Groovebelly stingray
Encyclopedia
The groovebelly stingray, Dasyatis hypostigma, called the butter stingray by fishery
workers, is a species
of stingray
in the family
Dasyatidae. It is found over sandy or muddy bottoms in shallow coastal waters off southern Brazil
, and probably Uruguay
and Argentina
. The groovebelly stingray can be distinguished by a prominent "W"-shaped furrow on its underside behind the last pair of gill slit
s, as well as completely smooth skin in all but the largest individuals. It reaches a maximum known width of 65 cm (25.6 in). This species is aplacental viviparous, with one observed female gestating two young. The International Union for Conservation of Nature (IUCN) does not yet have enough data to assess the conservation status of the groovebelly stingray; the main threat to its population is likely bycatch
mortality from shrimp
trawlers, although habitat degradation is also a concern.
Article 24.2). The type specimen is a 76 cm (29.9 in) long adult male trawled from off the Brazilian state of Paraná
. Prior to its description, the groovebelly stingray specimens caught off Brazil have been misidentified as either the bluntnose stingray
(D. say) or the common stingray
(D. pastinaca), neither of which in fact occur in the region.
to Rio Grande do Sul
, though it likely occurs as far north as Bahia
and as far south as Mar del Plata
, Argentina
. It inhabits inshore waters at depths of 5–40 m (16.4–131.2 ft), though it has been reported from as far down as 80 m (262.5 ft). This benthic species favors sandy or muddy substrates, and may also enter estuaries.
s. There is a flap of skin between the nares with rounded corners and a fringed posterior margin. The mouth is small and the lower jaw is strongly bow-shaped. There are 37–46 upper and 43–50 lower tooth rows, with a quincunx
arrangement. The teeth are blunt in juveniles and females, while in adult males the central teeth are slender and sharp. Adults have 3, 5, or 7 papilla
e in a row across the floor of the mouth. There is a distinctive "W"-shaped furrow on the underside behind the fifth pair of gill slit
s; only one other stingray, the pitted stingray
(D. matsubarai), shares this feature.
The pelvic fins are pointed with slightly curving trailing margins, and extend just past the disk margin. The whip-like tail measures up to around one and a half times the disk length, with 1 (occasionally 2) serrated stinging spine positioned on top past the first third of the tail. There are fin folds running along the dorsal and ventral sides of the tail behind the spine; the upper fold is fleshier and less than half as long as the lower fold. In most individuals the skin is completely smooth, which distinguishes this species from the pitted stingray (which has spines on the back and tail); in the largest known female specimen, tiny denticles are scattered atop the disk around the tail base. The dorsal coloration is yellowish to greenish brown above, becoming more reddish towards the disk margins. The underside is white with dark fin margins, while the tail fin folds are black. This species attains a width of 65 cm (25.6 in).
s hatch inside the mother's uterus
and are sustained by yolk, later supplemented by histotroph ("uterine milk") delivered by the mother into the embryos' spiracles via trophonemata (villi-like structures). Females have a single functional uterus (on the left). The only pregnant female thus far examined contained two embryos 55 millimetre long, which were in an early stage of development.
by artisanal
and commercial
shrimp bottom trawlers, mainly off Rio Grande do Sul, Santa Catarina
, Paraná, São Paulo
and Rio de Janeiro
states. This species may also be negatively affected by habitat degradation from coastal development, and water pollution
. However, there is presently insufficient information for the International Union for Conservation of Nature (IUCN) to assess its conservation status beyond Data Deficient
.
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
workers, is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stingray
Stingray
The stingrays are a group of rays, which are cartilaginous fishes related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes, and consist of eight families: Hexatrygonidae , Plesiobatidae , Urolophidae , Urotrygonidae , Dasyatidae , Potamotrygonidae The...
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...
Dasyatidae. It is found over sandy or muddy bottoms in shallow coastal waters off southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, and probably Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
and Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. The groovebelly stingray can be distinguished by a prominent "W"-shaped furrow on its underside behind the last pair of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s, as well as completely smooth skin in all but the largest individuals. It reaches a maximum known width of 65 cm (25.6 in). This species is aplacental viviparous, with one observed female gestating two young. The International Union for Conservation of Nature (IUCN) does not yet have enough data to assess the conservation status of the groovebelly stingray; the main threat to its population is likely bycatch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
mortality from shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
trawlers, although habitat degradation is also a concern.
Taxonomy
Hugo Santos and Marcelo de Carvalho formally described the groovebelly stingray in a 2004 volume of Boletim do Museu Nacional, giving it the name Dasyatis hypostigma, from the Greek hypo ("ventral") and stigma ("mark"). The original publication sometimes used the spelling hipostigma, which was subsequently struck as incorrect by the authors, under the Principle of the First Reviser (International Code of Zoological NomenclatureInternational Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
Article 24.2). The type specimen is a 76 cm (29.9 in) long adult male trawled from off the Brazilian state of Paraná
Paraná (state)
Paraná is one of the states of Brazil, located in the South of the country, bordered on the north by São Paulo state, on the east by the Atlantic Ocean, on the south by Santa Catarina state and the Misiones Province of Argentina, and on the west by Mato Grosso do Sul and the republic of Paraguay,...
. Prior to its description, the groovebelly stingray specimens caught off Brazil have been misidentified as either the bluntnose stingray
Bluntnose stingray
The bluntnose stingray or Say's stingray is a species of stingray in the family Dasyatidae, native to the coastal waters of the western Atlantic Ocean from the U.S. state of Massachusetts to Venezuela. It is a bottom-dwelling species that prefers sandy or muddy habitats deep, and is migratory in...
