The modern Vampire Squid, Vampyroteuthis infernalis, is considered to be a relict species, having a mosaic of features associated with the Octobrachia (Octopus) and Decabrachia (Squid, Cuttlefish, and the extinct Belemnites). Notably, it has a well-developed gladius (mineralised internal support equivalent to the pen of Squid or the cuttlebone of Cuttlefish), and a rudimentary tenth pair of arms, both features of the Decabrachia, leading to the common name 'Vampire Squid', although molecular studies have placed this Cephalopod firmly within the Octobrachia. Vampyroteuthis infernalis is therefore considered to be the sole living member of the Order Vampyromorpha. This order has a fossil record dating back to the Mesozoic, and has been divided into two suborders, the Vampyromorphina, which contains the living Vampire Squid and a single Oligocene species, Necroteuthis hungarica, and the Loligosepiina, which contains 13-14 genera from the Jurassic and Early Cretaceous.
In a paper published in the Swiss Journal of Palaeontology on 14 February 2024, Dirk Fuchs of the Bayerische Staatssammlung Für Paläontologie Und Geologie, and Robert Weis and Ben Thuy of the Musée National d’histoire Naturelle Luxembourg, describe a new species of Vampyromorph Cephalopod from the Early Jurassic Schistes Carton of Luxembourg.
The new species is described on the basis of a single specimen from a bituminous black shale exposed in Bascharage, southeast Luxembourg, which is considered to be of equivalent age to the better known Posidonia Shale of southwest Germany. These deposits are thought to have been laid down in a shallow part of the northwestern peri-Tethys, close to the London-Brabant landmass. The shales lack any sign of bioturbation or benthic fauna, have a high organic carbon content, and contain fossils of pelagic Animals with articulated skeletons and soft tissue preservation, leading palaeontologists to interpret the environment as being a shallow, enclosed sea with sheltered conditions and an oxygen-depleted seafloor.
The new species is named Simoniteuthis michaelyi, where 'Simoniteuthis' Jo Simon, a volunteer palaeontologist at the Musée National d’histoire Naturelle Luxembourg, who skilfully and patiently cleaned the fossil in the nodule and unveiled the soft part preservation (the sufix '-teuthis' means 'Squid'), and 'michaelyi' honours Patrick Michaely, the director of the museum.
The specimen is preserved as part and counterpart on a split shale slab, and consists of the gladius and head-arm complex, including the proximal and middle parts of the arms, and the eyeballs. The remains of two small Fish can be observed within the tentacle area. Seen under UV light, the musculature of the arms can be observed. Like other members of the Suborder Loligosepiina, Simoniteuthis michaelyi has only eight pairs of arms, lacking the rudimentary tenth pair found in the living Vampyroteuthis infernalis. Details of the gladius are largely obscured by leaked ink, but it is 23 cm in length, and has distinct lateral wings, a diagnostic feature of Vampyromorphs.
The number of arms in Vampire Squid remains somewhat of a puzzle. The common ancestor of all Coleoid Cephalopods is thought to have had five pairs of arms, a state retained in the living Squid and Cuttlefish. Members of the Octobrachia, including Octopus and the Mesozoic Loligosepiina, appear to have lost one pair of arms, leaving them with four. The living Vampire Squid, however, retains a rudimentary fifth pair of retractable, filamentous arms. Since it is unlikely that the species would have re-evolved a fifth pair of arms, it is assumed that it is a member of a lineage that has never lost the fifth pair of arms, implying that the Octopus and Loligosepiina lineages lost their fifth pair of arms separately. Confusingly, the extinct Suborder Prototeuthina, variously thought to be the ancestor of all Octobrachians, the ancestor of Vampyromorphs but not Octopus, or Octopus but not Vampyromorphs, also appear to have had only four pairs of arms. Possible filamentous arms have been reported on two Jurassic Vampyromorphs; a specimen of Mastigophora brevipinnis from Wiltshire, England (though other members of the same species appear to lack these extra arms), and possibly a specimen of Jeletzkyteuthis coriaceus from the Posidonia Shale. Niether of these species are thought to be closely related to the Vampyromorphina, nor to one-another, which, combined with the uncertainty as to whether they have a tenth pair of arms at all, provides palaeontologists with little help in unravelling the history of the fifth pair of tentacles.
The presence of two small Fish associated with the head-arm complex of Simoniteuthis michaelyi has implications for the taphonomy of the Schistes Carton. The most logical explanation for Fish being found in this location is predation by the Mollusc, and such small Fish are known to have been an important part of the diet of many Early Jurassic Cephalopods. Cephalopods with captured prey Fish have been found in several other deposits where the bottom waters are thought to have been anoxic, which has led to the suggestion that they may have been distracted by the capture of the Fish, causing them to drift into anoxic waters and die.
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