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Rare ammonite 'death drag' fossil discovered

The "death drag" of a prehistoric "squid" - or ammonite - made 150-million-years-ago has been preserved as an incredible fossil.
The animal's shell made the 8.5m-long mark as it drifted along the seafloor after its death.
Ammonites are one of the most common and popular fossils collected by amateur fossil hunters.
This specimen (Subplanites rueppellianus) was found in a quarry in southern Germany. Its shell was preserved alongside the mark it made as it drifted along the floor of a tropical lagoon in a steady current.
 
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Ammonite fossils found in Sichuan

A villager recently came across a pile of strange-looking rocks in Wanyuan, Sichuan province. The rocks were covered with a pattern of chrysanthemums, shells and maggots. According to Liu Shisu, a local archaeologist, the strange patterns in the rock layers are actually ammonite fossils dating back hundreds of millions of years. Ammonites are an extinct group of marine mollusk animals. The earliest ammonites appeared during the Devonian era, and the last species died out during the CretaceousPaleogene extinction event. The animal's Chinese name references its chrysanthemum-like surface.
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Melanin pigment preserved in 160 million-year-old Jurassic fossils

Researchers have detected intact melanin in 160 million-year-old fossilised cephalopod ink sacs in the United Kingdom, according to a study. To ascertain the presence of the colouring pigment melanin in the fossil record, researchers have long relied on indirect methods, suggesting poor preservation of the pigment over geologic time. For example, researchers have reconstructed the plumage patterns of dinosaurs through visual evidence of organelle-like structures bearing melanin pigments. John D. Simon and colleagues used a combination of direct, high-resolution chemical techniques and identified a wide range of signatures unique to a form of brownish-black melanin called eumelanin, known to play biologically-important roles in display and camouflage, in 160 million-year-old fossils of cephalopod ink sacs preserved in Jurassic-age deposits in Wiltshire and Dorset in the United Kingdom. The authors report that the chemical signatures strongly suggest the similarity of the eumelanin pigment in the fossilised ink sacs to the melanin of the modern cuttlefish Sepia officinalis, found in the Mediterranean, North, and Baltic Seas. The authors' chemical analysis revealed that the fossil pigment was unlikely to be of the less-common, orange-hued variety of melanin called pheomelanin. Given that melanin appears to have survived fossilisation, the authors reason, other biologically relevant organic compounds might lie undiscovered in the fossil record.

Title: Direct chemical evidence for eumelanin pigment from the Jurassic period
Authors: Keely Glass, Shosuke Ito, Philip R. Wilby, Takayuki Sota, Atsushi Nakamura, C. Russell Bowers, Jakob Vinther, Suryendu Dutta, Roger Summons, Derek E. G. Briggs, Kazumasa Wakamatsu, and John D. Simon

Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions, including display, evasion, photoprotection, detoxification, and metal scavenging. To date, evidence of melanin in fossil organisms has relied entirely on indirect morphological and chemical analyses. Here, we apply direct chemical techniques to categorically demonstrate the preservation of eumelanin in two > 160 Ma Jurassic cephalopod ink sacs and to confirm its chemical similarity to the ink of the modern cephalopod, Sepia officinalis. Identification and characterisation of degradation-resistant melanin may provide insights into its diverse roles in ancient organisms.

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 First fertile, then futile: ammonites or the boon and bane of many offspring

Ammonites changed their reproductive strategy from initially few and large offspring to numerous and small hatchlings. Thanks to their many offspring, they survived three mass extinctions, a research team headed by palaeontologists from the University of Zurich has discovered.
For 300 million years, they were the ultimate survivors. They successfully negotiated three mass extinctions, only to die out eventually at the end of the Cretaceous along with the dinosaurs: Ammonoids, or ammonites as they are also known, were marine cephalopods believed to be related to todays squid and nautiloids. Ammonoids changed their reproductive strategy early on in the course of evolution. However, what was once a successful initial strategy may well have proved to be a fatal boomerang at the end of the Cretaceous, as an international team of researchers headed by palaeontologists from the University of Zurich demonstrate in a study recently published in the science journal "Evolution".

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 Mobile Ammonites Stayed Put at Plains Methane Seeps

Research led by Museum scientists shows that ammonites, an extinct type of shelled mollusk that's closely related to modern-day nautiluses and squids, made homes in the unique environments surrounding methane seeps in the seaway that once covered America's Great Plains. The findings, recently published in the journal Geology, provide new insights into the mode of life and habitat of these ancient animals.
In the Black Hills region of South Dakota, researchers are investigating a 74-million-year-old mound of fossilized material where methane-rich fluids once migrated through the sediments onto the sea floor. When the face of this cliff recently slumped off, a wide variety of bivalves, sponges, corals, fish, crinoids, and, as recently documented, ammonites, were revealed.

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Eavesdropping on the squid world

Marine biologists are starting to get a good idea now of how squid hear and how they react to sounds in the ocean.
It is only recently that scientists have come to accept that cephalopods have any auditory capability at all.
But new experiments show noises of varying loudness and frequency will elicit a range of behaviours in the animals - such as jetting or inking, and even a change of colour.

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Ammonites

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Ammonite diet revealed in X-ray

Ask someone to name their favourite fossils and the chances are they will point to the ammonites.
These coiled remains of ancient squid-like creatures are in every child's rock collection.
The animals were a big success, filling the oceans for 350 million years before going extinct with the dinosaurs.
Now, exquisite X-ray images featured in Science magazine are providing new insights on how the ammonites lived and perhaps also on why they died out.



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Ammonites Dined on Plankton

Powerful synchrotron scans of Baculites fossils found on American Museum of Natural History expeditions to the Great Plains suggests that the extinct group of marine invertebrates to which they belong, the ammonites, had jaws and teeth adapted for eating small prey floating in the water. One ammonite also provided direct evidence of a planktonic diet because it died with its last meal in its mouth -- tiny larval snails and crustacean bits. The detailed description of internal structure of ammonites, published by a Franco-American research team this week in Science, also provides new insights into why ammonites became extinct 65.5 million years ago when an asteroid impact led to the demise of the world's nonavian dinosaurs and much of the plankton.



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Ammonites were eaten by squid

A new research paper published by the Geological Society suggests why many ammonites on the Jurassic Coast have "bite marks" in the same place.
Zoologist Chris Andrew and geologist Paddy Howe in Lyme Regis say that one in four of the fossils bears the mark, which is visible to the naked eye.
Their research supports similar findings from experts in Belgium.
The pair, who wrote the paper, believe the ammonites were eaten by a fellow cephalopod such as a soft-bodied squid.

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