Subjects -> PALEONTOLOGY (Total: 46 journals)
Showing 1 - 21 of 21 Journals sorted alphabetically
Acta Palaeontologica Polonica     Open Access   (Followers: 6)
Alcheringa: An Australasian Journal of Palaeontology     Hybrid Journal   (Followers: 7)
Ameghiniana     Open Access   (Followers: 1)
Annales de Paléontologie     Full-text available via subscription   (Followers: 7)
Annals of Carnegie Museum     Full-text available via subscription   (Followers: 1)
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 12)
Comptes Rendus Palevol     Full-text available via subscription  
European Journal of Protistology     Hybrid Journal   (Followers: 6)
EvoDevo     Open Access   (Followers: 4)
Facies     Hybrid Journal   (Followers: 10)
Fossil Record     Open Access   (Followers: 5)
Geobios     Full-text available via subscription   (Followers: 6)
Historical Biology: An International Journal of Paleobiology     Hybrid Journal   (Followers: 9)
Ichnos: An International Journal for Plant and Animal Traces     Hybrid Journal  
International Journal of Speleology     Open Access   (Followers: 3)
Journal of Paleolimnology     Hybrid Journal   (Followers: 6)
Journal of Paleontology     Hybrid Journal   (Followers: 11)
Journal of Quaternary Science     Hybrid Journal   (Followers: 32)
Journal of Vertebrate Paleontology     Full-text available via subscription   (Followers: 12)
Marine Micropaleontology     Hybrid Journal   (Followers: 2)
Micropaleontology     Full-text available via subscription  
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen     Full-text available via subscription   (Followers: 4)
Novitates Paleoentomologicae     Open Access   (Followers: 1)
Open Quaternary     Open Access   (Followers: 1)
Palaeogeography, Palaeoclimatology, Palaeoecology     Hybrid Journal   (Followers: 13)
Palaeontology     Hybrid Journal   (Followers: 18)
Palaeoworld     Hybrid Journal   (Followers: 3)
PALAIOS     Hybrid Journal   (Followers: 7)
Paläontologische Zeitschrift     Hybrid Journal   (Followers: 4)
Paleobiology     Full-text available via subscription   (Followers: 6)
PaleoBios     Open Access   (Followers: 1)
Paleoceanography and Paleoclimatology     Full-text available via subscription   (Followers: 4)
Paleontological Journal     Full-text available via subscription   (Followers: 5)
Paleontological Research     Full-text available via subscription   (Followers: 3)
Palynology     Hybrid Journal   (Followers: 2)
Papers in Palaeontology     Hybrid Journal   (Followers: 1)
Quaternaire     Open Access   (Followers: 3)
Quaternary Research     Full-text available via subscription   (Followers: 20)
Quaternary Science Reviews     Hybrid Journal   (Followers: 25)
Review of Palaeobotany and Palynology     Hybrid Journal   (Followers: 2)
Revue de Micropaleontologie     Full-text available via subscription  
Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy)     Open Access   (Followers: 2)
Spanish Journal of Palaeontology     Open Access  
Swiss Journal of Palaeontology     Hybrid Journal   (Followers: 4)
Vertebrate Anatomy Morphology Palaeontology     Open Access   (Followers: 2)
Zitteliana     Open Access   (Followers: 4)
Similar Journals
Journal Cover
Swiss Journal of Palaeontology
Journal Prestige (SJR): 0.396
Citation Impact (citeScore): 1
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1664-2376 - ISSN (Online) 1664-2384
Published by Springer-Verlag Homepage  [2656 journals]
  • Invertebrate borings from the Eocene of Seven Rivers, parish of St.
           James, western Jamaica
    • Abstract: The fossil biota of the Eocene Yellow Limestone Group of Jamaica is diverse in vertebrates and, particularly, invertebrates. However, its invertebrate trace fossils remain understudied. Herein, we document the borings of the Seven Rivers vertebrate site in western Jamaica. This is in the Litchfield Formation, high in the Lutetian (about mid-Middle Eocene). The suite of borings identified from this site comprises Apectoichnus longissimus (Kelly and Bromley); Entobia isp.; Oichnus simplex Bromley; and Oichnus paraboloides Bromley. Substrates infested by Entobia isp. include both molluscs and sirenian ribs. Oichnus ispp. occur only in bivalves and are mainly non-penetrative, which may be a taphonomic artifact. Tubes of the common A. longissimus are preserved free from any woody substrates, which have presumably rotted away; however, one specimen has a dark, carbonaceous external film and others have carbonized wood inclusions. The occurrence of A. longissimus in the Jamaican rock record coincides with periods of sub-aerial exposure.
      PubDate: 2019-03-21
      DOI: 10.1007/s13358-019-00190-8
       
