Taxonomic revision of “Onychoteuthis” conocauda Quenstedt, 1849 (Cephalopoda: Coleoidea) (original) (raw)
Related papers
Predatory behaviour and taphonomy of a Jurassic belemnoid coleoid (Diplobelida, Cephalopoda)
Scientific Reports, 2019
We describe four complete specimens of the early squid-like cephalopod Clarkeiteuthis conocauda from the Toarcian Posidonienschiefer (Jurassic) each preserved with the bony fish Leptolepis bronni in its arms. Based on the arrangement of prey and predator, we suggest that the cephalopods caught and killed the fishes while still in well-oxygenated waters and then descended into oxygen-depleted water layers (distraction sinking) where the cephalopod suffocated. This explains the exceptional preservation, for which the posidonienschiefer is famed. this association raises the question for the hunting behaviour of belemnoid Coleoidea. Using the proportions of soft and skeletal body parts of diplobelids and belemnitids, we estimated their body mass and buoyancy and determined the centres of mass and buoyancy. these two points were very close to each other in belemnitids, implying a low hydrodynamic stability (when ignoring the fins), while in diplobelids, the distance between those centres was greater. this suggests that diplobelids usually assumed an oblique to vertical orientation of the body axis while belemnitids could effortlessly achieve a horizontal orientation of their body. Presuming larger fins were attached to the bigger belemnitid rostra, belemnitids were better swimmers and perhaps pursuit predators while diplobelids rather ambushed their prey. Among Mesozoic coleoids (cephalopods with internal hard parts that include octopuses, squid, and cuttlefish), belemnoids represent the most abundant and best documented clade. In the Jurassic, it is mainly the Belemntitida that can regionally be found in rock-forming numbers, but remains of the Diplobelida also occur occasionally. Despite their abundance, direct evidence for the swimming and hunting behaviour of these extinct cephalopods is extremely rare 1-4. Here, we document four cases of Early Jurassic coleoids, which all hold a small bony fish in their arm crowns (Fig. 1, Suppl. Figs 2, 4). Such preservation requires exceptional taphonomic conditions, for which the Early Jurassic Posidonienschiefer is world-renowned 5-10. Repeated hypoxic to anoxic bottom water conditions 11,12 decelerated decay processes and allowed pyritization or phosphatization of soft tissues that are only rarely fossilized otherwise 13-16. These conditions persisted over a long time and in a rather vast area from southern France via northern Switzerland throughout much of Germany and into Great Britain; therefore, these widely distributed conditions allowed the formation of one of the most famous Konservatlagerstätten 8,17 , the Posidonienschiefer (= Posidonia Shale or 'Schistes cartons'). From this point of view, it is not surprising that the first rostrum-bearing belemnite preserved with soft-parts was found in the Posidonienschiefer 6,18,19. Some other cephalopods also show anatomical details of soft tissues that are usually not preserved (e.g., digestive tract in ammonites 6 ; musculature and gills in non-belemoid coleoids 20-22). Despite the extreme scarcity of cephalopods preserved with their prey, the specimen presented here was never described in detail and only figured once without detailed discussion 23. Recently, a second specimen documenting the same behaviour was published 10. In the Posidonienschiefer, molluscs represent the most common macrofossils; among those, bivalves are very abundant followed by ammonites and belemnites 5,6. Other molluscs such as non-belemnoid coleoids and nautilids are rarer and complete specimens preserved with intact arm crowns are very rare. The diplobelids described
Papers in Palaeontology
We describe a new archaeostracan phyllocarid from the famous Early Devonian Hunsrück Slate, Germany. Morphological features suggest a new ceratiocaridid species for which we propose the name Ceratiocaris harpago sp. nov. The exceptionally well‐preserved holotype specimen is the most completely known ceratiocaridid with an almost entire set of appendages including biflagellate antenniform antennules, robust uniramous antennae with hook‐like flagellum, thoracopods densely covered with setae and probably six pairs of pleopods. A nectobenthic lifestyle is considered the most probable and the clasper‐like morphology of the antennae suggests the presence of a sexual dimorphism in this taxon, with the holotype specimen being a male individual.
Palaeontology, 2012
Groenlandibelus rosenkrantzi from the Maastrichtian of Greenland has long been thought to constitute an early representative of spirulid coleoids. This study shows that this view must be reassessed, at least in part. A re-investigation of the types and of material recorded subsequently has revealed that none of these specimens is conspecific with the holotype of G. rosenkrantzi. Cyrtobelus birkelundae gen. nov, sp. nov. differs from the type of G. rosenkrantzi in having lower chambers and in lacking an apically elongated sheath. The longiconic phragmocone of G. rosenkrantzi has more features in common with the presumed spirulid genus Naefia. A specimen described in detail by J. A. Jeletzky in the mid 1960s as 'G. rosenkrantzi' is designated holotype of C. birkelundae sp. nov., which means that internal phragmocone features are still unknown in G. rosenkrantzi. Cyrtobelus hornbyense gen. nov, sp. nov. from the Campanian of western Canada constitutes the first record of early spirulids from the northeast Pacific, being based on seventeen extraordinarily well-preserved phragmocones. This species differs from C. birkelundae sp. nov. only in the width of the siphuncular tube. The presence of a caecum, a nacre-less conotheca that represents the continuation of the protoconch conotheca, conothecal flaps that anchor the mural parts of the septa, and a thin investmentlike sheath are characters shared only with Recent Spirula. In particular, the unusual protoconch architecture of Cyrtobelus gen. nov. challenges a phylogenetic origin within bactritoid-like coleoids.
