The Burgess Shale

Worthenella cambria

Worthenella cambria (USNM 57643) – Holotype, part and counterpart. Left, plate 22 of Walcott (1911), showing a retouched image of the original specimen described (figure 2) together with other “worms.” Right, images of the same specimen. Specimen length = 60 mm. Specimen wet – direct light (left column), dry – polarized light (right column). Walcott Quarry.

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

Taxonomy:

Class: Unranked clade (stem group arthropods)
Remarks:

This animal is related to arthropods, but its systematic status within this group is unknown (Briggs and Conway Morris, 1986).

Species name: Worthenella cambria
Described by: Walcott
Description date: 1911
Etymology:

Worthenella – Possibly after the American palaeontologist Amos Henry Worthen, who died in 1888, just as Walcott’s career was taking off.

cambria – from the Welsh Cambria meaning Wales, in reference to the age of the fossil.

Type Specimens: Holotype –USNM57643 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none

Other deposits: none

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Worthenella was first described by Walcott from a single specimen in a 1911 monograph dealing with various Burgess Shale worms. Walcott interpreted this animal as a polychaete annelid (or bristle worm), in the same family as the animal Wiwaxia (which is now interpreted as a primitive mollusc). However, this interpretation was questioned (Conway Morris, 1979), and the affinities of Worthenella have remained difficult to establish because this singular fossil is too poorly known (Briggs and Conway Morris, 1986).

Description:

Morphology:

The animal is elongate with a small head and bears at least 46 segments of similar dimensions. Appendages or tentacles are present beneath the head, but their preservation is poor and it is difficult to know their precise nature and arrangement. The anterior 34 segments seem to bear filamentous branches on their ventral sides, with the following 8 segments equipped with longer appendages. The gut is straight and the anus is terminal.

Abundance:

This animal is known from a single specimen.

Maximum Size:
60 mm

Ecology:

Ecological Interpretations:

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

References:

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

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

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

Other Links:

None

Waputikia ramosa

3D animation of Waputikia ramosa.

ANIMATION BY PHLESCH BUBBLE © ROYAL ONTARIO MUSEUM

Taxonomy:

Class: Non applicable
Remarks:

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

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

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

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

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

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

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

Description:

Morphology:

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

Abundance:

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

Maximum Size:
60 mm

Ecology:

Ecological Interpretations:

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

References:

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

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

Other Links:

None

Walcottidiscus typicalis

Walcottidiscus typicalis (GSC 45368). Complete but poorly preserved specimen. Specimen diameter = 18 mm. Specimen dry – direct light. Walcott Quarry.

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

Taxonomy:

Class: Edrioasteroidea (Order: Edrioasteroida, stem group echinoderms)
Remarks:

Walcottidiscus is a poorly known edrioasteroid, an extinct group of echinoderms (Smith, 1985).

Species name: Walcottidiscus typicalis
Described by: Bassler
Description date: 1935
Etymology:

Walcottidiscus – from Charles Walcott, the discoverer of the Burgess Shale, and the Greek diskos, “disc.” The name refers to the flattened appearance of the fossils.

typicalis – from the Greek typikos, “type,” perhaps in reference to the single specimen originally described.

Type Specimens: Holotype –USNM90754 (W. typicalis),USNM90755 (W. magister) in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: W. magister Bassler, 1935 from the Walcott Quarry on Fossil Ridge (but see below paragraph brief history of research).

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Two species known from a single specimen each were originally described by Bassler in 1935 and 1936: a small form W. typicalis, and a larger form W. magister respectively. However, W. magister is now thought to belong to W. typicalis (Smith, 1985) but additional fossil material would be required to confirm this hypothesis. Walcottidiscus resembles Kailidiscus chinensis, a chinese form from the Middle Cambrian Kaili deposit, but remains too poorly known to draw more detailed comparisons between the two genera (Zhao et al., 2010).

