The Burgess Shale

Yuknessia simplex

3D animation of Yuknessia simplex.
© Phlesch Bubble

Taxonomy:

Class: Non applicable
Remarks:

Walcott (1919) considered Yuknessia as a green alga, a view shared by Conway Morris and Robison (1988). However, no revision of the type material from the Burgess Shale has been published since its original description and its affinities remain uncertain.

Species name: Yuknessia simplex
Described by: Walcott
Description date: 1919
Etymology:

Yuknessia – from Yukness Mountain (2,847m), a Peak in Yoho National Park, east of the Burgess Shale.

simplex – from the Latin simplex, meaning “simple,” in reference to the simple morphology of this alga.

Type Specimens: Holotype –USNM35406 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none

Other deposits: Yuknessia sp. from the Lower Cambrian Niutitan Formation in China (Yang et al., 2003).

Age & Localities:

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

Burgess Shale and vicinity: The Walcott Quarry on Fossil Ridge and the Trilobite Beds on Mount Stephen.

Other deposits: Y. simplex is known from the Middle Cambrian Spence Shale and the Marjum and Wheeler Formations in Utah (Conway Morris and Robison, 1988).

History of Research:

Brief history of research:

This genus was described by Charles Walcott (1919) as a possible green alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription (see Dalyia). Conway Morris and Robison (1988) described specimens of this species from several Utah deposits.

Description:

Morphology:

This alga has long branches emerging from a short but wide hollow stem covered of small conical elements or plates. The plates were the attachment sites of the branches. The branches show strong similarities with Dalyia and suggest the two species might be synonymous, with Yuknessia representing the main stem structure of the Dalyia branches.

Abundance:

Yuknessia is very rare and represents only 0.04% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
30 mm

Ecology:

Ecological Interpretations:

The wide stem suggests this species was attached to the sea floor within the photic zone rather than being free floating.

References:

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

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, 122 p.

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

YANG, R., W. ZHANG, L. JIANG AND H. GAO. 2003. Chengjiang biota from the Lower Cambrian Niutitang Formation, Zunyi County, Guizhou Province, China. Acta Palaeontologica Sinica, 77: 145-150.

Other Links:

None

Waputikia ramosa

3D animation of Waputikia ramosa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Non applicable
Remarks:

No revisions of this alga have been published since its original description by Walcott (1919) and its affinities remain uncertain.

Species name: Waputikia ramosa
Described by: Walcott
Description date: 1919
Etymology:

Waputikia – from the Waputik Icefield, a glacier in Yoho National Park, east of the Burgess Shale.

ramosa – from the Latin ramosus, “full of branches,” in reference to the presence of clumps of branches.

Type Specimens: Syntypes –USNM35409, 35410, 35411 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

Period:
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:

This genus was described by Charles Walcott (1919) as a possible red alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription.

Description:

Morphology:

Waputikia has a large central stem with wide branches at irregular intervals. The large branches divide dichotomously (into two), and the smaller tertiary or quaternary branches divide into much finer branches forming small terminal bush-like structures.

Abundance:

Waputikia is very rare and represents only 0.02% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
60 mm

Ecology:

Ecological Interpretations:

No attachment structure for this alga has been preserved but it probably lived attached to the sea floor.

References:

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

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

Other Links:

None

Wahpia insolens

Wahpia insolens (USNM 35424) – Syntype. Specimen showing typical mode of branching. Specimen length = 90 mm. Specimen wet – direct light (left), polarized light (right). Trilobite Beds on Mount Stephen.

© SMITHSONIAN INSTITUTION – NATIONAL MUSEUM OF NATURAL HISTORY. PHOTOS: JEAN-BERNARD CARON

Taxonomy:

Class: Non applicable
Remarks:

No revisions of this alga have been published since its original description by Walcott (1919) and its affinities remain uncertain.

Species name: Wahpia insolens
Described by: Walcott
Description date: 1919
Etymology:

Wahpia – unspecified.

insolens – from the Latin insolens, “unusual, different.” This probably refers to the unusual branches of this alga.

Type Specimens: Syntypes –USNM35423-35424 (W. insolens); Holotypes –USNM35413 (W. mimica);USNM35425 (W. virgata) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: W. mimica Walcott, 1919 and W. virgata Walcott, 1919 from the Walcott Quarry.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge. The Trilobite Beds on Mount Stephen.

