Fossil and living porcupinefish, new research


This video says about itself:

Porcupine fish rescue

21 March 2016

Our guys came across an entangled porcupine fish while snorkeling. The little guy was freed using a broken bottle. Clever.

From the Smithsonian Tropical Research Institute in Panama:

Comparing the jaws of porcupine fish reveals three new species

August 16, 2017

Researchers at the Smithsonian Tropical Research Institute and colleagues compared fossil porcupine fish jaws and tooth plates collected on expeditions to Panama, Colombia, Venezuela and Brazil with those from museum specimens and modern porcupine fish, revealing three new species.

Startled porcupine fish suck in air or water to inflate their bodies, becoming a prickly balloon-like shape to defend themselves from predators and some contain a neurotoxin a thousand times more potent than cyanide in their ovaries and livers. They are also good at offense, crushing the shells of clams and other marine mollusks with beak-like jaws so tough that they are preserved as fossils to be discovered millions of years later.

Two of the newly discovered species, named Chilomycterus tyleri, in honor of the Smithsonian’s James C. Tyler, senior scientist emeritus at the National Museum of Natural History — an expert on this group of fish — and C. expectatus, named for the arrangement of its dental plates, were discovered in Panama’s Gatun formation.

The third new species, Diodon serratus, named for the serrated edge of its crushing dental sheet, comes from the Socorro Formation in Venezuela. When Darwin traveled to the tropics on the Voyage of the Beagle, he noticed this fish that swims upside down when inflated. He even mentioned a report from a fellow naturalist, that porcupine fish could gnaw their way out of the stomach of a shark.

Today 18 species of porcupine fish populate tropical seas worldwide. Species in the genus Diodon are common in shallow, tropical waters of both the Atlantic and Pacific. In contrast, only one species of the genus Chilomycterus is found in the Eastern Pacific. The rest are in the Atlantic.

When the Isthmus of Panama arose from the sea to connect North and South America and divide the Atlantic from the Pacific, the oceans on each side of this intercontinental bridge changed forever. The Eastern Pacific became cooler and more nutrient rich and the Caribbean because warmer and more nutrient poor, characterized by more coral reefs and seagrass beds.

This research team hopes to better understand why there was only one Chilomycterus species in a fossil deposit near Panama’s Tuira river on the Pacific side of the isthmus of Panama.

Goldfish survive harsh winters with alcohol


This video says about itself:

Goldfish go months without oxygen by making alcohol inside cells

11 August 2017

Goldfish and crucian carp have evolved enzymes that turn carbohydrates into alcohol when no oxygen is available – helping the fish survive in ice-locked pools. Read more here.

From the University of Liverpool in England:

How goldfish make alcohol to survive without oxygen

August 11, 2017

Scientists at the Universities of Oslo and Liverpool have uncovered the secret behind a goldfish’s remarkable ability to produce alcohol as a way of surviving harsh winters beneath frozen lakes.

Humans and most other vertebrate animals die within a few minutes without oxygen. Yet goldfish and their wild relatives, crucian carp, can survive for days, even months, in oxygen-free water at the bottom of ice-covered ponds.

During this time, the fish are able to convert anaerobically produced lactic acid into ethanol, which then diffuses across their gills into the surrounding water and avoids a dangerous build-up of lactic acid in the body.

The molecular mechanism behind this highly unusual ability, which is unique among vertebrates and more commonly associated with brewer’s yeast, has now been uncovered and is published in the journal Scientific Reports.

The international team has shown that muscles of goldfish and crucian carp contain not just the usual one, but two sets of the proteins normally used to channel carbohydrates towards their breakdown within a cell’s mitochondria — a key step for energy production.

While one set of these proteins appears very similar to that in other species, the second set is strongly activated by the absence of oxygen and shows a mutation that allows channelling of metabolic substrates to ethanol formation outside the mitochondria.

Further genetic analyses suggest that the two sets of proteins arose as part of a whole genome duplication event in a common ancestor of goldfish and crucian carp some 8 million years ago.

Dr Michael Berenbrink, an evolutionary physiologist at the University of Liverpool, said: “During their time in oxygen-free water in ice-covered ponds, which can last for several months in their northern European habitat, blood alcohol concentrations in crucian carp can reach more than 50 mg per 100 millilitres, which is above the drink drive limit in these countries.

“However, this is still a much better situation than filling up with lactic acid, which is the metabolic end product for other vertebrates, including humans, when devoid of oxygen.”

Lead author Dr Cathrine Elisabeth Fagernes, from the University of Oslo, said: “This research emphasises the role of whole genome duplications in the evolution of biological novelty and the adaptation of species to previously inhospitable environments.

“The ethanol production allows the crucian carp to be the only fish species surviving and exploiting these harsh environments, thereby avoiding competition and escaping predation by other fish species with which they normally interact in better oxygenated waters.

“It’s no wonder then that the crucian carp’s cousin the goldfish is arguably one of the most resilient pets under human care.”

The work is the result of a collaboration between scientists at the University of Liverpool, UK, and the University of Oslo, Norway. The work was funded by the Research Council of Norway.