Description:

Morphology:

The body (theca) is ovoid in outline and has a relatively small dorsal surface compared to the ventral one. The upper central part of the theca is not calcified, but the outer zone is composed of small calcified plates. A five star-shaped food groove lined with small plates (the ambulacra) is present on the upper surface. The five arms of the ambulacra are arranged in a 2:1:2 fashion around the mouth, and they are at first straight and then turn to the left near the edge of the theca. Differences between the two species are the size and degree of ambulacral curvature, but those differences could simply be a factor of growth.

Abundance:

Walcottidiscus is very rare only two specimens were originally described. A few additional specimens are known in the Burgess Shale collections of the Geological Survey of Canada and the Royal Ontario Museum.

Maximum Size:
64 mm

Ecology:

Ecological Interpretations:

Walcottidiscus was most likely resting on the seafloor. Food particles were transported by food grooves (ambulacrum) into a central mouth at the top of the theca.

References:

BASSLER, R. S. 1935. The classification of the Edrioasteroidea. Smithsonian Miscellaneous Collections, 93: 1-11.

BASSLER, R. S. 1936. New species of American Edrioasteroidea. Smithsonian Miscellaneous Collections, 95: 1-33.

SMITH, A. B. 1985. Cambrian eleutherozoan echinoderms and the early diversification of edrioasteroids. Palaeontology, 28: 715-756.

ZHAO, Y., C. D. SUMRALL, R. L. PARSLEY AND J. I. N. PENG. 2010. Kailidiscus, a new plesiomorphic edrioasteroid from the basal Middle Cambrian Kaili biota of Guizhou province, China. Journal of Paleontology, 84: 668-680.

Other Links:

None

Ulospongiella ancyla

Ulospongiella ancyla (ROM 43830) – Holotype. Nearly complete individual. Specimen height = 19 mm. Specimen dry – direct light (left), wet – polarized light (right). Trilobite Beds on Mount Stephen.

© ROYAL ONTARIO MUSEUM. PHOTOS: JEAN-BERNARD CARON

Taxonomy:

Class: Demospongea (Order: Monaxonida)
Remarks:

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

Species name: Ulospongiella ancyla
Described by: Rigby and Collins
Description date: 2004
Etymology:

Ulospongiella – from the Greek oulus, “wooly or curly,” and spongia, “sponge.” The name refers to the curled or curved spicules forming the skeleton.

ancyla – from the Greek anklyos, “bent or hooked.” The name makes reference to the curved spicules.

Type Specimens: Holotype –ROM43830 (wrongly referred asROM48830 in Rigby and Collins 2004) in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Trilobite Beds on Mount Stephen.

History of Research:

Brief history of research:

Ulospongiella was described by Rigby and Collins in 2004 based on collections made by the Royal Ontario Museum.

Description:

Morphology:

Ulospongiella is a small sponge less than 2 cm in height. Its shape is subcyclindrical with a rounded base. Most spicules forming the skeleton are pointed at both ends (oxeas). These oxeas are strongly curved or hooked shape and form a relatively dense mesh. A few coarser and longer spicules with a round base extend upward from the wall. There is no clear indication of canals within the sponge there is no evidence of a central cavity (spongocoel).

Abundance:

Only three specimens are known, all from the Trilobite Beds.

Maximum Size:
19 mm

Ecology:

Ecological Interpretations:

Ulospongiella 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:

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.

Other Links:

None

Thelxiope palaeothalassia

Thelxiope palaeothalassia (GSC 74990). Articulated specimen (close up to the right), associated with several individuals of the arthropod Canadaspis perfecta. Specimen length = 29 mm. Specimen dry – polarized light. Walcott Quarry.

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

Taxonomy:

Class: Unranked clade (stem group arthropods)
Remarks:

The affinity of Thelxiope has not been considered in detail because the appendages are unknown.

