''Rhina ancylostoma'', also known as the bowmouth guitarfish, shark ray or mud skate, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

ray Ray or RAY may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), the bony or horny spine on ray-finned fish Science and mathematics * Half-line (geometry) or ray, half of a line split at an ...

and a member of the

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 ...

Rhinidae Wedgefishes are rays of the family Rhinidae, comprising eleven species in three genera. Classified in the order Rhinopristiformes along with guitarfishes and sawfishes, they have also been known as giant guitarfishes or sharkfin guitarfishes. T ...

. Its evolutionary affinities are not fully resolved, though it may be related to true guitarfishes and

skate Skate or Skates may refer to: Fish *Skate (fish), several genera of fish belonging to the family Rajidae * Pygmy skates, several genera of fish belonging to the family Gurgesiellidae * Smooth skates or leg skates, several genera of fish belongin ...

s. This rare species occurs widely in the

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

coastal waters of the western

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

, at depths of up to . Highly distinctive in appearance, ''Rhina ancylostoma'' has a wide and thick body with a rounded snout and large shark-like

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and tail fins. Its mouth forms a W-shaped undulating line, and there are multiple thorny ridges over its head and back. It has a dorsal color pattern of many white spots over a bluish gray to brown background, with a pair of prominent black markings over the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s. This large species can reach a length of and weight of . Usually found near the

sea floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

, the bowmouth guitarfish prefers sandy or muddy areas near underwater structures. It is a strong-swimming

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

es,

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s, and

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s. This species gives live birth to litters of two to eleven pups, which are nourished during

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregn ...

yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...

. The

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

(IUCN) has assessed ''Rhina ancylostoma'' as

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

because it is widely caught by

artisanal An artisan (from , ) is a skilled craft worker who makes or creates material objects partly or entirely by hand. These objects may be functional or strictly decorative, for example furniture, decorative art, sculpture, clothing, food ite ...

and

commercial fisheries 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 p ...

for its valuable fins and meat. It is viewed as a nuisance by

trawl Trawling is an industrial method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch di ...

ers, however, because its bulk and thorny skin cause it to damage netted catches.

Habitat degradation Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and

destruction Destruction may refer to: Concepts * Destruktion, a term from the philosophy of Martin Heidegger * Destructive narcissism, a pathological form of narcissism * Self-destructive behaviour, a widely used phrase that ''conceptualises'' certain kin ...

pose an additional, significant challenge to this ray's survival. The ''bowmouth guitarfish'' adapts well to captivity and is displayed in

public aquarium A public aquarium () or public water zoo is the aquatic counterpart of a zoo, which houses living aquatic animal and aquatic plant, plant specimens for public viewing. Most public aquariums feature tanks larger than those kept by home aquarists, ...

Taxonomy and phylogeny

German

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Marcus Elieser Bloch Marcus Elieser Bloch (1723–1799) was a German physician and naturalist who is best known for his contribution to ichthyology through his multi-volume catalog of plates illustrating the fishes of the world. Brought up in a Hebrew-speaking Jewish ...

and

Johann Gottlob Schneider Johann Gottlob Theaenus Schneider (18 January 1750 – 12 January 1822) was a German classicist and naturalist. Biography Schneider was born at Collm in Saxony. In 1774, on the recommendation of Christian Gottlob Heine, he became secretary to ...

described ''Rhina ancylostoma'' in their 1801 ''Systema Ichthyologiae''. Their account was based on a long

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository f ...

, now lost, collected off the

Coromandel Coast The Coromandel Coast is a coastal region along the southeastern front of the Indian peninsula. Its delimitations are numerous, but generally admitted to be bounded by the Krishna River, Krishna river River mouth, mouth to the north, the Bay of B ...

of India. The genus name ''Rhina'' comes from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''rhinos'' ("snout"); the

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''ancylostoma'' is derived from the Greek ''ankylos'' ("curved" or "crooked") and ''stoma'' ("mouth"). Although Block and Schneider wrote the epithet as ''ancylostomus'' and that form appears in some literature, most modern sources regard the correct form to be ''ancylostoma''. Other

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

s for this species include shark ray, mud skate, shortnose mud skate, bow-mouthed angel fish, and bow-mouthed angel shark. The evolutionary relationships between ''Rhina ancylostoma'' and other rays are debated. Morphological evidence generally points to a close relationship between ''Rhina'', ''

Rhynchobatus ''Rhynchobatus'' is a group of rays commonly known as wedgefishes in the family Rhinidae. They are found in the tropical and subtropical Indo-Pacific with a single species (''R. luebberti'') in the eastern Atlantic. All species in this genus are ...