  • Siphonal tube structure of the Late Devonian orthocerid Dolorthoceras from
           the Polar Urals (NW Russia) preserving nacre and organic fibres as well as
           its persistence in cephalopod evolution
    • Abstract: A juvenile orthocerid Dolorthoceras sp. from the Frasnian (Late Devonian) of the Polar Urals in NW Russia is the first recorded ectocochleate cephalopod showing fibrous structures and the first Devonian cephalopod preserving nacreous structures within its conch. Like Nautilus, Dolorthoceras sp. has columnar nacre in its shell wall and septa, which are composed of differentiated nacreous tablets that are c. 3 µm and 10 µm in diameter. The central, small, cylindrical, hollow siphonal tube—studied in median section using scanning electron microscope—comprises short columnar-nacreous suborthochoanitic septal necks and thin, apparently primarily chitinous, connecting rings; swollen, lens-shaped in median section, two-part fibrous non-biomineralized structures—here named clutches—envelope the posterior parts of the septal necks. Together with the adjacent connecting ring, the outer part of the clutch may extend onto adapical septal surfaces; their inner part and adjoining from inside next connecting ring line the septal neck. The clutches are comparable, to some degree, to the auxiliary deposits and cuffs of the siphonal tubes found in ammonoids; these are interpreted as being protective structures of the conjunctions between the connecting rings and septal necks reinforcing it against hydrostatic pressure, which was probably also the case in Dolorthoceras. Tracing the Silurian to Cretaceous longiconic cephalopods with narrow, central to eccentric, hollow siphonal tubes and swollen posterior portions of the septal necks shows that the Dolorthoceras-type siphonal tube may represent a conch structure that persisted throughout about 370 million-year-long evolutionary history of orthocerid cephalopods.
      PubDate: 2019-03-15
      DOI: 10.1007/s13358-019-00188-2
       
  • High-level classification of the nautiloid cephalopods: a proposal for the
           revision of the Treatise Part K
    • Abstract: High-level classification of the nautiloid cephalopods has been largely neglected since the publication of the Russian and American treatises in the early 1960s. Although there is broad general agreement amongst specialists regarding the status of nautiloid orders, there is no real consensus or consistent approach regarding higher ranks and an array of superorders utilising various morphological features has been proposed. With work now commencing on the revision of the Treatise Part K, there is an urgent need for a methodical and standardised approach to the high-level classification of the nautiloids. The scheme proposed here utilizes the form of muscle attachment scars as a diagnostic feature at subclass level; other features (including siphuncular structures and cameral deposits) are employed at ordinal level. We recognise five subclasses of nautiloid cephalopods (Plectronoceratia, Multiceratia, Tarphyceratia nov., Orthoceratia, Nautilia) and 18 orders including the Order Rioceratida nov. which contains the new family Bactroceratidae. This scheme has the advantage of relative simplicity (it avoids the use of superorders) and presents a balanced approach which reflects the considerable morphological diversity and phylogenetic longevity of the nautiloids in comparison with the ammonoid and coleoid cephalopods. To avoid potential confusion arising in the higher levels of nautiloid classification employed in the revision of the Treatise Part K, we propose herein to replace the suffix ‘-oidea’ at subclass level with the suffix ‘-ia’. Apart from removing ambiguity and clarifying the nomenclature, this approach also brings greater consistency and affinity with modern zoological classification schemes used for cephalopods. The original Treatise Part K adopted an ‘abbreviated’ form of name for nautiloid orders using the ending ‘-cerida’ rather than ‘-ceratida’ (e.g., Order Actinocerida rather than Actinoceratida). For the revision of Treatise Part K, we propose using the ‘full’ version of the ordinal names. This approach re-employs several order names in their original form, e.g., Ellesmeroceratida, Oncoceratida, and Tarphyceratida. For reasons of consistency, we also apply the same to ordinal names created since the original Treatise Part K; therefore, Order Bisonocerida becomes Bisonoceratida.
      PubDate: 2019-03-14
      DOI: 10.1007/s13358-019-00186-4
       
