The Burgess Shale

Yohoia tenuis

3D animation of Yohoia tenuis.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Unranked clade Megacheira? (stem group arthropods)
Remarks:

Yohoia was originally considered to be a branchiopod crustacean (Walcott, 1912; Simonetta, 1970), but was also described as being closely related to the chelicerates (Briggs and Fortey, 1989; Wills et al., 1998; Cotton and Braddy, 2004). Other analyses suggest that Yohoia belongs in the group of “great appendage” arthropods, the Megacheira, together with LeanchoiliaAlalcomenaeus and Isoxys (Hou and Bergström, 1997; Budd, 2002). The megacheirans have been suggested to either be stem-lineage chelicerates (Chen et al. 2004; Edgecombe, 2010), or stem-lineage euarthropods (Budd, 2002).

Species name: Yohoia tenuis
Described by: Walcott
Description date: 1912
Etymology:

Yohoia – from the Yoho River, Lake, Pass, Glacier, Peak (2,760 m) and Park, British Columbia, Canada. “Yoho” is a Cree word expressing astonishment.

tenuis – from the Latin tenuis, “thin,” referring to its slender body.

Type Specimens: Lectoype –USNM57699 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, Raymond and Collins Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Yohoia was first described by Walcott (1912), who designated the type species Y. tenuis based on six specimens, and a second species, Y. plena, based on one specimen. Additional specimens of Y. tenuis were described by Simonetta (1970), and a major redescription of Yohoia tenuis was then undertaken by Whittington (1974), based on over 400 specimens of this species. Whittington (1974) invalidated Y. plena, upgrading it to its own genus, Plenocaris plena, leaving Y. tenuis as the only species of YohoiaYohoia has since been included in several studies on arthropod phylogeny and evolution (e.g., Briggs and Fortey, 1989; Hou and Bergström, 1997; Wills et al., 1998; Budd, 2002; Chen et al., 2004; Cotton and Braddy, 2004).

Description:

Morphology:

The body of Yohoia consists of a head region encapsulated in a cephalic shield and 14 body segments, ending in a paddle-shaped telson. The dorsal head shield is roughly square and extends over the dorsal and lateral regions of the head. There is a pair of great appendages at the front of the head. Each appendage consists of two long, thin segments that bend like an elbow at their articulation, with four long spines at the tip. Three pairs of long, thin, segmented appendages project from beneath the head shield behind the great appendages.

The body behind the head consists of ten segments with tough plates, or tergites, that extend over the back and down the side of the animal, ending in backward-facing triangular points. The first of these body segments may have an appendage that is segmented and branches into two (biramous), with a segmented walking limb bearing a flap-like extension. The following nine body segments have only simple flap-shaped appendages fringed with short spines or setae. The next three body segments have no appendages, and the telson is a paddle-shaped plate with distal spines.

Abundance:

Over 700 specimens of Yohoia are known from the Walcott Quarry, comprising 1.3% of the specimens counted (Caron and Jackson, 2008) but only few specimens are known from the Raymond and Collins Quarries.

Maximum Size:
23 mm

Ecology:

Ecological Interpretations:

Yohoia is thought to have used its three pairs of cephalic appendages, and possibly the biramous limb on the first body segment, to walk on the sea floor. The animal could also swim by waving the flap-like appendage on the body trunk. The setae on these appendages may have been used for respiration. The pair of frontal appendages were likely used to capture prey or scavenge food particles from the sea floor.

References:

BRIGGS, D. E. G. AND R. A. FORTEY. 1989. The early radiation and relationships of the major arthropod groups. Science, 246: 241-243.

BUDD, G. E. 2002. A palaeontological solution to the arthropod head problem. Nature, 417: 271-275.

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., D. WALOSZEK AND A. MAAS. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia, 37: 3-20.

COTTON, T. J. AND S. J. BRADDY. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences, 94: 169-193.

EDGECOMBE, G. D. 2010. Arthropod phylogeny: An overview from the perspectives of morphology, molecular data and the fossil record. Arthropod Structure and Development, 39: 74-87.

HOU, X. AND J. BERGSTRÖM. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45: 1-116.

SIMONETTA, A. M. 1970. Studies on non trilobite arthropods of the Burgess Shale (Middle Cambrian). Palaeontographia Italica, 66 (New series 36): 35-45.

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

WHITTINGTON, H. B. 1974. Yohoia Walcott and Plenocaris n. gen. arthropods from the Burges

Other Links:

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Vauxia gracilenta

3D animation of Vauxia bellula and other sponges (Choia ridleyiDiagoniella cyathiformisEiffelia globosaHazelia confertaPirania muricata, and Wapkia elongata) and Chancelloria eros a sponge-like form covered of star-shaped spines.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Demospongea (Order: Verongida)
Remarks:

Vauxia was placed within the hexactinellids by Walcott in his 1920 original description but Rigby (1980) transferred the genus and family to the Demospongea. Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Species name: Vauxia gracilenta
Described by: Walcott
Description date: 1920
Etymology:

Vauxia – from Mount Vaux (3,319 m), a mountain Peak in Yoho National Park, British Columbia. The name refers to William Sandys Wright Vaux (1818-1885) an antiquarian at the British Museum.

gracilenta – from the Latin gracilis, “slender,” referring to the delicate structure of the sponge.

Type Specimens: Lectotypes –USNM66515 (V. gracilenta),USNM66508 (V. bellula),USNM66517 (V. densa),USNM66520 (V. venata), in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Holotype –ROM53572 (V. irregulara) in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: V. bellula Walcott, 1920; V. densa Walcott, 1920; V. irregulara Rigby and Collins, 2004; V. venata Walcott, 1920.