'' and ''

Rhynchorhina The false shark ray (''Rhynchorhina mauritaniensis'') is a species of fish in the Rhinidae family and the only species in the genus ''Rhynchorhina''. This rare ray is only known from shallow coastal Atlantic waters in Banc d’Arguin, Maurita ...

'', which are a group of rays known as the wedgefishes that also have large, shark-like fins. Morphological analyses have tended to place these two genera basally among rays, though some have them as basal to just the

guitarfish The guitarfish, also referred to as shovelnose rays, are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small, ray-like wings. The combined range of the various species is tro ...

es (Rhinobatidae) and

s (Rajidae) while others have them basal to all other rays except

sawfish Sawfish, also known as carpenter sharks, are a family of very large rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the lar ...

es (Pristidae). A 2012 study based on

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

upheld ''Rhina'' and ''Rhynchobatus'' as

sister taxa In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

related to the guitarfishes, but also unexpectedly found that they formed a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

with the sawfishes rather than the skates. Following the description of ''Rhynchorhina'' in 2016, a study of mtDNA found that it is part of the same group and their phylogenetic relationship is ((''Rhynchobatus''+''Rhynchorhina'')+''Rhina''). In terms of classification, Bloch and Schneider originally placed the bowmouth guitarfish in the order Abdominales, a now-obsolete grouping of fishes defined by the positioning of their

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s directly behind the

s. Modern sources have included it variously in the order

Rajiformes Rajiformes is one of the four Order (biology), orders in the clade Batomorphi, often referred to as the superorder Batoidea, flattened cartilaginous fishes related to sharks. Rajiforms are distinguished by the presence of greatly enlarged pector ...

, Rhinobatiformes, Rhiniformes, or the newly proposed Rhinopristiformes. The placement of the bowmouth guitarfish in the family

originates from the group "Rhinae", consisting of ''Rhina'' and ''Rhynchobatus'', in Johannes Müller and

Jakob Henle Friedrich Gustav Jakob Henle (; 9 July 1809 – 13 May 1885) was a German physician, pathologist, and anatomist. He is credited with the discovery of the loop of Henle in the kidney. His essay, "On Miasma and Contagia," was an early argument for ...

's 1841 ''Systematische Beschreibung der Plagiostomen''. Later authors have also assigned this species to the family Rhinobatidae or Rhynchobatidae. Joseph Nelson, in the 2006 fourth edition of ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'', placed this species as the sole member of Rhinidae in the order Rajiformes, which is supported by morphological but not molecular data. More recent authorities have placed it in Rhinidae together with ''Rhynchobatus'' and ''Rhynchorhina'', reflecting both genetic data and the morphologically intermediate position of ''Rhynchobatus'' between ''Rhina'' and ''Rhynchorhina''.

Description

''Rhina ancylostoma'' is a heavily built fish growing to long and in weight. The head is short, wide, and flattened with an evenly rounded snout; the front portion of the head, including the medium-sized eyes and large spiracles, is clearly distinct from the body. The long nostrils are transversely oriented and have well-developed skin flaps on their anterior margins. The lower jaw has three protruding lobes that fit into corresponding depressions in the upper jaw. There are around 47 upper and 50 lower tooth rows arranged in winding bands; the teeth are low and blunt with ridges on the crown. The five pairs of ventral

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 and rays, as well as deep-branching vertebrates such as lampreys. In c ...

s are positioned close to the lateral margins of the head. Jaw of Rhina ancylostoma

The body is deepest in front of the two tall and falcate (sickle-shaped)

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

s. The first dorsal fin is about a third larger than the second and originates over the

origins. The second dorsal fin is located midway between the first dorsal and the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. The broad and triangular

s have a deep indentation where their leading margins meet the head. The

s are much smaller than the pectoral fins, and the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

is absent. The tail is much longer than the body and ends in a large, crescent-shaped

; the lower caudal fin lobe is more than half the length of the upper. The entire dorsal surface has a grainy texture from a dense covering of tiny

dermal denticle A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scale (zoology), scales, which can also provide effective Underwater camouflage, camouflage through the us ...