History of Research:

Brief history of research:

Wahpia was described by Charles Walcott (1919) as a possible red alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription.

Description:

Morphology:

This simple alga has a long central stem with long narrow branches diverging from it at a 45 degree angle; these branches give rise to smaller branches with up to two additional branchings. The central stem is hollow. W. mimica and W. virgata differ from W. insolens based on size differences of the central stem and the number and flexibility of the branches.

Abundance:

Wahpia is very rare and represents only 0.06% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
90 mm

Ecology:

Ecological Interpretations:

The morphology of this alga suggests it was attached to the sea floor rather than being free floating.

References:

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

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

Other Links:

None

Dictyophycus gracilis

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

Taxonomy:

Class: Non applicable
Remarks:

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

Species name: Dictyophycus gracilis
Described by: Ruedemann
Description date: 1931
Etymology:

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:

Period:
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.

Description:

Morphology:

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.

Abundance:

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

Ecology:

Ecological Interpretations:

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

References:

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.

Other Links:

None

Bosworthia simulans

Bosworthia simulans (USNM 35426) – Syntype. Specimen showing multiple branches emerging from a central axis (near the middle). Approximate specimen length (of the most complete branch) = 70 mm. Specimen dry – polarized light. Walcott Quarry.

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

Taxonomy:

Class: Non applicable
Remarks:

No revisions of this alga have been published since its original description by Walcott (1919) and its affinities remain uncertain.

Species name: Bosworthia simulans
Described by: Walcott
Description date: 1919
Etymology:

Bosworthia – from Mount Bosworth (2,769 m) on the British Columbia-Alberta border, in Yoho and Banff National Parks. Named in 1904 after George Morris Bosworth, the Canadian Pacific Railway freight traffic manager from 1896-1901.

simulans – from the Latin simulans, “make like” or “imitate”. The name refers to the repeated shape of the subdividing branches.

Type Specimens: Bosworthia simulans – Syntypes –USNM35426-35427 (Bosworthia simulans); HolotypeUSNM35428 (Bosworthia gyges) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
Other species:

Burgess Shale and vicinity: Bosworthia gyges Walcott, 1919.

Other deposits: none.

Age & Localities:

Period:
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:

Bosworthia was described by Charles Walcott (1919) as a possible red alga. However, like all the algae from the Burgess Shale, it awaits a modern redescription.

Description:

Morphology:

This alga is composed of a long flexible central thallus, from which long and relatively thick branches emerge. These branches may further subdivide into smaller branches and narrow along their length. Walcott (1919) described B. gyges as having more rigid branches than B. simulans. He hypothesized that there was probably a central stem and attachment structure that would have allowed the alga to attach to the seafloor although this structure has not yet been observed in the fossils. Bosworthia has been described from fragments only (up to 8 cm in length) and the complete size is unknown.

Abundance:

Bosworthia represents less than 0.04% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
82 mm

Ecology:

Ecological Interpretations:

The mode of life of this alga is uncertain. Its structure suggests it was attached to the sea floor within the photic zone, rather than being free floating.

References:

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

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

Other Links:

None

Morania confluens

3D animation of Morania confluens (being grazed by Wiwaxia corrugata).

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Cyanophyceae (Order: Nostocales?)
Remarks:

Walcott (1919) considered Morania to be related to the modern cyanobacteria Nostoc. No revisions to the affinities of this cyanobacterium have been published since.

Species name: Morania confluens
Described by: Walcott
Description date: 1919
Etymology:

Morania – from Moraine Lake (1,885 m), in Banff National Park.

confluens – from the Latin fluere, “flow or stream,” and the prefix con, “together.” The name refers to the abundance of this species.

Type Specimens: Syntypes–USNM35378-35390, 35398 (M. confluens); USMN 35391, 35392 (M. costellifera);USNM35393 (M. elongata);USNM35394 (M. fragmenta);USNM35395 – 35397, 35401 (M.? globosa);USNM57718 (M. parasitica);USNM35402 (M.? reticulata) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: M. costellifera Walcott, 1919; M. elongata Walcott, 1919; M. fragmenta Walcott, 1919; M.? globosa Walcott, 1919; M. parasitica Walcott, 1919; M.? reticulata Walcott, 1919, all from the Walcott Quarry.