Bahamas pupfish, new study


Bahamas pupfish

This picture about Bahamas pupfish shows San Salvador Island generalists (red), molluscivores (green), large-jawed scale-eaters (dark blue), small-jawed scale-eaters (light blue), and outgroup species (black) in the Caribbean, California, and Mexico. Credit: Emilie Richards and Christopher Martin; CC-BY.

From PLOS:

San Salvador pupfish acquired genetic variation from island fish to eat new foods

Study finds that ecological and genetic factors both contributed to rise of new pupfish species

August 10, 2017

Pupfish living in salty lakes on San Salvador Island were able to diversify into multiple species with different eating habits, in part, by interbreeding with pupfish from other islands in the Caribbean, report Emilie Richards and Christopher Martin, of the University of North Carolina at Chapel Hill, August 10, 2017 in PLOS Genetics.

Pupfish are small, brightly colored fish that commonly live in coastal areas and salty lakes and feed off of algae. But on San Salvador Island in the Bahamas, a group of pupfish has undergone adaptive radiation, a process where existing species rapidly evolve and differentiate into new species, to take advantage of a new environment. Where most pupfish species eat algae, one San Salvador species has a protruding nasal region that allows it to eat snails, while another has enlarged jaws that enable it to bite the scales off of other fish. To understand why these specialized species evolved only on San Salvador Island, despite the availability of scales and snails across the Caribbean, the researchers used whole genomes to identify regions of the San Salvador pupfish genome that came from outside sources.

They examined 42 pupfish genomes collected from populations on San Salvador Island, two distant Caribbean islands, Laguna Chichancanab in Mexico, and Devil’s Hole in California, to identify regions of the genome that have been exchanged between San Salvador Island and outside pupfish populations. They identified 11 gene variants in the San Salvador fish that came from other Caribbean pupfish populations, with four of these regions known to affect jaw size and shape, traits important in the evolution of their specialized diets.

The study suggests that multiple outside sources of genetic variation contributed to the adaptations found in pupfishes on San Salvador Island. These findings indicate that a complex suite of factors, including breeding with related species, in addition to new ecological opportunities, may be necessary for adaptive radiations to occur.

“The really intriguing thing here is that new species are assembled from different pots of genetic variation over a very large range. Our own species is likely no different,” says study corresponding author Dr. Martin.

Sardines and their predators


This video says about itself:

Sardine Feeding Frenzy: Whale, Shark, Dolphin and Sea Lions – The Hunt – BBC Earth

28 July 2017

A sizeable shoal of sardines proves to be quite a magnet for a variety of different sea predators. Surprisingly, none of the predators on display attack each other, instead they corral the ball of fish, taking turns to eat.

Big Triassic fossil fish discovered in Nevada, USA


Possible look of the newly discovered predatory fish species Birgeria americana with the fossil of the skull shown at bottom right. Artwork: Nadine Bösch

From the University of Zurich in Switzerland:

Large-mouthed fish was top predator after mass extinction

July 26, 2017

Summary: The food chains recovered more rapidly than previously assumed after Earth’s most devastating mass extinction event about 252 million years ago as demonstrated by the fossilized skull of a large predatory fish called Birgeria americana discovered by paleontologists from the University of Zurich in the desert of Nevada.

The most catastrophic mass extinction on Earth took place about 252 million years ago — at the boundary between the Permian and Triassic geological periods. Up to 90 percent of the marine species of that time were annihilated. Worldwide biodiversity then recovered in several phases throughout a period of about five million years. Until now, paleontologists have assumed that the first predators at the top of the food chain did not appear until the Middle Triassic epoch about 247 to 235 million years ago.

Unexpected find of a large predatory fish

Swiss and U.S. American researchers led by the Paleontological Institute and Museum of the University of Zurich have discovered the fossil remains of one of the earliest large-sized predatory fishes of the Triassic period: an approximately 1.8-meter-long primitive bony fish with long jaws and sharp teeth. This fish belongs to a previously unknown species called Birgeria americana. This predator occupied the sea that once covered present-day Nevada and the surrounding states already one million years after the mass extinction.

Triassic “Jaws

In the United States, almost no vertebrate fossils from the Early Triassic epoch (252 to 247 million years ago) have been scientifically described until now. “The surprising find from Elko County in northeastern Nevada is one of the most completely preserved vertebrate remains from this time period ever discovered in the United States,” emphasizes Carlo Romano, lead author of the study. The fossil in question is a 26-centimeter-long partial skull of a fierce predator, as evidenced by three parallel rows of sharp teeth up to 2 centimeters long along the jaw margins, as well as several smaller teeth inside the mouth.

Birgeria hunted similarly to the extant great white shark: the prey fish were pursued and bitten, then swallowed whole. Species of Birgeria existed worldwide. The most recent discovery is the earliest example of a large-sized Birgeria species, about one and a half times longer than geologically older relatives.

