Creatures: Descent



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Wiwaxia corrugata

3D animation of Wiwaxia corrugata grazing on Morania confluens.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Unranked clade halwaxiids (stem group molluscs)
Species name: Wiwaxia corrugata
Remarks:

The relationship of Wiwaxia is hotly debated; its similarities to the molluscs have been highlighted (Conway Morris, 1985; Scheltema et al., 2003; Caron et al., 2006; Caron et al., 2007), but Matthew’s original view that it was related to the annelid worms (Matthew, 1899) still finds some adherents (Butterfield, 1990; Conway Morris and Peel, 1995; Butterfield, 2006; 2008). It is also possible that Wiwaxia branched off before the molluscs and annelids diverged (Eibye-Jacobsen, 2004). Wiwaxia has recently been placed in a group called the halwaxiids, along with the halkieriids, Orthrozanclus, and Odontogriphus (Conway Morris and Caron, 2007).

Described by: Matthew
Description date: 1899
Etymology:

Wiwaxia – from Wiwaxy Peaks (2,703 m) in Yoho National Park. The word wiwaxy is originally from the Stoney First Nation Nakoda language, meaning “windy.”

corrugata – from the Latin corrugis, “folded, or wrinkled,” in reference to the wrinkled aspect of the sclerites.

Type Specimens: Holotype –ROM8596 in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none described, although sclerites have been reported from a number of Middle Cambrian deposits extending from northern Canada (Butterfield, 1994) to China (Zhao et al., 1994).

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge. The Trilobite Beds, Tulip Beds (S7) and Collins Quarry on Mount Stephen. Additional smaller localities are known on Mount Field and Mount Odaray.

History of Research:

Brief history of research:

In an early review of fossils collected from the Trilobite Beds on Mount Stephen by Walker, Canadian palaeontologist G. F. Matthew (1899) described several forms he thought represented tubes of various annelid worms, including one he named Orthotheca corrugata. At the time, Matthew did not know this particular fossil was only part of a much larger organism. It was only when Walcott (1911) discovered articulated and much better preserved specimens from the Phyllopod Bed that the morphology of this species became clearer. Walcott placed corrugata in his new genus Wiwaxia and interpreted it as a polychaete annelid worm (Walcott, 1911). The single best specimen of Walker’s “Orthotheca corrugata” remained unrecognized until it was “rediscovered” in the ROM collections in 1977.

Walcott’s interpretation was called into question in a comprehensive reassessment of the genus (Conway Morris, 1985), and Conway Morris’s link between Wiwaxia mouthparts and the molluscan radula was built upon by Scheltema et al. (2003) and Caron et al. (2006). Butterfield (1990), however, defended an annelid affinity mostly based on the study of individual sclerites, first at the crown-, and later at the stem-group level (Butterfield, 2003; 2006), but further work suggested that the evidence does not conclusively support a close relationship with annelids (Eibye-Jacobsen, 2004). A connection with the halkieriids was drawn early on (Bengtson and Morris, 1984; Conway Morris and Peel, 1995), and expanded more recently (Conway Morris and Caron, 2007).

Other studies have dealt more specifically with the ecology and taphonomy of this animal. The finely spaced patterning of ridges on the scale may have given Wiwaxia an iridescent aspect in life (Parker, 1998). Wiwaxia has proven useful in calculating the extent of decay in fossil assemblages (Caron and Jackson, 2006) and in reconstructing the longer term taphonomic processes responsible for the preservation of the Burgess Shale fossils (Butterfield et al., 2007).

Description:

Morphology:

Wiwaxia corrugata is a slug-like organism up to 5.5 cm in length almost entirely covered (except on the ventral surface) with an array of scale-like elements referred to as sclerites and spines. The body is roughly oval, and lacks evidence of segmentation. The body-covering sclerites are arranged in about 50 rows. In addition, two rows of 7–11 blade-like spines are present on the dorsal surface. Spines and sclerites were inserted directly into the body wall. Wiwaxia’s feeding apparatus consists of two (in rare cases three) toothed plates that have been compared to a molluscan radula or annelid jaws.

Abundance:

Wiwaxia is mostly known from the Walcott Quarry where it is relatively common, representing 0.9% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
55 mm

Ecology:

Life habits: Descent
Feeding strategies: Descent
Ecological Interpretations:

The similarity of Wiwaxia’s feeding apparatus to that of Odontogriphus suggests that it too fed on the cyanobacterial Morania mats growing on the Cambrian sea floor. Its sclerite armour-plating and long spines, sometimes found broken, suggest that it was targeted by unidentified predators.

References:

BENGSTON, S. AND S. CONWAY MORRIS, 1984. A comparative study of Lower Cambrian Halkieria and Middle Cambrian Wiwaxia. Lethaia, 17:307-329.