Other deposits: none.

Age & Localities:

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

Burgess Shale and vicinity: Vauxia species are known in the Walcott, Raymond and Collins Quarries on Fossil Ridge, the Trilobite Beds, Tulip Beds (S7) and the Collins Quarry on Mount Stephen, and smaller sites on Mount Field and Odaray Mountain. Vauxia is also known from Monarch in Kootenay National Park.

Other deposits: V. bellula Walcott, 1920 from the Middle Cambrian Wheeler and Marjum Formations in Utah (Rigby et al., 2010); V. magna Rigby, 1980 from the Middle Cambrian Spence Shale in Utah (Rigby, 1980).

History of Research:

Brief history of research:

This sponge was originally described by Walcott in 1920. The genus was reviewed by Rigby (1980) and the species redescribed by Rigby (1986) and Rigby and Collins (2004) in their examination of the Burgess Shale sponges.

Description:

Morphology:

Specimens of Vauxia gracilenta can range from simple unbranched forms to more complex branching forms and reach up to 8 cm in height. Each branch is deeply conical and almost cylindrical, with a simple open central cavity (spongocoel) ending in a rounded of flat opening (osculum). The skeleton is double layered with a thin dermal layer and an inner layer (endosomal). The dermal layer has small openings (ostia) and is composed of a dense network of ladder-like fibers supported by radial fibers from the inner layer. The inner layer forms a regular reticulated net-like skeleton of fibers with 4-6 sided polygons which is characteristic of the genus and species. The fibrous elements (spongin) represent tough collagen proteins. There is no evidence of siliceous spicules in the skeleton.

The different species have been identified mostly based on variations of the skeletal elements and the shape of the branches. Some species can reach up to at least 15 cm in height (V. bellulaV. densa).

Abundance:

Vauxia is relatively common in the Raymond Quarry and other sites on Mount Stephen but is rare in the Walcott Quarry where it represents less than 0.05% of the community (Caron and Jackson, 2008).

Maximum Size:
80 mm

Ecology:

Ecological Interpretations:

Vauxia 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. 1980. The new Middle Cambrian sponge Vauxia magna from the Spence Shale of Northern Utah and taxonomic position of the Vauxiidae. Journal of Paleontology, 54(1): 234-240.

RIGBY, J. K. 1986. Sponges of the Burgess Shale (Middle Cambrian), British Columbia. Palaeontographica Canadiana, 2: 1-105 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.

RIGBY, J. K., S. B. CHURCH AND N. K. ANDERSON. 2010. Middle Cambrian Sponges from the Drum Mountains and House Range in Western Utah. Journal of Paleontology, 84: 66-78.

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

Other Links:

None

Sidneyia inexpectans

3D animation of Sidneyia inexpectans.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Unranked clade (stem group arthropods)
Remarks:

Sidneyia is usually considered to be closely related to the chelicerates, but its exact position relative to this group remains unclear (Budd and Telford, 2009). Sidneyia has been variously placed as the sister group to the chelicerates (Hou and Bergström, 1997), close to the crown on the chelicerate stem lineage (Bruton, 1981; Edgecombe and Ramsköld, 1999; Hendricks and Lieberman, 2008), or basal in the chelicerate stem lineage (Briggs and Fortey, 1989; Wills et al., 1998; Cotton and Braddy, 2004).

Species name: Sidneyia inexpectans
Described by: Walcott
Description date: 1911
Etymology:

Sidneyia – after Walcott’s son Sidney, who discovered the first specimen in August of 1910.

inexpectans – from the Latin inexpectans, “unexpected,” since Walcott did not expect to find such a fossil in strata older than the Ordovician.

Type Specimens: Lectotype –USNM57487 (S. inexpectans) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: A single specimen from the Chengjiang Fauna in China was used to describe a second species, Sidneyia sinica (Zhang et al. 2002), however this was later shown to be incorrectly attributed to Sidneyia (Briggs et al. 2008).

Age & Localities:

Period:
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, Mount Field and Mount Stephen – Tulip Beds (S7) and other smaller localities – Odaray Mountain and Stanley Glacier.

Other deposits: Sidneyia has been described from the Wheeler Formation (Briggs and Robison, 1984) and the Spence Shale (Briggs et al. 2008) in Utah, and the Kinzers Formation in Pennsylvania (Resser and Howell, 1938).

History of Research:

Brief history of research:

Sidneyia was the first fossil to be described by Walcott (1911) from the Burgess Shale. Further details were added by Walcott the following year (Walcott, 1912), and Strømer (1944) and Simonetta (1963) made minor revisions to Walcott’s reconstruction. A large appendage found in isolation was originally suggested to be the large frontal appendage of Sidneyia (Walcott, 1911), but this was later found to belong to the anomalocaridid Laggania (Whittington and Briggs, 1985). A major study by Bruton (1981) redescribed the species based on the hundreds of available specimens.

Description:

Morphology:

Sidneyia has a short, wide head shield that is convexly domed and roughly square. The two front lateral corners are notched to allow an antenna and a stalked eye to protrude. Other than the pair of antennae, which are long and thin with at least 20 segments, there are no cephalic appendages. The hemispherical and highly reflective eyes are above and posterior to the antennae.

The thorax of Sidneyia has nine wide, thin body segments that widen from the first to the fourth segment and then get progressively narrower posteriorly. The first four thoracic segments bear appendages with a large, spiny basal segment (the coxa) and 8 thinner segments, ending in a sharp claw. The next five thoracic appendages have a similar appendage but also have flap-like filaments in association with the limbs.

