Sharpnose guitarfish

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Sharpnose guitarfish
Glaucostegus granulatus TSCK.jpg
Living specimen in Kuwait
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Rhinopristiformes
Family: Glaucostegidae
Genus: Glaucostegus
Species:
G. granulatus
Binomial name
Glaucostegus granulatus
(Cuvier, 1829)
Synonyms

Rhinobatos granulatusCuvier, 1829

The sharpnose guitarfish also known as the granulated guitarfish (Glaucostegus granulatus) is a species of ray in the Glaucostegidae family. They belong to the subclass Elsamobranchii which are cartilaginous fish that include sharks, rays, and skates as shown in their morphology. They have a flattened ray-like body and shark-like elongated snout. [1] This species was first described by Georges Cuvier in 1829, and despite their appearance, they don't pose any threat to humans. [3] As of April 2022, the IUNC has classified the sharpnose guitarfish as critically endangered. [1]

Contents

Distribution

The sharpnose guitarfish is endemic to the Indo-Pacific region. The populations are found near Australia, India, Indonesia, Kuwait, Myanmar, Pakistan, Papua New Guinea, the Philippines, Sri Lanka, Thailand, Vietnam, and possibly China and Oman. Its natural habitats are open seas, coral reefs, and estuarine waters. It ranges from intertidal to offshore continental shelves down to 119 m. [4] The sharpnose guitarfish feeds on large shellfish and other invertebrates. [4] Due to the distribution across the Indo-Pacific, the sharpnose guitarfish have experienced environmental pressures based on their habitat degrading and overfishing. [5]

Description

The Glaucostegidae family are classified as rays that have a flattened body that is adapted for a benthic lifestyle. [3] Glaucostegus granulatus is a large ray species that can reach a total length of 2.3 meters. [6] Its body is flattened and wedge-shaped, with a long, narrow truck and a pointed snout with oblique nostrils. [6] The dorsal surface of the body is yellowish to brownish or greyish and has rough skin in small denticles. [6] The dorsal fins are closely together, with a spacing of 1.3 to 1.6 times the length of the base of the dorsal fin, and the tail length is roughly 1 to 1.4 times the disc length. [6] The wedge disc has a long and narrow pointed tip snout with broad oblique nostrils and with narrow anterior opening. [6] Mature males can be as long as 98 cm, although larger individuals that are up to 2.7 meters have been recorded. [6] The skin has fine denticles, with a midline, small patches near the eye, on the shoulder, and sometimes snout that are generally more visible with younger guitarfish. [6] The long snout and rough skin texture that has more of a granular dorsally can help to correctly identify sharpnose guitarfish from similar species in their family.

Feeding

Sharpnose guitarfish are cartilaginous benthic organisms that consume crustaceans, mollusks, and benthic organisms that inhabit the sediment. [7] They are well-suited for hunting on the seafloor even though visibility might be low, and prey might be under the sediment. There is little information surrounding sharpnose guitarfish feeding habits but like other rays, sharpnose guitarfish have electroreceptive organs known as the ampullae of Lorenzini on their snout. [8] These organs can detect weak electric fields that are generated from the muscle movements of prey. [8] Also, elasmobranchs possess a lateral line that can detect hydrodynamic movements to spot prey or evade potential predators. [9] The flattened body and the long snout enable them to maneuver near the seafloor which maximizes their access to benthic creatures.