Species name: Thelxiope palaeothalassia
Described by: Simonetta and Delle Cave
Description date: 1975
Etymology:

Thelxiope – from the Greek thelx meaning “enchanting,” and ops, meaning “voice,” referring to the muse-like appearance of the animal.

palaeothalassia – from the Greek palaios, meaning “ancient,” and thalassios, meaning “marine,” in reference to the age and environment where the animal lived.

Type Specimens: Holotype –USNM144914 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Walcott (1912) figured two fragmentary specimens as Mollisoniarara; these were first reinterpreted by Simonetta (1964) within a new genus Parahabelia rara, along with three additional specimens that he thought were related. However, Simonetta and Delle Cave (1975) considered that among those five specimens, the two originally figured by Walcott as M? rara had to be synonymized with M. symmetrica and the other three had to be placed within a new genus and species called Thelxiope palaeothalassia, a name in use since then.

Description:

Morphology:

This species has a relatively wide cephalon and seven segments and resembles Habelia in overall shape. However, in T. palaeothalassia, each segment bears a single prominent spine pointing dorsally. The last segment is armed with a very long pointed telson.

Abundance:

Thelxiope is extremely rare, with only four known specimens.

Maximum Size:
43 mm

Ecology:

Ecological Interpretations:

Thelxiope is too poorly known to allow detailed studies of its ecology.

References:

SIMONETTA, A. M. 1964. Osservazioni sugli arthropodi non trilobiti della “Burgess Shale” (Cambriano medio). Monitore Zoologico Italiano, 72 (3-4: III Contributo: I Generi MolariaHabeliaEmeraldellaParahabelia (Nov.) Emeraldoides (Nov.): 215-231.

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.

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

Other Links:

None

Thaumaptilon walcotti

Thaumaptilon walcotti (USNM 468028) – Holotype, part and counterpart. Complete specimen. Specimen height = 212 mm. Specimen dry – direct light (far left and far right), wet – polarized light (middle images). Walcott Quarry.

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

Taxonomy:

Class: Unranked clade (stem group cnidarians)
Remarks:

Thaumaptilon was first interpreted as a Cambrian member of the frondose Ediacaran Biota, related to cnidarians and particularly to a group of modern anthozoans called pennatulaceans or sea pens (Conway Morris, 1993). This connection is no longer widely accepted (Antcliffe and Brasier, 2008); Thaumaptilon has also been proposed as a critical link between Ediacaran fronds and ctenophores (Dzik, 2002). A position in the cnidarian stem group (i.e. more primitive than the anthozoans) has been supported by the discovery of similar fossils in the Chengjiang Biota (Shu et al., 2006).

Species name: Thaumaptilon walcotti
Described by: Conway Morris
Description date: 1993
Etymology:

Thaumaptilon – from the Greek thauma, “wonderful,” and ptilon, “soft feather,” after its feather-like appearance.

walcotti – after Charles Walcott, discoverer of the Burgess Shale.

Type Specimens: Holotype –USNM468028 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Walcott had studied and photographed Thaumaptilon, but never published his work. The fossil specimens were formally described in 1993 by Conway Morris, who had also alluded to them in previous work (1979; 1989; 1990).

Description:

Morphology:

Thaumaptilon is an oblong frond that somewhat resembles a feather; it is bilaterally symmetrical, with a central axis supporting a number of lateral branches. The branches appear to be connected to one another by narrow canals. A blunt holdfast attached the animal to the sea floor. Of the three known specimens, the largest is 21 cm tall and reaches 5 cm across; the smaller specimens – presumed to be juveniles – are only a few centimetres long. The frond is flattened, and tapers slightly towards its tip. It consists of about three dozen branches angled at 45º to the central axis, and primarily grew by inflation – perhaps with some addition of branches by apical budding. Unlike modern sea pens, Thaumaptilon’s branches attach to a common base. Lines of pustules on one side of the frond have been interpreted as retracted zooids (individual members of a colonial organism), which are arranged very haphazardly in comparison to the neat combs seen in modern sea pens.