  • Homology problems in cephalopod morphology: deceptive (dis)similarities
           between different types of ‘caecum’
    • Abstract: Homoplasy is a common phenomenon in the evolution of the Cephalopoda. Many homology problems accordingly light up phylogenetic debates. The initial segment of the siphuncle, the so-called ‘caecum’, is one of these characters difficult to be unambiguously evaluated. Although rarely discussed, the caecum of the endocochleate decabrachian Spirula is traditionally seen as a plesiomorphy directly inherited from its ectocochleate ancestors. However, the Spirula caecum must be—according to recent phylogenetic analyses—derived from a substructure of the belemnoid protoconch. Here, I review the morphology of different types of ectocochleate and endocochleate protoconchs. Detailed comparisons show that belemnoid protoconchs are structurally closer to the bactritoid/ammonoid protoconch than to the spiruloid protoconch. The most striking difference between the caecum of Spirula and bactritoids or ammonoids concerns its ultrastructure, which is lamello-fibrillar nacre (Spirula nacre or nacre type II) in the former and organic in the latter. The Spirula caecum is consequently equivalent to the first septum, while in bactritoids/ammonoids, the caecum is a separate structure independent of the proseptum. To conclude, the spiruloid protoconch (including caecum) has been derived either from a belemnitid or diplobelid protoconch. Similarities between the bactritoid/ammonoid and spiruloid caecum are superficial and only concern its shape.
      PubDate: 2019-03-06
      DOI: 10.1007/s13358-019-00183-7
       
  • The Allemann collection from the Santa Cruz Formation (late early
           Miocene), Argentina, in Zurich, Switzerland
    • Abstract: One of the best-known faunal assemblages that characterizes the past ecosystems from South America comes from the Santa Cruz Formation in Argentina. This assemblage is formed by an endemic fauna, which included ground sloths, glyptodonts, native ungulates, terror birds (phorusrhacids), among others. The Santacrucian South American Land Mammal Age is dated 18.0–15.6 Ma, late early Miocene. Current curatorial efforts revealed a large collection of over 1100 fossil remains from the Santa Cruz Formation, donated in 2007 to the Paleontological Museum, University of Zurich, Switzerland. The fossils were brought to Switzerland in the late 1880s by Theodor Allemann, an engineer and amateur collector. The collection includes skulls, isolated teeth, mandibles, and isolated postcranial elements. Postcranials are mainly represented by astragali, calcanei, and osteoderms. The study of the remains allowed us to recognize 20 families of mammals, one of birds, and one of amphibians: Abderitidae, Palaeothentidae (Paucituberculata); Hathliacynidae (Sparassodonta); Dasypodidae, Peltephilidae, and Glyptodontidae (Cingulata); Megatheriidae and Megalonychidae (Tardigrada); Astrapotheriidae (Astrapotheria), Protherotheriidae and Macraucheniidae (Litopterna); Toxodontidae, Homalodotheriidae, Hegetotheriidae and Interatheriidae (Notoungulata); Dasyproctidae, Dinomyidae, Neoepiblemidae, Chinchillidae, Erethizontidae, Echimyidae and Eocardidae (Rodentia); Phorusrhacidae (Cariamiformes); and Calyptocephalellidae (Anura). Among them, we identified 28 genera and 9 species. Reference to the previous work on the Santa Cruz fauna and the good preservation of the material allow us to achieve taxonomic resolution in the identifications. We discuss the potential usefulness of this collection for studying the paleobiology of specimens/species of this fauna.
      PubDate: 2019-02-28
      DOI: 10.1007/s13358-019-00185-5
       
