The Grenoble synchrotron sheds light on the predatory character of the ancestor of the vampire of the abyss

The Grenoble synchrotron sheds light on the predatory character of the ancestor of the vampire of the abyss

FOCUS – French scientists have shown that Vampyronassa rhodanica, one of the oldest ancestors of the Abyss Vampire, he was an active hunter. We are not talking here about the mythological creature, but about very real animals that are the ancestors of squids and octopuses. This discovery is the result of a collaboration between several laboratories, such as the Grenoble Synchrotron, which was responsible for the image.

Vampyronassa rhodanica is considered one of the oldest ancestors of the Abyss Vampire (Vampyroteuthis infernalis), only known living species of this family. As its name suggests, this species evolves in the depths, more than 500 meters from the surface. A species shrouded in mystery, particularly due to the limited number of fossils.

Alison Rowe, a doctoral student at Sorbonne University, and her colleagues were able to study three well-preserved specimens of this species, over 164 million years old, discovered in La Voulte-sur-Rhône (Ardèche, France). Fossils of Jurassic animals, about 10 cm long, made up of eight arms, an elongated oval-shaped body and two small fins.

An abyssal vampire photographed in Monterey Bay, California, USA. The image is a still from a video taken at a depth of 717 meters. Public domain

20,000 times more accurate than hospital images

These precious vestiges of the past were taken to the ESRF, to obtain more precise images. “We use synchrotron tomography at ESRF to better identify the contours of different anatomical features”explains Alison Rowe.

In fact, the Natural History Museum in Paris had already taken photographs, but the material lacked the power to discover more about vampires. Hence the interest in using a synchrotron to decipher its secrets.

This particle accelerator specializes in the production of X-rays. The principle: spin electrons at high speed in a ring. If the latter change direction, disturbances are created at the source of high-frequency electromagnetic radiation.

© Scientific Reports

Images acquired at the ESRF: in (a), the reconstruction of V. rhodanica © P. Loubry, CR2P. In (b), the section of the specimen. In ©, the 3D representation showing the crown of the arm and other supposed elements. In (d), the external 3D reconstruction. In (e), the section showing the profile view. © Scientific Reports

“The Grenoble synchrotron is 100 billion times brighter than the X-ray beam produced in a hospital”, explains Vincent Fernandez, ESRF scientist. Brightness is an essential factor in capturing an image as it affects accuracy. In fact, a photo taken in a dimly lit space will reveal less detail.

A hospital scanner is capable of seeing objects on the order of a millimeter. “Through the synchrotron we were able to observe objects of the order of 20 nanometers”, says the researcher. This is 20,000 times more accurate than in a hospital setting.

X-ray tomography to create “virtual slices”

Nonetheless, “Scanning a fossil is still complicated. It’s rock, it’s dense and it requires a very powerful beam.” says the ESRF scientist. “A fossil of a few millimeters could be made in all the synchrotrons, but in a block of about ten centimeters, it is only possible in a few places in the world. »

Fossil of the ancestor of the abyss vampire © P. Loubry, CR2P

Photograph of one of the fossils digitized at the ESRF © P. Loubry, CR2P

Paleontologist Vincent Fernandez working on the particle accelerator, this also allows him to be the link between the instrument and the scientists. And to be able to debate with the scientific community.

Specifically, X-ray tomography allows the creation of virtual sections of an object. “If you scan a sausage with this technique, you can create virtual slices without actually cutting the actual sausage. “, specifies the researcher.

The interest is therefore to be able to cut in any direction thanks to a computer. This made it possible to produce a 3D model of the Jurassic animal. And to go further, here is a video to understand the problems around the technique used.

Deep Vampire: bigger and stronger suction cups

Thus, the image revealed previously unknown details at the level of the tentacles. Alison Rowe and her colleagues thus compared their tomographic data with that of another fossilized vampire specimen from the abyss, digitized at the American Museum of Natural History in New York.

Therefore, they were able to conclude that the suckers and cirri of the Jurassic octopus were larger and more robust than those of the modern form. They were also distributed over the tentacles in a different configuration.

” Us believe that the morphology and location of the suckers and cirri of V. rhodanica have allowed this species to increase its power of aspiration and its sensory capacities through compared to the modern form, allowing it to better catch and hold its prey.explains Alison Rowe.

© Scientific Reports

3D reconstruction and CT image of the crown of the arm and a dorsal sucker of V. rhodanica. In (a), the reconstruction of the crown of the arm shows the longest pair of dorsal arms. In (b), a section of the distal section of the dorsal pair of arms. In © and (d), the 3D reconstruction of a dorsal sucker in profile and oral view, respectively. The yellow color shows the surface of the adhesion zone. © Scientific Reports

This suggests that the Jurassic abyssal vampire was an active predator, capable of exerting enough suction to attract, manipulate, and hold prey. A discovery that raises questions about the evolution of this species.

In fact, the vampire squid, its modern descendant, has adapted to a low-energy lifestyle in the deep ocean. To survive, it feeds on drifting organic matter and is therefore more of an opportunist than a predator.

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