Ichnogenus: Phycodes Richterl, 1850

Taxonomic Details

Ichnospecies: Phycodes flabellum (Miller & Dyer, 1878)
Formerly: Licrophycus flabellum, Inocaulis flabellum

Stratigraphic Occurrences

Geographic Occurrences

Stratigraphic Description

Sequences (Formations)

  • C3 Sequence (Corryville)

Identification in Hand Sample

  • General morphology: Bundled splayed pattern of horizontal burrows
  • Branching: Multiple branching tunnels at low angles
  • Surface ornamentation: None
  • Fill: Backfilled
  • Lining: None
  • Spreiten: None

Paleoenvironmental Parameters

  • Substrate: Softground
  • Oxygen content: Moderate-high
  • Nutrient content: Moderate-high
  • Energy: Moderate-high


  • Behavior: Feeding
  • Tracemaker: Burrowing organisms

Potential Environments

  • Fully marine, with some environments subject to frequent episodic depositional events
  • Common in tidally-influenced zones

Phycodes from the Middle Ordovician of Sinclair, Kentucky (CMC 63992)

Published Description

Hasiotis (KU, 2013):

  • Description: Bundled splayed pattern of horizontal burrows originating from a central base point and fan outwards in a broom-like pattern of individual burrows. Proximal part of main tunnels unbranched, distal tunnels divide at acute angles into several free cylindrical tunnels.
  • Interpretations: Feeding burrow made by repeated probes by an organism into the sediment; fully marine, environments subjected to frequent episodic depositional events… Common in tidally-influenced zones such as tidal point bars and tidal flats; burrowing marine organisms such as worms.

Han & Pickerill (1994):

  • Diagnosis: Horizontally bundled burrows preserved outwardly as convex hyporeliefs. Overall pattern reniform, fasciculate, flabellate, broomlike, ungulate, linear, falcate or circular. Most forms consist of a single or a few main branches showing a spreite-like structure that give rise distally to numerous free branches. In other forms, the spreiten are lacking and branching tends to be second or more random. Individual branches are terete and finely annulate or smooth (after Osgood, 1970; Fillion and Pickerill, 1990).

Treatise on Invertebrate Paleontology, Part W, Miscellanea Supplement 1 (1975):

  • Bundled structures of flabellate or broom-like pattern, consisting of horizontal tunnels; proximal part of main tunnels unbranched, distal tunnels divide at acute angles into several free cylindrical tunnels showing delicate annulations beneath thin smooth “bark”; main branches may show structure similar to retrustive spreiten (absent in P. flabellum from Cincinnatian of USA); other “species” (e.g., P. pedum and P. flabellum) vary considerably in morphology from type species which is also variable (e.g., falcate or featherstitch-like pattern of feeding tunnels); about 15 cm. long in entirety; generally preserved as convex hyporeliefs in quartzites.
  • Interpretation: Originally interpreted as “fucoids”or even as inorganic structures; certainly feeding structure of typical flabellate pattern; probably produced by sediment-feeding wormlike animal; relations of Phycodes to Teichichnus were discussed by Hantzschel & Reineck (1968, p. 26); Arthrophycus Hall, 1852, regarded by Seilacher (19955, p. 386) as junio synonym; P. pedum Seilacher, according to Osgood (1970, p. 342), should be assigned to a separate genus; for detailed discussion see Magdefrau (1934), Seilacher (1955, p. 383-388), and Osgood (1970, p. 341-343)