s. A thick ridge is present along the midline of the back, which bears a band of sharp, robust thorns. There are also a pair of thorn-bearing ridges in front of the eyes, a second pair running from above the eyes to behind the spiracles, and a third pair on the "shoulders". This species is bluish to brownish gray above, lightening towards the margins of the head and over the pectoral fins. There are prominent white spots scattered over the body and fins, a white-edged black marking above each pectoral fin, and two dark transverse bands atop the head between the eyes. The underside is light gray to white. Young rays are more vividly colored than adults, which are browner with fainter patterning and proportionately smaller spots.

Distribution and habitat

While uncommon, ''Rhina ancylostoma'' is widely distributed in the coastal

waters of the western

. In the Indian Ocean, it is found from

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

in South Africa to the

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

(including the

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...

), across the

Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...

and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

(including the

Maldives The Maldives, officially the Republic of Maldives, and historically known as the Maldive Islands, is an Archipelagic state, archipelagic country in South Asia located in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, abou ...

), to

Shark Bay Shark Bay () is a World Heritage Site in the Gascoyne region of Western Australia. The area is located approximately north of Perth, on the westernmost point of the Australian continent. UNESCO's listing of Shark Bay as a World Heritage S ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

. Its Pacific range extends northward to Korea and southern Japan, eastward to New Guinea, and southward to

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

. Found between deep, this ray spends most of its time near the

but can occasionally be seen swimming in midwater. It favors sandy or muddy

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s, and can also be found in the vicinity of rocky and

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s and

shipwreck A shipwreck is the wreckage of a ship that is located either beached on land or sunken to the bottom of a body of water. It results from the event of ''shipwrecking'', which may be intentional or unintentional. There were approximately thre ...

Ecology

''Rhina ancylostoma'' is a strong swimmer that propels itself with its tail like a shark. It is more active at night and is not known to be territorial. This species feeds mainly on

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer o ...

es such as

croakers Sciaenidae is a family of ray-finned fishes belonging to the order Acanthuriformes. They are commonly called drums or croakers in reference to the repetitive throbbing or drumming sounds they make. The family consists of about 293 to 298 species ...

and

s such as

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s and

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

;

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

s and

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s are also consumed. Its bands of flattened teeth allow it to crush hard-shelled prey. Curiously, two ''Rhina ancylostoma'' examined in a 2011

stable isotope Stable nuclides are Isotope, isotopes of a chemical element whose Nucleon, nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The Atomic nucleus, nuclei of such isotopes are no ...

study were found to have fed on

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

rather than demersal animals, in contrast to previous observations. The

tiger shark The tiger shark (''Galeocerdo cuvier'') is a species of ground shark, and the only extant member of the genus '' Galeocerdo'' and family Galeocerdonidae. It is a large apex predator, with females capable of attaining a length of over . Popula ...

(''Galeocerdo cuvier'') is known to prey on ''Rhina ancylostoma''. The ray is protected by the thorns on its head and back, and it may ram perceived threats.

Parasites

Parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

s documented from this species include the

tapeworm Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass being Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Ce ...

s '' Carpobothrium rhinei'', '' Dollfusiella michiae'', '' Nybelinia southwelli'', '' Stoibocephalum arafurense'', and '' Tylocephalum carnpanulatum'', the

leech Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...

'' Pontobdella macrothela'', the

trematode Trematoda is a Class (biology), class of flatworms known as trematodes, and commonly as flukes. They are obligate parasite, obligate Endoparasites, internal parasites with a complex biological life cycle, life cycle requiring at least two Host ( ...

'' Melogonimus rhodanometra'', the

monogenea Monogeneans, members of the class Monogenea, are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they ...

ns '' Branchotenthes robinoverstreeti'' and '' Monocotyle ancylostomae'', and the

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s '' Nesippus vespa'', '' Pandarus cranchii'', and '' P. smithii''. There is a record of a ''Rhina ancylostoma'' being cleaned by

bluestreak cleaner wrasse The bluestreak cleaner wrasse (''Labroides dimidiatus'') is one of several species of cleaner wrasses found on coral reefs from Eastern Africa and the Red Sea to French Polynesia. Like other cleaner wrasses, it eats parasites and dead tissue off ...

s (''Labroides dimidiatus'').