Abundance:

Only three specimens are known.

Maximum Size:
210 mm

Ecology:

Ecological Interpretations:

The holdfast would have anchored the organism to the soft sediment of the sea floor, and could perhaps contract to adjust the height and angle of the frond. Based on the interpretation of the pustules as zooids, a colonial, suspension-feeding lifestyle has been proposed. It has been suggested that Thaumaptilon could retract into its stem when threatened, for protection (Conway Morris, 1998).

References:

ANTCLIFFE, J. B. AND M. D. BRASIER. 2008. Charnia at 50: Developmental models for Ediacaran fronds. Palaeontology, 51(1): 11-26.

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

CONWAY MORRIS, S. 1989. Burgess Shale faunas and the Cambrian explosion. Science, 246(4928): 339.

CONWAY MORRIS, S. 1990. Late Precambrian and Cambrian soft-bodied faunas. Annual Review of Earth and Planetary Sciences, 18(1): 101-122.

CONWAY MORRIS, S. 1993. Ediacaran-like fossils in Cambrian Burgess Shale-type faunas of North America. Palaeontology, 36(3): 593-635.

CONWAY MORRIS, S. 1998. The Crucible of Creation, the Burgess Shale and the Rise of Animals. Oxford University Press, 242 p.

SHU, D. G., S. CONWAY MORRIS, J. HAN, Y. LI, X. L. ZHANG, H. HUA, Z. F. ZHANG, J. N. LIU, J. F. GUO, Y. YAO AND K. YASUI. 2006. Lower Cambrian vendobionts from China and early diploblast evolution. Science, 312(5774): 731-734.

Other Links:

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

Tegopelte gigas

Tegopelte gigas (USNM 189201) – Holotype. Complete specimen showing antennae and appendages partially prepared near the back. Specimen length = 270 mm. Specimen dry – direct (top) and polarized light (bottom). Walcott Quarry.

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

Taxonomy:

Class: Unranked clade (stem group arthropods)
Remarks:

Tegopelte is usually compared to the soft-bodied “trilobites” such as Naraoia and Saperion, but the exact relationships of these taxa to the mineralized trilobites is uncertain (Whittington, 1977). The tegopeltids and other trilobite-like arthropods are sometimes referred to as Trilobitoidea, which when grouped together with the trilobites form the Lamellipedians (Hou and Bergström, 1997; Wills et al., 1998; Edgecombe and Ramsköld, 1999). This group has been variously placed in the upper stem lineage of the arthropods (Budd, 2002), or in the stem lineage of either the mandibulates (Scholtz and Edgecombe, 2006) or the chelicerates (Cotton and Braddy, 2004).

Species name: Tegopelte gigas
Described by: Simonetta and Delle Cave
Description date: 1975
Etymology:

Tegopelte – from the Greek tegos, “tile,” and pelte, “leather-shield,” referring to the shape of the dorsal body covering.

gigas – from the Greek gigas, “giant,” referring to the large size of the animal.

Type Specimens: Holotype –USNM189201 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Tegopelte was first described by Simonetta and Delle Cave (1975) to include only two relatively large specimens. This original description showed Tegopelte to have a cephalon with six or seven pairs of walking appendages, a thorax of four tergites each bearing five appendages, and a tail segment with ten appendages. Whittington (1985) re-examined the animal, reducing the number of head appendages to three, and describing the thorax as having only three tergites with three appendages each. The tail in Whittington’s (1985) reconstruction had two segments with a total of 20 appendages. Later re-examination by Ramsköld et al. (1996) suggested that the body has no tergites, but instead consists of an undivided dorsal shield. Tegopelte has been grouped together with the Chengjiang taxon Saperion to form the Tegopeltidae (Ramsköld et al., 1996; Hou and Bergström, 1997), a clade later confirmed by cladistic analysis (Edgecombe and Ramsköld, 1999; Hendricks and Lieberman, 2008).