Reproductive

Sharpnose guitarfish exhibit an ovoviviparous reproductive lifestyle which is the embryos are in the form of eggs that remain within the mother until they're ready to hatch. [4] The internal feralization strategy allows the female to incubate the embryos and provide nutrition from the yolk sack. [10] Reproduction such as this is common for rays because it allows the young to be fully formed and not be suitable for predation during their larvae forms. Female sharpnose guitarfish can produce 6 to 10 offspring per litter. [6] With low reproductive rates and long gestation periods, the sharpnose guitarfish is vulnerable to being overfished which results in population decline. This combination of slow growth rates and late sexual maturity means the population has a limited capacity for recovery once populations have started to decline. [3]

Conservation Status

The sharpnose guitarfish is classified as a critically endangered species. [1] The rhinopristoid rays (sawfishes, wedgefises, giant guitarfishes, and guitarfishes) have experienced a severe reduction in their populations-based overfishing, particularly as incidental catch. [1] [10] As a result of exploitation, the sharpnose guitarfish populations are facing drastic declines and some localized populations are disappearing entirely. [5] One of the primary threats to sharpnose guitarfish is overfishing and incidental catch by commercial fishermen. [11] Unintentionally trawls, nets, and other forms of industrial fishing gear have caused the sharpnose population to not recover quickly from these fishing pressures. [5] They had demand for their fins in the international markets. The finning practice where sharks and rays are solely captured for their fins remains a challenge for conservation strategies even though there are regulations banning these practices in many countries. [12] Also, unintentional catches pose a serious threat for sharpnose guitarfish. They aren't the target fishes for fisheries but because they are returned to the water unalive, their populations decline. [12] Having a correct assessment of the number of sharpnose guitarfish can be difficult since there is a lack of species-specific time series data that is available to view the reductions for the sharpnose guitarfish. [13] Assessing the true population of sharpnose guitar fish is challenging due to the lack of species-specific time-series and incorrect taxonomic identification. [13] [14] So, the true extent of the population decline is difficult to calculate. However, the mitochondrial genome and partial nuclear genome of the sharpnose guitarfish have been successfully sequenced which provides more detail about the phylogenetic assessment of this species. [15] The genetic data is expected to enhance the species-specific population and help assessments for effective conservation efforts. [15]


Related Research Articles

<span class="mw-page-title-main">Guitarfish</span> Family of cartilaginous fishes

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 tropical, subtropical, and warm temperate waters worldwide.

<span class="mw-page-title-main">Shovelnose guitarfish</span>

The shovelnose guitarfish is a ray in the family Rhinobatidae. The genus is derived from the Greek word rhinos, meaning nose, and the Latin word batis, which means ray. R. productus was first described by ichthyologist William Orville Ayre in 1854. As its common name suggests, this species possesses a pointed shovel-shaped snout and a body similar to that of a guitar with a larger head and long, slender body. The shovelnose is considered to be a primitively developed ray, with many features of both sharks and rays. The shovelnose guitarfish was first considered to be a shark because of its dorsal fins' shape. Fossils of R. productus ancestors have been recovered, dating back over 100 million years.

<span class="mw-page-title-main">Rajiformes</span> Order of fishes in the superorder Batoidea

Rajiformes is one of the four 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 pectoral fins, which reach as far forward as the sides of the head, with a generally flattened body. The undulatory pectoral fin motion diagnostic to this taxon is known as rajiform locomotion. The eyes and spiracles are located on the upper surface of the head and the gill slits are on the underside of the body. Most species give birth to live young, although some lay eggs enclosed in a horny capsule.

<span class="mw-page-title-main">Gray smooth-hound</span> Species of shark

The gray smooth-hound is a houndshark of the family Triakidae. It is spotless and smooth with a narrow head and long blunted snout. This shark is found on continental shelves of the subtropical eastern Pacific. Its range extends from northern California to the Gulf of California, usually residing in waters less than 80 meters deep. Adults are between 0.5 and 1.6 meters long. Furthermore, this shark is viviparous with an egg yolk placenta. Reproduction occurs annually and inland estuaries are common nursery grounds. Although there is little data on the shark’s population trends and catch quantities, the gray smooth-hound is not considered as vulnerable to overfishing. Additionally, there have been three reported sightings of albinism in this species, which is rare for elasmobranchs.

