The Burgess Shale

Dictyophycus gracilis

A possible algal frond with a delicate net-like structure

Dictyophycus gracilis (USNM 83483e) – Syntype. Fragment associated with several other organisms including a couple of specimens of the arthropod Marrella splendens. Specimen length = 28 mm. Specimen dry – polarized light (left), wet – direct light (middle), wet – polarized light (right). Walcott Quarry.

© Smithsonian Institution – National Museum of Natural History. Photo: Jean-Bernard Caron


Kingdom: Plantae
Phylum: Unknown
Higher Taxonomic assignment: Non applicable
Species name: Dictyophycus gracilis

No revisions to the affinities of this possible alga have been published since its original description.

Described by: Ruedemann
Description date: 1931

Dictyophycus – from the Greek diktyon, “net,” and phykos, “sea weed.”

gracilis – from the Latin gracil, “thin, slender or simple.” The genus and species names refer to the shape and structure of the organism.

Type Specimens: Syntypes –USNM83483a-d in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 505 million years ago).
Principal localities:

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Dictyophycus was briefly described by Ruedemann (1931) as a possible alga. However, like all the other putative algae from the Burgess Shale, it awaits a formal redescription.



Dictyophycus has a frond-like shape, with a delicate net composed of smooth fibers forming irregular to regular meshes. No organic material is preserved between fibers. The attachment structure is also rarely preserved and may have been broken during burial.


Dictyophycus is only known in the Walcott Quarry where it is relatively common in some layers representing 0.59% of the total counts of specimens (Caron and Jackson, 2008).

Maximum Size:
50 mm


Life habits: Epibenthic, Sessile
Feeding strategies: Primary producer
Ecological Interpretations:

Dictyophycus probably lived attached to the sea floor within the photic zone.


CARON, J.-B. AND D. A. JACKSON. 2008. Paleoecology of the Greater Phyllopod Bed community, Burgess Shale. Palaeogeography, Palaeoclimatology, Palaeoecology, 258: 222-256.

RUEDEMANN, R. 1931. Some new Middle Cambrian fossils from British Columbia. Proceedings of the United States National Museum. 79: 1-18.

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