The abdomen consists of three circular rings that are much narrower than the thorax, with a terminal, triangular telson. The last segment of the abdomen has a pair of wide flaps that articulate with the telson to form a tail fan. A trace of the straight gut can be seen in some specimens extending from the anterior mouth to the anus on the telson, and pieces of broken trilobites are sometimes preserved in the gut.

Abundance:

Sidneyia is a relatively common arthropod in the Walcott Quarry, comprising 0.3% of the specimens counted (Caron and Jackson, 2008). Hundreds of specimens have been collected from the Walcott Quarry (Bruton, 1981) and in other nearby localities.

Maximum Size:
160 mm

Ecology:

Ecological Interpretations:

Sidneyia walked and swam above the sea floor. Its anterior four thoracic appendages were used for walking, and the spiny basal coxa would crush food items and move them towards the mouth. The posterior five thoracic appendages were used for swimming, with the flap-like filaments undulating through the water column to create propulsion. These filaments were also likely used for breathing, like gills.

The predatory nature of Sidneyia is indicated by its spiny coxa used to masticate food, and the presence of crushed fossil debris in its gut. Sidneyia would have walked or swam above the sea floor, using its eyes and antennae to seek out prey, which it would capture and crush with its anterior appendages.

References:

BRIGGS, D. E. G. AND R. A. FORTEY. 1989. The early radiation and relationships of the major arthropod groups. Science, 246: 241-243.

BRIGGS, D. E. G. AND R. A. ROBISON. 1984. Exceptionally preserved non-trilobite arthropods and Anomalocaris from the Middle Cambrian of Utah. The University of Kansas Paleontological Contributions, 111: 1-24.

BRIGGS, D. E. G., B. S. LIEBERMAN, J. R. HENDRICKS, S. L. HALGEDAHL AND R. D. JARRARD. 2008. Middle Cambrian arthropods from Utah. Journal of Paleontology, 82(2): 238-254.

BRUTON, D. L. 1981. The arthropod Sidneyia inexpectans, Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London B, 295: 619-653.

BUDD, G. E. AND M. J. TELFORD. 2009. The origin and evolution of arthropods. Nature, 457(7231): 812-817.

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., R. GAINES, G. MANGANO, M. STRENG, AND A. DALEY. 2010. A new Burgess Shale-type assemblage from the “thin” Stephen Formation of the Southern Canadian Rockies. Geology, 38: 811-814.

COTTON, T. J. AND S. J. BRADDY. 2004. The phylogeny of arachnomorph arthropods and the origin of the Chelicerata. Transactions of the Royal Society of Edinburgh: Earth Sciences, 94: 169-193.

EDGECOMBE, G. D. AND L. RAMSKÖLD. 1999. Relationships of Cambrian Arachnata and the systematic position of Trilobita. Jounral of Paleontology, 73: 263-287.

HENDRICKS , J. R. AND B. S. LIEBERMAN. 2008. Phylogenetic insights into the Cambrian radiation of arachnomorph arthropods. Journal of Paleontology, 82: 585-594.

HOU, X. AND J. BERGSTRÖM. 1997. Arthropods of the Lower Cambrian Chengjiang fauna, southwest China. Fossils and Strata, 45: 1-116.

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

SIMONETTA, A. M. 1963. Osservazioni sugli artropodi non trilobiti della Burgess Shale (Cambriano medio). II. Contributo: I Generai Sidneyia ed Amiella Walcott 1911. Monitore Zoologico Italiano, 70: 97-108.

STØMER, L. 1944. On the relationships and phylogeny of fossil and recent Arachnomorpha. Norsk Videnskaps-Akademi Skrifter I. Matematisk-Naturvidenskaplig Klasse, 5: 1-158.

WALCOTT, C. D. 1911. Middle Cambrian Merostomata. Cambrian geology and paleontology II. Smithsonian Miscellaneous Collections, 57: 17-40.

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

WHITTINGTON, H. B. AND D. E. G. BRIGGS. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British-Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 309: 569-609.

WILLS, M. A., D. E. G. BRIGGS, R. A. FORTEY, M. WILKINSON AND P. H. A. SNEATH. 1998. An arthropod phylogeny based on fossil and recent taxa, pp. 33-105. In G. D. Edgecombe (ed.), Arthropod fossils and phylogeny. Columbia University Press, New York.

ZHU, X., H. JIAN AND S. DEGAN. 2002. New occurrence of the Burgess Shale arthropod Sidneyia in the Early Cambrian Chengjiang Lagerstätte (South China), and revision of the arthropod Urokodia. Alcheringa: An Australasian Journal of Palaeontology, 26: 1-18.

Other Links:

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

Selkirkia columbia

3D animation of Selkirkia columbia.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Unranked clade (stem group priapulids)
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).

Species name: Selkirkia columbia
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:

Period:
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:

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

Isoxys acutangulus

3D animation of Isoxys carinatus.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Unranked clade (stem group arthropods)
Remarks:

The affinity of Isoxys is uncertain because for a long time it was known only from empty carapaces. Recent descriptions of soft parts show that the frontal appendage is similar to that of some megacheiran, or “great appendage,” taxa such as Leanchoilia, Alalcomenaeus, and Yohoia (Vannier et al., 2009; García-Bellido et al., 2009a). The affinity of Megacheira as a whole is uncertain, but it has been suggested that they either sit within the stem-lineage to the euarthropods (Budd, 2002) or they are stem-lineage chelicerates (Chen et al., 2004; Edgecombe, 2010).

Species name: Isoxys acutangulus
Described by: Walcott
Description date: 1908
Etymology:

Isoxys – from the Greek isos, “equal,” and xystos, “smooth surface”; thus referring to the pair of smooth valves.

acutangulus – from the Latin acutus, “sharp, pointed,” and angulus, “angle”; thus referring to the acute angle of the cardinal spines.