<span class="mw-page-title-main">Fiddler ray</span> Genus of cartilaginous fishes

Trygonorrhina, also known as the fiddler rays or banjo rays, is a genus of guitarfish, family Rhinobatidae. The two species are found along the eastern and southern coasts of Australia. They are benthic in nature, favoring shallow, sandy bays, rocky reefs, and seagrass beds. The eastern fiddler is found to a length of 120 cm and the southern fiddler to a length of 180 cm.

<span class="mw-page-title-main">Barndoor skate</span> Species of cartilaginous fish

The barndoor skate is a species of marine cartilaginous fish in the skate family Rajidae of the order Rajiformes. It is native to the northwestern Atlantic Ocean, and is found from the Grand Banks of Newfoundland and the southern side of the Gulf of St. Lawrence south to North Carolina. The fish is one of the largest skates found in the North Atlantic Ocean, reaching lengths up to 1.5 m (5 ft). It is carnivorous, feeding on invertebrates and other fish found near the sea floor.

<i>Rhina ancylostoma</i> Species of cartilaginous fish

Rhina ancylostoma, also known as the bowmouth guitarfish, shark ray or mud skate, is a species of ray and a member of the family Rhinidae. Its evolutionary affinities are not fully resolved, though it may be related to true guitarfishes and skates. This rare species occurs widely in the tropical coastal waters of the western Indo-Pacific, at depths of up to 90 m (300 ft). Highly distinctive in appearance, Rhina ancylostoma has a wide and thick body with a rounded snout and large shark-like dorsal 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 fins. This large species can reach a length of 2.7 m (8.9 ft) and weight of 135 kg (298 lb).

<span class="mw-page-title-main">Giant guitarfish</span> Species of cartilaginous fish

The giant guitarfish, also known as the whitespotted wedgefish, is a large species of guitarfish in the family Rhinidae. It is restricted to the Red Sea, Persian Gulf, and western Indian Ocean, but was formerly considered more widespread due to confusion with its relatives.

<span class="mw-page-title-main">Banded eagle ray</span> Species of fish

The banded eagle ray is a species of fish in the family Myliobatidae. The species was first described by Bloch and Schneider in 1801. As an elasmobranch, the banded eagle ray has a skeleton composed of cartilage. Like other eagle rays it has a depressiform, dorsoventrally flattened, shape to succeed in its benthic lifestyle. It preys mainly on benthic crustaceans, snails, and worms. Its natural habitats are open seas, shallow seas, and coral reefs. As of 2016, this species is classified as vulnerable by the IUCN. The main threats to the banded eagle ray are overfishing and habitat destruction.

<span class="mw-page-title-main">Thornback guitarfish</span> Species of cartilaginous fish

The thornback guitarfish is a species of ray in the family Platyrhinidae, and the only member of its genus. Despite its name and appearance, it is more closely related to electric rays than to true guitarfishes of the family Rhinobatidae. This species ranges from Tomales Bay to the Gulf of California, generally in inshore waters no deeper than 6 m (20 ft). It can be found on or buried in sand or mud, or in and near kelp beds. Reaching 91 cm (36 in) in length, the thornback guitarfish has a heart-shaped pectoral fin disc and a long, robust tail bearing two posteriorly positioned dorsal fins and a well-developed caudal fin. The most distinctive traits of this plain-colored ray are the three parallel rows of large, hooked thorns that start from the middle of the back and run onto the tail.

<span class="mw-page-title-main">Bottlenose skate</span> Species of cartilaginous fish

The bottlenose skate, spearnose skate, or white skate is a species of skate in the family Rajidae. It is a benthic fish native to the coastal eastern Atlantic Ocean. Due to overfishing, it has been depleted or extirpated in many parts of its former range in the northeastern Atlantic and the Mediterranean Sea, and is now endangered.

