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Published in X-Ray Magazine May 2020

SORTING OUT THE STINGRAYS
by Nigel Marsh

Gliding slowly over the rocky reef I was mesmerised watching all the colourful reef fishes going about their daily activities. I was so entranced that I was startled to look up and find I was on a collision course with a massive stingray. This was the first stingray I had ever seen and the giant creature terrified me. In the second it took my panicking brain to work out what to do, the stingray suddenly saw me and also got a shock. A mad splash of fins saw us both turn tail and flee in the opposite direction!

I can still clearly remember that first stingray encounter, even though I was only nine-years-old, snorkelling in a bay north of Sydney, Australia. Once my courage returned, I jumped back into the water and this time got a closer look at this magnificent animal, a Smooth Stingray, the largest stingray species in the world. This graceful ray was almost 2m wide and didn’t seem to be too bothered by an annoying little kid swimming alongside. However, I was still very wary, staying well away from the tail, where I could see a large and lethal spine.

I think my love of stingrays started that day, and almost fifty years later I still get a thrill whenever I encounter a member of this diverse and interesting group of animals. Not because they are potentially dangerous with their dagger-like tail spines, but because they are fascinating to watch as they go about their daily lives; be it digging in the sand for food, gliding gracefully around the reef or simply lazing on the bottom.

Stingrays are mainly found in tropical and subtropical waters, but a few venture into temperate zones. And as most stingrays inhabit shallow water, they can be found at many popular dive sites around the planet. At some dive sites the stingrays are the main attraction, and accustom to divers they are easy to approach, study and photograph. There are also a number of popular stingray feeds, like the famous Stingray City in the Cayman Islands, where divers can literally get mugged by dozens of hungry rays.

While many stingrays look the same, there are actually close to one hundred species that vary greatly in size, shape, colouration and tail length. In recent years the stingray family has had a major shakeup, with many new species described and many species rearranged within the family, which can make sorting out the stingrays very tricky.

Stingrays are a member of the large and diverse ray family, Batoidea, which contains over 600 species in 26 family groups. Stingrays (the family is also known as whiptail stingrays) are placed in the order Myliobatiformes, along with the devil rays, eagle rays, stingarees and several lesser known family groups. Stingrays are further placed in the super family Dasyatidae which contains four sub-families – Dasyatinae, Hypolophinae, Neotrygoninae and Urogyminae.

Until recently there was thought to be around 60 stingray species contained within five genera groups. However, a major review of the family in 2016 by researchers Peter Last, Gavin Naylor, and Mabel Manjaji-Matsumoto, looking at morphological and molecular differences, has drastically changed the family, with 95 species now recognised within 19 genera. This is such a drastic change that most guide books and websites used to identify stingrays are completely out of date.

To help divers’ sort through the changes within the stingray family, this article will look at many common stingrays found around the world and where they fit within the stingray family tree. I will look at these stingrays genus-by-genus, as each genus contains stingrays with similar features. The genus names are quite complex, like Bathytoshia, so I have included a common group name for each genus. Some of these are in general usage, but I have also had to create a few names based on a common feature.

IMAGE BELOW - SMOOTH STINGRAY

BATHYTOSHIA – ROUGHTAIL RAYS

This genus of stingrays contains three species that all have a rough tail, covered in dermal denticles. The best-known member of this family is the one I first met as a child, the largest stingray in the world, the Smooth Stingray (Bathytoshia brevicaudata). This species, like most stingrays, was once placed in the large Dasyatis genus, but the revisions have seen this genus reduced to just five species.

The Smooth Stingray is only found in the Southern Hemisphere, inhabiting the temperate waters of southern Australia, New Zealand and South Africa. Well known to divers in cooler waters, the Smooth Stingray reaches a width of 2.1m, and has a short tail and often a white-spotted V-shaped pattern around the head. In Australia this species is very common around jetties and boat ramps; spots where fishers clean their catch and throw scraps to the resident rays. The rays are almost local celebrities, well known to everyone in the local community. Unfortunately, this doesn’t stop some fishers from killing them or chopping off their tails if they are accidently hooked.