Type Specimens: Type status under review –USNM56521 (I. acutangulus) and Holotype –USNM189170 (I. longissimus) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: I. longissimus from Walcott, Raymond and Collins Quarries on Fossil Ridge.

Other deposits: I. chilhoweanus from the Chilhowee Group, Tennessee, USA; I. auritus, I. paradoxus and I. curvirostratus from the Maotianshan Shale of China; I. bispinatus from the Shuijingtuo Formation, Hubei, China; I. wudingensis from the Guanshan fauna of China; I. communis and I. glaessneri from the Emu Bay Shale of Australia; I. volucris from the Buen Formation, Sirius Passet in Greenland; I. carbonelli from the Sierro Morena of Spain, and I. zhurensis from the Profallotaspis jakutensis Zone of Western Siberia. Undescribed species from Canada; Mount Cap Formation in the Mackenzie Mountains, Northwest Territories and the Eager Formation near Cranbrook. Other undescribed species in the Kaili Formation, Guizhou Province, China and the Kinzers Formation, Pennsylvania, USA. See references in Briggs et al., 2008; García-Bellido et al., 2009a,b; Stein et al., 2010; Vannier and Chen, 2000.

Age & Localities:

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

The Walcott, Raymond and Collins Quarries on Fossil Ridge. Additional localities are known on Mount Field, Mount Stephen – Tulip Beds (S7) and the Trilobite Beds, and near Stanley Glacier.

History of Research:

Brief history of research:

Walcott gave the name Isoxys to specimens from the lower Cambrian Chilhowee Group of Tennessee, USA, in 1890. He then later designated the first species from the Trilobite Beds on Mount Stephen, Anomalocaris? acutangulus (Walcott, 1908), although he placed it erroneously in the genus Anomalocaris. Simonetta and Delle Cave (1975) renamed it Isoxys acutangulus and discovered a second Burgess Shale species, I. longissimus. The original designations were based on carapaces only, making research on the ecology and affinity of Isoxys difficult. Soft parts have recently been described from the Burgess Shale taxa (Vannier et al. 2009, García-Bellido et al. 2009a).

Description:

Morphology:

The most prominent feature of Isoxys is the non-mineralized carapace, which ranged in length from 1 cm to almost 4 cm, and covered most of the body. It was folded to give two equal hemispherical valves, and had pronounced spines at the front and back. A pair of bulbous, spherical eyes protrudes forward and laterally from under the carapace. They are attached to the head by very short stalks. A pair of frontal appendages that are segmented and non-branching (uniramous) is adjacent to the eyes. The flexible appendages are curved with a serrated outline and five segments in total, including a basal part, three segments with stout outgrowths, and a pointed terminal segment.

The trunk of the body has 13 pairs of evenly spaced appendages that are segmented and branch into two (biramous), with slender, unsegmented walking limbs and large, paddle-like flaps fringed with long setae. The telson has a pair of lateral flaps. A cylindrical gut passes from the head to the ventral terminus of the telson, and is lined by paired, lobate gut glands. I. longissimus is distinguished from I. acutangulus by the presence of extremely long spines and an elongated body shape.

Abundance:

Isoxys is known from hundreds of specimens collected on Fossil Ridge. In the Walcott Quarry, Isoxys acutangulus is relatively common and represents about 0.35% of the community whereas Isoxys longissimus is extremely rare (Caron and Jackson, 2008).

Maximum Size:
40 mm

Ecology:

Ecological Interpretations:

The streamlined body, thin carapace, and the presence of large paddle-shaped flaps in the appendages all suggest that Isoxys was a free-swimming animal. The spines and wide telson would have been use for steering and stability in the water column. A predatory lifestyle is indicated by the large eyes, frontal appendage, and gut glands. Isoxys would have swum just above the sea floor, seeking out prey in the water column and at the sediment-water interface.

References:

BRIGGS, D. E. G., B. S. LIEBERMAN, J. R. HENDRICK, S. L. HALGEDAHL AND R. D. JARRARD. 2008. Middle Cambrian arthropods from Utah. Journal of Paleontology, 82: 238-254.

BUDD, G. E. 2002. A palaeontological solution to the arthropod head problem. Nature, 417: 271-275.

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., D. WALOSZEK AND A. MAAS. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia, 37: 3-20.

EDGECOMBE, G. D. 2010. Arthropod phylogeny: An overview from the perspectives of morphology, molecular data and the fossil record. Arthropod Structure & Development, 39: 74-87.

GARCÍA-BELLIDO, D. C., J. VANNIER AND D. COLLINS. 2009a. Soft-part preservation in two species of the arthropod Isoxys from the middle Cambrian Burgess Shale of British Columbia, Canada. Acta Palaeontologica Polonica, 54: 699-712.

GARCÍA-BELLIDO, D. C., J. R. PATERSON, G. D. EDGECOMBE, J. B. JAGO, J. G. GEHLING AND M. S. Y. LEE. 2009b. The bivavled arthropods Isoxys and Tuzoia with soft-part preservation from the lower Cambrian Emu Bay Shale Lagerstätte (Kangaroo Island, Australia). Palaeontology, 52: 1221-1241.

SIMONETTA, A.M. AND L. DELLE CAVE. 1975. The Cambrian non trilobite arthropods from the Burgess Shale of British Columbia. A study of their comparative morphology, taxonomy and evolutionary significance. Palaeontographia Italica, 69: 1-37.

STEIN, M., J. S. PEEL, D. J. SIVETER AND M. WILLIAMS. 2010. Isoxys (Arthropoda) with preserved soft anatomy from the Sirius Passet Lagerstätte, lower Cambrian of North Greenland. 2010. Lethaia, 43: 258-265.