Predators appeared earlier than assumed

According to earlier studies, marine food chains were shortened after the mass extinction event and recovered only slowly and stepwise. In addition, researchers assumed that the ancient equatorial regions were too hot for vertebrates to live during the Early Triassic. Finds such as the newly discovered Birgeria species and the fossils of other vertebrates now show that so-called apex predators (animals at the very top of the food chain) already lived early after the mass extinction. The existence of bony fish close to the equator — where Nevada was located during the Early Triassic — indicates that the temperature of the sea was a maximum of 36°C. The eggs of today’s bony fish can no longer develop normally at constant temperatures above 36°C.

“The vertebrates from Nevada show that previous interpretations of past biotic crises and associated global changes were too simplistic,” Carlo Romano says. Despite the severity of the extinctions of that time and intense climatic changes, the food webs were able to redevelop faster than previously assumed.

New lantern shark species discovery


This video says about itself:

23 December 2015

In the Pacific Ocean, near the coasts of Costa Rica, Panama and Nicaragua, scientists discovered a new species of shark: Ninja Lanternshark. The species was named Etmopterus benchleyi, in honor of Peter Benchley, author of Jaws. Etmopterus benchleyi is a small shark, growing up to 50 cm, and lives at depths ranging between 836 and 1443 meters. In the darks of the ocean, Etmopterus benchleyi emits a faint glow.

And now, a relative of this small luminescent shark has been found.

From Florida Atlantic University in the USA:

New shark species glows in the dark, weighs about 2 pounds and has a huge nose

July 25, 2017

Summary: Just as “Shark Week” is gearing up, researchers have discovered a new species of shark 17 years in the making. Like finding a needle in a haystack, it was well worth the wait as this elusive creature is yet to be seen in the wild.

Like finding a needle in a haystack, a team of scientists has discovered a new species of shark measuring less than a foot long and weighing under 2 pounds full-grown. This miniature, “glow-in-the-dark” shark is a member of the Lanternshark family (Squaliformes: Etmopteridae), which was serendipitously found 1,000 feet below the Pacific Ocean off the coast of the Northwestern Hawaiian Islands. It has taken more than 17 years to identify this new species (Etmopterus lailae) since it was first discovered but was well worth the wait as this elusive creature is yet to be seen in the wild.

It often takes many years to identify a new species from the time it is discovered to the moment the news is shared with the scientific community. Results of the discovery of Etmopterus lailae were published in the journal Zootaxa. Stephen M. Kajiura, Ph.D., study co-author, a professor of biological sciences and director of the Elasmobranch Research Laboratory in the Charles E. Schmidt College of Science at Florida Atlantic University, is among the team of scientists who painstakingly worked on this project, which began while he was still in graduate school at the University of Hawaii.

“There are only about 450 known species of sharks worldwide and you don’t come across a new species all that often,” said Kajiura. “A large part of biodiversity is still unknown, so for us to stumble upon a tiny, new species of shark in a gigantic ocean is really thrilling. This species is very understudied because of its size and the fact that it lives in very deep water. They are not easily visible or accessible like so many other sharks.”

At first, Kajiura and his collaborators did not realize that they had discovered a new species until they submitted their research findings to a journal. The reviewer told them that the shark was not what they originally thought it was and that it might be a new species. Kajiura worked with David A. Ebert, Ph.D., study author, a taxonomist and program director of the Pacific Shark Research Center at Moss Landing Marine Laboratories in California, to identify this new species, now housed in the Bernice P. Bishop Museum in Hawaii.

Identifying the Etmopterus lailae required an extensive list of measurements, diligent categorization and thorough comparisons with other museum specimens.

“The unique features and characteristics of this new species really sets it apart from the other Lanternsharks,” said Kajiura. “For one thing, it has a strange head shape and an unusually large and bulgy snout where its nostrils and olfactory organs are located. These creatures are living in a deep sea environment with almost no light so they need to have a big sniffer to find food.”

Some of the other distinctive characteristics of this new species are its flank markings that go forward and backward on their bellies, a naked patch without scales on the underside of its snout, as well as internal differences such as the number of vertebrae they have as well as fewer teeth than the other sharks. Like other Lanternsharks, the Etmopterus lailae is bioluminescent and the flanks on the bottom of its belly glow in the dark. These markings on its belly and tail also were specific to this new species.

There are a number of hypotheses for why Lanternsharks glow in the dark including mate recognition to ensure they are mating with the right species, serving as a form of camouflage to protect them from predators in the deep sea and using bioluminescence to act as a lure to attract little fish or shrimp.

“The research team’s discovery of a new shark species is evidence of how much is still undiscovered in our world,” said Ata Sarajedini, Ph.D., dean of FAU’s Charles E. Schmidt College of Science. “This new species is the tip of the iceberg for what else might be out there and the great potential for all of the yet-to-be undescribed species that still need to be explored.”

The team of scientists also include Yannis P. Papastamatiou, Ph.D., Florida International University and Bradley M. Wetherbee, Ph.D., University of Rhode Island.

In 2000, Kajiura and Wetherbee discovered the Trigonognathus kabeyai or the Viper Dogfish in Hawaii, which also is part of the Lanternshark family. The Viper Dogfish’s distinctive feature is its snake-like mouth filled with crooked nail-like teeth that sets them apart from other Lanternsharks.