Coelacanths might be monogamous, to the surprise of researchers
by Cynthia McKelvey
They evaded humans for millions of years and live very private lives. The hulking, fleshy-finned fish known as the coelacanth has beguiled scientists for generations. But the coelacanth mystique that enchants researchers also makes it difficult to study. Researchers recently revealed in Nature Communications one startling aspect of the coelacanth lifestyle: they might be monogamous.
Presumed extinct for over 60 million years, the coelacanth (SEE-lah-kanth) was known only in fossil form until a fisherman caught a live one in 1938 near South Africa. Recently, scientists have found populations of dozens of coelacanths nestled in caves hundreds of meters deep in the Indian Ocean near Kenya, Tanzania and the Comoros Islands.
Monogamy poses a risk to coelacanths in part because of the onerous three-year-long pregnancies in females. The babies are fully developed when they’re born, but the mother sacrifices a lot of energy and is more vulnerable to predators while she carries her young. If one male with a bad set of genes sires the brood, all the offspring can suffer—and those three years might be wasted…
(read more: MongaBay)
photos: Hans Fricke and Mark V. Erdmann
Posts tagged ocean.
A Sea of Sponges
Sponges aren’t the stars of the Monterey Bay Aquarium, but their diversity of colors, shapes and sizes is eye-catching. And consider this: Every multi-celled animal on Earth is based on the genetic blueprint of sponges.They are truly the foundation of the animal kingdom.
Our sponges may not be as startling as the stove-pipe sponge that looks so much like the Cookie Monster from Sesame Street. They don’t have the personality of Spongebob Squarepants. But they’re fascinating animals with a vital role to play in healthy oceans.
Sponges populate many of our exhibits in the Ocean’s Edge galleries. You can get a closer look — and even discover what they feel like — at our touch pools.
They’re simple: a group of loosely connected, nearly independent cells, with no organs and no tissues. If broken apart, they can put themselves back together again. Many produce powerful chemicals to defend themselves — chemicals that have cancer-fighting properties.
Globally, it’s estimated there are upwards of 10,000 to 15,000 species of sponges in the ocean — with thousands left to be discovered. Not long ago, our colleagues at the Monterey Bay Aquarium Research Institute documented a new carnivorous sponge: the harp sponge, pictured above.
The yellow goiter sponge, also pictured here, was spotted on an MBARI dive to the Pioneer Seamount. Some goiter sponges can grow to be nearly 10 feet across.
Photo credits: red volcano sponge and cobalt blue sponge, © Monterey Bay Aquarium/Steve Webster; orange puffball sponge, © Monterey Bay Aquarium/David Cripe; harp sponge and goiter sponge, © MBARI
STARFISH WITH BABIES, BROODING BEHAVIOR REVEALED
This motherly starfish is taking care of her starbabies. Some starfish species, such as this one Diplasterias brandti, brood and carry their babies until they are ready to leave the nest, just like some vertebrate species.
SEVERAL different species of sea stars brood. Almost all of them are either cold-water species, living in the deep-sea or at the poles. Sometimes brooding is in temperate water species.. But typically not in the tropics.
Brooding also takes different forms. The oral ‘mouth’ or gastric brooding mode is but one kind. Here is Diplasterias from the Antarctic! MANY starfish in the Antarctic brood juvenile starfish!
- Photo: Smithsonian NMNH USARP
SCIENTISTS SOLVE MILLENNIA-OLD MYSTERY ABOUT THE ARGONAUT OCTOPUS
The argonauts are a group of octopuses unlike any other. The females secrete a thin, white, brittle shell called the paper nautilus. Nestled with their arms tucked inside this beautiful, translucent home, they drift through the open ocean while other octopus species crawl along the sea floor. The shell is often described as an egg-case, but octopus specialists Julian Finn and Mark Norman have discovered that it has another function – it’s an organic ballast tank.
An argonaut uses its shell to trap air from the surface and dives to a depth where the encased gas perfectly counteracts its own weight, allowing it to bob effortlessly without rising or sinking. Finn and Norman filmed and photographed live animals in the act of trapping their air bubbles, solving a mystery that has been debated for millennia.