VANNIER, J. AND J.-Y. CHEN. 2000. The Early Cambrian colonization of pelagic niches exemplified by Isoxys (Arthropoda). Lethaia, 35: 107-120.

VANNIER, J., D. C. GARCÍA-BELLIDO, S. X. HU AND A. L. CHEN. 2009. Arthropod visual predators in the early pelagic ecosystem: evidence from the Burgess Shale and Chengjiang biotas. Proceedings of the Royal Society of London Series B, 276: 2567-2574.

WALCOTT, C. D. 1890. The fauna of the Lower Cambrian or Olenellus Zone. Reports of the U.S. Geological Survey, 10: 509-763.

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

WILLIAM, M., D. J. SIVETER AND J. S. PEEL. 1996. Isoxys (Arthropoda) from the early Cambrian Sirius Passet Lagerstätte, North Greenland. Journal of Paleontology, 70: 947-954.

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Hurdia victoria

3D animation of Hurdia victoria.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Dinocarida (Order: Radiodonta, stem group arthropods)
Remarks:

Hurdia is an anomalocaridid, and is usually considered to represent either a basal stem-lineage euarthropod (e.g. Daley et al., 2009), a member of the crown-group arthropods (e.g. Chen et al., 2004), or a sister group to the arthropods (Hou et al., 2006).

Species name: Hurdia victoria
Described by: Walcott
Description date: 1912
Etymology:

Hurdia – from Mount Hurd (2,993 m), a mountain northeast of the now defunct Leanchoil railway station on the Canadian Pacific Railway in Yoho National Park. The peak was named by Tom Wilson for Major M. F. Hurd, a CPR survey engineer who explored the Rocky Mountain passes starting in the 1870s.

victoria – unspecified; perhaps from Mount Victoria (3,464 m) on the border of Yoho and Banff National Parks, named by Norman Collie in 1897 to honour Queen Victoria.

Type Specimens: Lectotypes –USNM57718 (H. victoria) andUSNM57721 (H. triangulata) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Hurdia triangulata.

Other deposits: Potentially other species are represented in Utah (Wheeler Formation) (Briggs et al., 2008), the Jince Formation in the Czech Republic (Chlupáč and Kordule 2002) and the Shuijingtuo Formation in Hubei Province, China (Cui and Huo, 1990) and possibly Nevada (Lieberman, 2003).

Age & Localities:

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

The Walcott, Raymond and Collins Quarries on Fossil Ridge. Also known from other localities on Mount Field, Mount Stephen – Tulip Beds (S7) – and near Stanley Glacier.

History of Research:

Brief history of research:

Hurdia is a relative newcomer to the anomalocaridids. Although isolated parts of its body were first identified in the early 1900s, no affinity could be determined until the description of whole body specimens by Daley et al. in 2009. Hurdia victoria was the name originally given to an isolated triangular carapace that Walcott (1912) suggested belonged to an unknown arthropod. Proboscicaris, another isolated carapace, was originally described as a phyllopod arthropod (Rolfe, 1962). Hurdia’s frontal appendages were first described by Walcott (1911a) as the feeding limbs of Sidneyia, but were later removed from this genus and referred to as “Appendage F” with unknown affinity (Briggs, 1979).

Like other anomalocaridids, the mouth parts were first described as the jellyfish Peytoia nathorsti (Walcott, 1911b). When Whittington and Briggs (1985) discovered the first whole body specimens of Anomalocaris, the mouth part identity of Peytoia was recognized and “Appendage F” was determined to be the frontal appendage of Anomalocaris nathorsti (later renamed Laggania cambria by Collins (1996). When describing Anomalocaris, Whittington and Briggs (1985) also figured a mouth apparatus with extra rows of teeth.

After two decades of collecting at the Burgess Shale, Desmond Collins from the Royal Ontario Museum (ROM) discovered that this extra-spiny mouth part actually belonged to a third type of anomalocaridid, which also had an “Appendage F” pair and a frontal carapace structure consisting of one Hurdia carapace and two Proboscicaris carapaces (Daley et al., 2009). This is the Hurdia animal. ROM specimens of “Appendage F” showed that it has three distinct morphologies, two of which belongs to the Hurdia animal (known from two species, victoria and triangulata) and one to Laggania cambria.

Description:

Morphology:

Hurdia has a bilaterally symmetrical body that is broadly divisible into two sections of equal lengths. The anterior region is a complex of non-mineralized carapaces consisting of one dorsal triangular H-element (previously called Hurdia) and two lateral subrectangular P-elements (or Proboscicaris). This complex is hollow and open ventrally. It attaches near the anterior margin of the head and protrudes forward. The surfaces of the H- and P-elements are covered in a distinctive polygonal pattern similar to that seen on Tuzoia carapaces. A pair of oval eyes on short stalks protrudes upwards through dorsal-lateral notches in the overlapping posterior corners of the H- and P-elements.

Mouth parts are on the ventral surface of the head, and consist of a circlet of 32 tapering and overlapping plates, 4 large and 28 small, with spines lining the square inner opening. Within the central opening are up to five inner rows of toothed plates. A pair of appendages flanks the mouth part, each with nine thin segments with short dorsal spines and seven elongated ventral spines. The posterior half of the body consists of a series of seven to nine reversely imbricated lateral lobes that extend ventrally into triangular flaps. Dorsal surfaces of the lateral lobes are covered in a series of elongated blades interpreted to be gill structures. The body terminates abruptly in two rounded lobes, and lacks a tailfan. Complete specimens are up to 20 cm in length, although disarticulated fragments may suggest a larger body size up to 50 cm long. Hurdia triangulata differs from Hurdia victoria by having a wider and shorter H-element.

