Trace fossils and palaeoenvironments of the Middle Devonian Caherbla Group, Dingle Peninsula, southwest Ireland

2011 ◽  
Vol 47 (1) ◽  
pp. 1-29 ◽  
Author(s):  
Lance B. Morrissey ◽  
Simon Braddy ◽  
Chris Dodd ◽  
Kenneth T. Higgs ◽  
Brian P. J. Williams
Keyword(s):  
Middle Devonian ◽  
Trace Fossils

Coral-crinoid biocoenosis and resulting trace fossils from the Middle Devonian of the Eifel Synclines (Rhenish Massif, Germany)

2012 ◽  
Vol 86 (2) ◽  
pp. 282-301 ◽  
Author(s):  
Jan Bohatý ◽  
William I. Ausich ◽  
Elise Nardin ◽  
Christian Nyhuis ◽  
Stefan Schröder
Keyword(s):  
Middle Devonian ◽  
Biotic Interactions ◽  
Trace Fossils ◽  
Rich Source ◽  
Rhenish Massif ◽  
Rugose Corals ◽  
Source Of Information

Fossil echinoderms are a rich source of information concerning biotic interactions. In this study we analyzed the premortem encrustation of the highly specialized Middle Devonian rugose coralsAspasmophyllum crinophilumand ?“Adradosia” sp. on camerate crinoid stems.Aspasmophylluminfested living crinoid stems by sclerenchymal outgrowth that formed a skeletal ring but ?“Adradosia” sp. encrusted the stems rapidly, without building a ring. These coral-crinoid biocoenoses indicate a settlement advantage for the rugose corals within densely populated communities of the lower Givetian. The corals could be interpreted as large epizoozoans that benefited as secondary tierers reaching relatively high tiering levels. It also suggests the ability for the affected crinoids to repel the coral by overgrowing the corallite with a local increased stereomic growth. Because the crinoid axial canals are not penetrated, the corals cannot be considered as predators or parasites of crinoids. Therefore, the described biocoenosis is interpreted as commensalism. The speciesA. crinophilumis redescribed, and a neotype is defined, because of the loss of the initial types. Two types of ichnofossils can be attributed to the premortem encrustation of both corals. They are described asOstiocavichnusn. ichnogen. and are attributed to the stereomic response of the infested hosts. These swellings are characterized as either elliptical (Ostiocavichnus ovalisn. ichnogen. n. ichnosp. due to the assumed reaction ofA. crinophilum) or subcircular concavities (O. rotundatusn. ichnogen. n. ichnosp. due to the reaction of ?“Adradosiasp.”).

First report of fish trace fossils (Undichna) from the Middle Devonian Achanarras Limestone, Caithness Flagstone Group

2021 ◽  
pp. sjg2020-023
Author(s):  
Benjamin H. Tindal ◽  
Anthony P. Shillito ◽  
Neil S. Davies
Keyword(s):  
Middle Devonian ◽  
Depositional Environment ◽  
Trace Fossils ◽  
Early Career ◽  
Low Oxygen ◽  
Fish Swimming ◽  
Content Type ◽  
Fish Locomotion ◽  
Research Collection ◽  
Career Research

Two newly-discovered specimens of the fish locomotion trace Undichna (U. britannica and Undichna isp.), are described from the Middle Devonian Achanarras Limestone Member (Caithness Flagstone Group, NE Scotland). Fish trace fossils have not previously been reported from the Achanarras Limestone Member, despite decades of study of the unit as a key locality for fish body fossils. The traces comprise discontinuous sinusoidal grooves; one showing multiple parallel incisions, created by the fins of an acanthodian fish swimming close to the substrate. The apparent absence of trace fossils attributable to infaunal or epifaunal benthic organisms suggests that the sediment at the bottom of the lake was relatively inhospitable. The low ichnodiversity of the Achanarras Limestone Member is likely due to low oxygen levels in the depositional environment.Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/cc/SJG-early-career-research

Putative arthropod trace fossils from the Orcadian Basin at Achanarras Quarry (Middle Devonian of Scotland)

2021 ◽  
pp. jgs2020-233
Author(s):  
Joseph T. Flannery-Sutherland
Keyword(s):  
Middle Devonian ◽  
Fish Fauna ◽  
Trace Fossils ◽  
Lake Ecosystem ◽  
Deep Lake ◽  
Lake Ecosystems ◽  
Deep Waters ◽  
Orcadian Basin ◽  
Water Ecosystems ◽  
Lacustrine Facies

Achanarras Quarry, Caithness, Scotland displays a diverse fossil fish fauna which is presumed to have inhabited shallow lacustrine environments present in the Orcadian Basin during the Early to Middle Devonian. While Achanarras Quarry itself exposes deep lacustrine facies, the ecology of their depositional environment remains unknown in stark contrast to the detailed environmental reconstructions available for the lake margin. I report putative arthropod trace fossils from Achanarras Quarry which are tentatively interpreted as having been formed in a deep lake environment. Transport of doomed pioneers from the thriving shallow-water ecosystems by turbidite flows is discussed as possible scenario for their formation. The infrequent and ephemeral intrusions of animals into the deep waters of Lake Orcadie fits the broader narrative of the colonisation of deep lake ecosystems after the Devonian. These interpretations of deep-lacustrine trace fossils from Achanarras, along with their place within the narrative of lake ecosystem evolution, are made cautiously, however, given the paucity of the specimens and the uncertainty surrounding their sedimentary setting.

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