  • Chieseiceras dolomiticum n. sp. (Ammonoidea) and its significance for the
           calibration of the Triassic platform interior stratigraphy at Latemar
           (Southern Alps, Italy)
    • Abstract: The species Chieseiceras dolomiticum n. sp. along with other ammonoid species (Latemarites latemarensis, Halilucites rusticus) helps constraining the age of the cyclic platform interior portion at Latemar (Dolomites, northern Italy). The comparison of ammonoids from the Latemar platform with the fossil record in basinal successions in the Southern Alps (including the Ladinian GSSP section at Bagolino) and Hungary suggests that the entire rhythmically bedded Latemar interval is entirely late Anisian in age. More than 400 stratigraphical metres of bedded shallow water carbonates at Latemar are found to correspond to less than 5 m of siliceous nodular limestone in the pelagic succession at Bagolino. The refined correlation will be significant for the reassessment of the cyclic Latemar stratigraphy in the light of new geochronological calibration of the South Alpine Middle Triassic.
      PubDate: 2019-02-13
      DOI: 10.1007/s13358-019-00184-6
       
  • Gigantism, taphonomy and palaeoecology of Basiloceras , a new oncocerid
           genus from the Middle Devonian of the Tafilalt (Morocco)
    • Abstract: The genus Basiloceras gen. nov. containing the two species B. goliath sp. nov. and B. david sp. nov. is described. It belongs to the Acleistoceratidae within the Oncocerida. Both species are from the Middle Devonian of the Tafilalt (Morocco). The genus exhibits a large interspecific size range between the small Eifelian B. david sp. nov. and the Givetian B. goliath sp. nov., the largest Devonian oncocerid currently known, altogether only second to some fragmentary remains of Calchasiceras from the Carboniferous of Russia. Several other large species are mainly known from the late Emsian of Bohemia and the Eifelian of Germany. The holotype of B. goliath sp. nov. contains numerous epicoles, trace fossils and shell debris, which are discussed in the context of its taphonomy. Compared to other oncocerids, Basiloceras is characterised by a short body chamber, which might be related to buoyancy regulation. In contrast to some older publications, we do not regard breviconic oncocerids with contracted aperture as benthic or nektobenthic animals, but instead, we think that they dwelled in the water column.
      PubDate: 2019-01-31
      DOI: 10.1007/s13358-019-00182-8
       
  • Fossil crabs in the Caribbean: taphonomic comparisons as an informed
           indicator of underexploited occurrences
    • Abstract: The Antilles include over 100 islands, each with a rock record that embraces different slices of the stratigraphic succession; this is probably the most beguiling geological quality of the region. Both authors have been collecting fossil crabs (decapod crustaceans) from these islands for almost 30 years. Experience has demonstrated that, whatever fossil crustaceans have been described from an island, there are undoubtedly more waiting for attention. Marine decapods can commonly be collected in hand specimen. If there are poorly lithified sedimentary rocks, they will likely repay sieving with an abundance of fragments. For many stratigraphic horizons it is only the disarticulated elements such as these that are known, but they are identifiable and can be diverse. We promote three units from the Antilles as being highly likely to produce new and well-preserved faunas of decapod crustaceans: the Yellow Limestone Group (Eocene, Jamaica); the Anguilla Formation (Miocene, Anguilla); and the Rockly Bay Formation (Pliocene, Tobago). Both the Yellow Limestone Group and Anguilla Formation have produced fossil decapods, albeit indifferently preserved. In contrast, both units have yielded a diversity of well-preserved echinoids; the reasons for this contrast remain speculative. The Rockly Bay Formation is the most barnacle-rich unit in the Antilles, yet decapods, another marine arthropod group with a calcareous skeleton, remain undescribed, but are present. These units need to be exploited for fossil decapods and, in so doing, these new data will improve the known palaeobiodiversity of the Antillean region.
      PubDate: 2019-01-16
      DOI: 10.1007/s13358-018-0181-x
       