One of the best places to see this species is the Poor Knights Islands in New Zealand, where they are called the Short-tailed Stingray. Seen on almost every dive at this wonderful dive destination, these rays are known to occasionally gather on mass over the summer months, cruising in midwater in caves and arches.

The other common member of this genus has caused quite a bit of confusion since the recent review. The Broad Stingray (Bathytoshia lata) looks very similar to the Smooth Stingray, but has a long tail and a row of thorns along its back. This species varies in colour from black to brown and grows to 1.8m wide. Once thought to occur only around the Hawaiian Islands, the review found that several other stingray species from around the world were actually this species. However, since the Hawaiian one was the first to be described, the other scientific names have become obsolete. For this reason, this species has many common names around the world, including the Longtail Stingray, Black Stingray, Brown Stingray and Thorntail Stingray. The Broad Stingray is found in both temperate and subtropical waters, with two of the best places to see them being the Canary Islands and Poor Knights Islands in New Zealand.

IMAGE BELOW - BROAD STINGRAY

DASYATIS – ROUGH RAYS

This poor genus took a beating in the recent review, losing almost all its members apart from five species that are limited to the Atlantic Ocean. The Rough Rays get their name from the Greek, with dasys meaning rough. But only some older rays in this genus have rough skin, a row of thorns along the back, but they all have the classic diamond-shape and a medium length tail with upper and lower skin folds.

Well known to the ancient Greeks and Romans, the Common Stingray (Dasyatis pastinaca) is the archetypal member of this genus. One of the first rays described by science, the Common Stingray is found in the Eastern Atlantic, including the Mediterranean and Black Sea. Typically grey to golden-brown in colour, there is a bit of a dispute as to how big this species grows, with some sources saying 60cm wide, and others 1.4m wide. The Common Stingray is not as common as it once was, due to fishing pressures, and is now listed as ‘near threatened’. This species is mostly seen by divers in the Mediterranean and Canary Islands, but is not really common anywhere anymore.

A more common member of this genus is the closely related Tortonese’s Stingray (Dasyatis tortonesei). This species is found over much the same area as the Common Stingray, and looks very similar, so telling them apart can be tricky, with the Tortonese’s Stingray having a larger spiracle. The Canary Islands appears to be the best destination to see this ray, especially at Los Gigantes on Tenerife. At this site a ray feed is conducted, attracting up to six species of rays, with the Tortonese’s Stingrays the most common and numerous of attendees.

IMAGE BELOW - TORTONESE'S STINGRAY

HYPANUS – THORNY BACK RAYS

The stingrays in this family all have a row of thorny dermal denticles along their back, and a medium sized whip-like tail. The genus contains eight members that are only found in the warmer waters of the eastern Pacific and western Atlantic. While a few of these stingrays are seen by divers, the most famous member of this clan is the Southern Stingray (Hypanus americanus). Found from the southern United States to Brazil, this species is best seen in the Caribbean. The Southern Stingray varies in colour from grey to brown, with the females growing to 1.5m in width, while the poor males only reach 67cm wide. The best place to see dozens of these rays is Stingray City in the Cayman Islands.

IMAGE BELOW - SOUTHERN STINGRAY

TAENIUROPS – FANTAIL RAYS

The Fantail Rays typically have a round disc and a short tail with a long skin fold. The most common member of this genus, which only contains two species, is the Botched Fantail Ray (Taeniura meyeni). This wide-ranging tropical and subtropical species is found throughout the Indo-Pacific region. This species has many common names, such as the Marble Stingray, Black-blotched Ray and Black-spotted Stingray. The Blotched Fantail Ray varies greatly in colour from black, to black with white or grey blotches and even grey with black blotches. This species grows to 1.8m in width and while it spends most of its time on the bottom, they also like to hoover in midwater when a current is running. Blotched Fantail Rays can be seen almost everywhere, but there are particularly common in Australia. While you will run into the occasional one on the Great Barrier Reef or Ningaloo Reef, they are most abundant in subtropical waters, with large numbers seen off southern Queensland and northern New South Wales.

