The Burgess Shale

Fossil Ridge: Raymond Quarry

Priscansermarinus barnetti

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

© Royal Ontario Museum. Photos: Jean-Bernard Caron

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Non applicable
Species name: Priscansermarinus barnetti
Remarks:

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

Described by: Collins and Rudkin
Description date: 1981
Etymology:

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

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

Type Specimens: Holotype –ROM36064a in the Royal Ontario Museum, Toronto, Ontario, Canada
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge, Mount Field.

History of Research:

Brief history of research:

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

Description:

Morphology:

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

Abundance:

Moderately common at some Raymond Quarry levels; uncommon elsewhere.

Maximum Size:
50 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

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

References:

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

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

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

Other Links:

None

Isoxys acutangulus

3D animation of Isoxys carinatus.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Unranked clade (stem group arthropods)
Species name: Isoxys acutangulus
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).

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:

Age:
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:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
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.

Other Links:

None

Hurdia victoria

3D animation of Hurdia victoria.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Dinocarida (Order: Radiodonta, stem group arthropods)
Species name: Hurdia victoria
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).

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:

Age:
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:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
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.

Other Links:

http://www.sciencemag.org/content/323/5921/1597.abstract

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:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Demospongea (Order: Monaxonida)
Species name: Hazelia palmata
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.

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:

Age:
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:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
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:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Hyolitha (Order: Hyolithida, stem group molluscs)
Species name: Haplophrentis carinatus
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.

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:

Age:
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:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
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.

Other Links:

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

http://www.kumip.ku.edu/cambrianlife/Utah-Mollusks-Hyolithids.html

Hallucigenia sparsa

3D animation of Hallucigenia sparsa.

Animation by Phlesch Bubble © Royal Ontario Museum

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Xenusia (Order: Scleronychophora, stem group onychophorans)
Species name: Hallucigenia sparsa
Remarks:

Hallucigenia is regarded as a member of the “lobopodans,” a group of vermiform Cambrian organisms possessing pairs of leg-like extensions of the body. The affinities of these animals are controversial; they have been placed at the base of a clade comprised of anomalocaridids and arthropods (Budd, 1996), or in a stem-group to modern onychophorans (Ramsköld and Chen, 1998).

Described by: Walcott
Description date: 1911
Etymology:

Hallucigenia – from the Latin hallucinatio, “wandering of the mind,” after the bizarreness of the animal.

sparsa – from the Latin sparsus, “rare, or scattered,” reflecting the rarity of the specimens available in the original study.

Type Specimens: Holotype –USNM83935 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: H. fortis from the Middle Cambrian Chengjiang biota (Hou and Bergström 1995).

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge. The Tulip Beds (S7) on Mount Stephen.

History of Research:

Brief history of research:

Hallucigenia was originally described as “Canadia sparsa” by Walcott (1911) in a review of various Burgess Shale “annelids.” One specimen was illustrated twenty years later (Walcott, 1931), but the first thorough study of this animal wasn’t published until Conway Morris (1977) demonstrated that it did not belong to the genus Canadia or to the annelids at all. His reconstruction showed a bizarre animal walking on spines, with dorsal tentacles interpreted as a feeding apparatus (Conway Morris, 1977). The new genus name Hallucigenia was coined in reference to this “dreamlike” appearance and also reflected the organism’s uncertain affinities. It was later shown that the supposed tentacles represented just one row of paired “legs” – the others were buried under a layer of rock and the paired spines were on the dorsal surface (Ramsköld and Hou, 1991, Ramsköld, 1992). The anteroposterior orientation was also reversed, with the former head interpreted as possible decay fluids seeping from the body (Ramsköld, 1992).

Description:

Morphology:

Hallucigenia has a worm-like body with a small head at the end of a long neck; the trunk bears seven pairs of long dorsal spines and seven pairs of slender leg-like lobes. The spacing between lobes and spines is relatively constant. The spine pairs are shifted forward so that the posterior pair of legs does not have a corresponding pair of spines above. Each leg terminates in a pair of claws and the rigid spines have inflexible basal plates. The neck area bears two or three pairs of very fine anterior “appendages” lacking terminal claws. The head is indistinct but the mouth is anterior; a straight gut ends in a posterior anus. It is possible the posterior end is in fact more bulbous than previously thought.

Abundance:

About thirty specimens were studied by Conway Morris (1977). Overall, Hallucigenia is rare, and in the Walcott Quarry it represents 0.19% of the specimens counted in the community (Caron and Jackson, 2008).

Maximum Size:
30 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

Hallucigenia is often found in association with the sponge Vauxia and other organic debris. This co-occurrence has led to suggestions that Hallucigenia fed on sponges, using its clawed legs to hang on, with its spines protecting it from predation. It is also possible that Hallucigenia scavenged on decaying animal remains.

