42 research outputs found
Computed 3D visualisation of an extinct cephalopod using computer tomographs
AbstractThe first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal
Shell accumulation of the brachiopod Pygope catulloi PICTET, 1867 (Lower Valanginian; Northern Calcareous Alps, Upper Austria): Palaeoecological implications
Abstract A shell accumulation of the brachiopod Pygope catulloi from the upper Steinmühl Formation (Lower Cretaceous; Northern Calcareous Alps, Upper Austria) is recorded for the first time. Extraordinary environmental conditions during the Lower Valanginian led to an accumulation within a single layer. The acme of Pygope catulloi within the investigated area seems to coincide with drastic sea-level falls during the Lower Valanginian. The pygopid assemblage most probably inhabited a submarine ridge where bottom currents hindered rapid accumulation of pelagic sediments and the sedimentation rate was very low
Early Cretaceous araucarian driftwood from hemipelagic sediments of the Puez area, South Tyrol, Italy
AbstractWe describe a calcareously permineralised fossil tree-trunk, preserved as driftwood, within hemipelagic sediments of the Cretaceous Puez Formation near Wolkenstein, South Tyrol, Italy. Planktic foraminiferal assemblages recovered from the marls containing the fossil wood indicate a latest middle Albian age. Based on its wood anatomy, the trunk is assigned to Agathoxylon and probably has an affinity with the conifer family Araucariaceae. The wood lacks pronounced tree-rings consistent with tree growth within the broad humid tropical belt that existed at that time. The trunk contains cylindrical chambers filled within faecal pellets, demonstrating that oribatid mites infested the tree, either during life, or shortly after death. Prior to final burial, the tree-trunk drifted out into the open sea for a considerable period as indicated by extensive borings assigned to the ichnospecies Teredolites longissimus and produced by teredinid bivalves. Relatively little is known about the Cretaceous floras of Italy, so this new finding fills a gap in our knowledge of the composition and ecology of the vegetation of this region
Evidence of two lineages of metriorhynchid crocodylomorphs in the Lower Cretaceous of the Czech Republic
Metriorhynchid crocodylomorphs were an important component in shallow marine ecosystems during the Middle Jurassic to Early Cretaceous in the European archipelago. While metriorhynchids are well known from western European countries, their central and eastern European record is poor and usually limited to isolated or fragmentary specimens which often hinders a precise taxonomic assignment. However, isolated elements such as tooth crowns, have been found to provide informative taxonomic identifications. Here we describe two isolated metriorhynchid tooth crowns from the upper Valanginian (Lower Cretaceous) of the Stramberk area, Czech Republic. Our assessment of the specimens, including multivariate analysis of dental measurements and surface enamel structures, indicates that the crowns belong to two distinct geosaurin taxa (Plesiosuchina? indet. and Torvoneustes? sp.) with different feeding adaptations. The specimens represent the first evidence of Metriorhynchidae from the Czech Republic and some of the youngest metriorhynchid specimens worldwide.Web of Science66236735
Comparative actualistic study hints at origins of alleged Miocene coprolites of Poland
Excrement-shaped ferruginous masses have been recovered from the Miocene of Turów mine in south-western Poland. These siderite masses have been the subject of much controversy, having been interpreted either as being coprolites, cololithes or pseudofossils created by mechanical deformation of plastic sediment. Here we present the results of mineralogical, geochemical, petrographic and microtomographical analyses. Our data indicate that these masses consist of siderite and iron oxide rather than phosphate, and rarely contain recognizable food residues, which may suggest abiotic origins of these structures. On the other hand, evidence in support of a fecal origin include: (i) the presence of two distinct morphotypes differing in size and shape, (ii) the presence of rare hair-like structures or coalified inclusions and (iii) the presence of rare fine striations on the surface. Importantly, comparative actualistic study of recent vertebrate feces shows overall resemblance of the first morphotype (sausage-shaped with rare coalified debris) to excrements of testudinoid turtles (Testudinoidea), whose shell fragment was found in the investigated locality. The second morphotype (rounded to oval-shaped with hair-like structures), in turn, is similar to the feces of some snakes (Serpentes), the remains of which were noted in the Miocene of the neighborhood areas. Other potential producers (such as lizards and crocodiles) and even abiotic origins cannot be fully excluded but are less likely
Comparative actualistic study hints at origins of alleged Miocene coprolites of Poland