IMAGE BELOW - BLOTCHED FANTAIL RAY

The only other member in this genus is the Round Fantail Ray (Taeniura grabata). Found in the warmer waters of the eastern Atlantic, this species grows to 1m in width and is typically a brownish colour with darker spots and blotches. The Round Fantail Ray is most commonly seen by divers around the Canary Islands. These two stingrays were some of the few that didn’t get a name change in the recent review, but two members of this genus were removed to form the next genus, Taeniura.

IMAGE BELOW - ROUND FANTAIL RAY

TAENIURA – RIBBONTAIL RAYS

The two members of this genus were removed from Taeniurops as phylogenetic research showed they were not related, even though they have a similar fan-like tail, but an oval shaped disc. The most common member of this family seen by divers is the Bluespotted Ribbontail Ray (Taeniura lymma). Found in tropical waters throughout the Indo-West Pacific, this species is one of the easiest to identify when exploring coral reefs, due to its oval-shape and bright blue spots. This small stingray only reaches a width of 30cm and they tend to hide under plate corals and holes in the reef more often than burying in the sand. Divers can see this species anywhere across its range, from the Red Sea to the Solomon Islands. There are several other small blue-spotted stingray species, but it is easy to identify which-is-which as these other stingrays have a kite-shape, less vivid spots and a dark mask across the eyes which has led to them being called Maskrays.

IMAGE BELOW - BLUESPOTTED RIBBONTAIL RAY

NEOTRYGON – MASKRAYS

One of the biggest shakeups in the stingray family happened to the Maskrays. These small stingrays got their own genus and what was once thought to be one wide-ranging Bluespotted Maskray, is now known to be eight different regional species. The Maskray genus now contains 16 species that are found throughout the Indo-Pacific region. These stingrays are small, with a short tail and a distinctive dark mask colouration across the eyes. While species with blue-spots are the best-known members of this family, others have black-spots and some rarer ones have pretty mosaic patterns.

IMAGE BELOW - ORIENTAL BLUESPOTTED MASKRAY

Divers exploring the reefs and muck sites of Southeast Asia often come across the Oriental Bluespotted Maskray (Neotrygon orientale). This small ray naturally has blue-spots and was one of the rays commonly called the Bluespotted Maskray. A far more common member of this genus is found off the east coast of Australia that also has blue spots and is now called the Coral Sea Maskray (Neotrygon trigonoides). This is one of three Maskrays with blue-spots found in Australian waters, but this is the most abundant species, especially off southern Queensland and northern New South Wales. One of the best places to see this species is Julian Rocks off Byron Bay, and while several are always seen on a dive, sometimes over the summer months thousands gather in the sandy gutters at this site for some unknown reason.

IMAGE BELOW - CORAL SEA MASKRAY

PASTINACHUS – COWTAIL RAYS

Until recently there was only thought to be one wide-ranging Cowtail Stingray species found across the Indo-Pacific region, but the research found there are five regional species with the distinctive long skin fold at the end of the tail. The original Cowtail Stingray (Pastinachus sephen) is not as wide ranging as originally thought, and is only found in the northwest Indian Ocean area.

The most abundant and wide spread member of this genus is the Broad Cowtail Stingray (Pastinachus ater). One of the newly described species, this large ray grows to 1.8m wide and is found in tropical and subtropical waters throughout the Indo-West Pacific. Targeted by fishers for its flesh and skin, this species is listed as ‘near threatened’, so is not as common as it once was. The only area that I have found this species to be common is off southern Queensland, Australia.

IMAGE BELOW - BROAD COWTAIL STINGRAY

HIMANTURA – PATTERNED WHIPRAYS

Many more stingray species were once found in this genus, but the shakeup created six additional genera from the members of this group, leaving only four species in Himantura. The Patterned Whiprays have a very long whip-like tail and are the prettiest of all the stingrays with their beautifully patterned skin. These rays are only found in the tropical and subtropical waters of the Indo-West Pacific.

