The finback catsharks are a small
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
, the Proscylliidae, of
ground shark
Ground may refer to:
Geology
* Land, the solid terrestrial surface of the Earth
* Soil, a mixture of clay, sand and organic matter present on the surface of the Earth
Electricity
* Ground (electricity), the reference point in an electrical circ ...
s.
They can be found in warm seas worldwide and are often the most numerous and common shark in tropical regions. They are generally less than 1 m in length, and are slow-moving predators that feed on bony fish and small invertebrates. Although some bear live young, the majority lay eggs with almost fully developed young; these egg cases, known as
"mermaid's purses", are unique in appearance to each species.
Taxonomy
Genus ''
Proscyllium
The genus ''Proscyllium'' is a small genus of finback catsharks in the family Proscylliidae.
Species
* '' Proscyllium habereri'' Hilgendorf, 1904 (graceful catshark)
* '' Proscyllium magnificum'' Last
A last is a mechanical form shaped ...
''
Hilgendorf 1904
*
Graceful catshark
The graceful catshark (''Proscyllium habereri'') is a species of finback catshark, belonging to the family Proscylliidae. This shark is found in the western Pacific Ocean, from southeastern Japan to Vietnam and northwestern Java
Java is one ...
(''Proscyllium habereri'') was first discovered by Hildendorf in 1901.
* ''
Proscyllium venustum
The spotted smooth dogfish (''Proscyllium venustum'') is a finback catshark of the family Proscylliidae, found in the temperate northwest Pacific Ocean, in the Okinawa Trough. Little else is known about this harmless oviparous
Oviparous anim ...
'' is found in temperate regions. It is distributed along the Northwest Pacific, primarily Japan. These sharks are oviparous; they lay eggs in pairs in which the embryos feed solely on yolk. This species is considered harmless to humans.
*
Magnificent catshark
The magnificent catshark or clown catshark (''Proscyllium magnificum'') is a species of finback catshark, belonging to the family Proscylliidae, known only from five specimens collected in the northern Andaman Sea near the edge of the Myanmar con ...
(''Proscyllium magnificum'') A newly discovered species within the family Proscyllidae, it has little supporting research. It is tan in coloration with dark spots and blotches.
The body is considered slender and firm. This species grows to be at least 450 mm in length. They have been found in tropical waters throughout the eastern Indian Ocean off the coast of Myanmar.
Genus ''
Eridacnis
The genus ''Eridacnis'', the ribbontail catsharks, is a small genus of fin-back catsharks in the family Proscylliidae. It currently consists of the following species:
* '' Eridacnis barbouri'' ( Bigelow & Schroeder, 1944) (Cuban ribbontail cats ...
''
H. M. Smith, 1913
*
Pygmy ribbontail catshark
The pygmy ribbontail catshark (''Eridacnis radcliffei'') is a species of finback catshark, family Proscylliidae, distributed patchily in the western Indo-Pacific from Tanzania to the Philippines. It occurs around the edges of continental and i ...
(''Eridacnis radcliffei'')
It is known to be one of the smallest sharks within its species, with a maximum length around 257 mm. It is distributed in the waters surrounding the Philippines, along with the Indo-West Pacific Ocean. They are found located near muddy bottoms of the continental shelves. It is not a species directly targeted by the fishing industry; however, it is negatively impacted as bycatch by the shrimping industry due to shrimp being its primary food source. They are considered harmless to humans.
*
Cuban ribbontail catshark
The Cuban ribbontail catshark (''Eridacnis barbouri''), is a finback catshark of the family Proscylliidae, found off western central Atlantic Ocean at depths of between 430 and 613 m. It can grow up to a length of 34 cm.
The Cuban rib ...
(''Eridacnis barbouri''), can be found in deep water along the upper continental shelf. They are distributed throughout the western central Atlantic. Their primary food source is small fishes, crustaceans, and cephalopods. Having two young per litter, ranging in size at birth to over 10 cm, this species is ovoviviparous. This species is viewed as harmless to humans.
*
African ribbontail catshark
The African ribbontail catshark, ''Eridacnis sinuans'', is a finback catshark of the family Proscylliidae, found in the western Indian Ocean, from Tanzania, South Africa, and Mozambique, at depths between 180 and 480 m. It can grow up to a l ...
(''Eridacnis sinuans''), is grey-brown in color. They are distributed within the western Indian Ocean, but confined to the South Africa, Mozambique, and Tanzania. This species is primarily found along the upper continental shelf in deep water. This species feeds on small bony fishes, crustaceans, and cephalopods. Their ovoviviparous reproductive system allows them to have two young per litter between 15 and 17 cm in length when born. This species is also considered harmless to humans.
Genus '' Ctenacis'' Compagno, 1973
The
harlequin catshark (''Ctenacis fehlmanni'') has some unique characteristics that set it aside from the others. Its large mouth, small teeth and large pharynx with
gill raker papillae make it unique among the family Proscyllidae. They are found in the tropical outer continental shelves of the western Indian Ocean, off the coast of Somalia, feeding on very small invertebrates.
They are oviparous, laying paired eggs in which their embryos feed solely on yolk.
Distribution
Found primarily along the continental shelves, these species are scattered throughout the world. They have been documented and seen primarily in: Japan,
Myanmar,
the Philippines,
South Africa, Mozambique, Tanzania,
and Somalia.
Lifecycle
Reproduction
Within this family, species are either oviparous or ovoviviparous.
Oviparous
Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...
refers to many benthic sharks that lay their eggs on the seafloor and attach them to a substrate. The eggs have a hard and leathery shell surrounding them to serve as protection. The eggs feed solely on the yolk present within the casing. Other species within this family are
ovoviviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...
. Ovoviviparous sharks give birth to live young.
Human interactions
This family of small ground sharks is not targeted by humans for any fishing or food purposes. Although not endangered or threatened, these species are negatively impacted by fisheries as a result of bycatch. The shrimping industry has affected them the most.
References
{{Taxonbar, from=Q334892
Carcharhiniformes
Shark families
Taxa named by Leonard Compagno