Abundance:

Over 700 specimens of Hurdia have been identified, most of which are disarticulated. Hurdia is found in all Burgess Shale quarries on Fossil Ridge, and is particularly abundant in Raymond Quarry, where it makes up almost 1% of the community (240 specimens). A total of 7 complete body specimens exist.

Maximum Size:
500 mm

Ecology:

Ecological Interpretations:

Hurdia was likely nektonic, since there are no trunk limbs for walking, and the numerous gills suggest an active swimming lifestyle. The animal propelled itself through the water column by waving its lateral lobes and gills. The large eyes, prominent appendages and spiny mouth parts suggest that Hurdia actively sought out moving prey items. Although the function of the frontal carapace remains unknown, it may have played a role in prey capture. If Hurdia were swimming just above the sea floor, it could have used the tip of its frontal carapace to stir up sediment and dislodge prey items, which would then be trapped beneath its frontal carapace. Prey items were funneled towards the mouth by a sweeping motion of the long ventral blades of the frontal appendages, which formed a rigid net or cage. Like other anomalocaridids, Hurdia likely ingested soft-bodied prey.

References:

BRIGGS, D. E. G. 1979. Anomalocaris, the largest known Cambrian arthropod. Palaeontology, 22: 631-663.

BRIGGS, D. E. G., B. S. LIEBERMAN, J. R. HENDRICK, S. L. HALGEDAHL AND R. D. JARRARD. 2008. Middle Cambrian arthropods from Utah. Journal of Paleontology, 82: 238-254.

CHEN, J. Y., D. WALOSZEK AND A. MAAS. 2004. A new ‘great-appendage’ arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia, 37: 3-20.

CHLUPÁČ, I. AND V. KORDULE. 2002. Arthropods of Burgess Shale type from the Middle Cambrian of Bohemia (Czech Republic). Bulletin of the Czech Geological Survey, 77: 167-182.

COLLINS, D. 1996. The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov) and order Radiodonta (nov). Journal of Paleontology, 70: 280-293.

CUI, Z. AND S. HUO. 1990. New discoveries of Lower Cambrian crustacean fossils from Western Hubei. Acta Palaeontologica Sinica, 29: 321-330.

DALEY, A. C., G. E. BUDD, J. B. CARON, G. D. EDGECOMBE AND D. COLLINS. 2009. The Burgess Shale anomalocaridid Hurdia and its significance for early euarthropod evolution. Science, 323: 1597-1600.

HOU, X., J. BERGSTRÖM AND P. AHLBERG. 1995. Anomalocaris and other large animals in the Lower Cambrian Chengjiang fauna of Southwest China. GFF, 117: 163-183.

HOU, X., J. BERGSTRÖM AND Y. JIE. 2006. Distinguishing anomalocaridids from arthropods and priapulids. Geological Journal, 41: 259-269.

LIEBERMAN, B. S. 2003. A new soft-bodied fauna: The Pioche Formation of Nevada. Journal of Paleontology, 77: 674-690.

ROLFE, W. D. I. 1962. Two new arthropod carapaces from the Burgess Shale (Middle Cambrian) of Canada. Breviora Museum of Comparative Zoology, 60: 1-9.

WALCOTT, C. D. 1911a. Middle Cambrian Merostomata. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections, 57: 17-40.

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

WALCOTT, C. D. 1912. Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata. Smithsonian Miscellaneous Collections, 57: 145-228.

WHITTINGTON, H. B. AND D. E. G. BRIGGS. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British-Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 309: 569-609.

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Hazelia palmata

3D animation of Hazelia conferta and other sponges (Choia ridleyi, Diagoniella cyathiformis, Eiffelia globosa, Pirania muricata, 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:

Class: Demospongea (Order: Monaxonida)
Remarks:

Hazelia is considered a primitive demosponge, close to Falospongia and Crumillospongia (Rigby, 1986). Demosponges, the same group that are harvested as bath sponges, represent the largest class of sponges today.

Species name: Hazelia palmata
Described by: Walcott
Description date: 1920
Etymology:

Hazelia – from Hazel Peak (3,151 m), the older name for Mount Aberdeen, located 4 km SSW of Lake Louise in Banff National Park, Alberta. Mount Aberdeen was named in honor of Lord Gordon in 1897, the Marquis of Aberdeen and the Governor General of Canada from 1893 to 1898.

palmata – from the Latin palm, “palm of the hand,” referring to the broad cup-shape of this sponge and its resemblance to a cupped hand.

Type Specimens: Lectotypes – USNM 66463 (H. palmata – type species), 66465 (H. delicatula), USNM 66505 (H. dignata), USNM 66473 (H. grandis), USNM 66474 (H. nodulifera), USNM 66472 (H. obscura); Holotypes – USNM 66476 (H. conferta), USNM 66779 (H. crateria), USNM 66475 (H. luteria) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. Holotype –ROM53573 (H. lobata) in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: H. conferta Walcott, 1920, H. crateria Rigby, 1986, H. delicatula Walcott, 1920, H. dignata Walcott, 1920, H. grandis Walcott, 1920, H. lobata Rigby and Collins, 2004, H. luteria Rigby, 1986, H. nodulifera Walcott, 1920, H. obscura Walcott, 1920. Most species known from the Walcott Quarry (See Rigby, 1986 and Rigby and Collins, 2004).

Other deposits: H. walcotti (Resser and Howell, 1938) from the Early Cambrian Kinzers Formation of Pennsylvania (See Rigby, 1987).