The Reticulated Whipray (Himantura uarnak) is the most wide-ranging member of this genus, found throughout the Indo-West Pacific, but not in Australia. These pretty rays can grow to 2m in width and have a spectacular skin pattern of reticulations and sometimes leopard-like spots. Encounters with this ray are rare. This ray was also thought to be found in Australia until the recent review, when it was discovered that the Australian Whipray (Himantura australis) is a separate species. These two stingrays look almost identical, so locality is the best way to tell them apart. Divers have more chance of seeing this pretty ray, especially off southern Queensland. Groups of Australian Whipray are sometimes found at dive sites off Rainbow Beach, Brisbane and the Gold Coast.

IMAGE BELOW - AUSTRALIAN WHIPRAY

The confusing thing about this genus is that these two stingrays can have leopard-like skin patterns, and the two other members of the group, the Leopard Whipray (Himantura leoparda) and the Honeycomb Whipray (Himantura undulata) also have a leopard-like skin patterns, but are less commonly seen by divers. The Honeycomb Whipray is found in the tropical waters of Southeast Asia to India, while the Leopard Whipray is more wide-spread, found from southern Africa to northern Australia.

IMAGE BELOW - LEOPARD WHIPRAY

PATEOBATIS – PLAIN WHIPRAYS

This is one of the groups that split from Himantura, they also have long whip-like tails, but have very plain colouration. This genus contains five species found in the Indo-Pacific region, with the most wide-spread and abundant species being the Pink Whipray (Pateobatis fai). Although called the Pink Whipray, this species is generally a brownish-grey colour and can reach a width of 1.8m. A very social stingray, Pink Stingrays are often seen in a fever (a group of rays) that can number from five to fifty. These rays also like to hang around other larger stingrays, and have been seen riding the backs of Blotched Fantail Rays. The Maldives is a good place to see Pink Whiprays, and they are seen in large numbers at a shark/ray feed at Alimatha Faru. They are also common off southern Queensland, Australia, with large groups of them seen at Manta Bommie off Brisbane.

IMAGE BELOW - PINK WHIPRAY

The very similar looking Jenkins Whipray (Pateobatis jenkinsii) is found over an almost similar range to the Pink Whipray, but is less commonly seen by divers. It may look similar, but the easiest way to tell them apart is by the row of short spines along the back of the Jenkins Whipray. One of the best places to see this stingray is the Perhentian Islands off Malaysia.

IMAGE BELOW - JENKINS WHIPRAY

UROGYMNUS – PRICKLY WHIPRAYS

This genus was thought to contain only one species, the very strange Porcupine Stingray, but the recent review has found that several more species, once placed in Himantura, belong in this group. The genus now contains six species, all have a round disk, a long whip-like tail and dermal denticles on their backs and tail. A few of the Prickly Whiprays live in mangroves and rivers, including the famous Giant Freshwater Whipray (Urogymnus polylepis) of Southeast Asia.

The best-known member of this genus is the Porcupine Stingray (Urogymnus asperrimus), which is quite rare, but occasionally seen by divers in the tropical waters of the Indo-West Pacific. This strange ray is covered in short spines, hence the name, and is the only member of the stingray family to lack a tail spine. The Porcupine Stingray can reach a width of 1.2m and is listed as ‘vulnerable’. Australia is one of the best places to see this weird ray, with occasional sightings on the Great Barrier Reef and Ningaloo Reef.

IMAGE BELOW - PORCUPINE STINGRAY

The only other member of this genus seen by divers is the Mangrove Whipray (Urogymnus granulatus). Found on reefs and in mangroves, this ray is easily identified by its long white coloured tail. Found throughout the tropical Indo-West Pacific, the Mangrove Whipray reaches a width of 1.4m. This is another ray that is best seen in Australia, on the inner islands and reefs of the Great Barrier Reef.

IMAGE BELOW - MANGROVE WHIPRAY

There are many other genera in the stingray family that I haven’t included in this article, as they are rarely seen by divers, either living in rivers, mangroves or having a pelagic lifestyle.

Sorting out the stingrays must have been a mammoth task for the scientists that did the research work, and there is sure to be more changes in the future in this complex and diverse family of rays.

If you would like to know more about stingrays and other rays, I have started a Facebook group called the Ray Photography Group, so people can share photos, videos and their knowledge of this very interesting group of marine creatures.

