Taeniura+lymma+(Peter+Forsskål,+1775)

= Introduction =

Food, Friend or Foe?
toc When you think of stingrays, what is the first thing that comes to mind?



Whether food, friend or foe, stingrays are essentially fish. Yes, you read that right. Stingrays are fish. But delicious as they may be as a food source in Southeast Asia, Australia and East Africa, it is unfortunate that stingrays have earned a reputation of being dangerous and venomous creatures even when they are, in fact, considered timid and docile creatures by most experts. No doubt they are venomous with their tail spines but they are usually only used in self-defence (such as being accidentally stepped on) or when they feel threatened. With exceptions such as Steve Irwin’s death on 4th September 2006 and 81-year-old James Bertakis’ incident, both of whom were stabbed in the chest by a stingray [2], stingray-related injuries to humans typically occur in the lower parts of the body (due again to accidentally stepping on them) and are rarely fatal. The venom causes an excruciating pain but it is rarely deadly to humans (maybe except when delivered to critical areas) and the wound can even be treated if it is not too serious (read more about Defence Mechanisms).

 Now, even if we consider them as friendly, not-so-dangerous creatures, the way that we treat them still leaves much to be desired (read more about Conservation Status and Threats). We will see that this is especially problematic as we now turn our attention to one of the most abundant, beautiful and iconic stingrays to inhabit the nearshore, coral reef-associated habitats of the Indo-West Pacific region [1]. This is none other than the...

** BLUE-SPOTTED FANTAIL RAY (//Taeniura lymma//) ** media type="youtube" key="tFZM6i-ji_E" width="862" height="482" align="center"

 Belonging to the stingray family Dasyatidae (whiptail stingrays), //T. lymma// is a cartilaginous fish (their skeletal system is made of cartilage rather than bone like humans and other vertebrates) that is common throughout the tropical Indian and western Pacific Oceans, with a range that begins from the intertidal zone and extends up to a depth of 30 metres (100 feet). It can grow up to 35cm across and 80cm long, with a weight of up to 5kg [1].

Conservation Status and Threats
Given the charismatic looks of //T. lymma// (read more about Physical Description), it is not surprising that it is perceived more as a friend rather than food or foe. But are we really treating it as such? Our actions actually say otherwise.



 There is currently no data on the local status of //T. lymma// in Singapore but ever since 2005, //T. lymma// has been listed as "Near Threatened" (global status) under the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. This is due to the following human activities and practices that continue to threaten its survival.


 * = __**1. Habitat Destruction**__ ||= __**2. Over-fishing**__ ||= __**3. Aquarium Trade**__ ||
 * = With the rise in global population and the demand for space and resources, coastal development has been rapidly increasing over the years, as evident from land reclamation works. This has contributed to the degradation of coral reefs, which essentially translates to fewer and less viable habitats for //T. lymma// throughout its range [1].  Degradation of coral reef habitats for //T. lymma// can also be attributed to climate change as well as destructive fishing practices that use cyanide or dynamite [1] . ||= //Taeniura lymma// faces intensive fishing pressure throughout its range, be it being caught intentionally as food or gamefish, or unintentionally as bycatch. With fishing practices that utilize gillnets, longlines, spears and fence traps, all of which extend to the bottom of the sea floor and catch fish indiscriminately, it is no wonder //T. lymma// can get caught or trapped in them [1][4] . ||= As an attractive creature, //T. lymma// is popular with home aquarists as an aquarium pet <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1][4][5] <span style="font-family: Calibri,sans-serif; font-size: 14.6667px;"> and is in fact, the most common stingray found in private home aquariums <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1] . <span style="font-family: Calibri,sans-serif; font-size: 11pt;">This is despite the fact that it does not fare well in captivity <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1][4][5], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">with individuals outgrowing the aquariums <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[5] , <span style="font-family: Calibri,sans-serif; font-size: 11pt;">and even those seemingly healthy ones suddenly dying or refusing to feed <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1]. ||

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Having a positive image as a "friend" is generally perceived as a good thing. Especially in the field of conservation, it is likely the case that there will be less human-wildlife conflict and more reasons for protecting the organisms of interest and/or its habitat than removing or exterminating them, if it is seen positively. But having this positive image is only good until it starts to backfire and ironically cause more harm upon the organism, as evident from the involvement of //<span style="font-family: Calibri,sans-serif; font-size: 11pt;">T. lymma //<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> in the aquarium trade. The important conservation message here then is that charismatic creatures such as //<span style="font-family: Calibri,sans-serif; font-size: 11pt;">T. lymma //<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> are most beautiful when free to roam about in their natural habitats, not when they are kept in captivity whiile their natural habitats get destroyed by human activities.