Other deposits: M.? antiqua Fenton and Fenton, 1937 from the middle Proterozoic Altyn Limestone of Montana and the Little Dal Group, Mackenzie Mountains (see Hofmann and Aitken, 1979).

Age & Localities:

Period:
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:

Walcott described Morania, erecting eight species, in a 1919 paper along with Burgess Shale algae, comparing the genus to the extant cyanobacteria Nostoc. Walcott included thin sections and details of the microstructures of M. confluens showing that it was formed of tangled strings of pyrite. Satterthwait (1976) studied specimens of M. confluens from the Geological Survey of Canada collections as part of her PhD thesis and broadly agreed with Walcott’s original interpretations, in particular regarding a position within the Nostocaceae. Sattertwhait’s work has not been published but she suggested that many species erected by Walcott might not be valid and could represent parts of more complex algae. Mankiewicz (1992) re-observed Walcott’s thin sections and confirmed the presence of Morania in several samples. Rigby (1986) identified M.? frondosa Walcott 1919, as a sponge and reassigned it to a new genus (see Crumillospongia frondosa).

Description:

Morphology:

Morania ranges in shape from spherical to sheet-like. The sheet-like form M. confluens is by far the most common species. Specimens typically range in length between 1 to more than 13 centimeters. The sheets are characteristically perforated, with holes up to 3 centimeters in diameter. The shape, size, number and distribution of holes are highly variable. Thin sections show that the microstructure of M. confluens is represented by a tangle mass of filaments called trichomes. These filaments have a beadlike structure with little spheroids of pyrite ranging 3 to 7 micrometers in diameter, and originally interpreted by Walcott as defining cellular structures.

Abundance:

Estimating the abundance of Morania is difficult since some bedding planes have large tangled masses of this cyanobacterium, and many could represent fragments of the same colony. Morania is very common in the Walcott Quarry and represents 4.9% of the community (Caron and Jackson, 2008).

Maximum Size:
130 mm

Ecology:

Ecological Interpretations:

Caron and Jackson (2006) suggested that Morania covered large areas of the benthos and might have provided a stable substrate and food source for benthic animals, in particular for a number of grazers, like Odontogriphus and Wiwaxia.

References:

CARON, J.-B. AND D. A. JACKSON. 2006. Taphonomy of the Greater Phyllopod Bed Community, Burgess Shale. Palaios, 21: 451-465.

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

HOFMANN, H. J. AND J. D. AITKEN. 1979. Precambrian biota from the Little Dal Group, Mackenzie Mountains, northwestern Canada. Canadian Journal of Earth Sciences, 16: 150-166.

MANKIEWICZ, C. 1992. Obruchevella and other microfossils in the Burgess Shale: preservation and affinity. Journal of Paleontology, 66(5): 717-729.

SATTERTHWAIT, D. F. 1976. Paleobiology and Paleoecology of Middle Cambrian Algae from Western North America. Unpublished PhD thesis, California, Los Angeles, 120 p.

WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.

Other Links:

None

Marpolia spissa

3D animation of Marpolia spissa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Cyanophyceae (Order: Oscillatoriales?)
Remarks:

Walcott (1919) considered this species to be a cyanobacterium, but Walton suggested a relationship to red algae instead (Walton, 1923). More recent studies concurred with Walcott’s original interpretation (Conway Morris and Robison, 1988).

Species name: Marpolia spissa
Described by: Walcott
Description date: 1919
Etymology:

Marpolia – from Mount Marpole (2,997 m), a peak located near the Burgess Shale, northwest of Emerald Lake in Yoho National Park.

spissa – from the Latin spissus, “crowded,” in reference to the bush-like aspect of this cyanobacteria.

Type Specimens: Lectotype –USNM35403 (M. spissa); holotype –USNM35412 (M. aequalis) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: M. aequalis Walcott 1919 from the Trilobite Beds on Mount Stephen (known from a single specimen).

Other deposits: Marpolia (possibly represented by different species) is common in various Cambrian exceptional fossil deposits, in particular from the Middle Cambrian Spence Shale and Wheeler Formation in Utah (Conway Morris and Robison, 1988) and the Middle Cambrian Kaili Formation in China (Yang et al., 2001).

Age & Localities:

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

The Walcott Quarry on Fossil Ridge, the Tulip Beds (S7) on Mount Stephen, and other smaller localities on Mount Field, Mount Stephen and Monarch Cirque.