Excrement-shaped ferruginous masses have been recovered from the Miocene of Turów mine in south-western Poland. These siderite masses have been the subject of much controversy, having been interpreted either as being coprolites, cololithes or pseudofossils created by mechanical deformation of plastic sediment. Here we present the results of mineralogical, geochemical, petrographic and microtomographical analyses. Our data indicate that these masses consist of siderite and iron oxide rather than phosphate, and rarely contain recognizable food residues, which may suggest abiotic origins of these structures. On the other hand, evidence in support of a fecal origin include: (i) the presence of two distinct morphotypes differing in size and shape, (ii) the presence of rare hair-like structures or coalified inclusions and (iii) the presence of rare fine striations on the surface. Importantly, comparative actualistic study of recent vertebrate feces shows overall resemblance of the first morphotype (sausage-shaped with rare coalified debris) to excrements of testudinoid turtles (Testudinoidea), whose shell fragment was found in the investigated locality. The second morphotype (rounded to oval-shaped with hair-like structures), in turn, is similar to the feces of some snakes (Serpentes), the remains of which were noted in the Miocene of the neighborhood areas. Other potential producers (such as lizards and crocodiles) and even abiotic origins cannot be fully excluded but are less likely
Comparative actualistic study hints at origins of alleged Miocene “coprolites” of Poland (supplementary movie : Tomographic animation of Miocene coprolite from Turów.avi)
Excrement-shaped siderite masseshave been the subject of much controversy. They have been variously interpreted either as being coprolites, cololithes or pseudofossils created by mechanical deformation of plastic sediment. Here we reportexcrement-shaped ferruginous masses recovered from the Miocene of Turów mine in south-western Poland.
Results of mineralogical, geochemical, petrographic and microtomographical analyses indicate that these masses consist of siderite and iron oxide rather than phosphate, and rarely contain recognizable food residues, which may suggest abiotic origins of these structures. On the other hand, evidence in support of a fecal origin include: (i) the presence of two distinct morphotypes differing in size and shape, (ii) the limited quantity of specimens, (iii) the presence of rare hair-like structures or coalified inclusions and (iv) the presence of rare fine striations on the surface. Importantly, comparative actualistic study of Recent vertebrate feces shows overall resemblance of the first morphotype (sausage-shaped with rare coalified debris) to excrements of testudinoid turtles (Testudinoidea), whose shell fragment was found in the investigated locality. The second morphotype (rounded to oval-shaped with hair-like structures), in turn, is similar to the feces of some snakes (Serpentes), the remains of which were noted in the Miocene of the neighborhood areas.This research Project is partially supported by the National Science Centre, Poland (www.ncn.gov.pl), Grant No. 2019/32/C/NZ4/00150
Data from: A new ammonoid fauna from the Carnian (Upper Triassic) Kasimlar Formation of the Taurus Mountains (Anatolia, Turkey)
We describe a new ammonoid fauna from the Taurus Mountains of southern Turkey. The Carnian ammonoid fauna from Aşağiyaylabel is presented for the first time. Ammonoids were obtained from limestone to marl beds of an approximately 35-m-thick section, which depicts the scarce possibility to investigate ammonoid faunas across the Lower–Upper Carnian boundary. Intense sampling near the village of Aşağiyaylabel led to the recognition of a new Lower Carnian (Julian 2) to Upper Carnian (Tuvalian 1) ammonoid fauna from the Kasimlar Formation. The genus Kasimlarceltites gen. nov. is reported for the first time from the Taurus Mountains, which represents the main faunal element and occurs as huge mass occurrence (n >> 1 million). Kasimlarceltites krystyni gen. et sp. nov., Klipsteinia disciformis sp. nov. and Anasirenites crassicrenulatus sp. nov. occur within the Lower Carnian Carbonate member (Unit A–B) of the Kasimlar Formation from the Taurus Platform Units. Ammonoids described from the marls of the Tuvalian Marlstone member were deposited during a major, Tethyan–wide climate crisis – the so-called Carnian Crisis – characterized by a demise of carbonate platforms. Based on the biostratigraphic relevance of certain ammonoid taxa described herein, the age of the analyzed parts of the Kasimlar Formation is Julian 2 to Tuvalian 1. The discovery of the new ammonoid assemblages from Aşağiyaylabel substantiates the significance of Upper Triassic faunas within the Taurus Mountains and facilitates the correlation with faunal assemblages from other regions in the Tethyan Realm. The ammonoid fauna and facies indicate a general deepening from open platform margins, over deeper shelf settings down to an open marine-influenced basinal environment. The tentative habitat for Kasimlarceltites gen. nov. is a shallow platform environment to upper mid ramp
Measurements of specimens found at Aşağiyaylabel as well as from type materials of related genera.
