Introducing the Tasselled Wobbegong

This remarkable little shark is brilliant example of an ambush predator. The tasselled wobbegong (Eucrossorhinus dasypogon) is a highly unusual looking shark, its patterning and coral like tassels on its head makes it blend in with sea beds and coral reefs. The latin name for the tasselled wobbegong (Eucrossorhinus dasypogon) roughly translates to ‘well fringed nose with shaggy beard’. This refers to the distinctive mass of branching skin flaps that run continuously around the jaws. The ‘beard’ helps this wonderful shark  blend into its habitat. This facial adaptation, coupled with lightning speed makes a nightmare for many reef fish, as the tasselled wobbegong is adapted to be the prefect ambush predator.

Growing to a maximum length of 117 – 125 cm, the tasselled wobbegong is found on the coastal reefs of eastern Indian Ocean and the western-central Pacific Ocean, around Indonesia, Papua New Guinea and Australia (Northern Territory, Queensland, Western Australia). This nocturnal hunter has a highly varied diet. It sits in the mouth of a cave and waits for squid, reef fish, crustaceans and cuttlefish to drift within range, and then pounces with lightening speed.

The wobbegong family is believed to have a very short-range, usually having several hunting spots on a single reef system. The flattened body helps this wonderful shark sink into the sand and remain unseen. Additionally, tasselled wobbegongs have a deadly behavioural adaptation, where it uses its flat tail to lure prey in. When the shark is laying in wait, buried in the sand, its flattened tail is held above the sea bed and it moves in the current, resembling a small fish. This tail movement draw in the sharks’ prey items.

The Teeth!

sharkteeth

Note how the teeth of the wobbegong have no pointy bits at the side (lateral cusplets)  these cusplets are clear to see on other species like the grey nurse shark teeth (Carcharias taurus). Additionally the wobbegongs’ teeth are unsarated like the teeth of great white sharks (Carcharodon carcharias). I will write a blog on specific tooth adaptations of sharks in the next few days which will shed more light on why these teeth are so different.

The tasselled wobbegong has two rows of razor-sharp, smooth, fang-like teeth on the palatoquadrate (upper jaw) and three rows located on the Meckel’s cartilage (lower jaw). The teeth are angled backwards like most sharks to help hold the prey. Like many other carpet sharks. The teeth of tasselled wobbegong have strong media cusps, and as mentioned the lateral cusplets are often absent or variable.(refer to image above)

There has been debate around the evolutionary relationship of the tasselled wobbegong, morphological studies has led to the current thought that the tasselled wobbegong is among the more derived wobbegong species. However, mitochondrial and nuclear DNA analysis contradicted these morphological findings, suggesting that this species was a closer relative to all the other wobbegongs, except for the northern wobbegongs (Orectolobus wardi).

Due to the limited distributional range of these animals, the tasselled wobbegong’s conservation status should be of concern. As this species lives primarily on coral reefs, the biggest threat this shark faces is habitat destruction from pollution and unsustainable, destructive fishing practices. It is currently listed as near threatened by IUCN (world conservation union). Fortunately for the tasselled wobbegong most of its habitat resides inside MPAs (marine protection areas) which are in place to preserve the great barrier reef. The IUCN, governmental and non-governmental organizations act in a partnership which assess the conservation status and manage the conservation of this species.

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