Marine Life & Conservation Blogs
Creature Feature: Sharks with Unusual Names
This month we’re talking about some sharks with unusual names. With names that range from the descriptive to the downright strange. Let’s look at three species with weird and wonderful names!
Tasseled Wobbegong
The Tasseled Wobbegong (Eucrossorhinus dasypogon) is a species of carpet shark found in the shallow coral reefs of the Indo-Pacific. This unique shark gets its name from the tassels that hang from its chin and the sides of its head, making it look like it’s wearing a fancy carpet. The scientific name of the Tasseled Wobbegong, Eucrossorhinus dasypogon, comes from the Greek words “eu” meaning good, “krossoi” meaning fringe, “rhinos” meaning nose, and “dasys” meaning hairy, and “pogon” meaning beard, referring to the shark’s characteristic tassels.
The Tasseled Wobbegong has a broad, flattened head and a body that is covered in small, thorn-like projections. These projections, called dermal denticles, are a common feature of shark skin and help to protect the shark from predators and parasites. The Tasseled Wobbegong’s skin is also covered in a unique pattern of dark spots and stripes that allows it to camouflage itself on the reef floor. With their striking appearance and docile nature, they are a favorite of divers and underwater photographers.
Despite their wild appearance, Tasseled Wobbegongs are relatively docile and are known to be tolerant of human divers. They are primarily nocturnal, spending most of their days hiding in crevices and under overhangs on the reef. At night, they venture out to hunt small fish and crustaceans, using their powerful jaws to crush their prey.
Although the Tasseled Wobbegong is not considered to be a threatened species, it is facing increasing pressure from habitat degradation and overfishing. In 2018, the International Union for Conservation of Nature (IUCN) listed the Tasseled Wobbegong as a species of “Least Concern” on their Red List, which is a positive sign that the population is currently stable.
SCIENTIFIC NAME: Eucrossorhinus dasypogon
FAMILY: Orectolobidae
MAXIMUM SIZE: 122cm
DIET: Bony fish, crustaceans, and cephalopods
DISTRIBUTION: Found in the waters around southern Australia, including Tasmania and the Bass Strait.
HABITAT: Shallow, coastal waters with rocky or coral reefs, as well as seagrass beds and sandy areas.
CONSERVATION STATUS:
Crocodile Shark
This unique species (Pseudocarcharias kamoharai) is a small and slender-bodied shark. Which was only disovered in 1985! The genus name, Pseudocarcharias, means “false shark,”. While the species name, kamoharai, honors the Japanese ichthyologist, Kamohara. The English common name “crocodile shark” is derived from its Japanese name mizuwani (水鰐, literally “water crocodile”), which refers to its sharp teeth and habit of snapping vigorously when taken out of the water.
The Crocodile Shark is named for its distinct crocodile-like appearance, with a long snout and sharp teeth. With a maximum length of 1.2 meters. This species is found in deep ocean waters around the globe, from the Atlantic to the Indian Ocean, typically at depths of 200 to 500 meters. However, it has been known to venture as deep as 1,000 meters.
What makes the Crocodile Shark particularly unusual is its opportunistic feeding behavior. This means that it will eat just about anything it comes across. Including small fish, squid, and even other sharks. The Crocodile Shark uses a unique hunting technique to catch its prey. Its slender body and elongated snout allow it to navigate through tight spaces and ambush unsuspecting prey, making it a formidable predator despite its small size.
Since being discovered, we’ve not uncovered much about this elusive species. Not much is known about the biology and behavior of Crocodile Sharks. They are rarely encountered. And in 2019, the Crocodile Shark was listed as “data deficient” on the IUCN Red List. This means that not enough is known about the species to determine its conservation status. This elusive species’ DNA has been analysed and they are determined to be closely related to the Megamouth Shark or sand sharks (Odontaspididae). Alternative research, analysis based on teeth structure, suggests that the closest relatives of the crocodile shark are the thresher sharks.
SCIENTIFIC NAME: Pseudocarcharias kamoharai
FAMILY: Pseudocarchariidae
MAXIMUM SIZE: 1.2m
DIET: Bony fish and cephalopods
DISTRIBUTION: They are found in tropical and warm temperate waters around the world, including off the coasts of Japan, Australia, South Africa, and Brazil.
HABITAT: Deep offshore waters, typically at depths of 200 to 500 meters, but have been known to come up to shallower depths at night to feed.
CONSERVATION STATUS:
Viper Dogfish
The Viper Dogfish (Trigonognathus kabeyai) is a species of deep-sea shark found in the North Pacific Ocean. This unique shark gets its name from its distinctive appearance, which resembles that of a viper snake, due to the long, fang-like teeth protruding from its jaws. The scientific name comes from the Greek words “trigonos” meaning triangular, “gnathos” meaning jaw, and “kabeya” in honor of the late Japanese ichthyologist, Toshiji Kabeya, who made significant contributions to the study of deep-sea sharks.
The Viper Dogfish is a relatively small species of shark, growing up to just 40 centimeters in length. Its body is slim and elongated, with a dark brown or black coloration that allows it to blend in seamlessly with its deep-sea environment. They’re typically found at depths of between 365 and 1,200 meters, where they feed on a variety of prey including small fish, squid, and crustaceans. Their long, fang-like teeth allow them to easily catch and hold onto their prey, despite their small size.
Despite being a relatively unknown species, the Viper Dogfish has been listed as a species of “Least Concern” on the International Union for Conservation of Nature (IUCN) Red List.
