small and wide. Adult male sharks have short, thick claspers with hooks on the inside.
The base of the anal fin is between 11 and 14 percent of the shark's total length. This is longer than the space between the pelvic and anal fins. It can be longer or shorter than the space between the dorsal fins. The caudal fin (tail fin) is short. It has a small lower part and a notch near the tip of the upper part.
The shark's body is covered in small, overlapping scales called dermal denticles. Each scale has a ridge and three teeth on its back edge. A special saw-like crest of larger scales runs along the front half of the top edge of its tail fin. The top of the shark is reddish-brown. It has large oval spots along each side of its back. These spots are darker and outlined in white. They become less clear towards the tail. Its fins are dark, sometimes with lighter edges. Its underside is off-white. The inside of its mouth is blackish.
Life Cycle and Habits
The southern sawtail catshark shares its habitat with many freckled catsharks (Scyliorhinus haeckelii). This shark lays eggs, which means it is oviparous. Adult females have only one working ovary, on the right side. They have two working oviducts. Only one egg develops in an oviduct at a time.
The egg is inside a reddish, vase-shaped capsule. It is about 5 to 6 centimeters (2.0 to 2.4 inches) long and 4 centimeters (1.6 inches) wide. It has coiled tendrils at its four corners. Male sharks become ready to reproduce when they are 36 to 38 centimeters (14 to 15 inches) long. Females are ready when they are 35 to 39 centimeters (14 to 15 inches) long.
How Humans Affect Them
Many southern sawtail catsharks are caught by accident. This is called bycatch. They are caught on bottom longlines and in bottom trawls and traps. These are used by people fishing for goosefish and squid. We don't know exactly how many are caught, but it's a significant number.
Because this shark lives in a very small area, its population might be at risk. This is due to more and more squid fishing. The International Union for Conservation of Nature (IUCN) has therefore listed this species as Vulnerable.