BUTTERFIELD, N. J. 1990. A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott. Paleobiology: 287-303.

BUTTERFIELD, N. J. 1994. Burgess Shale-type fossils from a Lower Cambrian shallow-shelf sequence in northwestern Canada. Nature, 369(6480): 477-479.

BUTTERFIELD, N. J. 2003. Exceptional fossil preservation and the Cambrian Explosion. Integrative and Comparative Biology, 43:166-177.

BUTTERFIELD, N. J. 2006. Hooking some stem-group “worms”: fossil lophotrochozoans in the Burgess Shale. BioEssays, 28: 1161-1166.

BUTTERFIELD, N. J. 2008. An early Cambrian radula. Journal of Paleontology, 82(3): 543-554.

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

CARON, J.-B., A. H. SCHELTEMA, C. SCHANDER AND D. RUDKIN, 2006. A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale. Nature, 442(7099): 159-163.

CARON, J.-B., A. H. SCHELTEMA, C. SCHANDER AND D. RUDKIN. 2007. Reply to Butterfield on stem-group “worms:” fossil lophotrochozoans in the Burgess Shale. BioEssays, 29:200-202.

CONWAY MORRIS, S. 1985. The Middle Cambrian metazoan Wiwaxia corrugata (Matthew) from the Burgess Shale and Ogygopsis Shale Shale, British Columbia, Canada. Philosophical Transactions of the Royal Society of London, Series B, 307(1134): 507-582.

CONWAY MORRIS, S. AND J.-B. CARON, 2007. Halwaxiids and the Early Evolution of the Lophotrochozoans. Science, 315(5816): 1255-1258.

CONWAY MORRIS, S. AND J. S. PEEL, 1995. Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 347(1321): 305-358.

EIBYE-JACOBSEN, D. 2004. A reevaluation of Wiwaxia and the polychaetes of the Burgess Shale. Lethaia, 37(3): 317-335.

MATTHEW, G. F. 1899. Studies on Cambrian Faunas, No. 3. Upper Cambrian fauna, Mount Stephen, British Columbia. The trilobites and worms. Transactions of the Royal Society, 5: 39-66.

PARKER, A. R. 1998. Colour in Burgess Shale animals and the effect of light on evolution in the Cambrian. Proceedings of the Royal Society B: Biological Sciences, 265(1400): 967.

SCHELTEMA, A. H., K. KERTH AND A. M. KUZIRIAN, 2003. Original molluscan radula: Comparisons among Aplacophora, Polyplacophora, Gastropoda, and the Cambrian fossil Wiwaxia corrugata. Journal of Morphology, 257(2): 219-245.

WALCOTT, C. D. 1911. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(2): 109-144.

ZHAO, Y.-l., Y. QIAN AND X.-S. LI, 1994. Wiwaxia from Early-Middle Cambrian Kaili Formation in Taijiang, Guizhou. Acta Palaeontologica Sinica, 33:359-366.

Other Links:

http://www.paleobiology.si.edu/burgess/wiwaxia.html



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Waputikia ramosa

3D animation of Waputikia ramosa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Non applicable
Species name: Waputikia ramosa
Remarks:

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

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:

Age:
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:

Life habits: Descent
Feeding strategies: Descent
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



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Wapkia grandis

3D animation of Wapkia elongata and other sponges (Choia ridleyi, Diagoniella cyathiformis, Eiffelia globosa, Hazelia conferta, Pirania muricata, and Vauxia bellula) and Chancelloria eros a sponge-like form covered of star-shaped spines.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Demospongia (Order: Monaxonida)
Species name: Wapkia grandis
Remarks:

Wapkia is considered a primitive demosponge (Rigby, 1986). Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Described by: Walcott
Description date: 1920
Etymology:

Wapkia – origin of name is unknown

grandis – from the Latin grandis, “large.” This name refers to the large size and complex skeleton of this sponge.

Type Specimens: Lectotype –USNM66458 (W. grandis), in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Holotype –ROM53544 (W. elongata), in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: W. elongata Rigby and Collins, 2004 from the Tulip Beds (S7) on Mount Stephen.

Other deposits: none.

Age & Localities:

Age:
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.

History of Research:

Brief history of research:

Wapkia was described by Walcott in his initial description of the Burgess Shale sponges in 1920. The genus was re-examined by Rigby in 1986. Rigby and Collins (2004) also redescribed the genus and proposed a new species, W. elongata.

Description:

Morphology:

Wapkia is a large elongate or oval sponge with bundles of coarse and fine spicules aligned in long vertical columns and distinct horizontal bundles. The surface of the sponge is smooth and lacks any vertical or horizontal ridges. Spicules are straight and pointed at both ends (oxeas). The exact position of the various bundles of spicules in the skeleton is still uncertain, but it seems that the inner part of the skeleton is reticulate with horizontal wrinkles that are typical of the species and produced by horizontal bundles of spicules. The dermal layer is formed by bundles of oxeas up to 60 mm long which give a characteristic plumose aspect to this sponge. W. elongata is distinguished from W. grandis based on the overall shape of the sponge and different skeletal structures (varying distance between the horizontal spicule bundles).

Abundance:

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

Maximum Size:
170 mm

Ecology:

Life habits: Descent
Feeding strategies: Descent
Ecological Interpretations:

Wapkia would have lived attached to the sea floor. Particles of organic matter were extracted from the water as they passed through canals in the sponge’s wall.

References:

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

RIGBY, J. K. 1986. Sponges of the Burgess shale (Middle Cambrian), British Columbia. Palaeontographica Canadiana, 2: 105 p.

RIGBY, J. K. AND D. COLLINS. 2004. Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia. Royal Ontario Museum Contributions in Science (1): 155 p.

WALCOTT, C. D. 1920. Middle Cambrian Spongiae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67(6): 261-365.

Other Links:

None



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Pirania muricata

3D animation of Pirania muricata and other sponges (Choia ridleyi, Diagoniella cyathiformis, Eiffelia globosa, Hazelia conferta, Vauxia bellula, and Wapkia elongata) and Chancelloria eros a sponge-like form covered of star-shaped spines.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Demospongea (Order: Monaxonida)
Species name: Pirania muricata
Remarks:

Pirania is considered a primitive demosponge (Rigby, 1986). Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Described by: Walcott
Description date: 1920
Etymology:

Pirania – from Mount Saint Piran (2,649 m), situated in the Bow River Valley in Banff National Park, Alberta. Samuel Allen named Mount St. Piran after the Patron Saint of Cornwall in 1894.

muricata – from the Latin muricatus, “pointed, or full of sharp points.” The name refers to the large pointed spicules extending out from the wall of the sponge.

Type Specimens: Lectotype –USNM66495 (erroneously referred as 66496 in Rigby, 1986), in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none

Other deposits: Pirania auraeum Botting, 2007 from the Lower Ordovician of Morocco (Botting, 2007); Pirania llanfawrensis Botting, 2004 from the Upper Ordovician of England (Botting, 2004).

Age & Localities:

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

The Walcott Quarry on Fossil Ridge. The Trilobite Beds and Tulip Beds (S7) on Mount Stephen and several smaller sites on Mount Field, Mount Stephen and Mount Odaray.

History of Research:

Brief history of research:

Pirania was first described by Walcott (1920). Rigby (1986) redescribed this sponge and concluded that the skeleton is composed of hexagonally arranged canals, large pointed spicules and tufts of small spicules. This sponge was also reviewed by Rigby and Collins based on new material collected by the Royal Ontario Museum (2004).

Description:

Morphology:

Pirania is a thick-walled cylindrical sponge that can have up to four branches. The skeleton of the sponge is composed of tufts of small spicules and has very distinctive long pointed spicules that emerge from the external wall. Long canals perforate the wall of the sponge to allow water flow through it. Branching occurs close to the base of the sponge.

Abundance:

Pirania is common in most Burgess Shale sites but comprises only 0.38% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
30 mm

Ecology:

Life habits: Descent
Feeding strategies: Descent
Ecological Interpretations:

Pirania would have lived attached to the sea floor. Particles of organic matter were extracted from the water as they passed through canals in the sponge’s wall. The brachiopods Nisusia and Micromitra a range of other sponges and even juvenile chancelloriids are often found attached to the long spicules of this sponge, possibly to avoid higher turbidity levels near the seafloor.

References:

BOTTING, J. P. 2004. An exceptional Caradoc sponge fauna from the Llanfawr Quarries, Central Wales and phylogenetic implications. Journal of Systematic Paleontology, 2: 31-63.

BOTTING, J. P. 2007. ‘Cambrian’ demosponges in the Ordovician of Morocco: insights into the early evolutionary history of sponges. Geobios, 40: 737-748.

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

RIGBY, J. K. 1986. Sponges of the Burgess shale (Middle Cambrian), British Columbia. Palaeontographica canadiana, 2: 105 p.

RIGBY, J. K. AND D. COLLINS. 2004. Sponges of the Middle Cambrian Burgess Shale and Stephen Formations, British Columbia. Royal Ontario Museum Contributions in Science (1): 155 p.

WALCOTT, C. D. 1920. Middle Cambrian Spongiae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67(6): 261-365.

Other Links:

None



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Nectocaris pteryx

3D animation of Nectocaris pteryx.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Cephalopoda (stem group molluscs)
Species name: Nectocaris pteryx
Remarks:

Nectocaris is regarded as an early stem-group mollusc close to the cephalopods. This stem-group also includes Vetustovermis from the Middle Cambrian Emu Bay Shale of Australia, and the Lower Cambrian Petalilium from the Chengjiang deposit in China (Smith and Caron, 2010).

Described by: Conway Morris
Description date: 1976
Etymology:

Nectocaris – from the Greek nekto, “swimming,” and the Latin caris, “shrimp,” based on its original interpretation as an arthropod.

pteryx – from the Greek pteryx, “fins,” in reference to the presence of fins.

Type Specimens: Holotype –USNM198667 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott, Raymond and Collins Quarries on Fossil Ridge.

History of Research:

Brief history of research:

As with Odontogriphus, another Burgess Shale animal related to molluscs, Walcott collected the first specimen of Nectocaris between 1909 and 1924. The fossil was photographed by Walcott, and its print sat with the unidentified specimen in the Smithsonian collections until noticed and described by Simon Conway Morris in 1976. Due to the lateral compression of the fossil, his resulting reconstruction was laterally-oriented. The funnel, bent back over the front, resembled the head-shield of an arthropod, and yet the fin, folded along the top of the organism, looked much like the ray-bearing dorsal fin of a chordate. A chordate affinity was further suggested by the myomere-like appearance of the bars, and although Conway Morris did not offer a firm diagnosis, Simonetta (1988) promoted a chordate status (Insom et al., 1995).

Meanwhile, Glaessner had described Vetustovermis, based on an ill-preserved specimen from Australia’s Emu Bay Shale, and because of its segmented appearance he suggested an affinity with annelid worms (Glaessner, 1979). Other workers noted the similarity of some Chengjiang fossils to this specimen and described them as slug-like relatives of the molluscs (Chen et al., 2005). During this period, the Royal Ontario Museum had been collecting similar fossils, which Desmond Collins recognized as representatives of Nectocaris. These were eventually described as stem-group cephalopods (Smith and Caron, 2010). The relationships among members of this clade are difficult to determine, and it may require further fossil finds to establish their diversity and range. The absence of a shell in Nectocarisindicates that cephalopods, which were previously thought to have evolved later in the Cambrian from snail-like monoplacophorans, did not require a buoyant shell to start swimming, but derived their shell independently of other mollusc lineages.

Description:

Morphology:

The body of Nectocaris is kite-shaped and can reach up to 72 mm in length, including two flexible tentacles that extend forwards from the head, which also bears a pair of camera-type eyes on short stalks. A long, nozzle-like funnel originates under the base of the head. The main body has wide lateral fins with transverse bars; a large axial cavity contains paired gills.

Abundance:

Nectocaris is known from 90 specimens on Fossil Ridge, mostly from the Collins Quarry; it is rare or absent at most other Burgess Shale localities. Only two specimens, including the holotype, have been found in the Walcott Quarry.

Maximum Size:
72 mm

Ecology:

Life habits: Descent
Feeding strategies: Descent
Ecological Interpretations:

A free-swimming predator or scavenger, Nectocaris would have fed on small prey items with its prehensile tentacles in a similar fashion to squid today. Its primary mode of propulsion would have been in the flexing of its fins; it may have supplemented this by squirting water from its funnel. The funnel was also used to inhale and exhale water, which entered the animal’s body cavity to oxygenate the large internal gills.

References:

CHEN, J.-Y., D.-Y. HUANG AND D. J. BOTTJER. 2005. An Early Cambrian problematic fossil: Vetustovermis and its possible affinities. Proceedings of the Royal Society B: Biological Sciences, 272(1576): 2003-2007.

CONWAY MORRIS, S. 1976. Nectocaris pteryx, a new organism from the Middle Cambrian Burgess Shale of British Columbia. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 12: 703-713.

GLAESSNER, M. F. 1979. Lower Cambrian Crustacea and annelid worms from Kangaroo Island, South Australia. Alcheringa, 3(1): 21-31.

INSOM, E. A. PUCCI AND A. M. SIMONETTA. 1995. Cambrian Protochordata, their origin and significance. Bollettino di Zoologia, 62(3): 243-252.

SIMONETTA, A. M. 1988. Is Nectocaris pteryx a chordate? Bollettino di Zoologia, 55(1-2): 63-68.

SMITH, M. AND J.-B. CARON. 2010. Primitive soft-bodied cephalopods from the Cambrian. Nature, 465: 469-472.

Other Links:

http://www.nature.com/nature/journal/v465/n7297/full/nature09068.html



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Marpolia spissa

3D animation of Marpolia spissa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Descent
Phylum: Descent
Higher Taxonomic assignment: Cyanophyceae (Order: Oscillatoriales?)
Species name: Marpolia spissa
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).

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:

Age:
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:

Life habits: Descent
Feeding strategies: Descent
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.

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