Measurements of specimens found at Aşağiyaylabel (Taurus Mountains, Turkey) as well as from type materials of related genera. Abbreviations: ad, adult; ah, aperture height; D, maximum diameter; d, diameter exclusive of last whorl; H, whorl height; H/D, proportional height; H/U, degree of involution; H/W, whorl compression; mOF, measured original figure; rOP, reported from original paper; sd, siphuncle diameter; sm, self measured; st, shell thickness; swt, siphuncle wall thickness; U, umbilical width; U/D, proportional umbilical width; W, whorl breadth; W/D, proportional whorl breadth; WER, whorl expansion rate = [D/(D-ah)]2, adapted after formula WER = [dm/(dm-ah)]2 of Korn (2000) for subdivision in ammonoid coiling (see also Klug 2001; Monnet et al. 2012). WER standard: l, low < 1.60; m, moderate 1.61–2.0; mh, moderately high 2.01–2.40; h, high 2.41–2.80; vh, very high > 2.80 (Korn 2000)]
Morphology, taxonomy and trophic interactions of rostrum-less coleoids from the Late Triassic Polzberg Konservat-Lagerstätte (Lower Austria)
Abstract Coleoid cephalopods are widespread from the Mesozoic till today. The extinct group of the Phragmoteuthida is thought to represent either stem-neocoleoids, stem-decabrachians, or stem-octobrachians. The well-known, almost complete specimens of Phragmoteuthis bisinuata from the Carnian Polzberg Konservat-Lagerstätte near Lunz am See (Lower Austria, Northern Calcareous Alps) and Cave del Predil (Northern Italy, Julian Alps) come from historical collections. These specimens do not reflect the entire coleoid assemblage within this environment. In order to obtain a more complete picture of the Carnian coleoid fauna, 430 coleoid specimens from the Polzberg locality and 60 specimens from contemporaneous localities around Cave del Predil were studied in detail. All available elements (phragmocones, proostraca, cartilages, hooks, beaks, ink sacs) attributed to the coleoid fauna were recorded, measured and evaluated taxonomically and taphonomically. Reviews of historical collection material permitted comparisons with recently collected material. The notation of co-occurrences of other faunal elements yielded insights into the palaeoecological context of this Upper Triassic environment within the Polzberg Basin. The new material from Polzberg does not support the previous assumption of a monospecific composition of the Polzberg coleoid fauna. Instead, we report the occurrence of the new phragmoteuthid Phragmoteuthis polzbergensis nov. sp. and a newly excavated specimen of Phragmoteuthis indicates the presence of ten arms within the group of the Phragmoteuthida for the first time. Phragmocones with small opening angles combined with cylindrical (roundly closed) body chambers, and arm hook types which are unusual for phragmoteuthids indicate the presence of the basal coleoid group comprising the rostrum-less genus Mojsisovicsteuthis