  • A new vertebrate continental assemblage from the Tortonian of Venezuela
    • Abstract: A wide variety of aquatic vertebrates from fluvio-lacustrine facies of northern South America (Colombia and Venezuela) have been used as unequivocal evidence to support hydrographic connections between western Amazonia and the Proto-Caribbean Sea during the Miocene. By the end of the Miocene, changes in the major hydrographic systems of the region produced losses of habitats and a regional faunal turnover, as has been documented in the geological record of the Urumaco region. Here, we report a new Tortonian aquatic and terrestrial vertebrate assemblage from two localities of the Caujarao Formation (El Muaco Member) in western Venezuela. The vertebrate assemblage includes a gharial (cf. †Gryposuchus pachakamue), alligatorid crocodylians (†Purussaurus and Alligatoridae indet.), a freshwater turtle (Chelus sp.), snakes (cf. Eunectes sp.), serrasalmids and pimelodids and thorny catfishes, a rodent (†Potamarchus sp.), pampatheres (†Scirrotherium sp.), sloths, as well as plant remains (coal and amber). Although the Caujarao Formation has been referred to as a fully marine environment, the new assemblage reported here suggests a freshwater input to the coastal area. Taxonomic and biogeographic affinities between the Muaco Member community and that reported from the Miocene proto-Amazonian systems are indicative of the persistence of ecological and hydrographic continuity at minimum until the end of the Miocene in at least an area of northwestern South America.
      PubDate: 2018-12-18
      DOI: 10.1007/s13358-018-0180-y
       
  • A new species of Stegophiura (Ophiuroidea, Ophiopyrgidae) from the
           mid-Cretaceous of southern Japan
    • Abstract: Well-preserved external moulds of articulated brittle stars from the middle to late Cenomanian (early–Late Cretaceous) “Lower formation” of the Mifune Group on the island of Kumamoto, southern Japan, are described as a new species of the genus Stegophiura, S. miyazakii. Extinct (Late Cretaceous) species previously assigned to Stegophiura are now shown to represent other genera; here, we transfer S.' hagenowi and S.' nekvasilovae to the extant ophiopezid genus Ophiopeza and S.' trispinosa to the extinct ophiacanthid Sabinacantha. The present specimens are thus inferred to be the sole wholly extinct representative and the oldest record of the genus Stegophiura.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0168-7
       
  • A noteworthy accumulation of disparid crinoids from the type Cincinnatian
           (Upper Ordovician) of southwestern Ohio, USA: implications for the
           palaeoecology and taphonomy of crinoid “logjam” assemblages
    • Abstract: Crinoids are a common and well-studied faunal component of the Upper Ordovician (Katian; Edenian) Kope Formation in the greater Cincinnati Arch region, USA. However, a relatively fresh outcrop exposing the Southgate and McMicken members of the Kope Formation at Cleves, Hamilton County, southwestern Ohio, has yielded a crinoid specimen worthy of description and comment. The specimen is a “logjam” of numerous articulated columns of Iocrinus subcrassus displaying parallel alignment, reflecting the influence of storm-generated currents. Iocrinus is not typically found in such a state; the genera Ectenocrinus and Cincinnaticrinus are generally associated with “logjams” in the type Cincinnatian, making this an unusual occurrence. At least one of the columns has the coiled dististele of another, smaller I. subcrassus tightly wrapped around it. Although I. subcrassus is known to employ a coiled dististele as an attachment strategy, ramose bryozoans are generally utilised as substrates and tight coiling around larger I. subcrassus columns has not previously been reported. Preservation of coiled dististeles, in general, is a feature not previously documented in Cincinnatian crinoid “logjams.” This specimen illustrates that unusual, noteworthy and/or rare material representing relatively common organisms continue to be discovered even within extensively studied units in the type Cincinnatian.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0159-8
       