Neues Jahrbuch f&# 252; r …, 2007
were previously the only two species of plesioteuthidid coleoids luiown from the Solnhofe n Plattenkalks . Based on morphological comparisons of 154 specimens from the Solnhofen area, a thir d taxon must be considered as valid: Plesioteuthis subovata (MONSTER, 1846) . Additionally, it turne d out that "Senefelderiteuthis Icaussi" is identical with Dorateuthis tricarinata (MONSTER, 1846) . The stratigraphical range of the genus Dorateuthis can now be extended from the Late Cretaceou s to the Late Jurassic . Despite a remarkable similarity between prototeuthid and teuthid gladii, Prototeuthidids are attributed to the Vampyropoda . Unambiguous characters of teuthid Decabrachia such as a ventrolateral pair of elongated tentacles are unknown from the fossil record . Instead, characters such as interbrachial web, radial suckers and cirri rather indicate a closer relationship with th e Vampyropoda .
First record of a true coleoid cephalopod from the Germanic Triassic (Ladinian)
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 2012
A small coleoid gladius is decribed from the Ladinian Oberer Muschelkalk of SW Germany. A new genus and species, Germanoteuthis donai is introduced for this fossil. It is the first and sole unequivocal record of a coleoid from the Germanic Basin and provides evidence that gladiusbearing coleoids have not been restricted to the oceanic Tethyan Realm but had entered shallow marine marginal seas even earlier as previously thought. A supposed coleoid from the Muschelkalk, Campylosepia PicarD, 1899 is revised. Since the holotype of its type species C. triassica PicarD, 1899 is obviously lost, the second species included in this genus, Campylosepia elongata PicarD, 1910, coming from the same bed and locality as C. triassica, was re-studied. It is now recogniozed as the fragment of a large gastropod shell, whereas Triadoteuthis Müller, 1967 is based on a coelacanth fish bone. For Loligosepia neidernachensis (reitner, 1978), coming from the Norian of the Northern Calcareous Alps, a new genus Reitneriteuthis is introduced, and the origin of gladii is discussed.
A 3-dimensionally preserved coleoid cephalopod from the Lower Callovian La Voulte-sur-Rhône lagerstätte is described. The comparison with Mastigophora brevipinnis from the Upper Callovian Oxford Clay of Christian Malford (U.K.) revealed remarkable similarities in their soft part morphologies. The shared presence of conspicuously short arms, one pair of near-terminal and ear-shaped fins, and an unusual thickening of the anterior mantle margin led the author to determine the specimen under investigation as Mastigophora aff. brevipinnis. The presence of uniserial and ringless suckers in Mastigophora aff. brevipinnis support a phylogenetic relationship with the Vampyropoda rather than with the Decabrachia. The previously discussed presence or non-presence of tentacles in Mastigophora is re-evaluated.
The belemnite family Holcobelidae GUSTOMESOV, 1977 is revised, based on ca. 200 rostra from recent fieldwork as well as historical museum collections. The studied specimens originate from various European localities and are dated from the Early Aalenian to the Early Bajocian (Middle Jurassic). Eight species of the genera Holcobelus STOLLEY, 1927 (including H. elmii n. sp.) and Calabribelus n. gen. (with type species C. pallinii) are described. The evolution of the morphological characters at the family level is outlined and compared with acrocoelitids (Belemnitina) and pachybelemnopseids (Pachybelemnopseina); the possible phylogenetic links between the Holcobelidae and the latter are discussed. The stratigraphic and palaeobiogeographic distribution of holcobelids is analysed in respect to morphological changes, leading to a hypothesis on different lifestyles among the investigated taxa. The peculiar distribution pattern of Holcobelidae represents a colonization event by belemnites i...
Journal of Paleontology, 2011
Redescription of the genus Anomalosaepia shows that the anomalous characters reported as defining the genus are partly preservational artifacts resulting from dissolution of aragonite from a skeleton composed of both calcite and aragonite. Thus, the presence of a slit-shaped opening and canal-like cavity in the skeleton is not supported. The skeleton of Anomalosaepia is composed of subequal amounts of aragonite and calcite, with an inner layer composed of radial-prismatic and fan-radial aragonite and an outer layer of elongate, non-prismatic calcite crystals secreted by the animal. The calcite microstructure has not been previously described. A new family, Anomalosaepiidae, is established and one new species, A. parmula, described. The species A. mariettani and A. andreanae are synonomized with A. alleni. The species A. jeletzkyi is valid and A. vernei is probably valid, but needs more documentation. Examination of North American and European specimens reveals that a bimineralic composition is a characteristic feature of species in the families Anomalosaepiidae and Belosaepiidae and implies that, in general, sepioids have a bimineralic skeleton with some calcite.