The Burgess Shale

Priscansermarinus barnetti

Priscansermarinus barnetti (ROM 36064) – Holotype (specimen A). Slab with 62 individuals including the holotype (white frame to the left and close up to the right). Specimen length (holotype) = 32 mm. Specimen dry – polarized light (both images). Walcott Quarry talus.

© Royal Ontario Museum. Photos: Jean-Bernard Caron

Taxonomy:

Class: Non applicable
Remarks:

Originally proposed as a crustacean arthropod and a possible member of the pedunculate lepadomorph barnacles within Maxillopoda (Subclass Thecostraca) (Collins and Rudkin, 1981), its affinities have since been questioned and remain equivocal.

Species name: Priscansermarinus barnetti
Described by: Collins and Rudkin
Description date: 1981
Etymology:

Priscansermarinus – from the Latin priscus “of ancient times;” anser, “goose” and marinus, “sea,” (together forming “sea goose”) in reference to the modern goose barnacles.

barnetti – after Robert Barnett, member of the 1975 ROMexpedition, who found the first specimens.

Type Specimens: Holotype –ROM36064a in the Royal Ontario Museum, Toronto, Ontario, Canada
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 and Raymond Quarries on Fossil Ridge, Mount Field.

History of Research:

Brief history of research:

The “discovery” slab bearing 62 individuals of a previously unknown organism was found by Robert Barnett in talus (scree) beneath the Walcott Quarry level during the ROM’s inaugural Burgess Shale expedition in 1975. Priscansermarinus barnetti was described and named in 1981, and interpreted as a probable stalked (pedunculate) lepadomorph (goose) barnacle, pending recovery of additional specimens preserving definitive characters. The barnacle, and even the arthropod, affinities of Priscansermarinus have since been questioned (Briggs, 1983; Briggs et al., 2005).

Description:

Morphology:

Priscansermarinus consists of two primary components – an ovate triangular shaped, laterally compressed “body,” and a short, thick “stalk.” The body region shows a highly reflective centralized subtriangular region that was originally interpreted as evidence for a thin non-biomineralized external “plate” on either side of the body. This is now recognized to be an internal structure of greater anatomical complexity. The stalk, or stolon, which appears to emerge from the body rather than blend into it, is cylindrical in shape and at least moderately flexible; the distal end bears a terminal disc exhibiting a radiating pattern. In most known specimens, the stalk comprises slightly more than half of the total length of the animal.

Abundance:

Moderately common at some Raymond Quarry levels; uncommon elsewhere.

Maximum Size:
50 mm

Ecology:

Ecological Interpretations:

This species is too poorly known to describe its ecology with great certainty. The terminal disk at the base of its stolon was probably used for anchoring the animal in or on the mud. Without any apparent tentacles and obvious feeding structures, a suspension feeding mode of life is a strong possibility.

References:

BRIGGS, D. E. G. 1983. Affinities and early evolution of the Crustacea: the evidence of the Cambrian fossils, p. 1-22. In F. R. Schram (ed.), Crustacean Phylogeny. Balkema, Rotterdam.

BRIGGS, D. E. G., M. D. SUTTON AND D. J. SIVETER. 2005. Metamorphosis in a Silurian barnacle. Proceedings of the Royal Society, B, 272: 2365-2369.

COLLINS, D. AND RUDKIN, D. M. 1981. Priscansermarinus barnetti, a probable lepadomorph barnacle from the Middle Cambrian Burgess Shale of British Columbia. Journal of Paleontology, 55: 1006-1015.

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Portalia mira

Portalia mira (USNM 83927) – Holotype, part and counterpart. Complete specimen preserved with Mackenzia costalis. Anterior possible to the right. Specimen length = 100 mm. Specimen dry – polarized light. Walcott Quarry.

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

Taxonomy:

Class: Non applicable
Remarks:

Portalia is regarded as a problematic organism awaiting a full redescription (Briggs and Conway Morris, 1986).

Species name: Portalia mira
Described by: Walcott
Description date: 1918
Etymology:

Portalia – from Portal Peak (2,911 m), north of the Burgess Shale in Banff National Park.

mira – from the Latin mirus, “wonderful,” in reference to the morphology of the animal.

Type Specimens: Holotype –USNM83927 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:

The only known specimen of Portalia was first illustrated by Walcott in a brief communication published in 1918 and refigured in a posthumous publication (Walcott, 1931). Walcott interpreted this fossil as a holothurian, a member of a group of echinoderms better known as sea-cucumbers. Madsen (1957) suggested Portalia might be a primitive sponge, but Durham (1974) thought that the holothurian affinity could not be rejected without further studies (see also Conway Morris, 1979). The relationships of Portalia remain difficult to establish (Briggs and Conway Morris, 1986).

Description:

Morphology:

The body of Portalia is sausage-shaped and the most distinctive features are a series of elongate tentacle-like structures covering the entire surface. These structures tend to split into several simple branches. A central strand within the body has been interpreted as part of the gut and the head has been tentatively identified as a darker indistinct area at one end.

Abundance:

Portalia is known from a single specimen.

Maximum Size:
100 mm

Ecology:

Ecological Interpretations:

Not enough is known about this organism to interpret its feeding strategy.

References:

BRIGGS, D. E. G. AND S. CONWAY MORRIS. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia, p. 167-183. In A. Hoffman and M. H. Nitecki (eds.), Problematic fossil taxa (Oxford Monographs on Geology and Geophysics No. 5). Oxford University Press & Clarendon Press, New York.

CONWAY MORRIS, S. 1979. The Burgess Shale (Middle Cambrian) fauna. Annual Review of Ecology and Systematics, 10(1): 327-349.

MADSEN, F. J. 1957. On Walcott’s supposed Cambrian holothurians. Journal of Paleontology, 31(1): 281-286.

WALCOTT, C. 1918. Geological explorations in the Canadian Rockies. From “Explorations and Field-Work of the Smithsonian Institution in 1917”. Smithsonian Miscellaneous Collections, 68: 4-20.

WALCOTT, C. 1931. Addenda to descriptions of Burgess Shale fossils. Smithsonian Miscellaneous Collections, 85(3): 1-46.

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Pollingeria grandis

Pollingeria grandis (GSC 8362). Slab with several specimens. Specimen length (largest) = 15 mm. Specimen dry – polarized light. Walcott Quarry.

© GEOLOGICAL SURVEY OF CANADA. PHOTO: JEAN-BERNARD CARON

Taxonomy:

Class: Non applicable
Remarks:

Pollingeria is one of the least understood Burgess Shale organisms, and its systematic status is unknown (Briggs and Conway Morris, 1986).

Species name: Pollingeria grandis
Described by: Walcott
Description date: 1911
Etymology:

Pollingeria – from Mount Pollinger (2,816 m), northwest of the Burgess Shale. The name was given after Joseph Pollinger (1873-1943).

grandis – from the Latin grandis, “big, large,” in reference to the purported large size of the fossils.

Type Specimens: Syntypes –USNM57639-57641 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 and Raymond Quarries on Fossil Ridge and smaller sites on Mount Field and Mount Stephen.

History of Research:

Brief history of research:

Pollingeria was first described by Walcott in a 1911 monograph dealing with various Burgess Shale worms. Walcott interpreted these fossils as the individual scales of a larger organism resembling Wiwaxia. However, this interpretation was doubted (Conway Morris, 1979), and firmly rejected after the restudy of Wiwaxia (Conway Morris, 1985). The affinities of Pollingeria have remained difficult to establish (Briggs and Conway Morris, 1986).

Description:

Morphology:

The shape of this fossil is ovoid but variable in details and most individuals range from 10 to 15 mm in length. A distinctive feature is a series of narrow tubular elements that are darker and often slightly raised; these are twisted and contorted and do not appear to be parts of a gut.

Abundance:

Pollingeria is locally very abundant with hundreds of specimens on some bedding surfaces. In the Walcott Quarry this species represents 5.83% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
15 mm

Ecology:

Ecological Interpretations:

Not enough is known about this organism to interpret its ecology.

References:

BRIGGS, D. E. G. AND S. CONWAY MORRIS. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia, p. 167-183. In A. Hoffman and M. H. Nitecki (eds.), Problematic fossil taxa (Oxford Monographs on Geology and Geophysics No. 5). Oxford University Press & Clarendon Press, New York.

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. 1979. The Burgess Shale (Middle Cambrian) fauna. Annual Review of Ecology and Systematics, 10(1): 327-349.

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, 307:507-582.

WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5): 109-145.

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Eldonia ludwigi

3D animation of Eldonia ludwigi.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Unranked clade Cambroernida (stem group ambulacrarians)
Remarks:

Eldonia, together with other discoidal or pedunculate fossils such as Herpetogaster, probably belongs in the stem group to a clade known as the Ambulacraria, represented by both echinoderms and hemichordates (Caron et al., 2010).

Species name: Eldonia ludwigi
Described by: Walcott
Description date: 1911
Etymology:

Eldonia – from Eldon, a train stop on the Canadian Pacific Railway 30 km east of Field. Eldon is named after a town in County Durham, England, and means “Aelle’s hill.”

ludwigi – after Hubert Ludwig, a German echinoderm expert who described many fossil holothurians.

Type Specimens: Lectotype –USNM57540 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: Stellostomites eumorphus (Sun and Hou, 1987), from the Lower Cambrian Chengjiang fauna, was redescribed as Eldonia eumorpha (Chen et al., 1995). However, S. eumorphus is retained in the literature as the only valid species (Zhu et al. 2002); E. berbera was described from the Upper Ordovician of Morocco (Alessandrello and Bracchi, 2003). If confirmed it would be the youngest stratigraphic occurrence for the genus.

Age & Localities:

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

Burgess Shale and vicinity: Walcott and Raymond Quarries on Fossil Ridge.

Other deposits: Middle Cambrian Spence Shale and Marjum Formation in Utah (Conway Morris and Robison, 1988).

History of Research:

Brief history of research:

Described by Walcott in 1911, Eldonia was originally interpreted as a holothurian (sea cucumber within the echinoderms), a view that was accepted by some eminent experts at the time (Clark A.H., 1913) and upheld by later re-examination of the material (Durham, 1974). However, this interpretation has always had detractors (Clark H.L., 1912; Dzik, 1991, 1997; Madsen, 1956, 1957, 1962; Paul and Smith, 1984), and the lack of key echinoderm features prohibits a close relationship with that group (Conway Morris, 1993; see also Zhu et al., 2002). Despite their resemblance to jellyfish (scyphozoans) there is a wide consensus that eldoniids do not share any affinities with cnidarians. A connection to “lophophorates” (e.g., brachiopods, phoronids) has been argued in more detail (Chen et al., 1995, Dzik, 1997), but this status remains rather problematic. The description of Eldonia’s close relative Herpetogaster provides a possible link to the Ambulacraria, a group that contains the echinoderms and hemichordates (Caron and Conway Morris, 2010).

Fragments of the reflective gut have been extracted by acid maceration and analyzed for taphonomic studies (Butterfield, 1990).

Description:

Morphology:

Eldonia has a discoidal body with both anus and mouth opening ventrally. Fine rays radiate from a central point within the disc. The gut coils clockwise (viewed from the dorsal surface) around the centre of the organism and is clearly separated into a pharynx, stomach (the darker area), and narrow intestine. There is a pair of relatively stout tentacles around the mouth which probably were used for feeding.

Abundance:

Walcott collected hundreds of specimens of Eldonia in a single fossil layer within the Phyllopod Bed that he called the Great Eldonia Layer. Additional specimens have since been collected from the Walcott Quarry, where they comprise 0.4% of the community (Caron and Jackson, 2008).

Maximum Size:
150 mm

Ecology:

Ecological Interpretations:

Eldonia has conventionally been interpreted as a free-floating filter-feeder. However, based on its morphology, preservational patterns, and its similarity with Herpetogaster, a benthic lifestyle has also been proposed, with its tentacles either collecting food from the water, or sweeping the sea floor for particles of detritus (Caron and Conway Morris, 2010). It is unclear whether the animal could move at least occasionally or was permanently stationary (sessile).

References:

ALESSANDRELLO, A. AND G. BRACCHI. 2003. Eldonia berbera n. sp. a new species of the enigmatic genus Eldonia Walcott, 1911 from the Rawtheyan (Upper Ordovician) of Anti-Atlas (Erfoud, Tafilalt, Morocco). Atti della Società italiana di scienze naturali e del Museo civico di storia naturale in Milano, 144(2): 337-358.

BUTTERFIELD, N. J. 1990. Organic preservation of non-mineralizing organisms and the taphonomy of the Burgess Shale. Paleobiology, 16(3): 272-286.

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., S. CONWAY MORRIS AND D. SHU. 2010. Tentaculate fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) interpreted as primitive deuterostomes. PLoS ONE, 5(3): e9586.

CHEN, J.-Y., M.-Y. ZHU AND G.-Q. ZHOU. 1995. The early Cambrian medusiform metazoan Eldonia from the Chengjiang Lagerstätte. Acta Palaeontologica Polonica, 40: 213-244.

CLARK, H. L. 1912. Fossil holothurians. Science, 35(894): 274-278.

CLARK, A. H. 1913. Cambrian holothurians. American Naturalist, 48: 488-507.

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals and algae from the Middle Cambrian of Utah and British Columbia. The University of Kansas Paleontological Contributions, 122: 23-84.

CONWAY MORRIS, S. 1993. The fossil record and the early evolution of the Metazoa. Nature, 361(6409): 219-225.

DURHAM, J. W. 1974. Systematic Position of Eldonia ludwigi Walcott. Journal of Paleontology, 48(4): 751-755.

DZIK, J. 1991. Is fossil evidence consistent with traditional views of the early metazoan phylogeny?, p. 47-56. In A. M. Simonetta and S. Conway Morris (eds.), The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge University Press, Cambridge.

DZIK, J. Y., L. ZHAO AND M. Y. ZHU. 1997. Mode of life of the Middle Cambrian eldonioid lophophorate Rotadiscus. Palaeontology, 40(2):385-396.

MADSEN, F. J. 1956. Eldonia, a Cambrian siphonophore-formerly interpreted as a holoturian[sic]. Videnskabelige meddelelser fra Dansk naturhistorisk forening i Københaven, 118: 7-14.

MADSEN, F. J. 1957. On Walcott’s supposed Cambrian holothurians. Journal of Paleontology, 31(1): 281-282.

MADSEN, F. J. 1962. The systematic position of the Middle Cambrian fossil Eldonia. Meddelelser fra Dansk Geologisk Førening, 15: 87-89.

PAUL, C. R. C. AND A. B. SMITH. 1984. The early radiation and phylogeny of echinoderms. Biological Reviews, 59(4): 443-481.

WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian holothurians and medusae. Smithsonian Miscellaneous Collections, 57(3): 41-68.

ZHU, M. Y., Y. L. ZHAO AND J. Y. CHEN. 2002. Revision of the Cambrian discoidal animals Stellostomites eumorphus and Pararotadiscus guizhouensis from South China. Geobios, 35(2): 165-185.

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Diraphora bellicostata

3D animation of Diraphora bellicostata and other brachiopods (Acrothyra gregaria, Micromitra burgessensis, Nisusia burgessensis, and Paterina zenobia).

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Rhynchonellata (Order: Orthida)
Remarks:

Diraphora belongs to the Family Bohemiellidae.

Species name: Diraphora bellicostata
Described by: Walcott
Description date: 1924
Etymology:

Diraphora – from the Greek deiras, “ridge,” and phoras, “bearing.”

bellicostata – from the Latin bellus, “beautiful,” and costatus, “ribbed.”

Type Specimens: Syntypes –USNM69731-69737 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none to date. The Burgess Shale brachiopods in particular from the Trilobite Beds on Mount Stephen need to be re-examined (see also Brief history of research).

Other deposits: Several species are known in North America and Australia.

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:

Originally assigned to Eoorthis by Walcott (1924), this species was subsequently reassigned by Bell as the type species of a new genus, Diraphora (Bell, 1941). Diraphora bellicostata has not been studied since its original description by Walcott in 1924. Walcott’s description is cursory, inadequately diagnosing the specimen, and no types were designated. The species needs to be redescribed.

Description:

Morphology:

Diraphora bellicostata possesses sharp ornamental lines (costae) radiating on its surface from the hinge. The shells would have been articulated with short and small teeth, like in Nisusia, a comparable form from the Burgess Shale. No preserved soft parts are known and the shell was originally mineralized.

Abundance:

Diraphora bellicostata is known from several hundred specimens in the Walcott Quarry and is the most abundant of all brachiopods but still represents a relatively small fraction of the entire fauna (<1.3%) (Caron and Jackson, 2008).

Maximum Size:
10 mm

Ecology:

Ecological Interpretations:

It is likely that Diraphora had a short, stout pedicle from which it was attached to the substrate. Some specimens are attached to spicules of sponges in particular of Pirania. Other organisms (for example Mackenzia) attached themselves on isolated valves of Diraphora (representing dead individuals), which they used as anchors. Extraction of food particles from the water would have been possible thanks to a filter-feeding apparatus (located between the shells) called a lophophore.

References:

BELL, C. W. 1941. Cambrian Brachiopoda from Montana. Journal of Paleontology, 15: 193-255.

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. D. 1924. Cambrian and Ozarkian Brachiopoda. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections, 67: 477-554.

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Dinomischus isolatus

Reconstruction of Dinomischus isolatus.

© Marianne Collins

Taxonomy:

Class: Non applicable
Remarks:

Although it has been suggested that Dinomischus may be related to the ectoprocts (Conway Morris, 1977), its unusual morphology has not yet been conclusively related to a known phylum and as such its affinities remain unclear.

Species name: Dinomischus isolatus
Described by: Conway Morris
Description date: 1977
Etymology:

Dinomischus – from the Greek dinos, “goblet,”, and michos, “stalk or stem.” The name refers to the wine glass-shape of the animal.

isolatus – from the Latin insula, “island.” The name refers to the non-gregarious life habit of this animal.

Type Specimens: Holotype –USNM198735 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: D. venutus Chen, Hou and Lu, 1989 from the Lower Cambrian Chengjiang fauna.

Age & Localities:

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

Burgess Shale and vicinity: Walcott Quarry, Raymond Quarry, Tulip Beds (S7)

Other deposits: A single specimen of D. isolatus was also reported from the Middle Cambrian Kaili Formation (Peng et al., 2006).

History of Research:

Brief history of research:

D. isolatus was among the original fossils collected by Walcott, although it was not formally described until 1977 by Conway Morris. The original description was based on three specimens. A second species was added by Chen et al. (1989) based on material from the Chengjiang in China. Further specimens have been collected by the Royal Ontario Museum from sites on both Fossil Ridge and Mount Stephen.

Description:

Morphology:

Dinomischus consists of a cup-shaped calyx supported by a long stem that terminates in a bulbous swelling. A circle of 20 stiff bracts up to 4.5 mm in length surround the upper margin of the calyx. These point upward and project beyond the level of the anus and the mouth and are interpreted as part of a filter feeding apparatus. Reflective material in the central part of the calyx has been interpreted as a U-shaped gut, with a large sac-like stomach positioned centrally and a mouth and anus on the upper surface. The stem appears to be a rigid structure and the bulbous termination is interpreted as an attachment structure.

Abundance:

Dinomischus is very rare. Only three specimens were originally described from the Burgess Shale. A few additional specimens are known in the Burgess Shale collections of the Royal Ontario Museum.

Maximum Size:
28 mm

Ecology:

Ecological Interpretations:

Dinomischus was a stalked filter feeder that lived anchored to the sea floor. Its ring of bracts would have captured food particles from passing water and moved them to the mouth.

References:

CONWAY MORRIS, S. 1977. A new entoproct-like organism from the Burgess Shale of British Columbia. Palaeontology, 20(4): 833-845.

CHEN, J. HOU, X. AND H. LU. 1989. Early Cambrian hock glass-like rare sea animal Dinomischus (Entoprocta) and its ecological features. Acta Palaeontologica Sinica., 28 (1): 58-71.

PENG, J., Y. L. ZHAO AND J. P. LIN. 2006. Dinomischus from the Middle Cambrian Kaili Biota, Guizhou, China. Acta Geologica Sinica-English Edition, 80: 498-501.

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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.

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Chancelloria eros

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

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Unranked clade Coeloscleritophora (Order: Chancelloriida)
Remarks:

Two main hypotheses exist for the affinity of the chancelloriids: they may form a group with Halkieria and relatives, nested close to the base of the bilaterian tree (Bengtson, 2005), or they may simply represent a sponge-grade organism with an unusual mode of spicule formation (Sperling et al., 2007).

Species name: Chancelloria eros
Described by: Walcott
Description date: 1920
Etymology:

Chancelloria – from the nearby Chancellor Peak (3,280 m), which was named to honour the Ontario Chancellor Sir John Boyd for his role in resolving an 1886 dispute between the Canadian Pacific Railway and the Canadian Government.

eros – unspecified; either from the Latin erosus, “gnawed off” or “consumed,” or the Greek erotikos, “pertaining to love.”

Type Specimens: Lectotype –USNM66524 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
Other species:

Burgess Shale and vicinity: none.

Other deposits: Walcott (1920) described C. drusilla, C. libo and C. yorkensis from Middle Cambrian deposits in the Conasauga shales of Georgia, the Conasauga shales of Alabama, and the York formation of Pennsylvania, respectively. Other workers have described C. maroccana Szduy, 1969 from the Lower Cambrian Campo Pisano Formation, Sardinia, Italy; C. pentacta Rigby, 1978, from the Middle Cambrian Wheeler Shale, Utah, USA (Rigby, 1978); C. sp., from the Cambrian Bright Angel Shale of Arizona (Elliott and Martin, 1987); C. cf. eros from the Early Cambrian (Branchian) Sekwi Formation, Mackenzie Mountains, Northwest Territories, Canada (Randell et al., 2005); C. sp., from the Elvinia Zone (Upper Cambrian) Collier Shale, Ouachita Mountains, west-central Arkansas (Hohensee and Stitt, 1989); C. sp. from King George Island, Antarctica (Wrona, 2004).

Age & Localities:

Period:
Cambrian Stage 2 (basal Botomian, upper Lower Cambrian) to uppermost Middle Cambrian, Bolaspidella Zone (approximately 525-505 million years ago).
Principal localities:

Burgess Shale and vicinity: Chancellorids are known from all Burgess Shale localities, in particular from the Walcott, Raymond and Collins Quarries on Fossil Ridge, as well as on Mount Stephen (Trilobite Beds, and Tulip Beds (S7)), Monarch Cirque and other smaller localities. Work is currently in progress to determine how many of these Chancelloria specimens in fact represent other genera, in particular Allonnia and Archiasterella (see below).

Other deposits: C. eros is globally distributed, and has been reported from the Middle Cambrian Wheeler Shale (and Marjum Formation), Utah, USA (Janussen et al., 2002); Lower Cambrian Comley Limestone, England (Reid, 1959); upper Lower to lower Middle Cambrian La Laja Formation, Argentina (Beresi and Rigby, 1994); Andrarum Limestone and the upper alum shale (Middle Cambrian) of Bornholm, Denmark (Berg-Madsen, 1985); Lower Cambrian of Nevada and California (Mason, 1938); the Lower Cambrian of Cape Breton Island (Landing, 1991); the Early Cambrian Todd River Dolomite, Amadeus Basin, central Australia (Laurie, 1986), the Çal Tepe Formation, Taurus Mountains, Turkey (Sarmiento et al., 2001); the Lower Cambrian Forteau Formation of western Newfoundland (Skovsted and Peel, 2007); the Lower Cambrian Hyolithes Limestone of Nuneaton, England (Brasier, 1984).

History of Research:

Brief history of research:

Walcott (1920) considered Chancelloria to represent a sponge, a position that was followed by the majority of subsequent workers. However its mode of sclerite formation is reputedly unlike anything known in modern sponges: the hollow sclerites are composed of multiple elements that are joined together (Bengtson and Missarzhevsky, 1981), with a structure similar to the sclerites of Halkieria (Porter, 2008). This detail convinced most that the chancelloriids could not belong to the sponges (Goryanski, 1973; Bengtson and Hou, 2001). However, some disagree, pointing out that the organic microstructure does have some similarity to the fibres of horny sponges (Butterfield and Nicholas, 1996), suggesting a position in the sponge total group (see also Sperling et al., 2007). The specimens from the Burgess Shale are currently undergoing a detailed re-study and some specimens will doubtlessly be reclassified into other chancelloriid genera (Bengtson and Collins, 2009).

Description:

Morphology:

Chancelloria resembled a cylindrical cactus up to 20 centimetres tall. An assortment of star-shaped spines constitutes a loose and unconnected net arranged in various fashions. These spines formed a tight ring around the top of the organism, which seems to have surrounded a pore. Water would probably have passed through this opening and any organic particles would have been filtered out for food.

The spicules of Chancelloria, which varied from millimetric to about a centimetre in diameter, were composed of hollow rays that were stuck together at a central point to form a three-dimensional structure shaped like an umbrella. A central ray pointed out from the organism, and other rays radiating outwards at an angle closer to the surface of the organism, presumably to aid in defence. The nature of the rays distinguishes between the chancelloriid genera and species; C. eros bears four to seven rays per spicule. The closely related Allonnia is differentiated from Chancelloria by its more globular shape and the details of its sclerite construction, which consists of three main rays. A third genus, Archiasterella, is also represented in the Burgess Shale and differs from the two other genera in sclerite morphology and numbers of rays.

Abundance:

Chancelloria accounts for under 0.5% of the Burgess Shale community (Caron and Jackson, 2008), including specimens that may belong to Allonnia or Archiasterella.

Maximum Size:
200 mm

Ecology:

Ecological Interpretations:

Chancelloria primarily attached itself to organisms, commonly sponges or other chancelloriids, but also on occasion to shell fragments that may have been partially buried in the sea floor. It remained in this anchored position and fed by extracting particles from seawater, which it sucked in and squeezed out through an opening in the top of its body. It spines probably served as a defence against predators.

References:

BENGTSON, S. 2005. Mineralized skeletons and early animal evolution, p. 101-124. In D. E. G. Briggs (ed.), Evolving form and function: fossils and development. Proceedings of a symposium honoring Adolf Seilacher for his contributions to paleontology, in celebration of his 80th birthday. Peabody Museum of Natural History, New Haven, Connecticut.

BENGTSON, S. AND D. COLLINS. 2009. Burgess Shale Chancelloriids – A Prickly Problem. International Conference on the Cambrian Explosion (Walcott 2009), Banff.

BENGTSON, S. AND X. HOU. 2001. The integument of Cambrian chancelloriids. Acta Palaeontologica Polonica, 46: 1-22.

BENGTSON, S. AND V. V. MISSARZHEVSKY. 1981. Coeloscleritophora-a major group of enigmatic Cambrian metazoans. United States Geological Survey Open-file Report, 81-743: 19-21.

BERESI, M. S. AND J. K. RIGBY. 1994. Sponges and Chancelloriids from the Cambrian of Western Argentina. Journal of Paleontology, 68: 208-217.

BRASIER, M. D. 1984. Microfossils and small shelly fossils from the Lower Cambrian Hyolithes Limestone at Nuneaton, English Midlands. Geological Magazine, 121: 229-253.

BUTTERFIELD, N. J. AND C. J. NICHOLAS. 1996. Burgess Shale-type preservation of both non-mineralizing and “shelly” Cambrian organisms from the Mackenzie Mountains, northwestern Canada. Journal of Paleontology, 70: 893-899.

ELLIOTT, D. K. AND D. L. MARTIN. 1987. Chancelloria, an Enigmatic Fossil from the Bright Angel Shale (Cambrian) of Grand Canyon, Arizona. Journal of the Arizona-Nevada Academy of Science, 21: 67-72.

GORYANSKY, V. Y. 1973. O neobkhodimosti isklucheniya roda Chancelloria Walcott iz tipa gubok. [On the necessity of exclusion of Chancelloria Walcott from the phylum Porifera.] Trudy Institute Geologia; Geofizika Sibirskoye Otdeieniye 49: 34-44. [in Russian].

HOHENSEE, S. R. AND J. H. STITT. 1989. Redeposited Elvinia Zone (Upper Cambrian) trilobites from the Collier Shale, Ouachita Mountains, west-central Arkansas. Journal of Paleontology, 63: 857-879.

JANUSSEN, D. M. STEINER, AND Z. MAOYAN. 2002. New well-preserved scleritomes of Chancelloridae from the Early Cambrian Yuanshan Formation (Chengjiang, China) and the Middle Cambrian Wheeler Shale (Utah, USA) and paleobiological implications. Journal of Paleontology, 76: 596-606.

LANDING, E. 1991. Upper Precambrian through Lower Cambrian of Cape Breton Island: Faunas, Paleoenvironments, and Stratigraphic Revision. Journal of Paleontology, 65: 570-595.

LAURIE, J. R. 1986. Phosphatic fauna of the Early Cambrian Todd River Dolomite, Amadeus Basin, central Australia. Alcheringa: An Australasian Journal of Palaeontology, 10: 431-454.

MASON, J. F. 1938. Cambrian Faunal Succession in Nevada and California. Journal of Paleontology, 12: 287-294.

PORTER, S. M. 2008. Skeletal microstructure indicates Chancelloriids and Halkieriids are closely related. Palaeontology, 51: 865-879.

RANDELL, R. D., B. S. LIEBERMAN, S. T. HASIOTIS, AND M. C. POPE, 2005. New chancelloriids from the Early Cambrian Sekwi Formation with a comment on chancelloriid affinities. Journal of Paleontology, 79: 987-996.

REID, R. E. H. 1959. Occurrence of Chancelloria Walcott in the Comley Limestone. Geological Magazine, 96: 261-262.

RIGBY, J. K. 1978. Porifera of the Middle Cambrian Wheeler Shale, from the Wheeler Amphitheater, House Range, in Western Utah. Journal of Paleontology, 52: 1325-1345.

SARMIENTO, G. N., D. FERNÁNDEZ REMOLAR, AND M. CEMAL GONCÜOGLU. 2001. Cambrian small shelly fossils from the Çal Tepe Formation, Taurus Mountains, Turkey. Coloquios de paleontología:117.

SKOVSTED, C. B. AND J. S. PEEL. 2007. Small shelly fossils from the argillaceous facies of the Lower Cambrian Forteau Formation of western Newfoundland. Acta Palaeontologica Polonica, 52: 729.

WALCOTT, C. D. 1920. Cambrian geology and paleontology. IV. Middle Cambrian Spongiae. Smithsonian Miscellaneous Collections, 67: 261-364.

WRONA, R. 2004. Cambrian microfossils from glacial erratics of King George Island, Antarctica. Acta Palaeontologica Polonica, 49: 13-56.

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Amiskwia sagittiformis

Reconstruction of Amiskwia sagittiformis.

© Marianne Collins

Taxonomy:

Class: Non applicable
Remarks:

The phylogenetic position of Amiskwia is uncertain. Despite significant objections to its traditional interpretation as a chaetognath (Conway Morris, 1977; Owre and Bayer, 1962), some workers still hold this view (Butterfield, 1990). Nemertine (Owre and Bayer, 1962) and molluscan (Chen and Huang, 2002; Chen et al., 2005) affinities have also been suggested, but not substantiated.

Species name: Amiskwia sagittiformis
Described by: Walcott
Description date: 1911
Etymology:

Amiskwia – from the Cree amiskwi, “beavertail,” a name given to various topographical features in Yoho National Park.

sagittiformis – from the Latin sagitta, “arrow,” and formis, “shape,” in reference to the general outline of the animal.

Type Specimens: Lectotype – UNSM 57644 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: A. sinica (Chen et al., 2002) from the Lower Cambrian Chengjiang deposits, Yunnan, China.

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:

Described by Walcott in 1911, Amiskwia was originally interpreted as an arrow-worm (Walcott, 1911). Originally popular, this interpretation fell into disrepute after further studies (Conway Morris, 1977; Owre and Bayer, 1962), but it has more recently been reconsidered as a possible arrow-worm (Butterfield, 1990).

Description:

Morphology:

Amiskwia is a symmetrical, flattened worm. It bears a pair of lateral fins in addition to a paddle-like tail fin. A pair of small tentacles is situated on the bottom of its head, just in front of its mouth. The trace of a gut and other internal organs are preserved in the fossils.

Abundance:

A. saggitiformis is known from only a couple dozen specimens from the Walcott Quarry, comprising only 0.025% of the specimens counted (Caron and Jackson, 2008).

Maximum Size:
25 mm

Ecology:

Ecological Interpretations:

The presence of fins demonstrates that Amiskwia was well adapted for swimming. Its rarity in the Burgess Shale suggests that it may have spent much of its time well above the sea bed, above the depth at which it could be caught in submarine mudslides.

References:

BUTTERFIELD, N. J. 1990. Organic preservation of non-mineralizing organisms and the Taphonomy of the Burgess Shale. Paleobiology, 16(3): 272-286.

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

CHEN, J.-Y. AND D.-Y. HUANG. 2002. A possible Lower Cambrian chaetognath (arrow worm). Science, 298(5591): 187.

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.

CHEN, L., H. LUO, S. HU, J. YIN, Z. JIANG, Z. WU, F. LI AND A. CHEN. 2002. Early Cambrian Chengjiang fauna in Eastern Yunnan, China. Yunnan Science and Technology Press, Kunming, China, 199 p.

CONWAY MORRIS, S. 1977. A redescription of the Middle Cambrian worm Amiskwia sagittiformis Walcott from the Burgess Shale of British Columbia. Palaontologische Zeitschrift, 51(3): 271-287.

OWRE, H. B. AND F. M. BAYER. 1962. The systematic position of the Middle Cambrian fossil Amiskwia Walcott. Journal of Paleontology, 36(6): 1361-1363.

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

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Herpetogaster collinsi

3D animation of Herpetogaster collinsi.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Unranked clade Cambroernida (stem group ambulacrarians)
Remarks:

Herpetogaster, together with other pedunculate or discoidal fossils such as Eldonia, probably belongs in the stem group to a clade known as the Ambulacraria, represented by both echinoderms and hemichordates (Caron et al., 2010).

Species name: Herpetogaster collinsi
Described by: Caron and Conway Morris
Description date: 2010
Etymology:

Herpetogaster – from the Greek, herpo, “to creep,” and gaster, “stomach.” The name refers to the creeping aspect of the animal and the large stomach.

collinsi – after Desmond Collins, a former curator of palaeontology at the Royal Ontario Museum who led expeditions to the Burgess Shale between 1975-2000.

Type Specimens: Holotype –ROM58051 in the Royal Ontario Museum, Toronto, Canada.
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 and Raymond Quarries on Fossil Ridge. The Collins Quarry on Mount Stephen and Stanley Glacier in Kootenay National Park.

History of Research:

Brief history of research:

Herpetogaster was described in 2010 as a possible member of the ambulacrarians (Caron and Conway Morris, 2010).

Description:

Morphology:

Herpetogaster consists of a main body with a pair of tentacles at the front and a flexible stolon. The body is divided into thirteen segments and coils clockwise when seen dorsally. The tentacles are long and flexible and branch several times. The stomach is the most conspicuous portion of the gut and is often preserved as a highly reflective film, as in Eldonia, a closely related form. The anus is terminal and the mouth is located between the tentacles. The stolon sometimes exceeds the length of the main body, and terminates with a flat disk. This structure was evidently used for anchoring the organism to the seabed, or to other organisms).

Abundance:

This animal is known from 101 specimens. Only 6 come from the Walcott Quarry, where it represents only 0.011% of the specimens counted in the community (Caron and Jackson, 2008); most specimens (68) come from the Raymond Quarry.

Maximum Size:
48 mm

Ecology:

Ecological Interpretations:

Specimens of Herpetogaster were found associated with the sponge Vauxia, suggesting the animal lived on or near the seabed. It is not clear if Herpetogaster was permanently anchored, and whether or not it fed only on particulate matter in the water column, or could hunt small preys using its prehensile tentacles.

References:

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., S. CONWAY MORRIS AND D. SHU. 2010. Tentaculate fossils from the Cambrian of Canada (British Columbia) and China (Yunnan) interpreted as primitive deuterostomes. PLoS ONE, 5(3): e9586.

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