Longtail stingray
Encyclopedia
The longtail stingray (Dasyatis longa, often misspelled longus), is a species
of stingray
in the family
Dasyatidae, found in the eastern Pacific Ocean
from Baja California
to Colombia
. It inhabits sandy habitat
s down to a depth of 90 m (295.3 ft). Measuring up to 1.56 m (5.1 ft) across, this species has a rhomboid
pectoral fin disc, a lower (but not upper) fin fold on the tail, and numerous dermal denticles along the back and behind the stinging spine. The longtail stingray feeds mainly on bottom-dwelling bony fishes and crustacean
s. It is aplacental viviparous, with females giving birth to 1–5 young in late summer. At present, the International Union for Conservation of Nature (IUCN) is unable to assess this species beyond Data Deficient
. It is caught for food, likely throughout its range, but specific fishery data is lacking.
Bulletin of the Museum of Comparative Zoology. He gave it the name Trygon longa, in reference to the long tail, and designated a specimen from Acapulco
, Mexico
and another from Panama
as the syntype
s. Subsequent authors placed this species in the genus
Dasyatis
. A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphological
characters, found that the southern stingray
(D. americana) of the western Atlantic is the sister species of the longtail stingray. These two species may have evolutionarily diverged
with the formation of the Isthmus of Panama
(c. 3 Ma).
, from central Baja California
(though it may occur as far north as San Diego, California
) to Colombia
, including the Revillagigedo
and Galapagos Islands
. This species inhabits sandy or muddy flats to a depth of 90 m (295.3 ft), often near rocky or coral reef
s, or in estuaries. In the Galapagos, it was reportedly abundant in the shallow lagoon
s of mangrove swamps at Fernandina Island
.
e across the floor of the mouth; the two on the sides are smaller than the others. The pelvic fins are rounded. The whip-like tail bears a stinging spine and measures more than twice as long as the disc. Behind the spine, the tail becomes laterally compressed with a low keel above and a short, narrow fin fold below.
There is a row of pointed tubercles running along the midline of the back from between the "shoulders" to the base of the tail. Two much shorter rows of smaller tubercles, slightly converging backward, are found alongside the central row behind the shoulders. Numerous small dermal denticles are also found between the eyes and on the tail behind the spine. The dorsal coloration varies from plain reddish-brown to dark gray, and the underside is light. The extent of denticle coverage and number of oral papillae can vary among individuals. The longtail stingray closely resembles the diamond stingray
(D. dipterura), which is found in the same region, but can be distinguished by its lack of an upper tail fold. The length of the tail is not a reliable diagnostic character for this species, as it is frequently damaged.
s, in particular stomatopods, decapods
, and molluscs. Known parasites of this species include the tapeworms Acanthobothrium cimari, A. cleofanus, A. costarricense, A. puntarenasense, and A. vargasi, Anthocephalum lukei and A. michaeli, Parachristianella dimegacantha, Pseudochristianella elegantissima and P. nudiscula, and Pterobothrioides carvajali, and the monogenea
n Listrocephalos whittingtoni. Like other stingrays, the longtail stingray is aplacental viviparous with the developing embryo
s sustained initially by yolk and later by histotroph ("uterine milk") produced by the mother. Adult females have a single functional ovary
. Near-term females appear to swim into shallow estuaries and tidal creeks to give birth, following a gestation period
of 10–11 months, and may mate again immediately after. A litter contains 1–5 young, each measuring about 40 cm (15.7 in) across. Males mature sexually
at 0.8 m (2.6 ft) across, and females at 1.1 m (3.6 ft) across.
; it is caught by bottom trawls and longlines, and is especially susceptible to gillnet
s as its tail spine easily becomes entangled in the mesh. The impact of fishing on its population is unknown, as fishery landings in the region are poorly monitored and the longtail stingray is not reported separately from other ray species. As a result, the International Union for Conservation of Nature (IUCN) has listed this species as Data Deficient
, while noting that its slow reproductive rate would limit its capacity to recover from over-exploitation.
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, found in the eastern 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...
from Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
to Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. It inhabits sandy habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s down to a depth of 90 m (295.3 ft). Measuring up to 1.56 m (5.1 ft) across, this species has a rhomboid
Rhomboid
Traditionally, in two-dimensional geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are oblique.A parallelogram with sides of equal length is a rhombus but not a rhomboid....
pectoral fin disc, a lower (but not upper) fin fold on the tail, and numerous dermal denticles along the back and behind the stinging spine. The longtail stingray feeds mainly on bottom-dwelling bony fishes and 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. It is aplacental viviparous, with females giving birth to 1–5 young in late summer. At present, the International Union for Conservation of Nature (IUCN) is unable to assess this species 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...
. It is caught for food, likely throughout its range, but specific fishery data is lacking.
Taxonomy and phylogeny
American zoologist Samuel Garman published the original description of the longtail stingray in an 1880 issue of the scientific journalScientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
Bulletin of the Museum of Comparative Zoology. He gave it the name Trygon longa, in reference to the long tail, and designated a specimen from Acapulco
Acapulco
Acapulco is a city, municipality and major sea port in the state of Guerrero on the Pacific coast of Mexico, southwest from Mexico City. Acapulco is located on a deep, semi-circular bay and has been a port since the early colonial period of Mexico’s history...
, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and another from Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
as the syntype
Syntype
In biological nomenclature, a syntype is a term used to indicate a specimen with a special status.In zoological nomenclature, a syntype is defined as "Each specimen of a type series from which neither a holotype nor a lectotype has been designated [Arts. 72.1.2, 73.2, 74]. The syntypes...
s. Subsequent authors placed this species in the genus
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...
Dasyatis
Dasyatis
Dasyatis is a genus of stingray. The members of the genus Neotrygon were formerly included in Dasyatis.-Species:...
. A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
characters, found that the southern stingray
Southern stingray
The southern stingray, Dasyatis americana, is a stingray of the family Dasyatidae found in tropical and subtropical waters of the Western Atlantic Ocean from New Jersey to Brazil. It has a flat, diamond-shaped disc, with a mud brown, olive, and grey dorsal surface and white underbelly...
(D. americana) of the western Atlantic is the sister species of the longtail stingray. These two species may have evolutionarily diverged
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...
with the formation of the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...
(c. 3 Ma).
Distribution and habitat
The longtail stingray is found along the tropical Pacific coast of the AmericasAmericas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
, from central Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
(though it may occur as far north as San Diego, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
) to Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, including the Revillagigedo
Revillagigedo Islands
The Revillagigedo Islands or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem...
and Galapagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
. This species inhabits sandy or muddy flats to a depth of 90 m (295.3 ft), often near rocky or coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s, or in estuaries. In the Galapagos, it was reportedly abundant in the shallow lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s of mangrove swamps at Fernandina Island
Fernandina Island
Fernandina Island is the third largest, and youngest, island of the Galápagos Islands. Like the others, the island was formed by the Galápagos hotspot...
.
Description
The longtail stingray reaches a maximum known disc width of 1.58 m (5.2 ft), length of 2.57 m (8.4 ft), and weight of 46.4 kg (102.3 lb). It has a diamond-shaped pectoral fin disc about a sixth wider than long, with the outer corners broadly rounded. The front margins are nearly straight, meeting the tip of the snout at a blunt angle. There is a row of five papillaPapilla (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 across the floor of the mouth; the two on the sides are smaller than the others. The pelvic fins are rounded. The whip-like tail bears a stinging spine and measures more than twice as long as the disc. Behind the spine, the tail becomes laterally compressed with a low keel above and a short, narrow fin fold below.
There is a row of pointed tubercles running along the midline of the back from between the "shoulders" to the base of the tail. Two much shorter rows of smaller tubercles, slightly converging backward, are found alongside the central row behind the shoulders. Numerous small dermal denticles are also found between the eyes and on the tail behind the spine. The dorsal coloration varies from plain reddish-brown to dark gray, and the underside is light. The extent of denticle coverage and number of oral papillae can vary among individuals. The longtail stingray closely resembles the diamond stingray
Diamond stingray
The diamond stingray is a species of stingray in the family Dasyatidae. It is found in the coastal waters of the eastern Pacific Ocean from southern California to northern Chile, and around the Galápagos and Hawaiian Islands...
(D. dipterura), which is found in the same region, but can be distinguished by its lack of an upper tail fold. The length of the tail is not a reliable diagnostic character for this species, as it is frequently damaged.
Biology and ecology
Apparently solitary in nature, the longtail stingray is a predator of bottom-dwelling bony fishes and invertebrateInvertebrate
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, in particular stomatopods, decapods
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, and molluscs. Known parasites of this species include the tapeworms Acanthobothrium cimari, A. cleofanus, A. costarricense, A. puntarenasense, and A. vargasi, Anthocephalum lukei and A. michaeli, Parachristianella dimegacantha, Pseudochristianella elegantissima and P. nudiscula, and Pterobothrioides carvajali, and the monogenea
Monogenea
Monogenea are a group of largely ectoparasitic members of the flatworm phylum Platyhelminthes, class Monogenea.-Characteristics:Monogenea are very small parasitic flatworms mainly found on skin or gills of fish....
n Listrocephalos whittingtoni. Like other stingrays, the longtail stingray is aplacental viviparous with the developing embryo
Embryo
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 sustained initially by yolk and later by histotroph ("uterine milk") produced by the mother. Adult females have a single functional ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
. Near-term females appear to swim into shallow estuaries and tidal creeks to give birth, following a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of 10–11 months, and may mate again immediately after. A litter contains 1–5 young, each measuring about 40 cm (15.7 in) across. Males mature sexually
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at 0.8 m (2.6 ft) across, and females at 1.1 m (3.6 ft) across.
Human interactions
The tail spine of the longtail stingray is potentially dangerous to humans. This species is of some commercial importance in Mexico, where it is sold fresh or dried and salted. This species is likely landed by inshore fisheries targeting shark and ray throughout Central AmericaCentral America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
; it is caught by bottom trawls and longlines, and is especially susceptible to gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
s as its tail spine easily becomes entangled in the mesh. The impact of fishing on its population is unknown, as fishery landings in the region are poorly monitored and the longtail stingray is not reported separately from other ray species. As a result, the International Union for Conservation of Nature (IUCN) has listed this species as 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...
, while noting that its slow reproductive rate would limit its capacity to recover from over-exploitation.