A Common Mix-up
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Notice how so far, we have been using the scientific name (//T. lymma//) rather than the common name (blue-spotted stingray) when referring to this species of interest? Well, that is because this species goes by several common names, both English and non-English [1][3] <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> (Fig. 3) and the scientific name is the most straightforward and unambiguous way of referring to this species. The following figure presents some of the common names of //T. lymma// in selected languages used within the region it can be found in (read more about Geographical Range and Distribution).



<span style="font-family: Calibri,sans-serif; font-size: 80%; vertical-align: super;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">From one glance, it is easy to see how the common name of this species came about. 1) It is a stingray. 2) It has blue spots (read more about Distinctive Features). It makes sense for easier general communication //if// it was the //only// stingray with blue spots but guess what? There is another stingray species called //Neotrygon kuhlii// which also has blue spots and is, coincidentally, also known commonly as the blue-spotted (sting)ray (see the names in red) or Kuhl’s stingray. Not to mention that this second species also tends to occupy the same kind of habitat - inshore over coral reefs [4] (read more about Habitat) - which further complicates things. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Hence, scientists have devised a standardized naming system with vigorous rules to avoid such confusion. For more information on how scientific names work, check out this page. Having said all that, for the rest of this page, we will continue to use the scientific names of species.

<span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;"> __DID YOU KNOW?__ <span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;"> All of this mix-up seems to originate from two main things. On one hand, we have N. kuhlii, which is found almost everywhere in the world except the Red Sea and is commonly called the “blue-spotted (sting)ray”. On the other hand, T. lymma, which is actually found in the Red Sea and referred to as the “blue-spotted fantail/ribbiontail ray” everywhere else, is known by locals near the Red Sea as *the* “blue-spotted (sting)ray” since it is the only stingray that locals have seen in the region.

A New Discovery!!!
<span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;">Considering how recognizable and popular //T. lymma// is, it is reasonable to think that there would not be an surprises left in store for us but... we were wrong. In fact, just earlier this year in 2016, researchers have split the existing //T. lymma// species into two separate species, with the newly described one called //Taeniura lessoni//. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">In light of this, besides providing some general information on stingrays, with a focus on the species //T. lymma//, this page also aims to resolve part of the prevailing confusion by providing some diagnostic features that can allow one to tell //T. lymma// apart from species it is can be confused with such as //N. kuhlii// and //T. lessoni// (read more about Species Diagnosis and Identification). Fret not if some of the terms used get a little technical at times for explanations to these terms are provided where possible and links to the definitions of these terms are also given in cases where a short explanation is insufficient. You will also find many videos and pictures that accompany the information. The section on Taxonomy and Systematics will be the most technical section but do challenge yourself to read it to gain a better understanding of how //T. lymma// got its current name and more

= Physical Description =

Distinctive Features
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">//Taeniura lymma// is a fairly small ray with a rounded snout and numerous striking iridescent blue spots adorning its olive-green, dorsoventrally compressed, oval body [1][5][10]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">The spots vary in size and generally become smaller and increase in density towards the edge of the body disc [1]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">A pair of distinctive blue stripes also runs along each side of its tail [1][5] which is equipped with one or two (usually two) venomous tail spines //near// the end of the tail (Fig. 6) [4][10] .<span style="font-family: Calibri,sans-serif; font-size: 11pt;">This is contrary to the popular belief that tail spines are located at the end of the tail. Overall, its brightly-coloured skin serves as a warning to other animals that it Is venomous [5]. While some individuals off Southern Africa have been found to lack the blue stripes on the tail [1], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">it has been recently proposed that they are a new species distinct from //T.// //lymma// (read more about //T. lessoni// at Species Diagnosis and Identification).