<span class="mw-page-title-main">Southern banded guitarfish</span> Species of cartilaginous fish

The southern banded guitarfish, also known as the witch guitarfish, is a species of fish in the Trygonorrhinidae family found at reefs and other habitats from shallow water to a depth of 150 m in the tropical East Pacific. It ranges from Mazatlan, Mexico, to Colombia, but it likely also occurs off Ecuador and Peru. It is threatened by habitat loss. It is closely related to the more northernly distributed banded guitarfish.

<span class="mw-page-title-main">Mangrove whipray</span> Species of cartilaginous fish

The mangrove whipray or whitetail stingray, is a species of stingray in the family Dasyatidae. It is widely distributed in the Indo-Pacific region from the Red Sea to northern Australia and Micronesia. A benthic inhabitant of shallow inshore waters, juvenile mangrove whiprays favor mangrove and estuarine habitats, while adults favor sandy to rocky areas in lagoons and coral reefs. This species can be identified by its thick, oval pectoral fin disc that is dark gray above with numerous white flecks, and by its relatively short, whip-like tail that is white past the stinging spine. It grows up to 1.4 m (4.6 ft) across.

<span class="mw-page-title-main">Batomorphi</span> Superorder of cartilaginous fishes

Batomorphi is a clade of cartilaginous fishes, commonly known as rays, this taxon is also known as the superorder Batoidea, but the 5th edition of Fishes of the World classifies it as the division Batomorphi. They and their close relatives, the sharks, compose the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces.

<span class="mw-page-title-main">Common guitarfish</span> Species of cartilaginous fish

The common guitarfish is a species of cartilaginous fish in the family Rhinobatidae. It is native to the eastern Atlantic Ocean and the Mediterranean Sea. It is a bottom-dwelling fish feeding on crustaceans, other invertebrates and fish. The females give birth to live young. Its lifestyle makes it vulnerable to trawling and other fishing methods, populations seem to be declining and it has disappeared from parts of its range.

<i>Glaucostegus</i> Genus of cartilaginous fishes

Glaucostegus, also known as giant guitarfishes, is a genus of large Indo-Pacific rays, with a single species, Glaucostegus cemiculus, in the East Atlantic, and Mediterranean. They were formerly classified in the family Rhinobatidae but are now recognized as a distinct family, Glaucostegidae.

<span class="mw-page-title-main">Halavi guitarfish</span> Species of cartilaginous fish

The halavi guitarfish is a part of the Glaucostegidae family. It is a species of ray found in the Indo-West Pacific. Recorded twice, in 1997 and 2004, in the levantine waters, the question of its permanent settlement in the Mediterranean Sea remains open. Its name is derived from the Arabic word حلاوي (halawi).

<span class="mw-page-title-main">Blackchin guitarfish</span> Species of cartilaginous fish

The blackchin guitarfish is a species of cartilaginous fish in the family Rhinobatidae. It is native to the eastern Atlantic Ocean and the Mediterranean Sea. It is a bottom-dwelling fish feeding on crustaceans, other invertebrates and fish. The females give birth to live young. Its lifestyle makes it vulnerable to trawling and other fishing methods, populations seem to be declining and it is subject to intensive fishing pressure, with its fins being sold into the Asian market. The International Union for Conservation of Nature has assessed its conservation status as being "critically endangered".

<span class="mw-page-title-main">Rhinopristiformes</span> Order of cartilaginous fishes

Rhinopristiformes is an order of rays, cartilaginous fishes related to sharks, containing shovelnose rays and allied groups.

Glaucostegus younholeei, the Bangladeshi guitarfish, is a type of guitarfish of the family Glaucostegidae found in the northern Bay of Bengal, Bangladesh. This species is recorded from 13 specimens discovered in a fish landing center in Cox's Bazar. It is currently witnessing a population decline of more than 80 percent due to high exploitation rate.