(D. say) or the common stingray
Common stingray
The common stingray is a species of stingray in the family Dasyatidae, found in the northeastern Atlantic Ocean and the Mediterranean and Black Seas. It typically inhabits sandy or muddy habitats in coastal waters shallower than , often burying itself in sediment...
(D. pastinaca), neither of which in fact occur in the region.
Distribution and habitat
The groovebelly stingray is found along the coast of southern Brazil from Espírito SantoEspírito Santo
Espírito Santo is one of the states of southeastern Brazil, often referred to by the abbreviation "ES". Its capital is Vitória and the largest city is Vila Velha. The name of the state means literally "holy spirit" after the Holy Ghost of Christianity...
to Rio Grande do Sul
Rio Grande do Sul
Rio Grande do Sul is the southernmost state in Brazil, and the state with the fifth highest Human Development Index in the country. In this state is located the southernmost city in the country, Chuí, on the border with Uruguay. In the region of Bento Gonçalves and Caxias do Sul, the largest wine...
, though it likely occurs as far north as Bahia
Bahia
Bahia is one of the 26 states of Brazil, and is located in the northeastern part of the country on the Atlantic coast. It is the fourth most populous Brazilian state after São Paulo, Minas Gerais and Rio de Janeiro, and the fifth-largest in size...
and as far south as Mar del Plata
Mar del Plata
Mar del Plata is an Argentine city located on the coast of the Atlantic Ocean, south of Buenos Aires. Mar del Plata is the second largest city of Buenos Aires Province. The name "Mar del Plata" had apparently the sense of "sea of the Río de la Plata region" or "adjoining sea to the Río de la Plata"...
, Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. It inhabits inshore waters at depths of 5–40 m (16.4–131.2 ft), though it has been reported from as far down as 80 m (262.5 ft). This benthic species favors sandy or muddy substrates, and may also enter estuaries.
Description
The groovebelly stingray has a diamond-shaped pectoral fin disk slightly wider than long, with nearly straight front margins and a barely projecting snout tip. The eyes are large and protruding, and are immediately followed by wide, angular spiracleSpiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s. There is a flap of skin between the nares with rounded corners and a fringed posterior margin. The mouth is small and the lower jaw is strongly bow-shaped. There are 37–46 upper and 43–50 lower tooth rows, with a quincunx
Quincunx
A quincunx is a geometric pattern consisting of five points arranged in a cross, that is five coplanar points, four of them forming a square or rectangle and a fifth at its center...
arrangement. The teeth are blunt in juveniles and females, while in adult males the central teeth are slender and sharp. Adults have 3, 5, or 7 papilla
Papilla (fish mouth structure)
The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...
e in a row across the floor of the mouth. There is a distinctive "W"-shaped furrow on the underside behind the fifth pair of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s; only one other stingray, the pitted stingray
Pitted stingray
The pitted stingray is a species of stingray in the family Dasyatidae, endemic to the waters around Japan and the Sea of Japan. It typically found near the coast at depths of , but may also venture into the open sea. Measuring up to across, the pitted stingray has a diamond-shaped pectoral fin...
(D. matsubarai), shares this feature.
The pelvic fins are pointed with slightly curving trailing margins, and extend just past the disk margin. The whip-like tail measures up to around one and a half times the disk length, with 1 (occasionally 2) serrated stinging spine positioned on top past the first third of the tail. There are fin folds running along the dorsal and ventral sides of the tail behind the spine; the upper fold is fleshier and less than half as long as the lower fold. In most individuals the skin is completely smooth, which distinguishes this species from the pitted stingray (which has spines on the back and tail); in the largest known female specimen, tiny denticles are scattered atop the disk around the tail base. The dorsal coloration is yellowish to greenish brown above, becoming more reddish towards the disk margins. The underside is white with dark fin margins, while the tail fin folds are black. This species attains a width of 65 cm (25.6 in).
Biology and ecology
Older biological information available on the groovebelly stingray is confounded by its historical confusion with other species. Like other stingrays, the groovebelly stingray is aplacental viviparous: the embryoEmbryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s hatch inside the mother's uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
and are sustained by yolk, later supplemented by histotroph ("uterine milk") delivered by the mother into the embryos' spiracles via trophonemata (villi-like structures). Females have a single functional uterus (on the left). The only pregnant female thus far examined contained two embryos 55 millimetre long, which were in an early stage of development.
Human interactions
The groovebelly stingray is one of the most common stingrays caught unintentionallyBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
by artisanal
Artisan fishing
Artisan fishing is a term used to describe small scale low-technology commercial or subsistence fishing practices. The term particularly applies to coastal or island ethnic groups using traditional techniques such as rod and tackle, arrows and harpoons, throw nets and drag nets, and traditional...
and commercial
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
shrimp bottom trawlers, mainly off Rio Grande do Sul, Santa Catarina
Santa Catarina (state)
Santa Catarina is a state in southern Brazil with one of the highest standards of living in Latin America. Its capital is Florianópolis, which mostly lies on the Santa Catarina Island. Neighbouring states are Rio Grande do Sul to the south and Paraná to the north. It is bounded on the east by...
, Paraná, São Paulo
São Paulo (state)
São Paulo is a state in Brazil. It is the major industrial and economic powerhouse of the Brazilian economy. Named after Saint Paul, São Paulo has the largest population, industrial complex, and economic production in the country. It is the richest state in Brazil...
and Rio de Janeiro
Rio de Janeiro (state)
Rio de Janeiro is one of the 27 states of Brazil.Rio de Janeiro has the second largest economy of Brazil behind only São Paulo state.The state of Rio de Janeiro is located within the Brazilian geopolitical region classified as the Southeast...
states. This species may also be negatively affected by habitat degradation from coastal development, and water pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
. However, there is presently insufficient information for the International Union for Conservation of Nature (IUCN) to assess its conservation status beyond Data Deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
.