libutron
libutron:

Ocellate River Stingray - Potamotrygon motoro
Potamotrygon motor (Rajiformes - Potamotrygonidae) is a species of freshwater stingray endemic to, and widespread throughout, several South American river systems.
These stingrays can be distinguished from closely related species by the presence of orange to yellow dorsal eyespots, each surrounded by a black ring, with diameters larger than the eyes. Body color is otherwise greyish-brown. They are oval in shape with a robust tail, bearing a venomous spine. Maximum total length has been reported at 100 centimeters and maximum weight at 15 kg, though individuals tend to be much smaller.
Reference: [1]
Photo credit: ©Jason Hering | Locality: Cuiaba river, Matto Grosso, Amazon, Brazil - captive (2008)

libutron:

Ocellate River Stingray - Potamotrygon motoro

Potamotrygon motor (Rajiformes - Potamotrygonidae) is a species of freshwater stingray endemic to, and widespread throughout, several South American river systems.

These stingrays can be distinguished from closely related species by the presence of orange to yellow dorsal eyespots, each surrounded by a black ring, with diameters larger than the eyes. Body color is otherwise greyish-brown. They are oval in shape with a robust tail, bearing a venomous spine. Maximum total length has been reported at 100 centimeters and maximum weight at 15 kg, though individuals tend to be much smaller.

Reference: [1]

Photo credit: ©Jason Hering | Locality: Cuiaba river, Matto Grosso, Amazon, Brazil - captive (2008)

griseus

griseus:

Eclosión de raya de cola corta (Sympterygia brevicaudata) La cápsula desde donde salió es un huevo, se encuentran normalmente unidas a algas, corales o estructuras resistentes, es una carcasa que rodea los huevos fertilizados de algunos tiburones pequeños, rayas y quimeras. Tiene aberturas pequeñas (hendiduras respiratorias) donde entra y sale el agua, por lo que el embrión puede respirar sin problemas … 

Sharks Can Be ‘Social or Solitary’

by Jonathan Webb

The most feared predators in the sea have individual personalities that affect how readily they socialise, according to a study by UK scientists.

Individual sharks, studied in groups of ten, showed consistent social habits - either forming groups with other sharks or finding camouflage on their own.

When a group was shifted into a new environment, individual sharks showed the same patterns of behaviour.

This is the first study to show that sharks have their own personalities.

The research was done in large tanks at the Marine Biological Association of the UK, in Plymouth, in collaboration with the University of Exeter. The findings appear in the journal Behavioural Ecology and Sociobiology

(read more: BBC News)

Deep Sea Chimaera

Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014 (September 27, 2014)

Chimaera spotted while exploring a seamount within the Atlantis II Seamount Complex.

Video courtesy of NOAA Okeanos Explorer Program.

Bizarre, Prehistoric Ratfish Chomped Prey with Buzzsaw Jaws
by Brian Switek 
Helicoprion had saws for jaws. That’s really all there was to the 270 million year old ratfish’s dental cutlery. No upper teeth or anything else to slice against – just an ever-growing whorl of spiky teeth anchored to the lower jaw.
This new, definitive image of Helicoprion debuted last year thanks to the efforts of artist Ray Troll and a team of researchers led by Idaho State University paleontologist Leif Tapanila. A very special fossil – IMNH 37899 – preserved both the upper and lower jaws in a closed position, finally solving the mystery of what the ratfish’s head actually looked like. But determining the exact placement of that vexing spiral was just an initial step.
Paleontologists and artists had often supposed that Helicoprion had upper teeth to pierce slippery cephalopods and squirming fish, but the fossils Tapanila and colleagues examined showed that Helicoprion only had a buzzsaw embedded in the lower jaw. How did this long-lived and prolific genus of Permian fish eat with a saw for a jaw? …
(read more: Laelaps blog - National Geographic)
photograph by Brian Switek

Bizarre, Prehistoric Ratfish Chomped Prey with Buzzsaw Jaws

by Brian Switek 

Helicoprion had saws for jaws. That’s really all there was to the 270 million year old ratfish’s dental cutlery. No upper teeth or anything else to slice against – just an ever-growing whorl of spiky teeth anchored to the lower jaw.

This new, definitive image of Helicoprion debuted last year thanks to the efforts of artist Ray Troll and a team of researchers led by Idaho State University paleontologist Leif Tapanila. A very special fossil – IMNH 37899 – preserved both the upper and lower jaws in a closed position, finally solving the mystery of what the ratfish’s head actually looked like. But determining the exact placement of that vexing spiral was just an initial step.

Paleontologists and artists had often supposed that Helicoprion had upper teeth to pierce slippery cephalopods and squirming fish, but the fossils Tapanila and colleagues examined showed that Helicoprion only had a buzzsaw embedded in the lower jaw. How did this long-lived and prolific genus of Permian fish eat with a saw for a jaw? …

(read more: Laelaps blog - National Geographic)

photograph by Brian Switek

Sawfish Science in Florida
This just in — NOAA Fisheries Biologists Dr. John Carlson, Dana Bethea, Grace Casselbury and intern Ryan Jones are on their monthly expedition examining the distribution and abundance of smalltooth sawfish (Pristis pectinata), an ESA endangered species, in Everglades National Park. 
The scientists have recorded some extremely low salinity measurements this expedition and are measuring how the distribution of sawfish changes in response to low salinity. Today they tagged a 3 ft female near Chokoloskee Island. All of this research is designed to help implement recovery objectives in the ESA. 
Photo credit: Ryan Jones 
Check out our video on how we protect them: 
Protecting an Endangered Species:  Smalltooth Sawfish
(via: NOAA Fisheries)

Sawfish Science in Florida

This just in — NOAA Fisheries Biologists Dr. John Carlson, Dana Bethea, Grace Casselbury and intern Ryan Jones are on their monthly expedition examining the distribution and abundance of smalltooth sawfish (Pristis pectinata), an ESA endangered species, in Everglades National Park.