References

  1. 1 2 3 4 5 Kyne, P.M.; Haque, A.B.; Charles, R. & Jabado, R.W. (2022). "Glaucostegus granulatus". IUCN Red List of Threatened Species . 2022: e.T60166A215829219. Retrieved 30 April 2023.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 3 Jabado, R. W. (2019). Wedgefishes and giant Guitarfishes: A Guide to Species Identification. Wildlife Conservation Society. https://www.researchgate.net/publication/332978759_Wedgefishes_and_giant_guitarfishes_a_guide_to_species_identification
  4. 1 2 3 "Glaucostegus granulatus (Cuvier, 1829): Granulated guitarfish". FishBase. Retrieved 30 April 2023.
  5. 1 2 3 Flowers, K. I., Heithaus, M. R., & Papastamatiou, Y. P. (2021). Buried in the sand: Uncovering the ecological roles and importance of rays. Fish and Fisheries, 22(1), 105–127. https://doi.org/10.1111/faf.12508
  6. 1 2 3 4 5 6 7 8 Last, P., White, W., De Carvalho, M., Séret, B., Stehmann, M., & Naylor, G. (Eds.). (2016). Rays of the world. CSIRO Publishing. https://doi.org/10.1071/9780643109148
  7. ↑ Fisheries, N. (2023, October 30). Common guitarfish | noaa fisheries. NOAA. https://www.fisheries.noaa.gov/species/common-guitarfish
  8. 1 2 Newton, K. C., Gill, A. B., & Kajiura, S. M. (2019). Electroreception in marine fishes: Chondrichthyans. Journal of Fish Biology, 95(1), 135–154. https://doi.org/10.1111/jfb.14068
  9. ↑ Wueringer, B. E., Peverell, S. C., Seymour, J., Squire, Jr., L., & Collin, S. P. (2011). Sensory systems in sawfishes. 2. The lateral line. Brain, Behavior and Evolution, 78(2), 150–161. https://doi.org/10.1159/000329518
  10. 1 2 Sea wonder: Guitarfish. (n.d.). National Marine Sanctuary Foundation. Retrieved November 4, 2024, from https://marinesanctuary.org/blog/sea-wonder-guitarfish/
  11. ↑ Tapilatu, M. E., Wijayanti, D. P., Subagiyo, S., Sembiring, A., Yusmalinda, N. L. A., Ningsih, E. Y., Al Malik, M. D., & Pertiwi, N. P. D. (2023). Genetic diversity of wedgefishes and guitarfishes at landing sites in east Indonesia using Cytochrome Subunit I (Coi). Biodiversitas Journal of Biological Diversity, 24(6). https://doi.org/10.13057/biodiv/d240604
  12. 1 2 On a knife-edge: Saving sharpnose guitarfish in the Bay of Bengal. (n.d.). Save Our Seas Foundation. Retrieved October 18, 2024, from https://saveourseas.com/project/on-a-knife-edge-saving-sharpnose-guitarfish-in-the-bay-of-bengal/
  13. 1 2 Moore, A. (2017). Are guitarfishes the next sawfishes? Extinction risk and an urgent call for conservation action. Endangered Species Research, 34, 75–88. https://doi.org/10.3354/esr00830
  14. ↑ Golestaninasab, M., & Malek, M. (2016). Two new species of Rhinebothrium (Cestoda: Rhinebothriidea) from granulated guitarfish Glaucostegus granulatus in the Gulf of Oman. Journal of Helminthology, 90(4), 441–454. https://doi.org/10.1017/S0022149X15000553
  15. 1 2 Johri, S., Fellows, S. R., Solanki, J., Busch, A., Livingston, I., Mora, M. F., Tiwari, A., Cantu, V. A., Goodman, A., Morris, M. M., Doane, M. P., Edwards, R. A., & Dinsdale, E. A. (2020). Mitochondrial genome to aid species delimitation and effective conservation of the Sharpnose Guitarfish (Glaucostegus granulatus). Meta Gene, 24, 100648. https://doi.org/10.1016/j.mgene.2020.100648


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