Reproduction

Reproduction in ''Rhina ancylostoma'' is

viviparous In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

, with the developing

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

s sustained to term by

. Adult females have two

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

and two

uterine horns The uterine horns (cornua of uterus) are the points in the upper uterus where the fallopian tubes or oviducts exit to meet the ovaries. They are one of the points of attachment for the round ligament of uterus (the other being the mons pubis). T ...

. The litter size varies between two and eleven pups, and newborns measure long.

Sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

is attained at lengths of for males and over in females. Females grow larger than males.

Human interactions

Throughout its range, the ''bowmouth guitarfish'' is caught incidentally or intentionally by

and

using

gillnet Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...

s, and line gear. The fins are extremely valuable due to their use in

shark fin soup Shark's fin soup is a soup or stewed dish served in parts of China, Taiwan, and Southeast Asia. The shark fins provide texture, while the taste comes from the other ingredients. It is commonly served at special occasions such as weddings and ba ...

, and are often the only parts of the fish kept and brought to market. However, the meat may also be sold fresh or dried and salted, and it is highly sought after in India. When caught as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

in trawls, ''Rhina ancylostoma'' is considered a nuisance because its strength and rough skin make it difficult to handle, and as the heavy ray thrashes in the net it can damage the rest of the catch. In Thailand, the enlarged thorns of this species are used to make bracelets. The

(IUCN) has assessed ''Rhina ancylostoma'' as

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

in 2019, delisted from the vulnerable category, along with many other guitarfish species. It is threatened by fishing and by

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

and

degradation Degradation may refer to: Science * Degradation (geology), lowering of a fluvial surface by erosion * Degradation (telecommunications), of an electronic signal * Biodegradation of organic substances by living organisms * Environmental degradation ...

, particularly from

blast fishing Blast fishing, fish bombing, dynamite fishing or grenade fishing is a destructive fishing practice using explosives to stun or kill schools of fish for easy collection. This often illegal practice is extremely destructive to the surrounding eco ...

coral bleaching Coral bleaching is the process when corals become white due to loss of Symbiosis, symbiotic algae and Photosynthesis, photosynthetic pigments. This loss of pigment can be caused by various stressors, such as changes in water temperature, light, ...

, and

siltation Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary o ...

. Its numbers are known to have declined substantially in Indonesian waters, where it is one of the large rays targeted by a mostly unregulated gillnet fishery. The IUCN has given this species a regional assessment of

Near Threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

in Australian waters, where it is not a targeted species but is taken as bycatch in bottom trawls. The installation of

turtle excluder device A turtle excluder device (TED) is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net. In particular, sea turtles can be caught when bottom trawling is used by the commercial shrimp fishing indus ...

s on some Australian trawlers has benefited this species. Since it is rare and faces many conservation threats, the ''bowmouth guitarfish'' has been called "the

panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear or simply panda, is a bear species endemic to China. It is characterised by its white coat with black patches around the eyes, ears, legs and shoulders. Its body is ...

of the aquatic world". It is a popular subject of

s and fares relatively well, with one individual having lived for seven years in captivity. In 2007, the

Newport Aquarium The Newport Aquarium is a public public aquarium, aquarium located in Newport, Kentucky. Overview The Newport Aquarium located within the Newport on the Levee shopping mall is owned by Herschend Family Entertainment. Newport Aquarium is an a ...

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

initiated the world's first

captive breeding Captive breeding, also known as captive propagation, is the process of keeping plants or animals in controlled environments, such as wildlife reserves, zoos, Botanical garden, botanic gardens, and other Conservation biology, conservation facilitie ...

program for this species. Newport Aquarium announced in January 2014 that the female, "Sweet Pea", had become pregnant and given birth to seven pups. By February 2014, all seven pups had died. On January 7, 2016, Sweet Pea gave birth to nine shark pups which were eating on their own and still gaining weight by February 10, 2016. Newport Aquarium later announced that the pups would be moved into a coral reef exhibit where they can be viewed by the public starting on June 24. The species also bred at the S.E.A. Aquarium in

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

in 2015.

References

{{Taxonbar, from=Q1190545 Rajiformes Fish of the Red Sea Marine fish of East Africa Fish described in 1801 Taxa named by Marcus Elieser Bloch