ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2016-03-17
    Description: Problematic fossils, extinct taxa of enigmatic morphology that cannot be assigned to a known major group, were once a major issue in palaeontology. A long-favoured solution to the 'problem of the problematica', particularly the 'weird wonders' of the Cambrian Burgess Shale, was to consider them representatives of extinct phyla. A combination of new evidence and modern approaches to phylogenetic analysis has now resolved the affinities of most of these forms. Perhaps the most notable exception is Tullimonstrum gregarium, popularly known as the Tully monster, a large soft-bodied organism from the late Carboniferous Mazon Creek biota (approximately 309-307 million years ago) of Illinois, USA, which was designated the official state fossil of Illinois in 1989. Its phylogenetic position has remained uncertain and it has been compared with nemerteans, polychaetes, gastropods, conodonts, and the stem arthropod Opabinia. Here we review the morphology of Tullimonstrum based on an analysis of more than 1,200 specimens. We find that the anterior proboscis ends in a buccal apparatus containing teeth, the eyes project laterally on a long rigid bar, and the elongate segmented body bears a caudal fin with dorsal and ventral lobes. We describe new evidence for a notochord, cartilaginous arcualia, gill pouches, articulations within the proboscis, and multiple tooth rows adjacent to the mouth. This combination of characters, supported by phylogenetic analysis, identifies Tullimonstrum as a vertebrate, and places it on the stem lineage to lampreys (Petromyzontida). In addition to increasing the known morphological disparity of extinct lampreys, a chordate affinity for T. gregarium resolves the nature of a soft-bodied fossil which has been debated for more than 50 years.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McCoy, Victoria E -- Saupe, Erin E -- Lamsdell, James C -- Tarhan, Lidya G -- McMahon, Sean -- Lidgard, Scott -- Mayer, Paul -- Whalen, Christopher D -- Soriano, Carmen -- Finney, Lydia -- Vogt, Stefan -- Clark, Elizabeth G -- Anderson, Ross P -- Petermann, Holger -- Locatelli, Emma R -- Briggs, Derek E G -- England -- Nature. 2016 Apr 28;532(7600):496-9. doi: 10.1038/nature16992. Epub 2016 Mar 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, Connecticut 06511, USA. ; American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA. ; Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, Illinois 60605, USA. ; X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA. ; Yale Peabody Museum of Natural History, 170 Whitney Avenue, New Haven, Connecticut 06511, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26982721" target="_blank"〉PubMed〈/a〉
    Keywords: Animal Fins/anatomy & histology ; Animals ; Extinction, Biological ; Eye/anatomy & histology ; *Fossils ; Gastrointestinal Tract/anatomy & histology ; Illinois ; Lampreys/classification ; Notochord/anatomy & histology ; *Phylogeny ; Tooth/anatomy & histology ; Vertebrates/anatomy & histology/*classification
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2014-05-03
    Description: Land crabs are found in marine and terrestrial sediments and sedimentary rocks from the Pleistocene and Holocene throughout the Caribbean. Field surveys of two widespread and abundant species, Gecarcinus lateralis and Gecarcinus ruricola , were conducted three times a week for 4 weeks along the northern coast of San Salvador Island, the Bahamas, at three localities that varied in vegetation cover, available sediment, and wind and wave energy. A total of 1400 identifiable remains were found and scored for four taphonomic characters: fragmentation, edge modification, surface alteration, and color loss. The majority of specimens exhibited various levels of disarticulation, from complete limbs to only isolated podomeres. Overall, claws are overrepresented, and the distribution of recovered remains differed significantly (p 〈 0.0001) from that expected based on the anatomy of a single crab (eight legs, two claws, and one carapace per individual). Remains found in direct sunlight and open spaces consistently showed more surface alteration, edge modification, and more loss than those found within vegetation or on the beach. Fragmentation was not significantly different across localities (p = 0.045). This result suggests that the fossil record of land crabs may be biased as a result of their low preservation potential in terrestrial environments. The discovery of eight poorly preserved Holocene chelae on San Salvador Island contrasts starkly with the abundance and preservational quality of surficial remains. Rapid burial is likely required for their preservation but may not ensure the preservation of the cuticle.
    Print ISSN: 0883-1351
    Electronic ISSN: 0883-1351
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2016-04-02
    Description: Marattialean ferns and medullosan seed ferns are two dominant groups in late Carboniferous lowland tropical floras. Differences in their foliage suggest that some seed ferns may have had a higher preservation potential when compared to marattialean ferns. Should this be accurate, it would suggest that when the two groups are found together, marattialean ferns would be better preserved and potentially better represented than seed ferns. Such taphonomic biases would have direct implications for evaluating plant diversity in deep time. To evaluate this hypothesis, we analyzed more than 880 fern and seed fern fossils encased in siderite (FeCO 3 ) concretions from the ~ 308 Ma Mazon Creek Lagerstätte to test if seed fern foliage is better preserved than fern foliage with respect to taxonomic information. For comparative purposes, we conducted a series of decay experiments on two modern ferns and a cycad (the last providing a seed fern analogue) for 160 days. Despite anatomical and compositional differences, fossil analyses demonstrate that ferns and seed ferns are equally well preserved in the Mazon Creek Lagerstätte with respect to venation, which represents one of the most important taxonomic characters of the flora. The decay experiments support this conclusion: despite having a more robust leaf, cycad leaves decayed at a similar rate to the thinner, more hypothetically fragile ferns. Together, our results indicate that our ability to discriminate within and between ferns and seed ferns is not biased by differential preservation in the Mazon Creek flora.
    Print ISSN: 0883-1351
    Electronic ISSN: 0883-1351
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2013-03-22
    Description: Structural coloration underpins communication strategies in many extant insects but its evolution is poorly understood. This stems, in part, from limited data on how color alters during fossilization. We resolve this by using elevated pressures and temperatures to simulate the effects of burial on structurally colored cuticles of modern beetles. Our experiments show that the color generated by multilayer reflectors changes due to alteration of the refractive index and periodicity of the cuticle layers. Three-dimensional photonic crystals are equally resistant to degradation and thus their absence in fossil insects is not a function of limited preservation potential but implies that these color-producing nanostructures evolved recently. Structural colors alter directly to black above a threshold temperature in experiments, identifying burial temperature as the primary control on their preservation in fossils. Color-producing nanostructures can, however, survive in experimentally treated and fossil cuticles that now are black. An extensive cryptic record is thus available in fossil insects to illuminate the evolution of structural color.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2014-05-02
    Print ISSN: 0883-1351
    Electronic ISSN: 0883-1351
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...