Main Body
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">//Taeniura lymma// has generally smooth skin, with the exception of some small thorns scattered down the middle of its back in adults. On the dorsal side (upper side of the body), //T. lymma// also has large, broad spiracles which are located right behind large, bulbous eyes that are bright yellow in colour [1][4] (Fig. 9). Its pectoral fins are estimated to be approximately four-fifths as wide as it is long and its pelvic fins are narrow and angular [1].



<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">Its mouth, gills, nares (naris if singular) and cloaca (Fig. 8) are found on its ventral side (underside of the body), which is uniformly white in colour [1][4][5] .<span style="font-family: Calibri,sans-serif; font-size: 11pt;">The location of the mouth makes //T. lymma// adapted to efficiently scoop up animals hiding in the seafloor bed while its white underside provides some camouflage against the sunny waters above when it is viewed from below (countershading) [5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Between the nares, reaching past the mouth, there is also a narrow flap of skin with a fringed posterior (nearer the rear end of the stingray) margin. Meanwhile, the lower jaw dips at the middle with deep furrows at the corners of the mouth [1]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Within the mouth, numerous small teeth are arranged in two plates that are adapted for crushing the shells of their prey [4][5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">(read more about Feeding). This crushing power is aided by their strong yet lightweight jaws which have been strengthened due to several layers of calcified cartilage supported by hollow, mineralized struts.



Tail and Tail Spines
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Taeniura lymma has a thick, depressed tail that tapers at the end[4]. Measuring about 1.5 times the length of the body disc so as to allow it to strike enemies directly in front[8], the tail has a low midline ridge on the dorsal surface and a broad skinfold (or fin fold) on the ventral surface that reaches the tip of the tail[1][4]. This ventral skinfold is the very structure that contributes the “ribbontail” part to one of the common names of T. lymma[10].

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">As mentioned above, the tail of T. lymma usually has one or two venomous tail spines that are located near the base of the tail. These tail spines are serrated[1] with sharp barbs that face the body of the stingray[2] and narrow grooves that run lengthwise along the undersides. This entire tail spine structure is then covered by a thin layer of skin that acts like a sheath[4] (read more about how the tail is used for defence at Defence Mechanisms).





<span style="font-family: Calibri,sans-serif; font-size: 11pt;">__DID YOU KNOW?__ The tail spines of stingrays have been used to make weapons such as daggers[8].

Males versus Females
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">The males and females of Taeniura lymma, similar to most other stingrays and cartilaginous fish, look physically different. We describe these creatures as "sexually dimorphic". "Dimorphic" comes from the Greek words 'di-' and 'morphe' which translates to 'having two forms' and the term that describes this phenomenon in //T. lymma// is "sexual dimorphism". Sexual dimorphism in stingrays manifests in many ways, one of which is evident from size and the presence of a pair of claspers near the pelvic fin. Claspers are male anatomical structures that are used to channel semen into females via their cloaca during mating. Females are typically larger than males and as shown in the figure below, male stingrays possess claspers whereas female stingrays do not.



<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> //Taeniura lymma// also exhibits sexual dimorphism in the electrosensory system (read more about Sensory Mechanisms) with the males possessing a significantly lower total abundance of electrosensory nerve axons compared to the females. From this, it has been suggested that the greater number of electrosensory nerve axons in females may help in improving their sensitivity, thus allowing them to differentiate between approaching their own kind and potential predators, as well as to better identify suitable males for mating (read more about Reproduction and Breeding).

= Species Diagnosis and Identification =

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">As previously mentioned, //T. lymma// is often confused with // N. kuhlii //, both of which share the common name “blue-spotted (sting)ray” and are found in similar habitats. To avoid making such a mistake, simply look out for some of the diagnostic features of each species in the figures below.



= Geographical Range and Distribution =

Worldwide
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Said to be widespread in the Indo-West Pacific region [1][4][6][5], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">//T. lymma// has a range that extends around the periphery of the Indian Ocean all the way from East Africa to the Arabian Peninsula to Southeast Asia [1], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">including the Red Sea [4][6][5] , <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Madagascar, Zanzibar, the Seychelles, Sri Lanka, and the Maldives [1]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">While also found in the Persian Gulf and the Gulf of Oman [1][6], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">it is rare in those areas. In the Pacific Ocean, //T. lymma// has been recorded from the Philippines and Southern Japan to Northern Australia [1][4][6][5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">as well as around many Melanesian and Polynesian islands [1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">as far east as the Solomon Islands [1][4][5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">However, given the recent discovery of //T. lessoni//, it is possible that there may be overlaps in their geographical distribution or they may actually be found separately in various areas. More research will need to be conducted to gain a more accurate distribution of the species.