STINGRAY BIOLOGY AND BEHAVIOUR

Stingrays, like all the rays, are very closely related to their cousins the sharks, and share many similar body features. The main difference between the two is that rays have their pectoral fins fused with their head and also have their gills on their ventral surface (the underside of the body). Stingrays differ from other closely related members of the ray family by their longer tails, which lack dorsal, anal and caudal fins, but can have skin folds. Most stingrays are quite large, over one metre in width, but their disc can vary greatly in shape; from round to diamond-like to even oval. They also have small pelvic fins, and many have rough spines, dermal denticles or tubercles, on their tail or back. All stingrays have a tail spine (except for the Porcupine Stingray) for defence, which regrows when lost.

As most stingrays like to hide under a layer of sand, they have modified their breathing to suit this behaviour. While they can breath in through their mouth and out through their gills to extract oxygen, they have developed large respiratory openings behind the eyes called spiracles to intake water. These spiracles allow them to breath normally for extended periods when buried in the sand, without ingesting sand. Sharks also have spiracles, but they are very small in most species, apart from a few bottom-dwelling sharks.

IMAGE BELOW - CORAL SEA MASKRAY HIDDEN IN THE SAND AND BREATHING THROUGH ITS SPIRACLE

Like sharks, stingrays have an acute array of sensors that help them detect prey. As most of their prey lies buried in the sand, where it can’t be seen by the ray, they rely on other sensors to located prey. To find buried prey, stingrays use a combination of smell and special electrical sensors on their snout called the ampullae of Lorenzini, which detect weak electrical signals given off by animals. The rays then use their mouth to dig into the sand to grab their food, which can be fish, worms, crustaceans or molluscs. Many stingrays feed by day, others only feed at night, but some feed at any time, driven more by the tides, especially if they feed on mud flats.

Stingrays are typically solitary animals, only coming together to mate, or when feeding. But a few species are quite social, forming small groups, called a fever. Little is known about the dynamics of these groups; are they together for company, for ease of finding a mate, for defence in numbers or simply because there is abundant food in the area? Some gather into large aggregations when breeding, others get together for no apparent reason at all.

Romance and mating between stingrays is rarely witnessed. Premating rituals are poorly understood, but generally entail the male, or several males, following a female to see if she is in season, and then biting and shoving the female (if she is smaller, but in many cases the female is larger than the males). When mating the male typically bites the female on the edge of her disc, then either twists around her, or lies belly-to-belly to insert one of his two claspers into her cloaca. The claspers are penis-like organs, formed from modified pelvic fins, that deliver sperm into the female. Pregnant females are often seen with large swellings in their back. Stingrays give birth to live young, with litters varying in number from two to six after a gestation period of up to twelve months. Young rays are rarely seen, so either hide in deep water, mangroves, estuaries or rivers. The only juvenile stingrays I have seen are Bluespotted Ribbontail Rays at night on a reef at Uepi, Solomon Islands, with the small rays emerging from hiding spots amongst the coral.

Stingrays spend much of their time either resting or feeding, but many regularly visit cleaning stations to get rid of parasites, old skin and other blemishes. Over fifty species of fish are known to provide cleaning services, but most stingrays utilise the services of the wide-spread Common Cleaner Wrasse (Labroides dimidiatus). These tiny wrasse pick over the skin of the stingray, and even enter the mouth and gills. But I have also witnessed a group of Guenther's Butterflyfish (Chaetodon guentheri) picking over the skin of a Pink Whipray off Brisbane, Australia.

The main predators of stingrays, apart from humans, are sharks and Orca. To avoid being eaten stingrays hide under a layer of sand or rest in caves, shipwrecks or under ledges. But when these evasive measures fail, stingrays use their tail spines for defence. They use the spine like a dagger, bringing the tail over their head to either stab or slash at the attacker. The spine is serrated, covered in a venom secreting tissue and has two longitudinal grooves which enclose venom-secreting cells. The spine is designed to break off in the attacker and cause infections. Large stingrays have spines up to 20cm long, but even this doesn’t deter some attackers, with some Great Hammerheads (Sphyrna mokarran) found with dozens of stingray spines stuck in their heads. Stingrays pose little threat to divers and snorkelers, with fishers and people wading in shallow water the most likely ones to get jabbed. If ever jabbed by stingray, even if it is minor, seek immediate medical attention to get the wound properly cleaned to avoid infection.

