This week’s Featured Species is a rather rare, deepwater species that is only found in waters around New Zealand and South Australia. The Prickly Dogfish (Oxynotus bruniensis) is a species that has rarely been studied. Few images exist of this species in its natural environment.
The Prickly Dogfish is a member of the order Squaliformes, which contains approximately 100 species in 7 families including Squalidae (dogfishes), Somniosidae (sleeper sharks), Etmopteridae (lantern sharks), and Oxynotidae, which includes five species of rough sharks (Parker, 2008). Despite the name “Dogfish,” the Prickly Dogfish is one of the five species of rough sharks in Oxynotidae. The members of the Oxynotidae are:
- Angular rough shark (Oxynotus centrina)
- Caribbean rough shark (Oxynotus caribbaeus)
- Japanese rough shark (Oxynotus japonicus)
- Prickly Dogfish (Oxynotus bruniensis)
- Sailfin rough shark (Oxynotus paradoxus)
The rough sharks are known for their short stout bodies that have been laterally compressed. Their dorsal fins sit high and have a forward extension along their back with a prominent spine, giving their dorsal fins a distinct sail-like quality. Being a deepwater shark, their eyes are large to help them see in lower light environments. While we don’t know much about their behavior, we can gather that they most likely spend much of their lives at or near the sea floor from their lack of an anal fin- a common characteristic in benthic shark species. The presence of large spiracles and small gills also suggest that they spend time at or near the sea floor (Tricas, et al., 1997). Some sharks and all rays use spiracles, located on the top of the head just behind the eye, to draw oxygenated water from above, rather than passing it over the gills.
What sets the Prickly Dogfish apart from the rest of the members of Oxynotidae, is its incredibly rough dermal denticles. Shark skin has been used for centuries as sand paper for its abrasive qualities. But the Prickly Dogfish has dermal denticles so large that they can even give the Prickly Dogfish a fuzzy-like appearance. But don’t fluffy appearance fool you! These denticles have been described as barbed wire, leaving large abrasions and slicing through skin like it were paper (Parker, 2008)! Below you can see all spiky denticles of the Prickly Dogfish’s skin!
We still have so much to learn about the Prickly Dogfish. We don’t even know much about their diet. We know that they are a deepwater shark that most likely spends much of their life at or near the seafloor based on clues from their biology. Their teeth may also provide some insight to their diet. They have small, sharp, spear-like teeth in their upper jaw, and larger blade-like teeth in the lower jaw, similar to the cookiecutter shark. They also have fleshier lips, similar to the cookiecutter shark. It is likely they feed on benthic invertebrates and bony fishes, it may also be possible that they take advantage of larger prey items. However what we know of their diet is known from limited studies and further investigation is still required (Francis, 2003).
Authority: Ogilby, 1893
Family: Oxynotidae, 5 species
Length: Up to 2 feet (0.60 m); species in this family typically do not reach more than 5 feet (1.5 m)
Habitat: Continental and island shelves and slopes, deepwater
Depth: 100 – 1,600 feet (30 – 185 m)
Gestation: Period unknown
Litter Range: 7 pups were reported within one pregnant female.
Home Range: The Prickly Dogfish has a limited home range around Southern Australia and New Zealand; however, other members of Oxynotidae have patchy worldwide distributions in tropical and temperate waters.
Diet: Largely unknown; some items include benthic invertebrates and bony fishes.
IUCN Status: Data Deficient
(Francis, 2003; Parker, 2008; Skomal, 2016)
Thanks for checking out this mysterious shark this week! If you haven’t already, read about the exciting news for Oceanic Whitetip sharks that happened this week!! Remember to have a look at the Broadnose Sevengill Shark if you missed the last Featured Species. If you have a species of elasmobranch you’d love to see featured, please send me a message or leave me a comment! I’d love to know what you’d like to know more about!
The new Ocean For Sharks Shop is open! There’s handmade ocean inspired plush animals, canvas paintings, and of course my children’s book, Winifred the Wondrous Whale Shark, available in print and PDF. Be sure to stop by. Remember proceeds benefit shark research and conservation with a donation to Project AWARE!
Remember you can make a difference for marine ecosystems by contacting your Congress man or woman and telling them that you care about the quality of our waters! Sharks, rays, and other marine organisms cannot speak or be represented in Congress. They need your voice. Get involved and stand up for sharks. Until next time finatics.
Featured Image Source
New Zealand-American Submarine Ring of Fire, NOAA. (Photographer). (2013, Sep 13). A deepsea shark called a prickly dogfish swims by PISCES V at Rumble V volcano [Digital Image]. Retrieved from https://www.flickr.com/
Francis, M.P. (SSG Australia & Oceania Regional Workshop, March 2003). 2003. Oxynotus bruniensis. The IUCN Red List of Threatened Species 2003: e.T41840A10578144.
Parker, S. (2008). The encyclopedia of sharks (2nd ed.). Buffalo, NY: Firefly Books Ltd.
Skomal, G. (2016). The Shark Handbook: The Essential Guide for Understanding the Sharks of the World. (2nd ed.). Kennebunkport, ME: Cider Mill Press.
Tricas, T. C., Deacon, K., Last, P., McCosker, J. E., Walker, T. I., & Taylor, L. (1997). The Nature Company Guides: Sharks and Rays. (L. Taylor, Ed.). Hong Kong: The Nature Company, Time Life Books.