Singapore
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">//Taeniura lymma// is often encountered by divers and can be spotted (no pun intended) on sandy areas or near coral reefs on some of our shores. They have been encountered at the Southern Islands of Singapore such as Saint John’s Island and Sisters’ Island and even at Tanah Merah and Pulau Semakau [10]. The embedded map below shows sightings of //T. lymma// in Singapore. It was reconstructed from a Flickr Map and last updated on 23rd November 2016.

media type="custom" key="28867582" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> For more pictures of //T. lymma// found in Singapore, check out WildSingapore’s webpage [|here]. = Habitat =

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">//Taeniura lymma// is a bottom-dwelling species <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> that is commonly encountered in shallow temperate and tropical waters over continental shelves <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[4][5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">. Rarely found deeper than 30 metres (100 feet) <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">, the blue-spotted fantail ray can be seen on the sandy or rocky bottoms of coral reefs <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">, adjacent sandy flats, tidal pools and even near seagrass beds <span style="font-family: Calibri,sans-serif; font-size: 11.7333px; vertical-align: super;">[1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">. media type="vimeo" key="22803386" height="360" width="640" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Adults and juvenile rays are found to occupy dissimilar habitats, with the adults in cool deeper reef environments, and the juveniles in warm, shallow intertidal seagrass, mangal or rocky shoreline habitats <span style="font-family: Calibri,sans-serif; font-size: 11pt;">.

= Biology and Ecology =

General Behaviour
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">A shy creature that swims away when approached by divers [4], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">//T. lymma// lives either alone or in small groups [5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">It generally spends the day seeking shelter in reef caves and crevasses, under coral ledges and overhangs [1][4][5], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">or even in debris such as shipwrecks [1]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Unlike most other stingrays, //T. lymma// is rarely seen burying itself in the sand [1][4][5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">and it often leaves only its tail visible when it goes into hiding [1]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">During the high tide, //T. lymma// migrates in assembled groups from the deeper areas of the reef to the shallower sandy flats to feed (read more about Feeding). They later disperse and take up shelter once again in the deeper areas when the tide starts to recede [1][4][5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">When faced with danger, //T. lymma// will, in an attempt to shake off predators, flee at high speed in a zigzag pattern [1] .<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> If all else fails, it will then use its venomous tail spines to injure. However, given its shy nature, its tail spines are only used as a last resort [4] .<span style="font-family: Calibri,sans-serif; font-size: 11pt;">The video below showcases the typical shy/defensive behaviour that is exhibited by stingrays, including //T. lymma//. media type="youtube" key="FnWsqTIANQA" width="560" height="315" align="center"

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> <span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> Just a word of caution… despite the fact that the stingrays in the video typically flee before having their tails grabbed (from behind and not from the front), do not, under any circumstances, attempt what was done in the video. It goes without saying that if a stingray happens to be startled by a human stepping on them, it will not hesitate to use its tail spines so be careful of where you step (read more about how a stingray actually utilizes its tail spines at Defence Mechanisms).

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">__DID YOU KNOW?__ <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> Interestingly, T. lymma has been observed soliciting cleanings from shrimp and tiny fish such as the bluestreak cleaner wrasse (Labroides dimidiatus). How do they do it? They simply head to ‘cleaning stations’ and raise the margins of their disc and pelvic fins <span style="font-family: Calibri,sans-serif; font-size: 80%;">[1][5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Every summer, large numbers of blue-spotted fantail rays also arrive off South Africa <span style="font-family: Calibri,sans-serif; font-size: 80%; vertical-align: super;">[1].