Since 1923 and the work of Adolf Naef, the shell has been viewed as a container for the argonaut’s eggs. After mating with a male (who is around 8 times smaller and 600 times lighter), the female secretes the papery shell using the tips of two large tentacles. She lays her eggs within the structure before snuggling inside herself. Besides her eggs, her only housemate is one of the male’s arms – the hectocotylus. The arm doubled as a penis, snapped off during sex and stays inside the female’s body….
- continue here
- photo by Yasushi Okumura, Japan Underwater Films
Dolphins Talk to Each Other Using Personal Names
Scientists at the Univ. of St Andrews have shown that bottlenose dolphins can use copying of signature whistles as a way of addressing or labeling animals on an individual basis.
The research was carried out by marine biologists Stephanie King and Vincent Janik who conducted sound playback experiments with wild bottlenose dolphins on the east coast of Scotland.
Read more: www.laboratoryequipment.com/news/2013/07/dolphins-talk-each-other-using-personal-names
DNA Sheds Light on Rare Killer Whale Type
by Megan Gannon
Scientists have long suspected that the killer whale, Orcinus orca, may actually be four different species or subspecies based of subtle differences in appearance and variations in behavior. The rarest of them all is known as type D. These fat-headed orcas, marked by tiny white patches around their eyes, were only recently observed in the wild, some 50 years after they were first identified in photographs from a mass stranding in New Zealand.
The skeleton of one of the type D whales that washed ashore in 1955 ended up at a museum in Wellington. In a new study, scientists analyzed DNA from the bones, showing, yes, type D is likely a distinct subspecies or species. The research, detailed in the journal Polar Biology, also suggests type D diverged from other killer whales about 390,000 years ago, making it the second oldest orca type…
(read more: Live Science) (image: Shutterstock)
The Sea’s Strangest Square Mile
Lightning-quick eels! Coral-colored, pregnant frogfish stuffing their bellies with wriggling prey! Baby cuttlefish!! BABY CUTTLEFISH!!!
Noctilucas scintillans- a bioluminescent dinoflagellate also called the sea sparkle.
This is a closeup of the tentacles of Portuguese Man O’War (Physalia physalis)
Photo by Simon de Glanville
Because they spend so much time in remote waters, and don’t survive in captivity, great white sharks are deeply mysterious creatures. But over the last ten years, biologists have been able to track them using electronic tags which record their position and depth, and the ocean temperature.
On the face of it, that information can’t tell you what the sharks are actually doing. But Salvador Jorgensen of the Monterey Bay Aquarium in Monterey, California, and colleagues have developed a new statistical analysis that picks out patterns of behaviour from the tagging data.
It seems to confirm earlier suggestions that the sharks have a breeding ground in the east Pacific. What’s more, it suggests that the males go there to show off side-by-side in front of the choosy females – cattle-market style.
Watch helplessly as this mussel is slowly & inexorably consumed by a sea star. Oh yeah, you’re watching from inside the shell.
This is so cool! You might not know this about sea stars, but certain species have the ability to invert a portion of their stomach and digest their prey from outside their body. If you’re an invertebrate, you can’t exactly crack open a shell the way a bird can.
This sea star pulls open the mussel shell slightly, inserts its stomach and releases a flood of digestive enzymes that dissolve its prey from the inside. You can watch that happen, sped up in the video above.
No word on whether the sea star also releases a white wine/butter sauce.
(via Deep Sea News)
Photograph by Alessandro Kaitner (via Australian Sea Lion Picture — Animal Wallpaper — National Geographic Photo of the Day)
Ancient Pygmy Pipehorse Species Found
by Helen Scales
Fossils of a new species of pygmy pipehorse—a relative of the seahorse—have been discovered in Slovenia. Scientists discovered the 1-in-long (2.5-cm-long) species—dubbed Hippotropiscis frenki—in a fossil-rich region called the Tunjice Hills, where the team also found the oldest known seahorse fossils in 2009.
Pygmy pipehorses are thought to be an evolutionary link between seahorses and their close relatives, including pipefish and seadragons. The animals share so many features that at first study leader Jure Žalohar and colleagues thought the newfound fossils belonged to another type of ancient seahorse. Modern pygmy pipehorses also look and behave a lot like seahorses—pygmy pipehorse males, for instance, care for their fertilized eggs in a special pouch.
“The only major difference is that [pygmy pipehorses] do not swim upright,” Žalohar, a geologist at the University of Ljubljana, said by email…
(read more: National Geo) (images: Jure Žalohar)