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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Andrew K. Rindsberg</dc:contributor>
  <dc:creator>M. Gabriela Mángano</dc:creator>
  <dc:date>2002</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The ichnogenus&amp;nbsp;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Torell 1870 includes a wide variety of predominantly horizontal, sinuous to looped, backfilled traces, characterized by a distinctive median dorsal structure. Though commonly preserved in full relief on upper bedding surfaces, some ichnospecies of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;may be preserved in negative hyporelief.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;records the feeding activities of a subsurface animal using a siphon-like device. Several ichnogenera reflect this general behavioral pattern, including&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Plagiogmus&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Roedel 1929 and the Carboniferous ichnogenera&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Olivellites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Fenton and Fenton 1937a and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Aulichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Fenton and Fenton 1937b. Based on analysis of specimens from the United States, Spain, and the United Kingdom, three Carboniferous ichnospecies of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;are reviewed in this paper:&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P. plummeri&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(Fenton and Fenton, 1937a),&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P. grumula&lt;/i&gt;&lt;span&gt;(Romano and Meléndez 1979), and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P. implexus&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;(Rindsberg 1994).&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites plummeri&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is the most common Carboniferous ichnospecies and is characterized by a relatively straight, continuous dorsal ridge/groove, fine transverse ridges, larger size range, and non-looping geometric pattern. It represents a grazing trace of deposit feeders.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites grumula&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;differs from the other ichnospecies of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;by having median dorsal holes or protruding mounds. The presence of mounds or holes in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P. grumula&lt;/i&gt;&lt;span&gt;suggests a siphon that was regularly connected to the sediment-water interface. This ichnospecies is interpreted as produced by a deposit feeder using the siphon for respiration or as a device for a chemosymbiotic strategy.&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites implexus&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is characterized by its consistently smaller size range, subtle backfill structure, and tendency to scribble. Although displaying similarities with&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Dictyodora scotica&lt;/i&gt;&lt;span&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P. implexus&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;is a very shallow-tier, grazing trace. Changes in behavioral pattern, preservational style, and bedform morphology suggest a complex interplay of ecological and taphonomic controls in Carboniferous tidal-flat&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;. A first distributional pattern consists of guided meandering specimens preserved in ripple troughs, probably reflecting food-searching of buried organic matter concentrated in troughs. A second is recorded by concentration of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;on ripple crests and slopes. In some cases, the course is almost straight to slightly sinuous and closely follows topographic highs, suggesting a direct control of bedform morphology on trace pattern. Occurrences of Carboniferous&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;most likely represent an opportunistic strategy in marginal-marine settings. Analysis of Carboniferous&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;Psammichnites&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;indicates the presence of a siphon-like device in the producer and reestablishes the possibility of a molluscan tracemaker.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1080/10420940190034175</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Taylor &amp; Francis</dc:publisher>
  <dc:title>Carboniferous Psammichnites: Systematic re-evaluation, taphonomy and autecology</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>