Feeding
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">//Taeniura lymma// are predators in benthic habitats within their range, feeding on molluscs, polychaete worms, shrimps, crabs and small fishes [1][4][5][17] .<span style="font-family: Calibri,sans-serif; font-size: 11pt;">They detect their prey via electroreception (read more about Sensory Mechanisms) in which the ray senses electrical fields produced by the prey [5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">However, its potential prey does not include all small fish and invertebrates. This is evident from how some tiny fish and shrimp ‘clean’ //T. lymma// by picking dead skin and parasites off its body (read more about Predators and Parasites) [5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Feeding occurs mostly during high tides [4][5] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">and upon locating the prey, //T. lymma// excavates sand pits and traps the prey with its body. Using its disc, the ray then carefully manoeuvres the prey into its mouth [1].

media type="youtube" key="tJrD_FZtAEk" width="560" height="315" align="center"

media type="youtube" key="owhrj9bkslY" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> __DID YOU KNOW?__ Foraging //T. lymma// are often followed by other fish, such as the goatfish, that are ready to capture any prey missed by the ray [1].

Predators and Parasites
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Hammerhead sharks and bottlenose dolphins are known predators of //T. lymma,// with other large fish, such as sharks, and marine mammals as potential predators [1][4]

media type="youtube" key="pWiH7tfjKTo" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> //Taeniura lymma// is also host to various parasites which include tapeworms, flatworms, nematodes, copepods and protozoans [1].

<span style="font-family: Calibri,sans-serif; font-size: 11pt;">__DID YOU KNOW?__ <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> The hammerhead shark avoids injury from the venomous tail spines of //Taeniura lymma// by using its head to pin the ray to the sea floor while it removes flesh from the dorsal surface of the ray [4].

Reproduction and Breeding
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;">//Taeniura lymma//, similar to other stingrays, have an (aplacental) ovoviviparous mode of reproduction. This means that female rays give birth to live offspring that have hatched from egg cases within the body [4][5].

media type="youtube" key="cO2nBgqrVAs" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"><span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> During development, the embryos are initially sustained by yolk after which, as they continue to develop and deplete the yolk sac, they receive additional nourishment in the form of histotroph or “uterine milk” (enriched with mucus, fat and proteins) produced by the mother [1][4]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">The gestation period is uncertain but has been estimated to last anything from four months up to a year and each time, up to seven offspring can be born [1][4][5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">The young of //T. lymma// is essentially a miniature version of the adult, measuring 13-14cm across [1][5] and bearing similar markings and the same characteristic blue spots [4][5]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">While males reach sexual maturity at a disc width of 20-21cm, not much is known about the maturation size of females [1].

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> __<span style="font-family: Calibri,sans-serif; font-size: 11pt;">DID YOU KNOW? __ <span style="font-family: Calibri,sans-serif; font-size: 11pt;"><span style="font-family: Calibri,sans-serif; font-size: 11pt;"> <span style="font-family: Calibri,sans-serif; font-size: 11pt;">The young of stingrays is referred to as a “pup” and a group of them is referred to as a “litter” [1]. . <span style="font-family: Calibri,sans-serif; font-size: 11pt;">To add on to that, a group of stingrays is referred to as a “school” [8].

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> Breeding usually occurs from late spring and lasts through summer [1][5], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">with the female //T. lymma// emitting a chemical signal to indicate to the males that they are receptive. The males, upon detecting the signal with their acutely sensitive ‘nose’ [5], <span style="font-family: Calibri,sans-serif; font-size: 11pt;">start to follow the females and nip at their discs. Eventually, the male will bite and hold onto the female for copulation through internal fertilization [1]. If you like, you can watch the video below from 3:20 onwards. media type="youtube" key="dEcG-vqBZ-E" width="560" height="315" align="center"

Defence Mechanisms
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;">It is common knowledge that //T. lymma//, as a stingray, defends itself using its tail spines and that the two main things that cause the resulting pain are the barbs on the tail spines and the venom that the stingray injects into its victim. But how does a stingray attack? The process is actually pretty simple. The stingray has to first face the victim then all it has to do is to flip its long tail upward and over its body to strike the victim in front [2]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">When the tail pierces the skin of the victim, in most cases, the pressure causes the sheath covering the tail spines to tear, thus exposing the sharp barbs of the tail spine and allowing venom to be delivered into the wound through the narrow grooves running lengthwise along the underside of the tail spine (Fig. 7) [2]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">If you like, you can watch the video below from 1:23 to 2:26.

media type="youtube" key="JaG62zHxBHs" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"><span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> The venom may not be fatal but it causes excruciating pain for the victim. It consists of the enzymes 5-nucleotidase and phosphodiesterase which essentially cause tissue and cell death, as well as the neurotransmitter serotonin, which causes the severe contraction of smooth muscle. It is the latter that makes the venom especially painful. Fortunately, if the venom is released into an area like the ankle, the wound can usually be treated with the help of heat. Applying heat breaks down the venom and limits the amount of damage it can render. However, in the worst-case scenario, if the wound is not treated in time, amputation might still be necessary [2]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Not to mention that being attacked by a stingray can result in death when the tail spines and/or venom enter critical areas where the major organs are located at.