Description:

Morphology:

The dorsal morphology of Tegopelte consists of an elongated oval-shaped dorsal shield that is featureless and undivided. The length of the two known specimens is 25.7 cm and 27.0 cm, making it one of the largest arthropods in the Burgess Shale. The ventral morphology consists of a pair of multi-segmented antennae at the front of the body, followed by a series of identical limbs that are segmented and branch into two (biramous), totaling approximately 33 along the entire body. The biramous limbs have a walking branch made up of six segments with a pair of spines on the terminal segment, and a filamentous branch where numerous elongated oval blades attach to a central shaft. The biramous limbs decrease in size towards the posterior end of the body.

Abundance:

Tegopelte is extremely rare, with only two known specimens.

Maximum Size:
270 mm

Ecology:

Ecological Interpretations:

Tegopelte probably spent much of its time walking on the seafloor, based on the presence of many appendages. It used the segmented branches of its biramous appendages for walking, and it is likely that the filamentous branches were used for oxygen exchange, and to propel the animal through the water during short bursts of swimming. The antennae would have been used to sense the environment. The lack of eyes, gut glands and feeding appendages make it difficult to allocate a feeding strategy to Tegopelte.

References:

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

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.

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.

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. New phylogenetic insights into the Cambrian radiation of arachnomorph arthropods. Journal of Paleontology, 83: 585-594.

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

RAMSKÖLD, L., J. CHEN, G. D. EDGECOMBE AND G. ZHOU. 1996. Preservational folds simulating tergite junctions in tegopeltid and naraoiid arthropods. Lethaia, 29: 15-20.

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.

WHITTINGTON, H. B. 1977. The Middle Cambrian trilobite Naraoia, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London, B, 280: 409-443.

WHITTINGTON, H. B. 1985. Tegopelte gigas, a second soft-bodied trilobite from the Burgess Shale, Middle Cambrian, British Columbia. Journal of Paleontology, 59: 1251-1274.

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, p. 33-105. In G. D. Edgecombe (ed.), Arthropod fossils and phylogeny. Columbia University Press, New York.

Other Links:

None

Stephenospongia magnipora

Stephenospongia magnipora (ROM 43127) – Holotype. Fragment of the only known specimen of the species showing large holes in the wall of this sponge. Specimen height = 44 mm. Specimen dry – polarized light. Trilobite Beds on Mount Stephen.

© ROYAL ONTARIO MUSEUM. PHOTO: JEAN-BERNARD CARON

Taxonomy:

Class: Hexactinellida (Order: Reticulosa)
Remarks:

Stephenospongia is placed in the Family Hintzespongiidae (primitive hexactinellids). Hexactinellid sponges (glass sponges) have a skeleton composed of four to six-pointed spicules. They are considered to be an early branch within the Porifera phylum due to their distinctive composition.

Species name: Stephenospongia magnipora
Described by: Rigby
Description date: 1986
Etymology:

Stephenospongia – from Mount Stephen (3,199 m), a mountain peak in Yoho National Park, named after George Stephen (1829 – 1921), first president of the Canadian Pacific Railway and the Latin spongia, meaning “sponge.”

magnipora – from the Latin magnus, “great,” and porus, “pore.” The name makes reference to the large pores present in the skeleton of this sponge.

Type Specimens: Holotype –ROM43127 in the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Trilobite Beds on Mount Stephen.

History of Research:

Brief history of research:

Stephenospongia was described by Rigby (1986) (see also Rigby and Collins 2004) based on a single specimen discovered by the Royal Ontario Museum in 1982.

Description:

Morphology:

Stephenospongia has a conical and almost cylindrical shape. The skeleton is composed of six rayed spicules (called hexactines) typical of the hexactinellid sponges. The spicules mesh together to form a single layer and are arranged in an irregular fashion especially around holes in the sponge wall. Prominent holes organized in vertical and horizontal rows are separated by tracts of spicules with ray lengths reaching more than one centimetre. The basal and top parts are not preserved.

