Egg-sucking sea slug from Florida's Cedar Key named after Muppets creator Jim Henson

Date:  June 18, 2019

Source:  Florida Museum of Natural History

Feet from the raw bars and sherbet-colored condominiums of Florida's Cedar Key, researchers discovered a new species of egg-sucking sea slug, a rare outlier in a group famous for being ultra-vegetarians.

Named Olea hensoni in honor of Muppets creator Jim Henson, the slug belongs to the sacoglossans, a group of more than 300 species that are such enthusiastic eaters of plants that many of them turn green and some resemble leaves. A few species, nicknamed "solar-powered slugs," have even developed the ability to keep algae alive inside their bodies to photosynthesize their food for them, becoming a fusion of plant and animal.

But O. hensoni has gone rogue, joining two other sacoglossan species -- Olea hansineensis from the northeast Pacific and Calliopaea bellula in the Mediterranean -- that abandoned a diet of seaweed to prey on the eggs of their fellow slugs and snails.

"In the middle of this group of super-herbivores, there are a couple of species that have rebelled in 'The Hills Have Eyes' kind of way and have gone almost full-blown cannibal," said Patrick Krug, professor of biological sciences at California State University. "These are like the Venus fly traps of the slug world. They've switched from being harmless, friendly creatures to predators."

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California's mighty predator, the mountain lion, faces 'extinction vortex'

JUNE 25, 2019

by Louis Sahagun

As the mountain lions of Southern California approach what some experts call an "extinction vortex," environmentalists are demanding that state officials grant the big cats protective status—a move that could potentially ban development on thousands of acres of prime real estate.

Mountain lions as a species are not threatened in California, but a petition submitted Tuesday to the state Fish and Game Commission argues that six isolated and genetically distinct cougar clans from Santa Cruz to the U.S.-Mexico border comprise a subpopulation that is threatened by extinction.

The petition, which is co-sponsored by the Center for Biological Diversity and the nonprofit Mountain Lion Foundation, argues that Central and Southern California mountain lions comprise an "evolutionarily significant unit" that should be declared threatened under the state Endangered Species Act.

Recent scientific studies suggest there's an almost 1 in 4 chance that Southern California mountain lions could become extinct in the Santa Monica and Santa Ana mountains within 50 years.

"This petition will be controversial," said Justin Dellinger, senior environmental scientist with the Wildlife Investigations Laboratory at the California Department of Fish and Wildlife.

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New species of rock-eating shipworm identified in freshwater river in the Philippines

International team of researchers studying biodiversity with an eye toward developing new drugs

Date:  June 19, 2019

Source:  University of Massachusetts at Amherst

A newly identified genus and species of worm-like, freshwater clam, commonly known as a shipworm, eats rock and expels sand as scat while it burrows like an ecosystem engineer in the Abatan River in the Philippines.

Local residents of Bohol Island tipped off an international group of scientists, including University of Amherst post-doctoral researcher Reuben Shipway, to the watery location of the bivalve, which the scientists named Lithoredo abatanica, using the Latin words for rock (litho) and the last two syllables of shipworm (teredo). Locals call the shipworm "antingaw," and new mothers are said to eat them in an effort to enhance lactation, Shipway says.

"These animals are among the most important in the river and in this ecosystem," says Shipway, a marine biologist working in the microbiology lab of professor Barry Goodell and lead author of the paper that describes L. abatanica, published in the Proceedings of the Royal Society B. "As they bore elaborate tunnels in the limestone bedrock, these animals change the course of the river and provide a really rich environment for other aquatic species to live in. So far, this is the only place on earth that we know these animals exist."

Co-authors include Marvin Altamia and Daniel Distel of Ocean Genome Legacy Center at Northeastern University, where Shipway previously worked; Gary Rosenberg of Drexel University; Gisela Concepcion of the University of the Philippines; and Margo Haygood of the University of Utah.