<span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;"> __DID YOU KNOW?__ <span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> Stingray venom is generally cardiotoxic and even after extracting it from the stingray, the venom remains potent. Yet, despite that, it is said that Ancient Greek dentists once used the venom of stingrays as anaesthetic [8].

<span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;"> As for the barbs on the tail spine, even without the injection of venom, they can do serious damage. While the sharp tip of the tail spine allows it to easily pierce through the skin, having barbs that face the body of the stingray means that any attempts to remove the tail spine will result in the massive tearing of tissue [2].

<span style="font-family: Calibri,sans-serif; font-size: 11pt; vertical-align: super;"> __DID YOU KNOW?__ <span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> The stingray is able to regenerate its tail spines if it is broken off [18].

Locomotion
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;">In order to generate thrust while keeping their dorsoventrally compressed body mostly rigid, //T. lymma// exhibits undulatory (wave-like) locomotion in which undulatory waves are propagated down their pectoral fins from the anterior end (nearer the head end of the stingray) to the posterior end (nearer the rear end of the stingray). To move backwards, all it has to do is to simply reverse the direction of the wave propagation [19].

media type="youtube" key="2aOh4ad0Li8" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> //Taeniura lymma// also possess fin muscles that are found throughout the entire length of the pectoral fin and all of them are typically active, except at lower speeds when there is no need for propulsion through the water [18]. [2] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Dissection of the pectoral fin muscle has shown that generally, the dorsal (abductor) muscle is used to elevate the fin while the ventral (abductor) muscle is used to depress the fin. To produce the undulatory waves down the pectoral fins, //T. lymma// alternately lengthens and shortens the dorsal and ventral muscles. The superficial layer was also revealed to mainly consists of red muscle while the deep layer mainly consists of white muscle. The former contributes to the periodic motion of the pectoral fins while the latter is often used for transient motion [19].

Sensory Mechanisms
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;">Ever wondered how stingrays like //T. lymma// are able to sense their surroundings or even know where to find their prey if their eyes are on the dorsal side while their mouths are on the ventral side? Well, they rely on electroreception to detect prey, navigate and communicate. This is achieved with the help of their peripheral electrosensory system which comprises hundreds to thousands of separate electrosensitive units called the ampullae of Lorenzini, which are tightly grouped into distinct subepidermal clusters. Each of these clusters is linked to an individual pore on the skin via a long canal that is filled with an electrically conductive gel (Fig. 14) [15].



<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;">Within each individual ampulla, sensory receptor cells line the epithelial wall and these cells have the ability to detect electrical potential differences between the apical side of the gel-filled canal and the basal side of the sensory receptor cell outside the ampulla. These cells allow each ampulla to detect and transduce weak electric fields into electrical impulses which can then be recognized by the nerves of the central nervous system [15]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">If that got too technical, then watch this video instead!

media type="youtube" key="JDPFR6n8tAQ" width="560" height="315" align="center"

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> For //T. lymma//, very few electrosensory pores are located on the dorsal side. The majority of them are found on the ventral side of the body instead, concentrated particularly around the mouth. In terms of adaption, this arrangement makes sense since it would facilitate and enhance detection of prey [15].

= Taxonomy and Systematics =

Taxonomic Hierarchy

 * **Kingdom** || Animalia ||  ||
 * **Phylum** || Chordata ||  ||
 * **Class** || Chondrichthyes || (cartilaginous fish) ||
 * **Subclass** || Elasmobranchii || (shark-like fish) ||
 * **Superorder** || Batoidea || (batoids) ||
 * **Order** || Myliobatiformes || (stingrays) ||
 * **Family** || Dasyatidae || (whiptail stingrays) ||
 * **Genus** || //Taeniura//<span style="font-family: Calibri,sans-serif; font-size: 11pt;">Müller and Henle, 1837 || (ribbontail rays) ||
 * **Species** || //Taeniura lymma//<span style="font-family: Calibri,sans-serif; font-size: 11pt;">(Forsskål, 1775) ||  ||

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left; vertical-align: super;"> Information retrieved from: Integrated Taxonomic Information System (ITIS) and Skates and Rays of Atlantic Canada. The WoRMS (World Register of Marine Species) taxon tree for the blue-spotted fantail ray can be found [|here].

