Indonesian angelshark facts for kids
Quick facts for kids Indonesian angelshark |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Squatina
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| Species: |
legnota
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| Range of the Indonesian angelshark | |
The Indonesian angelshark (Squatina legnota) is a very rare type of angelshark. It belongs to the family called Squatinidae. Scientists only know about this shark from a few sharks found at fishing spots in southern Indonesia.
This shark is thought to live in the deep parts of the ocean, along the continental slope. It can grow to be at least 1.34 meters (about 4.4 feet) long. It has a flat body, much like a ray, and a strong tail. The shark's nose whiskers (called barbels) do not have fringes. Also, it does not have thorns along its back. Its body is mostly grayish-brown. It has dark spots under its dorsal fins. The front edge of its belly fins (called pectoral fins) is black.
The International Union for Conservation of Nature (IUCN) says this shark is Critically Endangered. This means it is at a very high risk of disappearing forever. This is mainly because of a lot of fishing in its habitat.
Contents
Discovering the Indonesian Angelshark
Scientists Peter Last and William White first described the Indonesian angelshark. They were researchers from the Commonwealth Scientific and Industrial Research Organisation (CSIRO). They wrote about it in a science magazine called Zootoxa in 2008.
They found the sharks at places where fish are brought ashore in Indonesia. One of the sharks was a female, about 47 centimeters (18.5 inches) long. It was found in Cilacap, central Java. This shark became the main example, or holotype, for the species.
The shark's scientific name, legnota, comes from a Greek word. It means "having a colored border." This name refers to the dark edges on its pectoral fins.
Family Tree of Angelsharks
In 2010, scientists Björn Stelbrink and his team studied the shark's mitochondrial DNA. They found that the Taiwan angelshark (S. formosa) is the closest relative to the Indonesian angelshark. These two sharks are genetically very similar.
They also found that these two sharks are related to the Japanese angelshark (S. japonica) and the ocellated angelshark (S. tergocellatoides). All these angelshark species live in Asia.
Where the Indonesian Angelshark Lives
The Indonesian angelshark has only been found in a few places. These include fish landing sites in Palabuhanratu in West Java, Cilacap in Central Java, Kedonganan in Bali, and Tanjung Luar in Lombok. All these places are in Indonesia.
Because of this, scientists don't know exactly where it lives in the wild. However, they believe it is a bottom-dwelling shark. This means it lives on the seafloor. It probably prefers the deeper parts of the continental slope.
What the Indonesian Angelshark Looks Like
The biggest Indonesian angelshark ever found was 1.34 meters (about 4.4 feet) long. Like all angel sharks, it has a very flat body. Its pectoral fins (the ones on its belly) and pelvic fins (near its tail) are very large.
Its head is wide and flat, with a short, blunt snout. Its eyes are small and set wide apart, slightly on top of its head. Behind its eyes are much larger, crescent-shaped holes called spiracles. These help it breathe.
The shark's nostrils are big. They have skin flaps that reach its mouth. Each flap has two clear barbels (whiskers) that are smooth. Its mouth is wide and gently curved, located at the front of its head. It has long grooves from the corners of its mouth.
The shark has about 18 rows of teeth in both its upper and lower jaws. Each tooth is small and sharp, like a tiny dagger. It has five pairs of long gill slits on the sides of its head.
Fins and Skin
The pectoral fins are angled. Their front parts are not attached to the head. The tips of these fins form an angle of just under 120 degrees. The tips of the pelvic fins are rounded. Male sharks have thick claspers, which are used for reproduction.
The two dorsal fins (on its back) are similar in shape and size. They have rounded or angled tips. The first dorsal fin starts above the back tips of the pelvic fins. The second dorsal fin is close to the first. This shark does not have an anal fin.
Its tail is quite long. The part before the tail fin, called the caudal peduncle, is a bit flat. It also has ridges, or keels, on its sides. The lower part of its short, triangular caudal fin is bigger than the upper part. The upper part has a small notch.
The shark's top surface is covered in small, cone-shaped dermal denticles. These are like tiny teeth on its skin. The shark is grayish-brown on top. It gets darker around its eyes and snout. The edges of its fins are see-through. It has blackish saddle-like marks under its dorsal fins. Sometimes, it also has large, dark spots or "eyespots" scattered over its back. Its underside is almost completely white. The front edge of its pectoral fins is black.
Life Cycle and Habits
Scientists do not know much about the daily life of the Indonesian angelshark. Like other angel sharks, it is believed to be aplacental viviparous. This means the mother carries the eggs inside her body. The young hatch inside her and then are born live. They do not get food directly from the mother through a placenta.
The smallest adult male shark found was 1.25 meters (about 4.1 feet) long.
Why the Indonesian Angelshark is Endangered
The Indonesian angelshark is sometimes caught by accident. This happens when fishermen use demersal longlines to catch other fish. When caught, it is sold for its meat and fins.
Currently, deepwater fishing in Indonesia is not very widespread. However, if this type of fishing grows, the Indonesian angelshark could be in serious trouble. Other angel shark species have been greatly reduced by fishing.
As of 2020, the IUCN has listed the Indonesian angelshark as Critically Endangered. This means it faces a very high risk of becoming extinct in the wild.
