Batoidea

Here's where things get interesting! Batoids have ventral (bottom) gill openings, dorsal (top) eyes, and the pectoral fins are fused to their head! They have an extremely derived and recognizable shape, mainly because there are not many other fish that are flattened.


Torpediniformes: Electric Rays

This group of fishes is best known for their electrogenic abilities. These rays generate their electricity by modified muscles on either side of the head, which can generate electricity in a similar way to a battery. The organs contain many columns, each with hundreds of discs filled with a gelatinous substance. The ray can send a nerve impulse to the organs, discharging the columns and generating a voltage. Most rays swim with their pectoral fins, but the electric rays propel themselves with their tails.


torpedo

Torpedinidae: Torpedo Electric Rays

This family contains two genera, Hypnos and Torpedo. The Coffin Ray, Hypnos monopterygius, has a very short tail compared to the rest of its body, giving it a pear shape. The genus Torpedo has a longer tail and a more rounded body.


narcinid

Narcinidae: Numbfishes

This family does not generate as strong an electric charge as Torpedinidae.


sawfish

"Pristis pectinata - Georgia Aquarium Jan 2006" by Diliff - Own work. Licensed under Creative Commons Attribution 2.5 via Wikimedia Commons

Pristiformes: Sawfishes

This order contains one family (Pristidae) and two genera. This group is characterized by ventral gills slits, dorsal spiracles, and most obviously, an elongated, flattened rostrum. The sawfish rostrum is much longer than the sawshark rostrum, and has symmetrical teeth (the left side is a mirror image of the right side). These teeth are firmly lodged into sockets in the rostrum. The saw is used to sift through the mud for prey, or can be used to slash at prey swimming by, to either stun or kill.


Rajiformes: Skates

These fish have pointed pectoral fins, and an either diamond or elongate body. They all lay eggs.

rhinidae

Rhinidae: Bowmouth Guitarfishes

There is only one species, Rhina ancylostoma. This fish is much less flattened than its relatives, and has a body plan intermediate between sharks and rays. There is a ridge of enlarged scales running down the midline, and the caudal fin is much larger than in other rays.


wedgefish

"Giant guitarfish (Rhynchobatus djiddensis)" by Brian Gratwicke - Flickr: Giant guitarfish (Rhynchobatus djiddensis). Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons

Rhynchobatidae: Wedgefishes

This family contains only one genus, Rynchobatus. These fishes are similar in shape to guitarfishes, although they have a thicker body, more like a sawfish (without the saw). This group includes the poorly named Giant Guitarfish, Rynchobatus djiddensis.


guitar

Rhinobatidae: Guitarfishes

This family is appropriately named due to the shape of its body. The body plan is considered an intermediate between sharks and rays, because of the long, shark-like tail and the pointed shape of the head. There are two dorsal fins, which are also large like a shark.


rajidae

Rajidae: Skates

One of the larger families of rays. They are often confused with stingrays, as both are common groups. However, skates have more pointed pectoral fins, pelvic fins with two lobes, and lack the stinger that gives stingrays their name.


Myliobatiformes: Stingrays

There is not much that connects all of these families, but you may find some interesting individuals in each one! All families except Platyrhinidae and Zanobatidae are members of Myliobatoidei, and all have an elongated, modified dermal denticle on their tails, known as the stinger.


thorn

"Platyrhinoidis triseriata pismo" by PunkToad from oakland, us - Lesser Electric Ray. Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons

Platyrhinidae: Thornbacks

These rays may look similar to guitarfishes, but are more closely related to stingrays. The body is rounded with a slightly pointed snout, but the tail is long and muscular like a guitarfish or shark.


zanobatus

Zanobatidae: Panrays

There is only one species, Zanobatus schoenleinii. That's pretty much all I know. I'm goig to make an educated guess, and say that it is striped.


hexatrygon

Hexatrygonidae: Sixgill Stingrays

There is only one species, Hexatrygon bickelli. The most obvious characteristic is the presence of six gill slits (hence the name). This ray has an extremely long and pointed snout, and its pectoral fins curve in the back, giving it an ice-cream cone shape (with the tail coming off the top of the scoop). The snout is filled with a gelatinous substance, whose purpose does not seem to be well described.


deep

"Plesiobatis daviesi cochin" by Bineesh. K. K - http://www.fishbase.org/photos/thumbnailssummary.php?ID=7376#. Licensed under Creative Commons Attribution 3.0 via Wikimedia Commons

Plesiobatidae: Deepwater Stingrays

There is only one species, Plesiobatis daviesi. Its disc is leaf-shaped, and it also has a leaf-shaped caudal fin lobe.


stingaree

Urolophidae: Round Stingrays

These fish are sometimes known as "stingarees," which is kind of awesome. Therefore, I will write no more about them.


urotrygonid

Urotrygonidae: American Round Stingrays

This group includes the Yellow Stingray, Urobatis jamaicensis, which is commonly found in the Caribbean. It does stingray things, like frolicking on the seafloor and hunting for treats buried in the sand.


cowtail
bluespot

Dasyatidae: Whiptail Stingrays

This family has a few different interesting members. Shall we take a look?


potamo

Potamotrygonidae: River Stingrays

These stingrays are very circular in shape. They are greatly feared in South America due to their stingers.


butterfly

"Gymnura micrura" by Sean Loyless from Austin, USA - Manta ray. Licensed under Creative Commons Attribution 2.0 via Wikimedia Commons

Gymnuridae: Butterfly Rays

These rays are characterized by a broad disc with pointed pectoral fins, almost like a strangly pointed oval.


eagle

Myliobatidae: Eagle Rays

This family tends to be pelagic as opposed to benthic. The pectoral fins are long and pointed, and are slightly curved backwards.


manta