Age & Localities:

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

Burgess Shale and vicinity: Hazelia is particularly common in the Walcott Quarry and is less common in the Raymond and Collins Quarries on Fossil Ridge. Many species also occur on Mount Stephen at the Trilobite Beds, Tulip Beds (S7), and other smaller localities.

Other deposits: H. palmata Walcott, 1920 from the Middle Cambrian Marjum Formation (Rigby et al., 1997).

History of Research:

Brief history of research:

Walcott described seven species of Hazelia in his 1920 paper on the Burgess Shale sponges. The genus was redescribed by Rigby in 1986 when two new species were added and one excluded from the genus (H. mammillata now referred to Moleculospina mammillata). Rigby and Collins (2004) added another species based on new material collected by the Royal Ontario Museum.

Description:

Morphology:

Species of Hazelia have a large variation in morphology with wide cup-shaped forms (H. palmata, H. crateria, H. luteria), long cone-shaped forms (H. conferta, H. grandis, H. obscura), branched forms (H. delicatula, H. dignata), and nodular to lobate forms (H. lobata, H. nodulifera). While there is this significant variety of overall shapes, the different species of Hazelia have a common microstructure. The walls are thin and composed of small tightly packed simple spicules that form a net-like structure and diverge outwards producing a plumose pattern. The walls are perforated with small canals to allow water flow. The base of each sponge would have had a small attachment structure.

In addition to its open shield-like shape, H. palmata possesses distinct radial tracts of spicules which go beyond the margins of the sponge for at least a couple of millimeters.

Abundance:

Hazelia is very common in the Walcott Quarry and represents 9.5% of the community (Caron and Jackson, 2008).

Maximum Size:
150 mm

Ecology:

Ecological Interpretations:

Hazelia 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. 1987. Early Cambrian sponges from Vermont and Pennsylvania, the only ones described from North America. Journal of Paleontology, 61: 451-461.

RIGBY, J. K. L. F. GUNTHER AND F. GUNTHER. 1997. The first occurrence of the Burgess Shale Demosponge Hazelia palmata Walcott, 1920, in the Cambrian of Utah. Journal of Paleontology, 71: 994-997.

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

Haplophrentis carinatus

3D animation of Haplophrentis carinatus.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Class: Hyolitha (Order: Hyolithida, stem group molluscs)
Remarks:

Haplophrentis belongs to a group of enigmatic cone-shaped to tubular fossils called hyoliths that are known only from the Palaeozoic. Their taxonomic position is uncertain, but the Hyolitha have been regarded as a separate phylum, an extinct Class within Mollusca (Malinky and Yochelson, 2007), or as stem-group molluscs.

Species name: Haplophrentis carinatus
Described by: Matthew
Description date: 1899
Etymology:

Haplophrentis – from the Greek haploos, “single,” and phrentikos, “wall,” in reference to the single wall within the shell.

carinatus – from the Latin carinatus, “keel-shaped,” referring to the morphological similarity to the bottom of a boat.

Type Specimens: Lectotype –ROM8463a in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none

Other deposits: H. reesei Babcock & Robinson, 1988 (type species), from the lower Middle Cambrian Spence Shale and elsewhere in Utah; H.? cf. carinatus from the Middle Cambrian Kaili deposit in China (Chen et al., 2003).

Age & Localities:

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

The Walcott, Raymond and Collins Quarries on Fossil Ridge, the Trilobite Beds on Mount Stephen and Stanley Glacier in Kootenay National Park.

History of Research:

Brief history of research:

Matthew described Hyolithes carinatus from the Trilobite Beds in 1899 based on five incomplete specimens. Babcock and Robison (1988) reviewed the original fossils, along with additional specimens collected by the Royal Ontario Museum from various Burgess Shale localities. They concluded that the species carinatus didn’t belong in Hyolithes, and established a new genus, Haplophrentis, to accommodate it.

Description:

Morphology:

Like all hyoliths, Haplophrentis had a weakly-mineralized skeleton that grew by accretion, consisting of a conical living shell (conch), capped with a clam-like “lid” (operculum), with two slender, curved and rigid structures known as “helens” protruding from the shell’s opening. The function of these helens is still debated, but one possibility was to allow settlement and stabilization on the sea floor. Haplophrentis had a wiggly gut whose preserved contents are similar to the surrounding mud.

H. carinatus usually grew to around 25 mm in length, although some specimens reached as much as 40 mm; the species is distinguished from H. reesei, its cousin from Utah, by the faint grooves on its upper surface, the more pronounced net-like pattern on its “lid” (operculum), and its wider, more broadly-angled living shell (conch).

Haplophrentis can be distinguished from the similar hyolith genus Hyolithes because it bears a longitudinal wall running down the inner surface of the top of its living-shell.

Abundance:

Haplophrentis is relatively common on Fossil Ridge and in the Walcott Quarry in particular, accounting for 0.35% of the community there (Caron and Jackson, 2008).

Maximum Size:
40 mm

Ecology:

Ecological Interpretations:

Haplophrentis probably moved very little; its helens appear unsuited for use in locomotion (See Butterfield and Nicholas, 1996; Martí Mus and Bergström, 2005; Runnegar et al., 1975). Whilst Haplophrentis feeding mode remains somewhat conjectural, it probably consumed small organic particles from the seafloor. Numerous specimens have been found in aggregates or in the gut of the priapulid worm Ottoia prolifica suggesting Haplophrentis was actively preyed upon and ingested (Conway Morris, 1977; Babcock and Robison, 1988).

References:

BABCOCK, L. E. AND R. A. ROBISON. 1988. Taxonomy and paleobiology of some Middle Cambrian Scenella (Cnidaria) and hyolithids (Mollusca) from western North America. University of Kansas Paleontological Contributions, Paper, 121: 1-22.

