HomeFish encyclopediaSharks and RaysBramble, Sleeper and Dogfish sharksDogfish sharksBartail spurdog Bartail spurdog (Squalus notocaudatus) Scientific name: Squalus notocaudatus Last, White & Stevens, 2007 The Bartail spurdog (Squalus notocaudatus) is a marine fish of the family Squalidae. Native range: Western Pacific, Queensland, Australia. BiologyThis species in the 'highfin megalops group' is distinguished by the following set of characters: abdomen depth 8.6-11.1% TL; pre-vent length 45.3-46.5% TL, 1.9-2.0 times dorsal caudal margin; pre-second dorsal length 3.6-4.0 times pectoral-fin anterior margin, 2.4-2.6 times dorsal caudal margin; head width 1.4-1.6 times abdomen width; preoral length 2.8-3.2 times the horizontal prenarial length, 8.4-9.5% TL; head length 3.8-4.3 times its eye length; mouth width 3.4-4.3 times the length of upper labial furrow; interorbital width 1.4-1.5 times the horizontal preorbital length; fifth gill slit height 1.9-2.1% TL; strongly bifurcated anterior nasal flap; first dorsal fin upright, upper posterior margin almost vertical, greatest concavity closer to free rear tip than fin apex; posterior margin of second dorsal fin deeply concave; second dorsal-fin spine with a broad base; pectoral fin of adult weakly falcate, anterior margin long, 14.6-16.4% TL; both dorsal and ventral surfaces are paleSource: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameSqualus notocaudatusFamilySqualidae (Dogfish sharks)OrderSqualiformes (Bramble, Sleeper and Dogfish sharks)ClassElasmobranchii (Sharks and Rays)Maximum length61.9Depth range225–454 m (738–1490 ft)EnvironmentMarine; pelagic-oceanic; depth range 225 - 454 mClimateTropicalDistributionWestern Pacific: Queensland, Australia.Conservation status (IUCN)Data deficient (DD)Threat to humansHarmlessResilienceLow, minimum population doubling time 4.5 - 14 years (Preliminary K or Fecundity.) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026