IMAGE BELOW - THE TAIL SPINE OF A BLOTCHED FANTAIL RAY

DIVING WITH STINGRAYS

While the general public have the perception that stingrays are dangerous, especially after the death of Steve Irwin, stingrays are in fact docile animals that have a tail spine for defence only. Very few divers or snorkelers have been stabbed by stingrays, as they would rather flee than fight, but if cornered or grabbed they will lash out.

Over the years I have encountered thousands of stingrays, and I have only ever had two raise their tail at me in a threat display. Both were Smooth Stingrays, and both encounters are worth looking at. In the first case my buddy and I were diving off Jervis Bay, south of Sydney, through a series of interconnected caves off Point Perpendicular. In one of the caves we found a large Smooth Stingray resting on the bottom. Having encountered dozens of these large rays before I thought it would not be an issue swimming over the ray to exit the cave. The ray was okay at first, but as I got closer to the exit the ray felt trapped and raised its tail at me to back off. I quickly did, and my bubby and I decided to find another exit from the cave. Lesson learnt, don’t corner a stingray or block its exit.

Snorkelling off Sydney I encountered another pair of Smooth Stingrays in a rocky gutter at Little Bay. One of the rays was huge, 2m across, but the other one was only half this size. I watched them from the surface as the small ray swam around the large resting stingray. After observed them for several minutes I realised that the large one was a female and the smaller one an amorous male. I then dived down to get some photos, thinking I might witness the rays mating. But swimming towards the female she suddenly lifted her tail over her head and pointed her spine at me to stay away. I took note and headed back to the surface, but only minutes later saw her also do the same thing to the small male, telling him to back off. This was very interesting behaviour to see her warning both me and the horny male. I am still not sure if she thought I was another male stingray, or if she was just sick of being harassed. Another lesson learnt, don’t intrude on stingray romance.

IMAGE BELOW - AN UNDERWATER PHOTOGRAPHY GETTING CLOSE TO A BROAD COWTAIL STINGRAY

At stingray feeds the tail spine is not an issue, as the rays don’t feel threatened, it’s the mouth you have to worry about. Stingrays have small plate-like teeth that are designed to assist them grub in the sand for a variety of prey. However, as they need to crush the shells of some prey their jaws are quite powerful. I have never been bitten at a stingray feed in the wild, but have in an aquarium when photographing feeding time. The head diver warned me that the sharks and fish were not an issue, but to watch out for the stingrays, and to keep my hands well away from their mouth. This ended up being easier said than done as the stingrays, a gang of Blotched Fantail Rays, were all over us. This made it very hard to get photos, as I had to constantly push and bump the stingrays away to avoid being knocked over. The rays were constantly searching for our hands, knowing that this was the source of food, and eventually one latched onto my hand and BAM! It felt like my fingers had been hit by a hammer! Another lesson learnt, keep fingers away from a stingray’s mouth.

Getting close to stingrays underwater can be tricky, as most species are preyed upon by sharks, so are warry of large creatures heading towards them. Stingrays that regularly encounter divers at popular dive sites are often easy to get close to, as they are unperturbed by the close presence of a diver. However, most stingrays are shy, and take flight when a diver approaches. To get close to a stingray the best approach is to come in slowly from the side, and not charge in head first with a camera raised like a weapon. A trick I often use is to angle my body like I am swimming away from the ray, but then shuffle sideways towards the animal, which is not an easy manoeuvre, especially into a current. It is also good to slow your breathing, and not look directly at the ray, instead face away and look at it from the corner of your eye. Some stingrays will allow you to get right up beside them, while others will take off the second they see you. The less threatening you appear, the better the encounter, and generally the fewer divers, the better. Stingray encounters are the highlight of many diving adventures.