Abundance:

Only a single specimen is known and comes from the Trilobite Beds.

Maximum Size:
44 mm

Ecology:

Ecological Interpretations:

Stephenospongia 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:

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

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

Other Links:

None

Sphenothallus sp.

Taxonomy:

Sphenothallus sp. (GSC 134789). Fragment of a large specimen showing longitudinal thickenings clearly differentiated near the aperture area (to the right). A Micromitra (Dictyonina) brachiopod is attached to the lower part of the tube. Approximate specimen length = 50 mm. Specimen dry – direct light. Trilobite Beds on Mount Stephen.

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

Class: Unranked clade (stem group cnidarians)
Remarks:

Sphenothallus has been compared to some form of tubiculous annelid worm or the sessile polyp stage of a scyphozoan jellyfish that builds tapered, chitinous tubes fixed to the substrate by an attachment disc (Van Iten et al., 2002).

Species name: Sphenothallus sp.
Described by: Van Iten et al.
Description date: 2002
Etymology:

Sphenothallus – from the Greek sphen, “wedge”, and thallos, “branch.”

Species name not determined.

Type Specimens: Not applicable
Other species:

Burgess Shale and vicinity: Many shared similarities suggest that other thecate Burgess Shale fossils such as Byronia annulataCambrorhytium majorCfragilis and Tubulella flagellum, may be related to Sphenothallus sp.

Other deposits: Other species occur worldwide in rocks from the Cambrian to the Silurian periods. Sphenothallus is also known in the Kaili Formation (Zhu et al., 2000).

Age & Localities:

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

The Trilobite Beds on Mount Stephen.

History of Research:

Brief history of research:

Two specimens from the Trilobite Beds were illustrated in 2002 (Van Iten et al.). A third previously unrecognized specimen was identified in the Geological Survey of Canada collections in Ottawa (Billings collection) in the Spring of 2010. Owing to the relatively low degree of morphological variations among all known species, it is not currently possible to assign the Burgess Shale form to any particular species without better preserved specimens.

Description:

Morphology:

The chitinophosphatic tube (theca) of Sphenothallus consists of longitudinal thickenings which are particularly obvious towards the aperture area. The tube is gently curved and does not seem to branch. The maximum diameter of the largest specimen is about 4 mm for a length of about 75 mm. A thin wall is present between the longitudinal thickenings and terminates in a smooth margin near the aperture, a couple of millimeters beyond the longitudinal thickenings. The tube is roughly circular in the apical region and is very slender, with the two longitudinal thickenings less differentiated in this area. The surface of the entire tube including thickenings is smooth with no evidence of ridges or annulations. All three specimens lack the apical ends, so it is not evident that this species had a holdfast and there is no evidence of soft-tissue preservation.

Abundance:

Only three specimens known from the Trilobite Beds on Mount Stephen.

Maximum Size:
75 mm

Ecology:

Ecological Interpretations:

The theca of Sphenothallus was likely attached to the substrate via an apical disc as can be seen in other better known species. The absence of soft tissue preservation makes the assignment to a particular feeding strategy tentative. By comparison with possible related forms such as Cambrorhytium, a carnivorous or suspension feeding habit seems possible.

References:

VAN ITEN, H., M.-Y. ZHU AND D. COLLINS. 2002. First report of Sphenothallus Hall, 1847 in the Middle Cambrian. Journal of Paleontology, 76: 902-905.

ZHU, M.-Y., H. VAN ITEN, R. S. COX, Y.-L. ZHAO AND B.-D. ERDTMANN. 2000. Occurrence of Byronia Matthew and Sphenothallus Hall in the Lower Cambrian of China. Paläontologische Zeitschrift, 74: 227-238.

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:

Class: Unranked clade (stem group priapulids)
Remarks:

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

Species name: Scolecofurca rara
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:

Period:
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:

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