BUTTERFIELD, N. J. AND C. 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.

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

CHEN, X. Y. ZHAO AND P. WANG. 2003. Preliminary research on hyolithids from the Kaili Biota, Guizhou. Acta Micropalaeontologica Sinica, 20: 296-302.

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

MALINKY, J. M. AND E. L. YOCHELSON. 2007. On the systematic position of the Hyolitha (Kingdom Animalia). Memoir of the Association of Australasian Palaeontologists, 34: 521-536.

MARTÍ MUS, M. AND J. BERGSTRÖM. 2005. The morphology of hyolithids and its functional implications. Palaeontology, 48:1139-1167.

MATTHEW, G. F. 1899. Studies on Cambrian faunas, No. 3. Upper Cambrian fauna of Mount Stephen, British Columbia. The trilobites and worms. Transactions of the Royal Society of Canada, Series 2, 4: 39-66.

RUNNEGAR, B., J. POJETA, N. J. MORRIS, J. D. TAYLOR, M. E. TAYLOR AND G. MCCLUNG. 1975. Biology of the Hyolitha. Lethaia, 8: 181-191.

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Ehmaniella burgessensis

Ehmaniella burgessensis (ROM 60759) – Part and counterpart. Complete specimen. Specimen length = 6 mm. Specimen dry – direct light (left) and coated with ammonium chloride sublimate to show details (middle, right). Walcott Quarry

© Royal Ontario Museum. Photo: Jean-Bernard Caron

Taxonomy:

Class: Trilobita (Order: Ptychopariida)
Remarks:

Trilobites are extinct euarthropods, probably stem lineage representatives of the Mandibulata, which includes crustaceans, myriapods, and hexapods (Scholtz and Edgecombe, 2006).

Species name: Ehmaniella burgessensis
Described by: Rasetti
Description date: 1951
Etymology:

Ehmaniella – modification of Ehmania, a trilobite genus name coined in 1935 by C. E. Resser to honour Philip Ehman (Montana) for his geological assistance.

burgessensis – from the Burgess Shale.

Type Specimens: Holotype (E. burgessensis) – USNM116245; Holotype (E. waptaensis) – USNM116243 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Ehmaniella waptaensis Rasetti, 1951.

Other deposits: other species have been reported from elsewhere in the Cambrian of North America.

Age & Localities:

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

The Walcott, Raymond and Collins Quarries on Fossil Ridge. The Trilobite Beds on Mount Stephen, and smaller localities on Mount Odaray.

History of Research:

Brief history of research:

Walcott illustrated two Burgess Shale trilobite specimens in establishing Ptychoparia permulta in 1918. Resser (1937) saw that the two individuals belonged in different species, but erroneously used Walcott’s clearly designated primary type of permulta to found the new combination Elrathia dubia. Rasetti (1951) declared Resser’s dubia invalid, left the original type of permulta in Elrathia, and employed Walcott’s other specimen as a paratype of a new species (burgessesnsis), which he assigned to Resser’s 1937 genus Ehmaniella. Ehmaniella waptaensis, also described by Rasetti in 1951, is nearly indistinguishable.

Description:

Morphology:

Hard parts: adult dorsal exoskeletons may reach 2.8 cm long. The semicircular cephalon is about one-third the length of the dorsal shield, bordered by a well-defined rounded rim; wide free cheeks often show anastomosing ridges and carry short, sharp genal spines. Strong transverse eye ridges extend to relatively large eyes, which are located at or behind cephalic mid-length. The bluntly rounded glabella tapers evenly forward and bears three pairs of shallow lateral furrows; the pre-glabellar field is short. A thorax of thirteen parallel-sided segments has a barrel-shaped outline and a rather broad axial lobe. The short, wide, rounded triangular pygidium usually shows 4 or 5 axial rings with corresponding pleurae. The surface of the exoskeleton is variably granulate.

Unmineralized anatomy: rare specimens of Ehmaniella from the Walcott Quarry and above on Fossil Ridge preserve a pair of slender uniramous antennae (Walcott, 1918; Rudkin 1989). These are sometimes associated with a dark stain adjacent to the exoskeleton, presumably representing fluidized decay products.

Abundance:

Relatively common on Fossil Ridge and locally abundant in the Walcott Quarry (fourth most common trilobite with about 400 specimens observed, only 13 of which are E. waptaensis, Caron and Jackson, 2008).

Maximum Size:
28 mm

Ecology:

Ecological Interpretations:

Like similar-looking ptychoparioid trilobites, Ehmaniella may be interpreted as a fully mobile, epibenthic deposit (particle) feeder.

References:

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

RASETTI, F. 1951. Middle Cambrian stratigraphy and faunas of the Canadian Rocky Mountains. Smithsonian Miscellaneous Collections, 116 (5): 277 p.

RESSER, C. E. 1935. Nomenclature of some Cambrian trilobites. Smithsonian Miscellaneous Collections, 95(22): 29 p.

RESSER, C. E. 1937. Third contribution to nomenclature of Cambrian trilobites. Smithsonian Miscellaneous Collections, 93(5): 46 p.

RUDKIN, D. M. 1989. Trilobites with appendages from the Middle Cambrian Stephen Formation of British Columbia. 28th International Geological Congress, Washington, D.C. July 9-19, 1989. Abstracts: 2-729.

SCHOLTZ, G. AND G. D. EDGECOMBE. 2006. The evolution of arthropod heads: reconciling morphological, developmental and palaeontological evidence. Development Genes and Evolution, 216: 395-415.

WALCOTT, C. 1918. Cambrian Geology and Paleontology IV. Appendages of trilobites. Smithsonian Miscellaneous Collections, 67(4): 115-216.

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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: