The Burgess Shale

Spartobranchus tenuis

Spartobranchus tenuis, ROMIP 65137

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Enteropneusta
Species name: Spartobranchus tenuis
Remarks:

Spartobranchus is considered a stem-group enteropneust (acorn worm), and shares many similarities with modern acorn worms (Caron et al. 2013; Nanglu et al. 2020). It shows the tripartite body characteristic of this group, consisting of an acorn-shaped proboscis, cylindrical collar, and elongate trunk.

Described by: Walcott
Description date: 1911 (redescribed in 2013)
Etymology:

Spartobranchus — from the Greek “sparte,” for cord or rope (made from the Spartium shrub), and “brankhia” for gills.

tenuis — from the Latin, meaning thin or delicate.

Type Specimens: USNM 108494; Paralectotype – USNM 553526.
Other species:

Burgess Shale and vicinity: None
Other deposits: None

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (around 507 million years old).
Principal localities:

Walcott Quarry

History of Research:

Brief history of research:

Spartobranchus tenuis was first reported by Walcott in 1911 as a priapulid worm named Ottoia tenuis. It was removed from the genus Ottoia by Conway Morris in 1979, and formally redescribed as Spartobranchus tenuis, an acorn worm, by Caron et al. in 2013.

Description:

Morphology:

Spartobanchus is a small worm with a maximum length of 10 cm. The three major components of its body are a proboscis, a collar, and a long, thin section called the trunk. The proboscis is oval or “acorn” shaped, hence the common name of the group: acorn worms. The trunk is a relatively short cylindrical section behind the proboscis. The trunk comprises roughly 90%-95% of the total body length of the animal. The entire body is highly flexible, with the trunk often being recurved onto itself. The anterior part of the trunk is known as the pharynx. Inside the pharynx are presumably collagenous bars known as gill bars, which give the pharynx a strongly striated appearance. The posterior part of the trunk is where the gut is located and is relatively featureless. It is often preserved darkly compared to the rest of the body. At the most posterior end of the trunk is a bulbous structure, which may have served as an anchor for the animal. Roughly one quarter of Spartobranchus specimens are found associated with fibrous, collagenous tubes that the worms produced. These tubes have a corrugated appearance, and can take many forms including: straight tubes, forked, spiral, and circular.

Abundance:

More than 9000 specimens, making it one of the most abundant species in the Walcott Quarry.

Maximum Size:
About 10 cm.

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

Spartobranchus was likely a deposit feeder, as this is the most common mode of life of extant acorn worms that are morphologically highly similar. The presence of a pre-oral ciliary organ on the proboscis also suggests that food particles were transported from the proboscis to the mouth. It may have also been able to filter feed, given the ability of some burrowing hemichordates to draw in food from interstitial water. The tubes Spartobranchus is associated with would have served as a protective dwelling and were secreted by the proboscis. These worms shared this trait with their close relatives, the graptolites. Some large tubes from the Raymond Quarry (located roughly 20m above the Walcott Quarry) appear to also contain undescribed acorn worms similar in morphology to Spartobranchus (Nanglu and Caron 2021). These tubes also possessed polychaetes, suggesting a symbiotic relationship between these worms.

References:

  • CARON, J.-B., CONWAY MORRIS, S., AND C. B. CAMERON. 2013. Tubicolous enteropneusts from the Cambrian period. Nature 495: 503-506
  • CONWAY MORRIS, S. 1979. The Burgess Shale (Middle Cambrian) fauna. Annual Review of Ecology, Evolution, and Systematics 10: 327–349.
  • NANGLU, K. AND J.-B. CARON. 2021. Symbiosis in the Cambrian: enteropneust tubes from the Burgess Shale co-inhabited by commensal polychaetes. Proceedings of the Royal Society B 288 (1951): 20210061.
  • NANGLU, K., J.-B. CARON, AND C. B. CAMERON. 2020. Cambrian tentaculate worms and the origin of the hemichordate body plan. Current Biology 30 (21): 4238-4244
  • WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5): 109-145.
Other Links:

Stephenoscolex argutus

Stephenoscolex argutus (USNM 83936b) – Holotype. Specimen showing the head (top left) followed by the trunk, which is lined by narrow parapodia and setae. Filamentous structures around the body probably represent cyanobacteria. Specimen length = 32 mm. Specimen dry – direct light (left) and wet – direct light (right). Walcott Quarry.

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

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group polychaetes)
Species name: Stephenoscolex argutus
Remarks:

Stephenoscolex bears some resemblance to modern polychaetes but cannot be placed in any extant group (Conway Morris, 1979) suggesting a position as a stem-group polychaete (Eibye-Jacobsen, 2004).

Described by: Conway Morris
Description date: 1979
Etymology:

Stephenoscolex – from the Greek scolex, “worm,” and Mount Stephen. Mount Stephen (3,199 m) was named after George Stephen (1829 – 1921), first president of the Canadian Pacific Railway.

argutus – from the Latin argutus, “bright,” in recognition of the shininess of the fossils.

Type Specimens: USNM – 83936b in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Paratype –ROM32574 in the Royal Ontario Museum, Toronto, ON, Canada.
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:

Walcott (1911; 1931) included the holotype of this species within Canadia dubia, which Simon Conway Morris, in his 1979 re-examination of Burgess Shale polychaetes, reclassified as Stephenoscolex. Conway Morris found a further partial specimen in the ROMcollections, and further specimens have since been recovered by the ROMbelow the Walcott Quarry. However, this additional material awaits detailed study; since the published description rests on two specimens, it must be treated with caution (Eibye-Jacobsen, 2004).

Description:

Morphology:

The worm has a slim body, around 1 mm wide, reaching around 3 cm in length. Its head bears two pairs of appendages extending from its front and sides. It has around forty further segments, each of which bear simple lateral projections (uniramous) called parapodia. The parapodia each bear around fifteen short and simple setae. Cirri and branchiae are absent.

Abundance:

Stephenoscolex was considered one of the rarest annelids from the Burgess Shale but additional material has now been collected from the Walcott Quarry representing 0.28% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
32 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

There is little that can confidently be stated about the life habit of this animal, but the pattern of spines suggests that it crept or swum over or in the sediment.

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. 1979. Middle Cambrian polychaetes from the Burgess Shale of British Columbia. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 285(1007): 227-274.

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

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

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

Other Links:

None

Selkirkia columbia

3D animation of Selkirkia columbia.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group priapulids)
Species name: Selkirkia columbia
Remarks:

Selkirkia has been compared to the nemathelminth worms (Maas et al., 2007), but most analyses support a relationship with the priapulids at a stem-group level (Harvey et al., 2010; Wills, 1998).

Described by: Walcott
Description date: 1911
Etymology:

Selkirkia – from the Selkirk Mountains, a mountain range in southeastern British Columbia.

columbia – from British Columbia, where the Burgess Shale is located.

Type Specimens: Holotype –USNM57624 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: The genus Selkirkia ranges from the Lower to the Middle Cambrian and is represented by several species, including S. sinica from the Lower Cambrian Chengjiang Biota (Luo et al., 1999; Maas et al., 2007), S. pennsylvanica from the Lower Cambrian Kinzers Formation (Resser and Howell, 1938), Selkirkia sp. cf. and S. spencei from the Middle Cambrian Spence Shale of Utah (Resser, 1939; Conway Morris and Robison, 1986, 1988), and S. willoughbyi from the Middle Cambrian Marjum Formation of Utah (Conway Morris and Robison, 1986).

Age & Localities:

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

Burgess Shale and vicinity: The Walcott, Raymond and Collins Quarries on Fossil Ridge, and smaller localities on Mount Field and Mount Odaray. The Trilobite Beds, the Collins Quarry, the Tulip Beds (S7) and smaller localities on Mount Stephen.

Other deposits: The Middle Cambrian Spence Shale of Utah (Resser, 1939; Conway Morris and Robison, 1986, 1988).

History of Research:

Brief history of research:

Charles Walcott (1908) illustrated a single specimen of a simple tube that he named “Orthotheca major.” He interpreted the fossil as the tube of a polychaete worm, along with another famous species, “O. corrugata,” described by Matthew a decade earlier. O. corrugata is now referred to as Wiwaxia corrugata, which is not the tube of a worm but the scale of an armoured mollusc! The original specimen of “O. major” came from the Trilobite Beds on Mount Stephen, but it was not until the discovery of complete specimens from Fossil Ridge showing soft-bodied worms within the tubes that more details about this animal became available. Walcott (1911) created a new genus name Selkirkia to accommodate the new fossil material. In addition to the type species, S. major, he named two new species, S. gracilis and S. fragilis. In a revision of Walcott’s collections and other fossils discovered by the Geological Survey of Canada, Conway Morris (1977) synonymised Walcott’s three species into one that he called S. columbia, which is still in use today. S. columbia was described as a primitive priapulid worm (Conway Morris, 1977); later studies showed that it belongs to the priapulid stem group (Wills, 1998; Harvey et al., 2010).

Description:

Morphology:

Selkirkia lived in a tube and could reach up to 6 centimetres in length. The body of the worm itself is similar to most priapulids in having a trunk (which remained in the tube) and an anterior mouthpart that could be inverted into the trunk, called a proboscis. The proboscis has different series of spines along its length and is radially symmetrical. Small body extensions called papillae are present along the anterior part of the trunk and probably helped in anchoring the trunk in the tube. The gut is straight and the anus is terminal. The unmineralized tube is slightly tapered, open at both ends, and bears fine transverse lineations.

Abundance:

Selkirkia is the most abundant priapulid in the Walcott Quarry community, representing 2.7% of the entire community (Caron and Jackson, 2008); thousands of specimens are known, mostly isolated tubes.

Maximum Size:
60 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

The well developed proboscis and strong spines suggest a carnivorous feeding habit. Comparisons with modern tube-building priapulids suggest Selkirkia was capable of only limited movement, and spend most of the time buried vertically or at an angle to the sediment-water interface, where they might have “trap fed” on live prey. Empty tubes were often used as a substrate for other organisms to colonize, for example, brachiopods, sponges and primitive echinoderms (see Echmatocrinus).

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. 1977. Fossil priapulid worms. Special Papers in Palaeontology, 20: 1-95.

CONWAY MORRIS, S. AND R. A. ROBISON. 1986. Middle Cambrian priapulids and other soft-bodied fossils from Utah and Spain. The University of Kansas paleontological contributions, 117: 1-22.

CONWAY MORRIS, S. AND R. A. ROBISON. 1988. More soft-bodied animals and algae from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, Paper, 122: 23-48.

HARVEY, T. H. P., X. DONG AND P. C. J. DONOGHUE. 2010. Are palaeoscolecids ancestral ecdysozoans? Evolution & Development, 12(2): 177-200.

LUO, H., S. HU, L. CHEN, S. ZHANG AND Y. TAO. 1999. Early Cambrian Chengjiang fauna from Kunming region, China. Yunnan Science and Technology Press, Kunming, 162 p.

MAAS, A., D. HUANG, J. CHEN, D. WALOSZEK AND A. BRAUN. 2007. Maotianshan-Shale nemathelminths – Morphology, biology, and the phylogeny of Nemathelminthes. Palaeogeography, Palaeoclimatology, Palaeoecology, 254(1-2): 288-306.

RESSER, C. E. AND B. F. HOWELL. 1938. Lower Cambrian Olenellus Zone of the Appalachians. Geological Society of America, Bulletin, 49: 195-248.

RESSER, C. E. 1939. The Spence Shale and its fauna. Smithsonian Miscellaneous Collections, 97(12):1-29.

WALCOTT, C. 1908. Mount Stephen rocks and fossils. Canadian Alpine Journal, 1: 232-248.

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

WILLS, M. A. 1998. Cambrian and Recent disparity: the picture from priapulids. Paleobiology, 24(2): 177-199.

Other Links:

None

Scolecofurca rara

Scolecofurca rara (GSC 45331) – Holotype (part and counterpart). Only known specimen of the species showing the pair tentacles in direct light (anterior to the right). Specimen length = 65 mm. Specimen wet – direct light (top), dry – polarized light (middle and bottom). Raymond Quarry.

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

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group priapulids)
Species name: Scolecofurca rara
Remarks:

Scolecofurca belongs to the priapulid worm stem group (Harvey et al., 2010; Wills, 1998).

Described by: Conway Morris
Description date: 1977
Etymology:

Scolecofurca – from the Greek skolex, meaning “worm,” and the Latin furca, “fork,” in reference to the fork-like anterior of this worm.

rara – from the Latin rarus, “infrequent,” in reference to the rarity of the species.

Type Specimens: Holotype – GSC45331 in the Geological Survey of Canada, Ottawa, Canada.
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 Raymond Quarry on Fossil Ridge.

History of Research:

Brief history of research:

This worm was described by Conway Morris in 1977 as a possible primitive priapulid. Later analyses showed that S. rara belongs to the priapulid stem group (Harvey et al., 2010; Wills, 1998).

Description:

Morphology:

Scolecofurca is known from a single incomplete specimen, which is estimated to have reached nine centimeters in total length. Like other priapulids, the body is divided into a proboscis and a trunk. The proboscis is fringed with small extensions called papillae, and tipped with a pair of conspicuous tentacles giving the appearance of a two-pronged fork. The trunk is annulated and the gut appears to be represented by a simple tube. Contrary to all the other species of priapulids from the Burgess Shale, this form does not have spines or hooks on the proboscis or body.

Abundance:

This species is known from a single specimen.

Maximum Size:
90 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

The general body-shape and presence of a proboscis suggests Scolecofurca was a burrower. The tentacles might have had a sensory function rather than being used for prey manipulation, but the mode of feeding of this species is unknown.

References:

CONWAY MORRIS, S. 1977. Fossil priapulid worms. Special Papers in Palaeontology, 20: 1-95.

HARVEY, T. H. P., X. DONG AND P. C. J. DONOGHUE. 2010. Are palaeoscolecids ancestral ecdysozoans? Evolution & Development, 12(2): 177-200.

WILLS, M. A. 1998. Cambrian and Recent disparity: the picture from priapulids. Paleobiology, 24(2): 177-199.

Other Links:

None

Fieldia lanceolata

Fieldia lanceolata (ROM 32572) – Part (left) and counterpart (right). Complete specimen with anterior section burried vertically, the posterior is to the left on the part. Specimen length (preserved) = 38 mm. Specimen wet – direct light (top row), wet – polarized light (bottom row). Walcott Quarry talus.

© Royal Ontario Museum. Photos: Jean-Bernard Caron

 

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group priapulids)
Species name: Fieldia lanceolata
Remarks:

Fieldia belongs to the priapulid worm stem group (Harvey et al., 2010; Wills, 1998).

Described by: Walcott
Description date: 1912
Etymology:

Fieldia – from Field, the mountain peak (2,643 m) and small town near Fossil Ridge, British Columbia, Canada. The name was given by William Cornelius Van Horne (General Manager of the Canadian Pacific Railway), to honour Cyrus West Field, a promoter of the first telegraph cable across the Atlantic Ocean.

lanceolata – from the Latin lanceolatus, “lance-shaped,” in reference to the shape of the worm.

Type Specimens: Holotype –USNM57717 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:

Walcott (1912) was the first to describe Fieldia, which he mistook for the carapace of a crustacean. He later classified a different specimen with the priapulid Ancalagon (known then as “Ottoia minor” Walcott, 1931). Conway Morris (1977) re-described the genus as a primitive priapulid worm based on new material he had found in the Smithsonian’s collections; later studies showed that it belonged to the priapulid stem group (Harvey et al., 2010; Wills, 1998).

Description:

Morphology:

Fieldia is a cylindrical worm about five centimeters in length, with a spine-covered body (trunk) and a rather small, eversible mouthpart, called a proboscis. The proboscis is lined with small spines at the front and several rows of hooks posteriorly. It is not known if the proboscis could be fully retracted or inverted as in other fossil and Recent priapulid worms. The gut is often preserved with a mud infill, and runs along the centre of the body. The trunk does not have annulations and is divided into an anterior, middle and a posterior part. The mud infill is most conspicuous in the middle part of the trunk.

Abundance:

This species is very rare. Only a single specimen was originally described by Walcott (1912) and about a dozen specimens were studied by Conway Morris (1977).

Maximum Size:
53 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

Fieldia is commonly preserved with mud inside its gut, suggesting that it fed directly on the sea-floor sediments. Its tubular body-shape is well adapted for burrowing; it probably used its spines to pull itself through the mud.

References:

CONWAY MORRIS, S. 1977. Fossil priapulid worms. Special Papers in Palaeontology, 20: 1-95.

HARVEY, T. H. P., X. DONG AND P. C. J. DONOGHUE. 2010. Are palaeoscolecids ancestral ecdysozoans? Evolution & Development, 12(2): 177-200.

WALCOTT, C. 1912. Cambrian Geology and Paleontology II. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57(6): 145-228.

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

WILLS, M. A. 1998. Cambrian and Recent disparity: the picture from priapulids. Paleobiology, 24(2): 177-199.

Other Links:

None

Peronochaeta dubia

Taxonomy:

Peronochaeta dubia (ROM 61133). Complete specimen associated with an indeterminate fossil (top right). Specimen length = 8 mm. Specimen dry – polarized light. Walcott Quarry.

© ROYAL ONTARIO MUSEUM. PHOTO: JEAN-BERNARD CARON

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group polychaete)
Species name: Peronochaeta dubia
Remarks:

Peronochaetabears some resemblance to modern polychaetes but it cannot be placed in any extant group (Conway Morris, 1979) suggesting a position as a stem-group polychaete (Eibye-Jacobsen, 2004).

Described by: Walcott
Description date: 1911
Etymology:

Peronochaeta – from the Greek perone, “needle,” and khait, “long hair,” in reference to its bristles.

dubia – from the Latin dubius, “uncertain,” presumably reflecting Walcott’s uncertainty regarding his original classification of this worm as Canadia.

Type Specimens: Lectotype – UNSM 83936a; paralectotype – UNSM 83936d, 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 annelid worm was originally described as a species of Canadia by Charles Walcott (1911). When Simon Conway Morris (1979) re-examined these fossils, he concluded that the differences between this species and Canadia were too great to be contained within a single genus, and erected the new genus Peronochaeta.

Description:

Morphology:

This worm reached one to two centimetres in length, but its body is only 1 mm wide, or 2 mm wide, if its spines (setae) are included. The worm has approximately 25 segments, each bearing a pair of short lateral projections called parapodia. These are simple (uniramous) and the setae are short. A straight gut runs the length of its body. A pair of tentacles appears to be preserved on the sides of the head, although due to the small size and poor preservation, it is difficult to assert this with confidence.

Abundance:

Peronochaeta was considered one of the rarest annelids from the Burgess Shale but additional material has now been collected from the Walcott Quarry representing 0.03% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
20 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

On account of the scarcity of material, the ecology of this animal is difficult to ascertain. It may have been a scavenger, and its setae probably assisted in locomotion and perhaps even in burrowing.

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. 1979. Middle Cambrian Polychaetes from the Burgess Shale of British Columbia. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 285(1007): 227-274.

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

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

Other Links:

None

Ottoia prolifica

3D animation of Ottoia prolifica.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group priapulids)
Species name: Ottoia prolifica
Remarks:

Ottoia has been compared to the nemathelminth worms (Maas et al., 2007), but most analyses support a relationship with the priapulids at a stem-group level (Harvey et al., 2010; Wills, 1998).

Described by: Walcott
Description date: 1911
Etymology:

Ottoia – from Otto Pass (2,106 m), a few kilometres north-west of the Burgess Shale. The pass was named after Otto Klotz, an astronomer working for the Department of the Interior along the Canadian Pacific Railroad (read about Otto Klotz in the section “First Discoveries”)

prolifica – from the Latin proles, “offspring,” and ferax, “rich, fruitful,” in reference to the great number of specimens discovered.

Type Specimens: Lectotype –USNM57619 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none

Other deposits: Ottoia sp. from the Lower Cambrian Pioche Shale, Nevada (Lieberman, 2003).

Age & Localities:

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

Burgess Shale and vicinity: The Walcott and Raymond Quarries on Fossil Ridge, the Collins Quarry, the Tulip Beds (S7) and smaller localities on Mount Stephen. Smaller localities on Mount Field, Mount Odaray and Monarch Cirque.

Other deposits: The same species also occurs in the Middle Cambrian Spence Shale and Marjum Formations, Utah (Conway Morris and Robison, 1986).

History of Research:

Brief history of research:

Charles Walcott (1911) first described Ottoia as a tentative member of the now-dismantled grouping of worms called the Gephyrea, which included the priapulids as well as the sipunculans and echiurans. He emphasized a comparison with the sipunculans, leading some subsequent authors to consider it as a member of this phylum; others, however, suggested affinities with the parasitic acanthocephalans, or the priapulids (Banta and Rice, 1970). A re-analysis of the fossil material itself was not conducted until the 1970s, with work by Banta and Rice (1970) and Conway Morris (1977) supporting a relationship with the priapulids, which was later demonstrated to be at a stem-group level (Wills, 1998). Other work has focussed on the ecology of the Burgess Shale representatives (Bruton, 2001; Vannier, 2009; Vannier et al., 2010).

Description:

Morphology:

Ottoia is a priapulid worm with a tooth-lined mouthpart (proboscis) that could be inverted into the trunk; a short posterior tail extension could also be inverted. Ottoia reached 15 cm in length; the smallest specimens – presumably juveniles, but identical to adults – were just 1 cm long. The proboscis was adorned with 28 rows of hooks interspersed with a variety of spines. The worms are usually found curved into a U-shape, with their sediment-filled guts often visible running down the centre of the organism. The trunk was annulated, and bore two sets of four hooks arranged in a ring towards the rear end; these are the only traces of bilateral symmetry, with a radial symmetry superimposed on the organism. Ottoiaperiodically shed its cuticle to allow growth.

Abundance:

Ottoia is one of the more abundant Burgess Shale organisms, accounting for over 80% of the Walcott Quarry priapulids (Conway Morris, 1977) and over 1.3% of the entire Walcott Quarry community (Caron and Jackson, 2008); thousands of specimens are known.

Maximum Size:
150 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

Specimens of Haplophrentis carinatus preserved in the gut indicate that this hyolith was a staple of the Ottoia diet (Conway Morris, 1977). One fossil slab also shows nine specimens feeding on a recently-dead Sidneyia carcass (Bruton, 2001).

References:

BANTA, W. C. AND M. E. RICE. 1970. A restudy of the Middle Cambrian Burgess Shale fossil worm, Ottoia prolifica. International Symposium on the Biology of the Sipuncula and Echiura 2, Kotor: 79-90.

BRUTON, D. L. 2001. A death assemblage of priapulid worms from the Middle Cambrian Burgess Shale. Lethaia, 34(2):163-167.

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. 1977. Fossil priapulid worms. Special Papers in Palaeontology, 20: 1-95.

CONWAY MORRIS, S. AND J. S. PEEL. 2009. New Palaeoscolecidan Worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale. Acta Palaeontologica Polonica, 55(1): 141-156.

HARVEY, T. H. P., X. DONG AND P. C. J. DONOGHUE. 2010. Are palaeoscolecids ancestral ecdysozoans? Evolution & Development, 12(2): 177-200.

MAAS, A., D. HUANG, J. CHEN, D. WALOSZEK AND A. BRAUN. 2007. Maotianshan-Shale nemathelminths – Morphology, biology, and the phylogeny of Nemathelminthes. Palaeogeography, Palaeoclimatology, Palaeoecology, 254(1-2): 288-306.

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

Other Links:

http://paleobiology.si.edu/burgess/ottoia.html

Oesia disjuncta

Oesia disjuncta (USNM 57630) – Lectotype, part and counterpart. Complete specimen. Specimen length = 85 mm. Specimen wet – direct light (top row), wet – polarized light (bottom row). Walcott Quarry.

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

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Enteropneusta
Species name: Oesia disjuncta
Remarks:

Oesia is considered a stem-group enteropneust (acorn worms) and has the characteristic three-part anatomy of the group, consisting of a proboscis, collar and trunk (Nanglu et al. 2016; Nanglu et al. 2020).

Described by: Walcott
Description date: 1911
Etymology:

Oesia — from Lake Oesa, a small lake located a few kilometres southeast of the Burgess Shale.

disjuncta — from the Latin prefix dis, to signify a negation, and junctus, “joined.” The name is probably in reference to the crooked or bent shape of the early discovered specimens of Oesia.

Type Specimens: Lectotype –USNM57630 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, Wuliuan stage, Burgess Shale Formation (around 507 million years old).
Principal localities:

Marble Canyon (Kootenay National Park), the Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Walcott (1911) described this species as a polychaete worm, but this view was challenged by Lohman (1920) who suggested a tunicate (chordate) affinity instead. Conway Morris (1979) rejected both interpretations, and this animal was later regarded as a problematic organism of unknown affinity (Briggs and Conway Morris, 1986). Szaniawski suggested a chaetognath affinity in 2005, which was argued against by Conway Morris in 2009. Nanglu et al. formally redescribed Oesia as an enteropneust (hemichordate) in 2016.

Description:

Morphology:

Oesia ranged in length from 2.4mm – 120mm, with an average length of 53mm. The anteriormost region is an oval or “acorn” shaped proboscis, which gives the acorn worms (Enteropneusta) their common name. The proboscis is frequently preserved with a darker, more dense carbon content than surrounding tissues, suggesting that it was highly muscular as the proboscis is in modern acorn worms. Behind the proboscis was a short cylindrical region called the collar, which enclosed the mouth. Behind the collar was a long, cylindrical region called the trunk, which maintain a roughly even width throughout. Unlike in modern acorn worms or its contemporary Spartobranchus, the trunk of Oesia was not divided into a pharynx and a posterior trunk. Instead, the collagenous gill bars that define the pharynx continue throughout the entire length. This gives Oesia a relatively inflexible appearance. At the posterior end of Oesia was a bilobed shaped attachment structure. The interior of this structure also preserved highly concentrated carbon relative to surrounding tissue which, along with its shape, suggests that this appendage was for grasping. Oesia is often found inside another fossil previously described as the alga Margaretia dorus, but which is now recognized as the secreted dwelling of Oesia, which was likely used for feeding as a pre-filtration device. This tube was typically twice the width of Oesia and could reach nearly 50 cm in total length. The tube contained a series of spirally arranged pores and could bifurcate into branches as many as 5 or 6 times (although 1 or 2 bifurcations is more common).

Abundance:

Oesia is relatively rare at the Walcott Quarry, but is abundant at Marble Canyon where it represents the third most abundant species with 3,373 specimens (Nanglu et al. 2020).

Maximum Size:
120 mm.

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

Oesia was likely a suspension feeder, owing to its extended pharynx laden will gill bars. These gill bars would have been covered in small hair-like structures called cilia which would move to create a flow of water towards the mouth and into the body. Excess water would then be expelled through pores, while food was passed through the gut. The large tubes of Oesia would have projected from the muddy seafloor into the water, with the pores allowing for water to move in and out of the tube. This would allow for fresh water for Oesia to feed on and refresh the tube with oxygenated water.

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.
  • CONWAY MORRIS, S. 2009. The Burgess Shale animal Oesia is not a chaetognath: A reply to Szaniawski (2005). Acta Palaeontologica Polonica, 54(1): 175-179.
  • LOHMANN, H. 1920. Oesia disjuncta Walcott, eine Appendicularie aus dem Kambrium. Mitteilungen aus dem Zoologischen Staatsinstitut und Zoologischen Museum in Hamburg, 38: 69-75.
  • NANGLU, K., CARON, J.-B., CONWAY MORRIS, S.C., AND C. B. CAMERON. 2016. Cambrian suspension-feeding tubicolous hemichordates. BMC Biology 14: 1-9.
  • NANGLU, K., J.-B. CARON, AND C. B. CAMERON. 2020a. Cambrian tentaculate worms and the origin of the hemichordate body plan. Current Biology 30 (21): 4238-4244
  • NANGLU, K., CARON, J.-B. and GAINES, R. R. 2020b. The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia. Paleobiology, 46, 58-81.
  • SZANIAWSKI, H. 2005. Cambrian chaetognaths recognized in Burgess Shale fossils. Acta Palaeontologica Polonica, 50(1): 1-8.
  • WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5): 109-145.
Other Links:

None

Burgessochaeta setigera

Burgessochaeta setigera (ROM 61042) – Part and counterpart. Complete specimen showing gut contents and fecal material expelled from the anus (black strand visible on the counterpart, right images). Specimen length = 26 mm. Specimen wet – direct light (top row), wet – polarized light (bottom row). Walcott Quarry.

© Royal Ontario Museum. Photos: Jean-Bernard Caron

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group polychaetes)
Species name: Burgessochaeta setigera
Remarks:

Burgessochaeta bears some resemblance to modern polychaetes but it cannot be placed in any extant group (Conway Morris, 1979; Eibye-Jacobsen, 2004) suggesting a position as a stem-group polychaete (Budd and Jensen, 2000).

Described by: Walcott
Description date: 1911
Etymology:

Burgessochaeta – from Mount Burgess (2,599 m), a mountain peak in Yoho National Park. Mount Burgess was named in 1886 by Otto Klotz, the Dominion topographical surveyor, after Alexander Burgess, a former Deputy Minister of the Department of the Interior. Also from the Latin chaeta, “bristle”, a common suffix for polychaete worms, reflecting spiny structures along their body.

setigera – from the Latin saetula, “small bristle.”

Type Specimens: Lectotype –USNM57650 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:

First reported by Charles Walcott in 1911 and lumped into the genus Canadia (Walcott, 1911), Burgessochaeta was formally described as a separate genus by Simon Conway Morris in his 1979 treatise on the polychaetes of the Burgess Shale. Because it is rather common, Burgessochaeta has proven useful in calculating the extent of decay in fossil assemblages (Caron and Jackson, 2006).

Description:

Morphology:

This slender worm reached lengths of 1.8-4.9 cm (2.9 cm on average). Its width was constant (around 2 mm), except towards either end, where it tapered off. Its head bore a pair of long, smooth tentacles that reached 6 mm in length. The variation in shape seen among these tentacles suggests that the organism could contract and extend them. Its first segment also bears uniramous parapodia (paired single-branch appendages), while those of the other two dozen are biramous (divided into two). All of its body segments are similar to one another. Its parapodia bear in the range of 11-17 simple setae (usually 15), each about 2 mm in length, and which form a single plane that is inclined steeply with respect to the body. The tips of these setae form unequal forks, with one prong about half the length of the other. The animal had an unarmed eversible proboscis (prominent flexible apparatus capable of being turned inside-out like a tongue) that formed the front portion of its straight gut.

Abundance:

Burgessochaeta is relatively common in the Walcott Quarry representing 0.4% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
49 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

Burgessochaeta probably burrowed or moved along the surface of the mud, using its short parapodia. Its tentacles are thought to have been used to collect food; the presence of sediment in its gut suggests that it might have been a deposit feeder.

References:

BUDD, G. E. AND S. JENSEN. 2000. A critical reappraisal of the fossil record of the bilaterian phyla. Biological Reviews, 75: 253-295.

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.

CONWAY MORRIS, S. 1979. Middle Cambrian polychaetes from the Burgess Shale of British Columbia. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 285(1007): 227-274.

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

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

Other Links:

None

Ancalagon minor

Ancalagon minor (USNM 57646) – Holotype (part and counterpart). Left, plate 22 of Walcott (1911), showing a retouched image of the original specimen (upside down) (figure 5). Right, images of the same specimen showing a dark stain, probably representing decay fluids at the posterior end of the body. Specimen length = 70 mm. Specimen dry – direct light (top), dry – polarized light (middle, bottom). Walcott Quarry.

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

Taxonomy:

Kingdom: Endobenthic
Phylum: Endobenthic
Higher Taxonomic assignment: Unranked clade (stem group priapulids)
Species name: Ancalagon minor
Remarks:

Ancalagon belongs to the priapulid worm stem group (Harvey et al., 2010; Wills, 1998).

Described by: Walcott
Description date: 1911
Etymology:

Ancalagon – from Ancalagon the Black, a dragon in Tolkien’s fantasy writings (The Fellowship of the Ring, 1954; The Silmarillion, 1977), in reference to the worm’s strong rows of hooks.

minor – from the Latin minor, “inferior,” in reference to the small size of the worm.

Type Specimens: Holotype –USNM57646 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:

Walcott (1911, 1931) described and illustrated several specimens of this species as “Ottoia minor.” However, this species was pulled from the genus Ottoia to Ancalagon by Conway Morris (1977) and re-described as a primitive priapulid worm; later studies showed that it belongs to the priapulid stem group (Harvey et al., 2010; Wills, 1998).

Description:

Morphology:

The tubular body of this worm can reach up to 11 centimeters and is divided into a finely annulated trunk and an anterior eversible mouthpart, called a proboscis. The proboscis bears strong hooks at the front, and smaller hooks pointing backwards posteriorly. Fine hair-like setae are present on the trunk. The gut is straight and the anus is terminal.

Abundance:

This species is rare – less than 20 specimens are known.

Maximum Size:
110 mm

Ecology:

Life habits: Endobenthic
Feeding strategies: Endobenthic
Ecological Interpretations:

The tubular body-shape is well adapted for burrowing; Ancalagon probably used its spines to pull itself through the mud. The strong hooks at the front of the proboscis suggest a carnivorous feeding habit.

References:

CONWAY MORRIS, S. 1977. Fossil priapulid worms. Special Papers in Palaeontology, 20: 1-95.

HARVEY, T. H. P., X. DONG AND P. C. J. DONOGHUE. 2010. Are palaeoscolecids ancestral ecdysozoans? Evolution & Development, 12(2): 177-200.

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

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

WILLS, M. A. 1998. Cambrian and Recent disparity: the picture from priapulids. Paleobiology, 24(2): 177-199.

Other Links:

None