Hypothesised reconstruction of Vampyronassa rhodanica (Alexandre Lethiers, CR2P-SU).
Alison Rowe et plusieurs membres du CR2P ont participé à cette étude publiée dans Scientific Reports
A new analysis of fossilised specimens of Vampyronassa rhodanica — an ancient species of cephalopod related to octopus, squid and cuttlefish — uncovers how the animal may have been well adapted to actively hunt prey in the open ocean. The paper, published in Scientific Reports, reveals that the species likely had suckers that could hold on to prey, unlike its modern-day descendant, the vampire squid, which feeds on drifting organic matter.
Vampyronassa rhodanica is thought to be one of the oldest relatives of the modern-day vampire squid (Vampyroteuthis infernalis), which lives in extreme deep ocean environments, away from the shoreline, often with little oxygen. However, less is known about the physical characteristics of V. rhodanica as the body is rarely found fossilized due to being largely formed of soft tissue.
Alison Rowe and colleagues used a non-destructive 3-D imaging technique to reanalyse well-preserved V. rhodanica fossils from La Voulte-sur-Rhône (Ardèche, France) dating to more than 164 million years ago. The eight-armed specimens were small, measuring around 10 cm in length, and had elongated oval-shaped bodies with two small fins.
Similar to modern vampire squid, the suckers on V. rhodanica were likely not toothed. However, unlike vampire squid, the fossil specimens displayed evidence of robust suckers on the tips of two specialised, long dorsal arms.
Based on similar modern-day species, the authors propose that V. rhodanica used these suckers to create a watertight seal, producing a secure suction force. The authors suggest these suckers would also have aided the manipulation and retention of prey
The authors propose that the presence of muscular suckers on each of the arms and sensory conical appendages for detecting prey suggests that V. rhodanica was an active predatory hunter. This is in contrast with its more opportunistic descendant the vampire squid, which has adapted to a low energy, deep ocean lifestyle.
The Jurassic cephalopod Vampyronassa rhodanica, thought to be the oldest known ancestor of the modern-day vampire squid (Vampyroteuthis infernalis), was likely an active hunter - a mode of life that is in contrast with its opportunistic descendant. Scientists led by Sorbonne University came to this conclusion after analysing microtomographic data of this rare fossil, acquired at the ESRF and the Muséum national d’Histoire naturelle in Paris. The results are published today in Scientific Reports.
Vampyronassa rhodanica is thought to be one of the oldest relatives of the modern-day vampire squid (Vampyroteuthis infernalis), which is the only remaining living species of its family. This modern form lives in extreme deep ocean environments, often with little oxygen, and feeds on drifting organic matter. Like V. infernalis, the body of V. rhodanica was mostly made of soft tissue. As this rarely fossilises, little is known about the physical characteristics and evolutionary history of this family.
Despite the scarcity of fossil material from this family, Alison Rowe, from Sorbonne University and colleagues were able to study 3 well-preserved V. rhodanica specimens from La Voulte-sur-Rhône (Ardèche, France), dating to more than 164 million years ago. The eight-armed specimens were small, measuring around 10 cm in length, and had elongated oval-shaped bodies with two small fins.
They took them to the ESRF for non-destructive 3-D imaging: “We used synchrotron tomography at the ESRF in order to better identify the outlines of the various anatomical features”, says Rowe. However, the task was challenging, as Vincent Fernández, scientist at the ESRF, explains: “The fossils are on small slabs, which are very difficult to scan. On top of that, soft tissues are preserved but we needed phase contrast imaging to visualise the faint density variation in the data. The coherence of beamline ID19 was therefore very important to perform propagation phase-contrast computed-tomography and track all the minute details, such as the suckers and small fleshy extensions, called cirri”.
The imaging revealed previously unknown details regarding the suckers and arm crown. Comparison with tomographic data of an extant V. infernalis specimen scanned at the American Museum of Natural History in New York allowed the team to determine that the suckers and cirri of V. rhodanica were proportionately more robust than those of V. infernalis. The researchers also noticed that the configuration of the suckers and cirri on the longer dorsal arm pair was different than on the rest of the arms. “We believe that the morphology and placement of V. rhodanica suckers and cirri in the differentiated arm crown allowed V. rhodanica increased suction and sensory potential over the modern form, and helped them to manipulate and retain prey”, says Rowe.
The presence of muscular suckers on each of the arms and sensory conical appendages for detecting prey suggests that V. rhodanica was likely an active predatory hunter. This is in contrast with its more opportunistic descendant the vampire squid, which has adapted to a low energy, deep ocean lifestyle.
Reference : Alison J. Rowe, Isabelle Kruta, Neil H. Landman, Loïc Villier, Vincent Fernandez, Isabelle Rouget. Exceptional soft-tissue preservation of Jurassic Vampyronassa rhodanica provides new insights on the evolution and palaeoecology of vampyroteuthids, Scientific Reports, 2022 DOI: 10.1038/s41598-022-12269-3
Lire l'article : Rowe A.J. et al, Scientific Reports, 23 June 2022.
Hypothesised reconstruction of Vampyronassa rhodanica (Alexandre Lethiers, CR2P-SU).
Photograph of one of the fossil Vampyronassa rhodanica specimens in this study (Photo: Philippe Loubry, CR2P)
X-ray CT images (acquired at the ESRF (Grenoble, France)) and reconstructions of V. rhodanica. (a) Photograph (Philippe Loubry, CR2P) showing the exceptional 3-D preservation of the preserved soft tissue. (b) CT slice of the specimen. (c) 3-D representation showing the arm crown and other presumed elements (d) External 3-D reconstruction (e) CT slice showing the profile view.
3-D reconstruction and CT image of the arm crown, and a dorsal sucker of V. rhodanica. (a) The reconstruction of the arm crown shows the longer dorsal arm pair. (b) CT slice of the distal section of the dorsal arm pair. (c, d) 3-D reconstruction of a dorsal sucker in profile and oral view respectively. The yellow color shows the surface area for adhesion.
ScienceNews : Vampire squid are gentle blobs. But this ancestor was a fierce hunter, 23 juin 2022, par Carolyn Gramling
Sci-news : Vampire Squid’s Ancestor was Active Hunter, New Study Suggests, 23 juin 2022
Science Alert : This Ancient Vampire of The Deep Ocean Really Sucked, 23 juin 2022, par Michelle Starr
Nature World News : Vampyronassa Rhodanica Has Muscular Suckers Utilized for Entangling and Controlling Victims, 24 juin 2022, par Paw Mozter
Courthouse News Service : Reconstructed Jurassic tissue reveals passive vampire squid’s ancestor may have been an adept hunter, 23 juin 2022, par Amanda Pampuro
Maxiscience : Ce prédateur "vampire" terrifiait les fonds marins il y a 160 millions d'années, 24 juin 2022 par Tanguy Vallée
MailOnline UK : It sucked to be the prey of an ancient cephalopod: Oldest known ancestor of the vampire squid had extra-strong suckers on its arms for hunting sea life, 23 juin 2022 par Fiona Jackson