Historical Background
<span style="font-family: Calibri,sans-serif; font-size: 11pt;">The blue-spotted fantail ray, while now known as //Taeniura lymma//, was not always named as such. The earliest record shows that it was originally described as //Raja lymma// by Swedish naturalist Peter Simon Forsskål in 1775 [1][4] in the book //Descriptiones animalium, avium, amphibiorum, piscium, insectorum, vermium / quae in itinere orientali observavit Petrus Forskål. Post mortem auctoris edidit Carsten Niebuhr. Adjuncta est materia medica kahirina atque tabula maris Rubri geographica .//



<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> __DID YOU KNOW?__ <span style="font-family: Calibri,sans-serif; font-size: 11pt;">Interestingly, while //T. lymma// today fall under the class Chondrichthyes for cartilaginous fish, they were actually originally placed under the class Amphibia [21].

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> It is important to note, however, that sources have inaccurately cited the original description to be in the book //Descriptiones animalium quae in itinere ad maris australis terras per annos 1772, 1773, et 1774 suscepto collegit, observavit, et delineavit Joannes Reinlioldus Forster, etc., curante Henrico Lichtenstein//. An example is shown in the figure below.

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> In past scientific literature, the blue-spotted fantail ray also went by the name //Trygon ornatus// after being documented by British zoologist John Edward Gray in 1830 [1][4]. <span style="font-family: Calibri,sans-serif; font-size: 11pt;"> In a publication by Gray, titled //Illustrations of Indian zoology; chiefly selected from the collection of Major-General Hardwicke//, an illustration of //T. lymma// was included.



<span style="font-family: Calibri,sans-serif; font-size: 11pt;"><span style="font-family: Calibri,sans-serif; font-size: 11pt;"> However, as the naming of species works on the Principle of Priority, what Gray had done was to erroneously re-describe a species that already had an assigned species name. Hence, since //Trygon ornatus// (1830) came after //Raja lymma// (1775), the former name is now known as a junior synonym. But that is not the end of the story... In 1837, German biologists Johannes Peter Müller and Friedrich Gustav Jakob Henle created the genus //Taeniura// [1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">and grouped the blue-spotted fantail ray within that genus, thus essentially renaming it from //Raja lymma// to //Taeniura lymma//

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"> This change in the genus name from '//Raja//’ to ‘//Taeniura’// was made to better reflect the description of the blue-spotted fantail ray, with particular reference to its tail. ‘//Taeniura’// is derived from the Latin word ‘//taenia//’ meaning ‘stripe’ (or ‘ribbon’ when entered into Google Translate) and the Greek word ‘//ουρά//’ meaning ‘tail' [4]. Meanwhile, the specific epithet ‘//lymma//’ is an Arabic word that is said to mean ‘dirt’.<span style="display: inline !important;"> No type specimen was designated by Forsskål [1] <span style="font-family: Calibri,sans-serif; font-size: 11pt;">and no records of the designated type specimen could be found, possibly because it was Johann Christian Fabricius who compiled and edited the manuscript descriptions and names of various fish taxa left behind by Forsskål and Carsten Niebuhr who posthumously published Forsskål's work in 1775 [22].

Higher Level Classification
<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">The family Dasyatidae (Order Myliobatiformes) is one of the biggest families of batoid fishes, and the members within this family have a body that is “characterized by a large, oval, circular or rhomboidal disc usually covered with denticles, thorns and tubercles on the dorsal surface and sometimes on the tail”. However, given the large number of species described in the family Dasyatidae as well as taxonomic uncertainties, the classification and status of some species are still subject to change, especially at the family level (read more about Taxonomic Hierarchy).

Phylogeny and Morphology
<span style="font-family: Calibri,sans-serif; font-size: 11pt;"><span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">There are many taxonomic issues within rays, including the family Dasyatidae. Recently, these issues have become even more contentious based on studies that were conducted just two to three years ago. In fact, the discovery of the new species //T. lessoni// this year is just the tip of the iceberg. Within the genus //Taeniura// itself, there are issues of species placement. While some taxonomic sources recognize three species in the genus //Taeniura// (note that back then, //T. lessoni// was not discovered yet), others have removed the species //T. grabata// and //T. meyeni// and placed them in the genus //Taeniurops// instead. Of course, this means that //T. lymma// was the sole member of the genus for a while until //T. lessoni// came along (read more about //T. lessoni// at Species Diagnosis and Identification).

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> A study that proposed such a change in species placement was one that was conducted by Lim et al. (2015) with the following aims [24] :
 * 1) Elucidate the phylogenetic relationships of stingrays in the family Dasyatidae using COI, ND2 and RAG1 genes
 * 2) Re-examine the morphological characters used by Last //et al.// (2010) for species differentiation in the book “Sharks and Rays of Borneo” (Collingwood: CSIRO Marine and Atmospheric Research)

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> This was the first time these genes (or even any other genes for that matter) were successfully studied at the family level for rays and based on the results, it was suggested that the current family Dasyatidae is non-monophyletic and should be split, instead, into four different families – Neotrygonidae, Himanturidae, Pastinachidae and Dasyatidae – including itself. The results that they obtained are summarized in the respective trees below. Note that for the RAG1 gene, a cladogram was generated instead as the short distances among the taxa resulted in a crowded phylogenetic tree [24].



<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> It would be most ideal if a summarized tree using all three of the genes was generated. However, this was not done so in the study proposed by Lim //et. al// (2015). Nevertheless, all of the trees show that the Dasyatidae family (boxed up in green) is not monophyletic, forming four clades for the COI and RAG1 genes and two main clades (each with two subclades) for the ND2 gene. Hence, in order to maintain monophyly, the researchers proposed the following changes in classification in their discussion [24] :
 * Elevation of the three clusters to family level (three new families)
 * Retain original Dasyatidae family (//Dasyatis// and //Taeniurops// spp//.//)
 * 1st new family: Neotrygonidae (//Neotrygon// spp//.// and //Taeniura lymma//)
 * 2nd new family: Himanturidae (//Himantura// spp//.//)
 * 3rd new family: Pastinachidae (//Pastinachus// spp.)

<span style="font-family: Calibri,sans-serif; font-size: 11pt;"><span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> It is interesting to note that after resolving the problem of non-monophyly, members of the order Myliobatiformes could be accurately and correctly classified into their respective families based on morphology, using nine character measurements that have been identified as useful morphological information and removing previously used characters that caused //incertae sedis// (uncertain placements) and/or past misclassifications [24].

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> These characters are relative total length (TL), disc length (DL), tail width (TW), tail height (TH), eye diameter (ED), spiracle length (SPL), interspiracular length (ISL), distance between fifth gill slits (I5) and ventral tail fold length (VFL). These were the findings observed [24] :
 * Neotrygonidae <span style="font-family: Calibri,sans-serif; font-size: 11pt;">are separated from the other families by their relatively large ED
 * Himanturidae have no fin fold and the longest DL
 * Pastinachidae are separated from the rest by their relatively longer VFL

Genetic Sequences
<span style="font-family: Calibri,sans-serif; font-size: 11pt;"><span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;">In early 2015, the complete mitogenome of //T. lymma// was also sequenced and it was found to be 17,652 basepairs long (GenBank accession number: KM881715), containing 37 mitochondrial genes and a non-coding AT-rich region of 1906 basepairs in length. The base composition of the //T. lymma// mitogenome is A: 32.09%, T: 27.04%, G: 13.00% and C: 27.87%. Mitogenome comparisons indicate has a closer relationship between //T. lymma// and //N. kuhlii// (88%) than between //T. lymma// and //T. meyeni// (85%). This is consistent with previous analyses done based on the mitochondrial COI and 16S genes and the nuclear RAG1 markers, as well as the aforementioned phylogenetic study by Lim et al. (2015). Given the many unresolved questions with regards to the taxonomic boundaries in rays, the mitogenomic information for Taeniura will be a useful molecular resource for future studies [25].

<span style="display: block; font-family: Calibri,sans-serif; font-size: 11pt; text-align: left;"> A representative barcode sequence (the centroid of all available sequences) for //T. lymma// is shown below.

= Beyond This Page =