  • Editorial “Special Issue: Hans Hess: a lifelong passion for fossil
           echinoderms”
    • PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0178-5
       
  • Form and function of the strangest crinoid stem: Devonian of Morocco
    • Abstract: Trombonicrinus (col.) hanshessi gen. et sp. nov. is a crinoid species of unusual morphology and is based solely on the stem. It comes from the (probably Lower) Devonian of Tafraoute, Anti Atlas Mountains, Morocco. It is a long crinoid stem of circular section, tapering distally throughout, with a tight curvature through 180º between the mesistele and proxistele; attachment is distally by short, pointed, unsegmented pseudoradices. The overall appearance is reminiscent of the slide of a trombone. The dististele is essentially straight, the mesistele is more or less convoluted, and the proxistele is straight and parallels the more distal stem. The dististele was attached to an upright object around which the pseudoradices formed a close attachment. The crinoid’s stem was growing down towards the substrate. The mesistele was free of the attachment surface and grew in a more convoluted manner. The proxistele was adapted to elevate the crown, growing upwards and in the opposite direction of the rest of the crinoid. This is a form unique to T. (col.) hanshessi and not recognised hitherto in the Crinoidea. The conical, most proximal part of this stem in the holotype may suggest that it was immediately beneath the cup; the specimen is considered complete apart from the crown. The loss of the crown was most likely the result of autotomy. Although the proxistele of the paratype is relatively longer, it is probably incomplete. This crinoid was either a cladid or a camerate.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0149-x
       
  • Reconstructing predation intensity on crinoids using longitudinal and
           cross-sectional approaches
    • Abstract: Predation has been hypothesized as important to crinoid ecology, and numerous crinoid traits have been linked to predation. However, testing such hypotheses requires some assessment of predation intensity, or pressure. Although direct observations of predatory activity on crinoids are exceedingly rare in the Recent, and unobservable in the fossil record, evidence of predation exists in the form of sublethal damage, especially to their arms. Substantial data exist on the relative frequency, or prevalence, of such injuries, but estimating predation intensity in taxa with ephemeral injuries, such as crinoids, requires combining the prevalence of injuries with rates at which they heal (regenerate). An alternate, independent estimate of predation intensity involves gathering longitudinal data on the number of injuries incurred by particular individuals over a given time span. In this study, predation intensity on crinoids is explored experimentally using these two approaches. We demonstrate that for the two feather star species examined, Capillaster multiradiatus and Clarkcomanthus mirabilis, both methods produce reasonably consistent results and that predation intensity is slightly lower on the latter perhaps because it responds to tactile stimulation by crawling deeper into its perch, whereas the former shows no response.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0169-6
       
  • Big oyster, robust echinoid: an unusual association from the Maastrichtian
           type area (province of Limburg, southern Netherlands)
    • Abstract: Large, denuded tests of holasteroid echinoids were robust benthic islands in the Late Cretaceous seas of northwest Europe. A test of Hemipneustes striatoradiatus (Leske) from the Nekum Member (Maastricht Formation; upper Maastrichtian) of southern Limburg, the Netherlands, is encrusted by a large oyster, Pycnodonte (Phygraea) vesiculare (Lamarck). This specimen is a palaeoecological conundrum, at least in part. No other members of the same oyster spatfall attached to this test and survived. Indeed, only two other, much smaller bivalve shells, assignable to the same species, attached either then or somewhat later. The oyster, although large, could have grown to this size in a single season. The larval oyster cemented high on the test and this would have been advantageous initially, the young shell being elevated above sediment-laden bottom waters. However, as the oyster grew, the incurrent margin of the commissure would have grown closer to the sediment surface. Thus, the quality of the incurrent water probably deteriorated with time.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0151-3
       