SCIENTIFIC NAME: Trigonognathus kabeyai
FAMILY: Etmopteridae
MAXIMUM SIZE: 40cm
DIET: Small fishes and invertebrates
DISTRIBUTION: Northwest and central Pacific: Japan, Taiwan and Hawaiian Islands.
HABITAT: Deep waters, between 250 – 1000m. Possibly oceanic as some have been caught at 150m over water as deep as 1500m.
CONSERVATION STATUS:
Banner Image – © Frogfish Photography
Wobbegong – © Andy Murch
Crocodile Shark – © Dianne J. Bray, 2011, Crocodile Shark, Pseudocarcharias kamoharai, in Fishes of Australia, accessed 11 May 2014, http://www.fishesofaustralia.net.au/home/species/3001 | Wikimedia Commons
Viper Dogfish – © Stephen M Kajiura | Wikimedia Commons
In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.
This month we’re taking a look at the Dusky Shark, a highly migratory species with a particularly slow growth rate and late age at maturity.
Dusky sharks are one of the largest species within the Carcharhinus genus, generally measuring 3 metres total length but able to reach up to 4.2 metres. They are grey to grey-brown on their dorsal side and their fins usually have dusky margins, with the darkest tips on the caudal fin.
Dusky Sharks can often be confused with other species of the Carcharhinus genus, particularly the Galapagos Shark (Carcharhinus galapagensis). They have very similar external morphology, so it can be easier to ID to species level by taking location into account as the two species occupy very different ecological niches – Galapagos Sharks prefer offshore seamounts and islets, whilst duskies prefer continental margins.
Hybridisation:
A 2019 study found that Dusky Sharks are hybridising with Galapagos Sharks on the Eastern Tropical Pacific (Pazmiño et al., 2019). Hybridisation is when an animal breeds with an individual of another species to produce offspring (a hybrid). Hybrids are often infertile, but this study found that the hybrids were able to produce second generation hybrids!
Long distance swimmers:
Dusky sharks are highly mobile species, undertaking long migrations to stay in warm waters throughout the winter. In the Northern Hemisphere, they head towards the poles in the summer and return southwards towards the equator in winter. The longest distance recorded was 2000 nautical miles!
Very slow to mature and reproduce:
The Dusky Shark are both targeted and caught as bycatch globally. We already know that elasmobranchs are inherently slow reproducers which means that they are heavily impacted by overfishing; it takes them so long to recover that they cannot keep up with the rate at which they are being fished. Dusky Sharks are particularly slow to reproduce – females are only ready to start breeding at roughly 20 years old, their gestation periods can last up to 22 months, and they only give birth every two to three years. This makes duskies one of the most vulnerable of all shark species.
The Dusky Shark is now listed on Appendix II of the Convention on the Conservation of Migratory Species (CMS), but further action is required to protect this important species.
Scientific Name: Carcharhinus obscurus
Family: Carcharhinidae
Maximum Size: 420cm (Total Length)
Diet: Bony fishes, cephalopods, can also eat crustaceans, and small sharks, skates and rays
Distribution: Patchy distribution in tropical and warm temperate seas; Atlantic, Indo-Pacific and Mediterranean.
Habitat: Ranges from inshore waters out to the edge of the continental shelf.
Conservation status: Endangered.
For more great shark information and conservation visit the Shark Trust Website
Images: Andy Murch
Diana A. Pazmiño, Lynne van Herderden, Colin A. Simpfendorfer, Claudia Junge, Stephen C. Donnellan, E. Mauricio Hoyos-Padilla, Clinton A.J. Duffy, Charlie Huveneers, Bronwyn M. Gillanders, Paul A. Butcher, Gregory E. Maes. (2019). Introgressive hybridisation between two widespread sharks in the east Pacific region, Molecular Phylogenetics and Evolution 136(119-127), https://doi.org/10.1016/j.ympev.2019.04.013.
In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.
This month we’re looking at the Undulate Ray. Easily identified by its beautiful, ornate pattern, the Undulate Ray gets its name from the undulating patterns of lines and spots on its dorsal side.
This skate is usually found on sandy or muddy sea floors, down to about 200 m deep, although it is more commonly found shallower. They can grow up to 90 cm total length. Depending on the size of the individual, their diet can range from shrimps to crabs.
Although sometimes called the Undulate Ray, this is actually a species of skate, meaning that, as all true skates do, they lay eggs. The eggs are contained in keratin eggcases – the same material that our hair and nails are made up of! These eggcases are also commonly called mermaid’s purses and can be found washed up on beaches all around the UK. If you find one, be sure to take a picture and upload your find to the Great Eggcase Hunt – the Shark Trust’s flagship citizen science project.
It is worth noting that on the south coasts, these eggcases can be confused with those of the Spotted Ray, especially as they look very similar and the ranges overlap, so we sometimes informally refer to them as ‘Spundulates’.
Scientific Name: Raja undulata
Family: Rajidae
Maximum Size: 90cm (total length)
Diet: shrimps and crabs
Distribution: found around the eastern Atlantic and in the Mediterranean Sea.
Habitat: shelf waters down to 200m deep.
Conservation Status : As a commercially exploited species, the Undulate Ray is a recovering species in some areas. The good thing is that they have some of the most comprehensive management measures of almost any elasmobranch species, with both minimum and maximum landing sizes as well as a closed season. Additionally, targeting is entirely prohibited in some areas. They are also often caught as bycatch in various fisheries – in some areas they can be landed whilst in others they must be discarded.
IUCN Red List Status: Endangered
For more great shark information and conservation visit the Shark Trust Website
Image Credits: Banner – Sheila Openshaw; Illustration – Marc Dando
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