Ichnofossils

Palaeophycus Hall, 1847

Taxon description

Díez-Canseco et al., 2016

Trace maker. Palaeophycus are known to be produced by predaceous polychaetes in marine environments (e.g., Gingras et al., 1999), but other makers may have been involved in continental settings, such as semiaquatic insects (orthopteransand hemipterans) or semiaquatic and non-aquatic beetles (Krapovickas et al., 2010).

Fernández & Pazos, 2012

Diagnosis. Infrequently branched, distinctly lined, essentially cylindrical, predominantly horizontal to inclined burrows in which the sediment infilling is typically of the same lithology and texture as the host bed (Pemberton and Frey, 1982; modified by Frey and Howard, 1985).

Remarks. It is ethologically classified as a dwelling (domichnia) or feeding (fodinichnia) structure of mobile, suspensivorous or predatory worm-like organisms such as annelids (Fillion, 1989). Sediment fill is passive, gravity induced (for further detail on sediment fill see Fillion, 1989). The common type of preservation (epirelief or endichnia) suggests that the activity of the producer took place along sedimentologic interfaces (Pemberton and Frey, 1982).

A similar ichnogenus is Planolites Nicholson, and there has been a longtime debate about the criteria used to separate them (Aceñolaza and Yanev, 2001). Alpert (1975) proposed that the most useful criterion is the presence or absence of branching in Palaeophycus and Planolites, respectively. However, since the work of Pemberton and Frey (1982), this criterion has been disregarded (e.g., Buatois, 1989; Fillion, 1989). According to Pemberton and Frey (1982), Palaeophycus differs from Planolites because of the presence of a wall.
Such features may be of greater taxonomic value, as they reveal ethological aspects (Buatois, 1989).

Stachacz, 2012b

Diagnosis. Essentially cylindrical, predominantly horizontal, straight, slightly curved or undulating, ornamented or smooth, branched or un branched, lined burrow. Bifurcations irregular, with out swellings. Filling typically massive, similar to the host rock (compiled after: Pemberton and Frey, 1982; Fillion and Pickerill, 1984, 1990; Keighley and Pickerill, 1995).
 

Schlirf, 2000

Palaeophycus is generally interpreted as open burrow, probably produced by polychaetes (PEMBERTON & FREY, 1982).

Pemberton & Frey, 1982

Branched or unbranched, smooth or ornamented, lined, essentially cylindrical, predominantly horizontal burrows of variable diameter, infilling typically structurless or same lithology as host rock.

Selection of related publications
Toom, U., Vinn, O. & Hints, O. 2018. Ordovician and Silurian ichnofossils from carbonate facies in Estonia: A collection-based review. Palaeoworld , 1-22. DOI:10.1016/j.palwor.2018.07.001
Mikuláš, R., Meškis, S., Ivanov, A., Lukševičs, E., Zupinš, I. & Stinkulis, G. 2013. A rich ichnofossil assemblage from the Frasnian (Upper Devonian) deposits at Andoma Hill, Onega Lake, Russia. Bulletin of Geosciences 88, 2, 389-400. DOI:10.3140/bull.geosci.1358
Mikuláš R. & Dronov, A. V. 2005. Trace fossils. The Sixth Baltic Stratigraphical Conference. Cambrian and Ordovician of St. Petersburg Region, Guidebook for the pre-conference field trip. Dronov, A.V., Tolmacheva T., Raevskaya E. (Eds.), pp. 33-38.
Knaust, D. 2004. Cambro-Ordovician trace fossils from the SW-Norwegian Caledonides. Geological Journal 39, 1, 1-24. DOI:10.1002/gj.941
Orłowski, S. & Żylińska, A. 1996. Non-arthropod burrows from the Middle and Late Cambrian of the Holy Cross Mountains, Poland. Acta Palaeontologica Polonica 41, 4, 385-409.
Palij, V. M., Posti, E. & Fedonkin, M. A. 1979. Soft-bodied Metazoa and trace fossils of Vendian and Lower Cambrian. Upper Precambrian and Cambrian Paleontology of East-European Platform, pp. 49-82.
Crimes, T. P. 1970. Changes in the trace fossil biota across the Proterozoic–Phanerozoic boundary. Journal of the Geological Society 149, 97-119. DOI:10.1144/gsjgs.149.4.0637