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Scientist hails ‘jaw-dropping’ fish fossil discovery

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A leading British scientist has said that the discovery of a 419-million-year-old fish fossil in China is a stunning and spectacular development.

Palaeobiologist Matt Friedman claims that the fish provided crucial evidence about the evolutionary development of jawed vertebrates.

As a remote relative of humans, it provides important evolutionary clues.

“It is the deepest branch of our family tree that bears the kinds of jaw bones found in humans,” Dr Friedman said.

The fossil was found at China’s Xiaoxiang Reservoir, and was reported by the journal Nature on Thursday.

Scientists say that the heavily armoured fish, Entelognathus primordialis, is a previously unknown member of jawed vertebrates also known as gnathostomes. It has a complex small skull and jaw-bone structure.

“This is an unexpected discovery that inverts schoolbook teaching on the evolution of bony skulls,” Dr Friedman said.

“Up until now it had been thought that the anatomical peculiarities of bony fishes – the group that would eventually give rise to human beings – are specialisations that arose later in vertebrate evolutionary history in our own bony fish lineage.”

“But now that narrative has been turned on its head.”

Dr Friedman said that the fish’s jaw was much more like that of a modern bony fish – which is why its discovery may offer a new perspective on the early evolution of these creatures.

His review of the significance of the fossil find also appears in the latest edition of Nature.

Scientists say that the evolution of jaws is one of the key episodes in the evolution of vertebrates, but the gap between jawed and jawless vertebrates is so large that it is hard to work out the individual evolutionary steps in the transition.

“While this fossil does not tell us anything about the origin of jawed fishes from jawless ones, it does tell us about subsequent modifications to jaw structure that we thought were unique to bony fishes,” Dr Friedman said.

It is thought that modern jawed vertebrates, such as sharks and bony fishes, emerged from a collection of jawed, armoured fishes known as placoderms.

Entelognathus primordialis has jaw-bone features previously restricted to bony fishes (osteichthyans) as well as full body armour seen in placoderms, and it would have been around 20cm (7.8in) long.

Dr Friedman says that the fossil adds weight to the theory that many classic bony fish features were evolved “very deep in our family tree, before bony fish split from sharks”.

“This means that we – as in bony fishes – are the ones who have held on to more ancient structures, while it is the sharks that have gone off and done something new and interesting in an evolutionary sense.

“They are the ones that have most radically modified this pattern, which we now understand is probably primitive to all modern jawed vertebrates.”

 

Source: www.bbc.co.uk/news

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Heading out on the water this Summer? Watch for manatees

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manatee

As National Safe Boating Week approaches, Save the Manatee® Club is urging boaters, and anyone that enjoys Florida’s waterways, to respect and protect the defenseless manatees that inhabit our shared waterways. From May 18 to 24, leading up to Memorial Day Weekend, the campaign aims to raise awareness about recreational boating safety and the importance of safeguarding imperiled manatees during the summer boating season. This week also emphasizes the importance of encouraging boaters to enroll in a boating safety course.

Manatees are semi-migratory marine mammals that are commonly found in shallow estuaries, bays, rivers, canals, and coastal areas throughout Florida and neighboring states. With some manatees venturing as far west as Texas and as far north as Massachusetts, collisions between these gentle giants and watercraft have become distressingly frequent. Boat propellers and high-speed collisions pose significant threats to manatees, often resulting in severe injuries or even death.

Save the Manatee Club is calling on all water enthusiasts to follow essential manatee safety tips to ensure the well-being of the imperiled manatee:

  • Obey Speed Zone Signs: Familiarize yourself with and adhere to posted speed limits to prevent collisions with manatees.
  • Reduce Glare with Polarized Sunglasses: Wear polarized sunglasses to enhance visibility and spot manatees below the water’s surface.
  • Recognize Manatee Signs: Learn to identify signs of manatees in the area, such as swirls or flat spots on the water caused by their movements.
  • Respect Manatee Sanctuaries: Keep a safe distance from posted manatee sanctuaries and avoid pursuing or harassing these marine mammals, as it is illegal and can disrupt their natural behaviors.
  • Report Distressed Manatees: In Florida, promptly report distressed, injured, tagged, or orphaned manatees to the Florida Fish and Wildlife Conservation Commission (FWC) at 1-888-404-FWCC (3922). Outside of Florida, report sightings to the appropriate state agency or rescue organization. A list of agencies to contact is available at savethemanatee.org/report.
  • Protect Seagrass Beds: Avoid boating over seagrass beds and shallow areas where manatees may be feeding. Stick to deep water channels while remaining vigilant, as manatees also utilize these channels during their travels.
  • Dispose of Fishing Line Responsibly: Anglers should properly dispose of or recycle used fishing line to prevent entanglement hazards for manatees.

“Each year, National Safe Boating Week provides an excellent reminder for all of us to be aware that we share our waterways with vulnerable manatees,” emphasized Patrick Rose, Aquatic Biologist and Executive Director of Save the Manatee Club. “With the recent Unusual Mortality Event on Florida’s East Coast claiming an alarming number of manatees’ lives, it is more crucial than ever to prevent preventable deaths caused by watercraft collisions. By following manatee-safe boating guidelines, such as obeying speed zones and remaining vigilant for manatees, everyone on the water can contribute to the protection of these gentle giants.”

Save the Manatee Club offers a range of free materials to help safeguard manatees and raise awareness about manatee-safe boating practices. Shoreline property owners and park or marina managers can order aluminum dock signs to alert others about the presence of manatees in their areas. Boaters and paddlers can request packets containing a safety tips card, a waterproof boat banner, and a decal to display on their vessels, providing the number to report manatees in distress. To view and request these materials, visit savethemanatee.org/resources. Save the Manatee Club will also be hosting a live webinar for National Safe Boating Week on Tuesday, May 21st at 6pm EST. To register, visit savethemanatee.org/register.

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Marine Life & Conservation Blogs

Book Review: Shells of the World

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Shells of the World: A Natural History by M.G. Harasewych

Shells of the world is a guide to the world of marine, shelled molluscs. And what a varied and interesting world it is. Some of my favourite things to find on a dive are detailed in this book, including disco clams (or Electric File Clams as they are correctly names), the cephalopods, giant clams and sea hares. There are also many on my wish list, top of which is the Nautilus.

Each chapter provides a detailed description of the species, along with beautiful images. You can dive deeper and discover where they live, both with global distribution and the habitat they prefer. Learn about their diet, reproduction and diversity.

Having dipped in and out of this lovely book over the past few weeks, it has inspired me to learn more about this group of animals that we see on most divers, wherever we are in the world. Some of the shells are incredibly intricate and beautiful. I have always agreed with never collecting, or touching, marine life. The description of a certain set of cone shells should be a warning to those that are happy to pick up marine life! One of the cone shells has a local name called the cigarette snail. Why? Because once the venom is in your system from this animal, you only have time to smoke one cigarette before the affects of the venom are fatal!

What the publisher says:

Mollusks are invertebrate animals with a remarkable natural history and a rich fossil record, and their shells are prized for their breathtaking variety and exquisite beauty. Shells of the World provides a wide-ranging look at the incredible diversity of marine mollusks. An informative introduction outlines the lineages covered, followed by a directory section, split into classes, that profiles a broad selection of different taxa to give a sense of their sheer numbers and variety.

  • Features hundreds of beautiful color photos, depicting both the live animals and their shells
  • Discusses mollusk evolution, anatomy, life cycles, behavior, and ecology
  • Describes unique characteristics, distribution, habitat, and size
  • Provides valuable insights into the conservation of the world’s marine mollusks
  • Ideal for malacologists and shell collectors everywhere

About the Author:

M. G. Harasewych is research zoologist emeritus and former curator in the Department of Invertebrate Zoology at the Smithsonian Institution’s National Museum of Natural History. A fellow of the American Association for the Advancement of Science, he is the author (with Fabio Moretzsohn) of The Book of Shells: A Life-Size Guide to Identifying and Classifying Six Hundred Seashells.

Book Details

Publisher: Princeton University Press

Hardcover

Price: £25

ISBN: 9780691248271

Published: 9th April, 2024

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