Specimen Showcase | Angel in the Sea 🦈

Sharks, unfortunately, do not always have the best reputation😥, indeed only about 65 attacks are recorded annually all over the world 🩸. Our species today, however, is rather harmless to us but full of surprises🤩🎊!

𝘚𝘲𝘶𝘢𝘵𝘪𝘯𝘢 s𝘲𝘶𝘢𝘵𝘪𝘯𝘢 (Duméril, 1805), known as the Angelshark👼🏻, their name reflects their flat body with pectoral fins extending laterally ➡️ and fused to the side of the head, like wings that make them look like swimming angels👼🏻🌊. With a size reaching 1.5 to 2.5 meters in length as an adult, it may not seem so easy to hide in the ocean with such a massive body🤔! Yet, unlike most sharks, their skin is usually mottled with black⚫️, brown🟤, white⚪️, and red spots 🔴 to look similar to the sand in which they like to bury themselves in for camouflage, with only their eyes protruding👀. Their flattened body and the absence of anal fins 🙅🏻 allows them to hide very well in the sandy or muddle ocean floor too. Singularly, they are the only shark species 🥇 to possess on their tails a lower fin larger than the upper fin🤩, which is a great morphological adaptation helping them gaining momentum 💪🏻🔥 when they propel from the seafloor to catch prey🐠.

Angelsharks are migrating species 🌏 that will move to more comfortable temperatures🌤️ as seasons change. They live in shallow waters🏝️ and prefer habitats near the coastlines of the North Atlantic ocean🗺️ ranging from Scandinavia🏔️ to Northwestern Africa⛰️, as well as in the Mediterranean and Black Sea🌊. Their life habits, however, often conflict with areas used for active industrial🏗️ and recreational fisheries⚓️, which now place the species under threat 😭. Resting Angelsharks are usually found adjacent to either rock-sand interfaces or patch reefs because these sites serve as a refuge for potential prey. They usually orient themselves toward the upslope direction ⬆️ so the sediment falling downslope can help bury them, while at the same time, helps target prey swimming downslope ⬇️ from the reefs. This shows how well adapted they are to their environment🏅😎.

We seldom see Angelsharks move, as they are ‘nocturnal’ 😈 which means more active at night. They swim strongly off the sea bottom at night 🏊🏼🌌 traveling long distances to locate new ambush sites. Then they will stay at the new hunting spot for around 10 days🤩 , probably a time short enough to exhaust potential prey sources👅 or for the latter to identify the hiding spot of the predator 👀❗️ Angelshark are excellent camouflage experts with spiracles (small openings) next to their head and have very strong mouth muscles to keep oxygenated water running through their gills 💦 so they can keep looking for their prey. With remarkable smell💨, they can detect minute electric fields ⚡️and have sensory barbels near their mouth to detect any prey approaching nearby🐠. Extremely well-adapted to the dark, they even use the light 💡generated by bioluminescent plankton to see their prey!

Yet, buried in the sand, how can they catch food? Here we should note that Angelsharks have very wide mouths 🥴 and strong jaws 😎, along with needle-like teeth🔪. Their teeth will grow continuously and are arranged into 19 rows😱! 9 rows in the upper jaw and 10 rows in their lower jaw. There is, however, a gap located in the center of their mouth 🤏🏻 that allows the jaw to flex, bend and specifically hold onto their prey tightly💀. The anterior position of labial cartilages and the attached musculature form a circular-shaped mouth😮 for suction feeding. They also have nice skills to stay still while waiting for prey to wander by. Don’t be deceived by their name😏, Angelsharks are actually swift ambush predators 💫 presenting four attack action patterns, including 1️⃣cranial elevation, 2️⃣mouth expansion, 3️⃣upper-jaw protrusion, and 4️⃣jaw-closure. During these attacks, their head will raise at an extreme angle 📐of about 90 degrees toward the prey❗️After attacking at a right angle level, they will bury themselves again to the same location. We can see them in shallow water 🏝️ as it provides rich nutrients and abundant food sources like small fishes🐟, squid 🦑and prawns🦐. Although they can be observed near the coast, they are usually harmless to humans, unless you provoke them🔥.

If you want to take a deeper insight into this amazing shark species🤩, remember to visit the Hong Kong Biodiversity Museum💯! But look out for their sharp, pointy teeth🥶🔪!

Text: Macy Huen

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