Continued

Wearable device reveals how seals prepare for diving

Date:  June 18, 2019

Source:  PLOS

A wearable non-invasive device based on near-infrared spectroscopy (NIRS) can be used to investigate blood volume and oxygenation patterns in freely diving marine mammals, according to a study publishing June 18 in the open-access journal PLOS Biology by J. Chris McKnight of the University of St. Andrews, and colleagues. The results provide new insights into how voluntarily diving seals distribute blood and manage the oxygen supply to their brains and blubber, yielding important information about the basic physiological patterns associated with diving.

In response to submersion in water, mammals show a suite of cardiovascular responses such as reduced heart rate and constriction of peripheral blood vessels. But investigating dive-by-dive blood distribution and oxygenation in marine mammals has up to now been limited by a lack of non-invasive technology that can be used in freely diving animals.

The authors hypothesized that NIRS could address this gap in knowledge by providing high-resolution relative measures of oxygenated and deoxygenated hemoglobin within specific tissues, which can in turn be used to estimate changes in blood volume. In the new study, McKnight and colleagues adapted NIRS technology for use on freely diving harbor seals to investigate blood volume and oxygenation patterns specifically in the brain and blubber, using a device that they dub the PortaSeal.

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How Snakes Swallow – via Herp Digest

A snake’s ability to swallow enormous prey has long been a source of fascination, but the common explanation that they dislocate their jaws is a myth.

Wayward pythons are not uncommon in the Australian bush. Still, one camp manager was quite surprised when a python she relocated began to cough up its last meal: an even larger python.  A snake’s ability to swallow enormous prey has long been the stuff of nightmares and fascination, but just how do they do it?

Scientist Kenneth Kardong, writing in Copeia, explains that snake swallowing is all about the jaw. A snake cannot swallow something that won’t fit past its jaws, so snakes have  a unique adaptation that allows them to increase their jaw width, or “gape” as it is technically known. Contrary to popular myth, snakes do not in fact dislocate their jaws. But they can certainly perform some spectacular feats of jaw agility.

The snake’s head “walks” forward in a side-to-side motion over the prey’s body.

In snakes, the lower bones of the jaw, or mandibles, are not connected like they are in mammals. At the front, each mandible is attached by a stretchy ligament. The mandibles can therefore spread apart laterally, increasing the width of the mouth. The mandibles are loosely connected at the back to the skull, allowing for much greater rotation than most animals have. This is how the snake can open its mouth wider than its body. The mandibles move independently of each other, slowly inching the prey into the throat. Simultaneously, the snake’s head “walks” forward in a side-to-side motion over the prey’s body, so as the prey is levered backward the head moves forward. The process can take a while. Backward-pointing teeth help ensure the prey does not escape if it is still alive.

Swallowing is only half the battle, though, and prey must also be digested. Snakes don’t chew their food; they chemically digest it. So there is limited mechanical breakdown. Digestive enzymes can only act on the tough outside of a meal. Consequently, snake digestion can take a while, and snakes often cough up partially-digested meals.

According to scholars F. Harvey Pough and John D. Groves in American Zoologist, pit vipers have a particularly terrifying way of dealing with the digestion problem. Pit vipers have large heads and thick bodies, allowing them to swallow extremely large prey relative to their body size. As a result, digestion for pit vipers can be especially slow. This poses real risks to the snake, as snakes are vulnerable while digesting. Also, if digestion does not outpace putrefaction, partially-digested prey might expand inside the snake’s body with dangerous consequences. Pit vipers, however, have an ace in hole: venom. Their long fangs inject protein-dissolving venom deep into the prey’s body. The venom aids digestion by turning the prey’s insides into goo. Problem solved.

JSTOR is a digital library for scholars, researchers, and students. JSTOR Daily readers can access the original research behind our articles for free on JSTOR.

Kinesis of the Jaw Apparatus during Swallowing in the Cottonmouth Snake, Agkistrodonpiscivorus

By: Kenneth V. Kardong

Copeia, Vol. 1977, No. 2 (May 25, 1977), pp. 338-348

American Society of Ichthyologists and Herpetologists (ASIH)

Specializations of the Body Form and Food Habits of Snakes

By: F. Harvey Pough and John D. Groves

American Zoologist, Vol. 23, No. 2 (1983), pp. 443-454

Oxford University Press