Platyrhina
Encyclopedia
Platyrhina is a genus
of rays
in the family
Platyrhinidae
, containing three species. They are native to the warm-temperate to tropical marine
waters in the western Pacific Ocean
. They are little-known bottom-dwellers that feed on small invertebrate
s such as crustacean
s, molluscs, and worm
s. The fanray is found inshore to a depth of 60 m on rocky or rock sand
y bottoms.
Platyrhina species have rounded heart-shaped pectoral fin discs with short, blunt snout
s. Their tails are long and shark
-like, slightly flattened with lateral ridges. The two dorsal fin
s and the caudal fin are large and rounded; the caudal fin lacks a lower lobe. The teeth are small and arranged in pavement-like rows for crushing shelled prey. Their bodies are covered with minute dermal denticles; there are also several rows of denticles inside the buccopharyngeal cavity
. The shape of these denticles in Platyrhina and the similar Platyrhinoidis distinguish them from all other guitarfish species. There are large thorns around the eyes and on the shoulders, and arranged in rows along the back and tail. Unlike Platyrhinoidis, Platyrhina species have an additional lateral row of thorns on both sides of the tail, and no rostral
thorns.
As far as known, they are ovoviviparous, with the developing fetus
es primarily sustained by large yolk sac
s. Research on fanrays in Ariake Bay, Japan, indicates that they are faster-growing, earlier-maturing, and shorter-lived than many other ray
species. Male fanrays mature at 2.1 years and females at 2.9 years; the females grow larger and more slowly than males. The maximum known age is 5 years for males and 12 years for females. These rays are typically inoffensive but care should be exercised regarding their large, sharp thorns.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of rays
Batoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Platyrhinidae
Platyrhinidae
Platyrhinidae is a family of rays in the order Myliobatiformes, commonly known as thornbacks due to their dorsal rows of large thorns. They resemble guitarfishes in shape, but are in fact more closely related to stingrays.-Genera and species:...
, containing three species. They are native to the warm-temperate to tropical marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
waters in the western Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. They are little-known bottom-dwellers that feed on small invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s such as crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, molluscs, and worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s. The fanray is found inshore to a depth of 60 m on rocky or rock sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y bottoms.
Platyrhina species have rounded heart-shaped pectoral fin discs with short, blunt snout
Snout
The snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
s. Their tails are long and shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
-like, slightly flattened with lateral ridges. The two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s and the caudal fin are large and rounded; the caudal fin lacks a lower lobe. The teeth are small and arranged in pavement-like rows for crushing shelled prey. Their bodies are covered with minute dermal denticles; there are also several rows of denticles inside the buccopharyngeal cavity
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
. The shape of these denticles in Platyrhina and the similar Platyrhinoidis distinguish them from all other guitarfish species. There are large thorns around the eyes and on the shoulders, and arranged in rows along the back and tail. Unlike Platyrhinoidis, Platyrhina species have an additional lateral row of thorns on both sides of the tail, and no rostral
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
thorns.
As far as known, they are ovoviviparous, with the developing fetus
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
es primarily sustained by large yolk sac
Yolk sac
The yolk sac is a membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals...
s. Research on fanrays in Ariake Bay, Japan, indicates that they are faster-growing, earlier-maturing, and shorter-lived than many other ray
Batoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
species. Male fanrays mature at 2.1 years and females at 2.9 years; the females grow larger and more slowly than males. The maximum known age is 5 years for males and 12 years for females. These rays are typically inoffensive but care should be exercised regarding their large, sharp thorns.
Species
- Platyrhina hyugaensis Iwatsuki, Miyamoto & Nakaya, 2011 (Hyuga fanray)
- Platyrhina sinensis (BlochMarcus Elieser BlochMarcus Elieser Bloch was a German medical doctor and naturalist. He is generally considered one of the most important ichthyologists of the 18th century.- Life :...
& J. G. SchneiderJohann Gottlob SchneiderJohann Gottlob Theaenus Schneider was a German classicist and naturalist.-Biography:Schneider was born at Collm in Saxony...
, 1801) (Fanray) - Platyrhina tangi Iwatsuki, J. Zhang & Nakaya, 2011 (Yellow-spotted fanray)