History of Research:

Brief history of research:

Walcott described Marpolia in 1919 and named two species from the Burgess Shale, M. spissa from the Walcott Quarry and M. aequalis from the Trilobite Beds. M. spissa was compared to the modern Oscillatorialesin an unpublished thesis (Satterthwait, 1976), an interpretation followed by Conway Morris and Robison (1988) based on the study of fossil material from various Utah deposits. M. spissa is commonly found in thin sections (Mankiewicz, 1992) and can be isolated by acid maceration (Butterfield, 1990). A recent taphonomic study demonstrated that the preservation style of Marpolia is similar to other Burgess Shale organisms (Butterfield et al., 2007).

Description:

Morphology:

Marpolia forms dense tufts up to 5 cm in length composed of numerous filaments. Filaments tend to branch near the base of the tuft. Each filament averages about 40 microns in width. Filaments are composed of an outer sheath and one to four strands of inner cells. Each cell is about 2 microns in length. M. aequalis has a central stem and stronger branching structures than M. spissa.

Abundance:

Estimating the abundance of Marpolia is difficult since some bedding planes have large tangled masses of this cyanobacterium, and many could represent fragments of the same colony. M. spissa is rare and represents only 0.07% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
50 mm

Ecology:

Ecological Interpretations:

The absence of an attachment structure suggests that Marpolia may have been free-living, floating in large masses (i.e., planktonic). It may have attached to other floating objects as free-living cyanobacteria do today. It is also possible that the lack of attachment structure is taphonomic (a structure that is lost during deposition), due to detachment from the sediment during transport (caused by having been swept up in mud flows) prior to burial.

References:

BUTTERFIELD, N. J. 1990. Organic preservation of non-mineralizing organisms and the taphonomy of the Burgess Shale. Paleobiology, 16: 272-286.

BUTTERFIELD, N. J., U. BALTHASAR AND L. WILSON. 2007. Fossil diagenesis in the Burgess Shale. Palaeontology, 50: 537-543.

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

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, 122 p.

MANKIEWICZ, C. 1992. Obruchevella and other microfossils in the Burgess Shale: preservation and affinity. Journal of Paleontology, 66: 717-729.

SATTERTHWAIT, D. F. 1976. Paleobiology and Paleoecology of Middle Cambrian Algae from Western North America. Unpublished PhD thesis, California, Los Angeles, 120 p.

WALCOTT, C. D. 1919. Middle Cambrian Algae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67(5): 217-260.

WALTON, J. 1923. On the structure of a Middle Cambrian alga from British Columbia (Marpolia spissa Walcott). Proceedings of the Cambridge Philosophical Society-Biological Sciences, 1: 59-62.

YANG, R., J. MAO, Y. ZHAO, X. CHEN AND X. YANG. 2001. Branching macroalgal fossils of the Early-Middle Cambrian Kaili Formation from Taijiang, Guizhou Province, China. Acta Geologica Sinica, 75: 433-440.

Other Links:

None

Margaretia dorus

3D animation of Margaretia dorus.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Bryopsidophyceae (Order: Bryopsidales)
Remarks:

Walcott (1919) considered this species to be a green alga, but also noted some similarities with alcyonarian corals (closely related to the sea pens). Studies of specimens from the Burgess Shale and Utah suggest affinities with the modern green alga Caulerpa(Satterthwait, 1976; Conway Morris and Robison, 1988).

Species name: Margaretia dorus
Described by: Walcott
Description date: 1931
Etymology:

Margaretia – unspecified; possibly from the Greek margarites, “pearl,” in reference to the rounded structures present along the tegument.

dorus – unspecified; possibly from the Greek dora, “skin,” in reference to the skin-like tegument of this algae.

Type Specimens: Holotype –USNM83922 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: M. chamblessi from the Lower Cambrian Latham Shale of southeastern California (Waggoner and Hagadorn, 2004).

Age & Localities:

Period:
Upper Lower Cambrian, Olenellus Zone to the upper Middle Cambrian, Ptychagnostus punctuosus Zone.
Principal localities:

Burgess Shale and vicinity: The Walcott, Raymond and Collins Quarries on Fossil Ridge. The Trilobite Beds, Collins Quarry and smaller sites on Mount Stephen. Mount Odaray and Stanley Glacier.

Other deposits: M. dorus is known from several Cambrian deposits in particular from the Middle Cambrian Spence Shale and Marjum Formation in Utah (Conway Morris and Robison, 1988).

History of Research:

Brief history of research:

Walcott collected about 70 specimens of this new species from the Burgess Shale. It is only after his death that this material was formally published by his assistant Charles Resser in 1931. This species was compared to the modern green alga Caulerpa in an unpublished thesis (Satterthwait, 1976) an interpretation followed by Conway Morris and Robison (1988) based on the study of well preserved material from several Utah deposits. No revisions of this alga using specimens from the Burgess Shale have been published since its original description by Walcott (1931).

Description:

Morphology:

This alga is the largest known in the Burgess Shale. It is composed of single or dichotomous (divided into two) tubular axes which are erect and are connected perpendicularly to simple root-like elements called rhizomes. The tubular axes do not vary in width and can reach at least 40 cm in length. The distal ends were rounded. The surfaces are covered with small protuberances of similar size and shape called papillae. These papillae are organized in a spiral pattern. Papillae are visible along the margins of the fossils, but when preserved perpendicularly, they tend to split off at their base giving the impression of holes along the stems. Contrary to Walcott’s initial assessment, Margaretia is not a “thin membranous perforated sheet.” The rhizomes are usually smaller in diameter than the stems and tend to have irregular undulations but no papillae.

Abundance:

Margaretia is present in many sites but is usually rare. No specimens of this alga were found in the Walcott Quarry community out of 52,620 specimen observed (Caron and Jackson, 2008).

Maximum Size:
400 mm

Ecology:

Ecological Interpretations:

Margaretia lived attached to the sea floor via its rhizomes, with its fronds floating above it in the water. The presence of mostly fragmentary specimens in many fossil deposits suggests this alga could have been transported from nearby environments.

References:

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

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, 122 p.

SATTERTHWAIT, D. F. 1976. Paleobiology and Paleoecology of Middle Cambrian Algae from Western North America. Unpublished PhD thesis, California, Los Angeles, 120 p.

WAGGONER, B. AND J. W. HAGADORN. 2004. An unmineralized alga from the Lower Cambrian of California, USA. Neus Jahrbuch fur Geologie und Palaontologie-Abhandlungen, 231: 67-83.

WALCOTT, C. D. 1931. Addenda to descriptions of Burgess Shale fossils. Smithsonian Miscellaneous Collections, 85: 1-46.

Other Links:

None

Dalyia racemata

Sketch of Dalyia racemata.

© Marianne Collins

Taxonomy:

Class: Non applicable
Remarks:

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

Species name: Dalyia racemata
Described by: Walcott
Description date: 1919
Etymology:

Dalyia from Mount Daly (3,152 m), a mountain northeast of Fossil Ridge, just at the border between British Columbia and Alberta. The name was originally given by mountaineer Professor Charles E. Fay to honour Judge Charles P. Daly (1816-1899), president of the American Geographical Society (1864-1899).

racemata – from the Latin racemus, “the stalk of a cluster,” referring to the shape of the alga.

Type Specimens: Syntypes –USNM35415-35418 (D. racemata); Holotype –USNM35414 (D. nitens) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Dalyia nitens Walcott 1919 from the Walcott Quarry.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge and the Trilobite Beds on Mount Stephen.

History of Research:

Brief history of research:

Walcott (1919) described D. racemata and D. nitens, but the latter was based on only one specimen and may not be a separate species. The validity of this genus is also questionable and it is likely that Dalyia represents only the distal branches of Yuknessia. Walcott’s proposed affinity of Dalyia with the rhodophytes (red algae) was briefly questioned in an unpublished thesis (Satterthwait, 1976). However, the relationships of all Burgess Shale algae await thorough restudy and redescription.

Description:

Morphology:

This form is composed of a central axis, from which emerge almost perpendicular, slender, straight branching stems that terminate in whorls of short branchlets, not exceeding five in number. The surface of the stems is generally smooth, but transverse lines in some specimens give a jointed appearance, which Walcott likened to the modern rhodophyte Halurus equisetifolius. The central axes are 0.4 to 0.6 cm in diameter and the largest specimens found reach up to 4 cm in height.

Abundance:

Dalyia is very rare and represents only 0.07% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
40 mm

Ecology:

Ecological Interpretations:

The mode of life of this alga is uncertain. Its rigidity suggests it was attached to the sea floor within the photic zone, rather than free floating.

References:

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

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