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Glaucostegus obtusus  (Müller & Henle, 1841)

Widenose guitarfish
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Glaucostegus obtusus
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Classification / Names Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa

() > Rhinopristiformes (Shovelnose rays) > Glaucostegidae (Giant guitarfishes) > Rhinobatinae

Environment / Climate / Range Ecology

Marine; demersal; depth range ? - 60 m (Ref. 114953).   Tropical; 25°N - 0°N, 61°E - 105°E (Ref. 114953)

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

Northern Indian Ocean: Pakistan to Thailand, with eastern limits unclear (Ref. 114953). South African records refer to Rhinobatos blochii and Rhinobatos leucospilus (Compagno pers. comm.).

Size / Weight / Age

Maturity: Lm ?  range ? - 48 cm
Max length : 93.0 cm TL male/unsexed; (Ref. 9909)

Short description Morphology | Morphometrics

This species is distinguished by the following: colour uniform greyish to brownish body and shovel-shaped disc; short snout broadly triangular, broad oblique nostrils with an oval anterior opening; disc flattened centrally, its length ca 1.2 times its width, anterior margin largely convex, outer corner broadly rounded to abruptly angular; snout relatively obtuse, ca. 80° angle, tip broadly rounded and not extended forward as a lobe, very small orbit its length ca 6.5 time preorbital length, 2.5-2.7 in interorbital space; rostral ridges are well separated, margin of cranium sharply demarcated before eyes; one small spiracular fold; nostrils much shorter than mouth, subequal to internasal width, ca. 50-52 nasal lamellae; anterior nasal flaps barely penetrating into internasal space, the interspace equal to 2.4-2.5 times length of posterior nasal aperture; rough skin covered with small denticles, enlarged slightly and more granular on dorsal surface than ventrally; along midline of the body in young are thorns in irregular row, irregular in shape, often obscure in adults; no obvious patch on each shoulder or greatly enlarged thorns in snout tip and around orbits; long tail, 1.4-1.6 times disc length; short dorsal fins, apices rounded, close together, interspace exceeding twice base length of first dorsal fin, well separated from pelvic fins (Ref. 114953).

Biology     Glossary (e.g. epibenthic)

Found inshore and offshore (Ref. 9909). Ovoviviparous (Ref. 50449). Biology little known (Ref. 9909); but males are known to be mature ca. 48 cm TL (Ref. 114953). Probably utilized where it occurs, but details lacking (Ref. 9909).

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Exhibit ovoviparity (aplacental viviparity), with embryos feeding initially on yolk, then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus, fat or protein through specialised structures (Ref. 50449).

Main reference Upload your references | References | Coordinator | Collaborators

Compagno, L.J.V., 1999. Checklist of living elasmobranchs. p. 471-498. In W.C. Hamlett (ed.) Sharks, skates, and rays: the biology of elasmobranch fishes. Johns Hopkins University Press, Maryland. (Ref. 35766)

IUCN Red List Status (Ref. 115185)

CITES (Ref. 94142)

Not Evaluated

Threat to humans

  Harmless




Human uses

FAO(Publication : search) | FisheriesWiki | Sea Around Us

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Internet sources

BHL | Cloffa | Websites from users | Check FishWatcher | CISTI | Catalog of Fishes (gen., sp.) | DiscoverLife | ECOTOX | Faunafri | Fishes of Iran | Fishtrace | GenBank(genome, nucleotide) | GloBI | GOBASE | Google Books | Google Scholar | Google | IGFA World Record | MitoFish | Otolith Atlas of Taiwan Fishes | PubMed | Reef Life Survey | Scirus | SeaLifeBase | Tree of Life | Wikipedia(Go, Search) | World Records Freshwater Fishing | Zoological Record

Estimates of some properties based on models

Phylogenetic diversity index (Ref. 82805):  PD50 = 0.6250   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00389 (0.00180 - 0.00842), b=3.12 (2.94 - 3.30), in cm Total Length, based on all LWR estimates for this body shape (Ref. 93245).
Trophic Level (Ref. 69278):  3.5   ±0.5 se; Based on size and trophs of closest relatives
Resilience (Ref. 69278):  Low, minimum population doubling time 4.5 - 14 years (Fec assumed to be <100).
Vulnerability (Ref. 59153):  Moderate to high vulnerability (48 of 100) .