  • A new species of Hypselaster (Echinoidea, Spatangoida) from the Middle
           Eocene Midawara Formation of the Eastern Desert, Egypt
    • Abstract: The schizasterid echinoid genus Hypselaster Clark, 1917, is recorded for the first time from the Midawara Formation (Middle Eocene, Lutetian), which crops out east Maghagha area, east Nile Valley, Eastern Desert, Egypt. Except for Hypselaster sp. from the Upper Miocene (Messinian) of Morocco, no Hypselaster has been recorded in pan Africa. The material described in the present paper is considered to represent a new species (Hypselaster strougoi n. sp.) that is characterized by a medium, oval to subpentagonal test with distinct frontal sinus, a subcentral ethmolytic and wide apical disc (slightly behind the center of test) with two large and apart genital pores, an anteriorly excentric semilunal-shaped peristome, long, flexed and deeply sunken paired anterior petals, a longitudinally oval periproct in the topmost part of the oblique forwardly truncated posterior, and perforate, crenulated tubercles. Both peripetalous and incomplete latero-anal fascioles are present; the latero-anal fasciole is faint and incomplete laterally on the sides of the test.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0156-y
       
  • A fossil crinoid with four arms, Mississippian (Lower Carboniferous) of
           Clitheroe, Lancashire, UK
    • Abstract: One of the characteristic features used to define the echinoderms is five-fold symmetry. The monobathrid camerate crinoid genus Amphoracrinus Austin normally has five arms, but an aberrant specimen from Salthill Quarry, Clitheroe, Lancashire (Mississippian, lower Chadian), has only four. The radial plate in the B-ray supports only interbrachial and/or tegminal plates; there never has been an arm in this position. The reason why this arm failed to grow is speculative, but there is no evidence for the common drivers of aberrant growth in crinoids such as borings; rather, a genetic or developmental flaw, or infestation by an unidentified parasite, must be suspected. In the absence of the B-ray arm, the other arms of Amphoracrinus sp. have arrayed themselves at 90° to each other to make the most efficient feeding structure possible.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0163-z
       
  • A new paedomorphic protasterid brittle star (Echinodermata, Ophiuroidea)
           from the Early Devonian of Luxembourg and Germany
    • Abstract: A new genus of ophiuroid, Luxaster n. gen., is described based on articulated skeletal remains preserved as external molds. The new genus belongs to the Paleozoic stem-group family Protasteridae. It includes two species, Luxaster martini n. sp. from the Lower Devonian of Luxemburg, and Luxaster schweitzeri from the Lower Devonian of W-Germany. Within the Protasteridae, Luxaster stands out in showing a combination of characters best interpreted as strongly paedomorphic within the morphological spectrum of the family. This suggests that paedomorphosis played a role in ophiuroid evolution not only in the living clades but also in the extinct stem groups.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0174-9
       
  • A fossilized marble run: the peculiar taphonomy of Ordovician diploporitan
           blastozoans from Sweden
    • Abstract: Diploporitans had subspherical thecae, which usually were attached to hard substrates either directly with an attachment disc at the base of their theca or with a stem and holdfast. After the death of the animal, isolated thecae were easily transported by currents over more or less consolidated sediment. We describe a case where 13 diploporitan thecae were trapped in the remains of a cephalopod with an orthoconic conch. Most of the thecae show a perfect fit and are size-sorted within the conch or siphuncle. We discuss the taphonomic processes that might have been involved in this rare kind of alignment and sorting.
      PubDate: 2018-12-01
      DOI: 10.1007/s13358-018-0173-x
       
  • Hans Hess (1930–2017): a life-long passion for echinoderms
    • Authors: Walter Etter
      PubDate: 2018-01-16
      DOI: 10.1007/s13358-017-0143-8
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 3.235.139.152
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-