The scientists have recorded some extremely low salinity measurements this expedition and are measuring how the distribution of sawfish changes in response to low salinity. Today they tagged a 3 ft female near Chokoloskee Island. All of this research is designed to help implement recovery objectives in the ESA.

Photo credit: Ryan Jones

Check out our video on how we protect them:

Protecting an Endangered Species:  Smalltooth Sawfish

(via: NOAA Fisheries)

dendroica

seascienceweekly:   Plankton Eating Sharks

Lets start off with the not-so-much meat eating sharks.

Well, kinda, the Whale Shark (middle) still eats krill, and we don’t really know much about the Megamouth Shark (bottom), but it probably eats Jellyfish and other sorts of plankton. Either way, with the Basking Shark (top), these three sharks make up the filter feeding, planktivorous sharks.

They swim with their massive mouths open through the water and filter out all the tiny particles for food. Even though they have similar methods of feeding they’re actually quite different!

Whale sharks fall under the taxanomic classification of Orectolobiformes (or carpet sharks), similar to Nurse Sharks, while Megamouths and Basking Sharks fall under Lamniformes (Mackerel Sharks) like great whites.

Both Whale Sharks and Basking Sharks are classified as vulnerable by the IUCN, where as the Megamouth Shark is so rare  that we can’t really say - only 3 Megamouths have ever been recorded on film!

Whale Sharks are absolutely incredible animals, they can grow to 10 meters, weigh 10 tonnes and live to 70 years, while Basking Sharks are slightly smaller at 8 meters and 5 tonnes.

They might all look a bit scary, but are completely and absolutely harmless to humans, the only thing they’d hurt is krill!

The Whale Shark (Rhincodon typus) 
… is the largest living species of fish, with individuals reaching lengths of 41 feet (12.5 m) or more. Though fearsome in size, Whale Sharks are gentle giants. They feed on plankton and small fish, and are generally quite tame and docile around divers. 
Unlike dolphins and whales, which give birth to a single large baby, Whale Sharks are ovoviviparous - they produce up to a few hundred eggs, which the mother incubates within her body. They are fertilized slowly using stored sperm, and babies are birthed with regularity rather than in one large event. When born, young Whale Sharks are dwarfed by their mother, measuring only 16 to 24 inches (40 to 60 cm) long. Individuals take a long time to reach sexual maturity, first starting to breed around 30 years old, but may live to ages of 70 or more years. 
They inhabit tropical and sub-tropical oceans worldwide; on North America’s coasts, they are primarily found off California in the Pacific, and sometimes as far north as New York in the Atlantic.
photo by Zac Wolf, borrowed from Wikimedia
(via: Peterson Field Guides)

The Whale Shark (Rhincodon typus)

… is the largest living species of fish, with individuals reaching lengths of 41 feet (12.5 m) or more. Though fearsome in size, Whale Sharks are gentle giants. They feed on plankton and small fish, and are generally quite tame and docile around divers.

Unlike dolphins and whales, which give birth to a single large baby, Whale Sharks are ovoviviparous - they produce up to a few hundred eggs, which the mother incubates within her body. They are fertilized slowly using stored sperm, and babies are birthed with regularity rather than in one large event. When born, young Whale Sharks are dwarfed by their mother, measuring only 16 to 24 inches (40 to 60 cm) long. Individuals take a long time to reach sexual maturity, first starting to breed around 30 years old, but may live to ages of 70 or more years.

They inhabit tropical and sub-tropical oceans worldwide; on North America’s coasts, they are primarily found off California in the Pacific, and sometimes as far north as New York in the Atlantic.

photo by Zac Wolf, borrowed from Wikimedia

(via: Peterson Field Guides)

Bizarre Blue Shark Nursery Found in the North Atlantic

Rather than emerging in protected coves, baby blue sharks spend their first years in a big patch of open ocean

by Rachel Nuwer

The scientists trapped 37 blue sharks ranging in age from young juveniles to adults and outfitted them with satellite transmitters. They released the sharks and then waited for the data to arrive. As months rolled into years, an interesting pattern emerged.
Within the first two years of life, the researchers report in the journal PLOS ONE, the sharks spent most of their time in a patch of the North Atlantic.
Most shark species establish nurseries in protected bays or other sheltering areas. The notion that blue sharks grow up completely out in the open suggests that protection from predators is not a motivating factor. But figuring out what advantages, if any, that particular spot provides will require further study…
images: Photos by Nuno Sa/Nature Picture Library/Corbis and Mark Conlin/NMFS, graphic from Vandeperre et al., PLOS ONE
lostbeasts

strangebiology:

Paleontologists found this sweet whorl of teeth called a Helicoprion, but really didn’t know how it might have been situated in a fish’s mouth. 

There were many theories postulated about how the teeth fit in the animal’s mouth (fourth image). When another specimen was found, it was determined that the owner of this strange jaw (not a shark, but a ratfish) had no upper teeth at all.

Ladies and gentlemen, the most metal fish.

(via Laelaps/National Geographic) Art by Ray Troll.