References:

BUDD, G. E. 1996. The morphology of Opabinia regalis and the reconstruction of the arthropod stem-group. Lethaia, 29: 1-14.

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. A new metazoan from the Burgess Shale of British Columbia. Palaeontology, 20: 623-640.

CONWAY MORRIS, S. 1999. The crucible of creation: the Burgess Shale and the rise of animals. Oxford University Press, USA.

HOU, X. AND J. A. N. BERGTRÖM. 1995. Cambrian lobopodians – ancestors of extant onychophorans? Biological Journal of the Linnean Society, 114(1): 3-19.

RAMSKÖLD, L. 1992. The second leg row of Hallucigenia discovered. Lethaia, 25(2): 221–224.

RAMSKÖLD, L. AND X. HOU. 1991. New early Cambrian animal and onychophoran affinities of enigmatic metazoans. Nature, 351: 225-228.

RAMSKÖLD, L. AND J. Y. CHEN. 1998. Cambrian lobopodians: morphology and phylogeny, p. 107-150. In G. D. Edgecombe (ed.), Arthropod fossils and phylogeny. Volume 29. Columbia University Press, New York.

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

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

Other Links:

http://gsc.nrcan.gc.ca/paleochron/09_e.php

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

http://evolution.berkeley.edu/evolibrary/article/_0_0/cambrian_13

Halichondrites elissa

Halichondrites elissa (ROM 53575) – Part and counterpart. Nearly complete individual showing the pointed root tuft. Specimen height = 140 mm. Specimen dry – direct light (left), wet – direct light (right). Walcott Quarry.

© Royal Ontario Museum. Photos: Jean-Bernard Caron

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Demospongea (Order: Monaxonida)
Species name: Halichondrites elissa
Remarks:

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

Described by: Walcott
Description date: 1920
Etymology:

Halichondrities – from the Greek hal, meaning “belonging to the sea,” chon, meaning “funnel” or “tube,” and dri, meaning “thicket.” The name refers to the shape of this marine sponge with a thicket of long hair-like spicules.

elissa – from the Greek eliss, meaning “to roll, or to turn about.” This name may refer to the spiral pattern of the small spicules of this sponge.

Type Specimens: Holotype –USNM66447 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: An unidentified species, Halichondrites sp. from Mount Stephen (Rigby and Collins, 2004).

Other deposits: H. confusus Dawson, 1889 from the Ordovician of Quebec at Little Métis.

Age & Localities:

Age:
Lower Cambrian, Wutingaspis-Eoredlichia Zone to Middle Cambrian, Bathyuriscus-Elrathina Zone (approximately 510 to 505 million years ago).
Principal localities:

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

Other deposits: H. elissa from the Lower Cambrian Chengjiang fauna (Chen et al., 1997; Luo et al., 1999).

History of Research:

Brief history of research:

Walcott assigned this species to the genus Halichondrites in 1920. Ribgy (1986) re-described this genus and hypothesized that Halichondrites probably evolved from an early species of Leptomitus and established a new family called Halichondritidae to include this genus. New specimens collected by the Royal Ontario Museum were subsequently described by Rigby and Collins in 2004.

Description:

Morphology:

This sponge has a cone shaped base that extends upwards to form a long tube. The walls of the sponge are smooth with a thatch of small spicules that are vertically arranged in a clockwise spiraling pattern. There are no canals visible in the wall; they may be very small or run parallel to the wall. The most distinctive part of this sponge is the long thick, densely arranged spicules that emerge from the wall. These spicules are orientated upwards and may be up to 8.5 cm long. This sponge can be over 20 cm tall and is one of the tallest and most hirsute (densely covered in hair) of the Burgess Shale sponges. Water would have entered though small pores in the wall, moving into the central cavity and out the circular osculum at the top of the sponge.

Abundance:

Halichondrites is very rare and represents only 0.01% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
215 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

Halichondrites 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.

CHEN, J. Y., Y. N. CHENG AND H. V. ITEN. 1997. The Cambrian explosion and the fossil record. National Museum of Natural Science Taiwan, Taichung, 319 p.

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.

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

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

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

Other Links:

None

Pollingeria grandis

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

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

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Non applicable
Species name: Pollingeria grandis
Remarks:

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

Described by: Walcott
Description date: 1911
Etymology:

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

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

Type Specimens: Syntypes –USNM57639-57641 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge and smaller sites on Mount Field and Mount Stephen.

History of Research:

Brief history of research:

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

Description:

Morphology:

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

Abundance:

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

Maximum Size:
15 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

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

References:

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

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

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

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

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

Other Links:

None

Habelia? brevicauda

Habelia? brevicauda (USNM 144910) – Holotype. Complete individual preserved without appendages. Total specimen length = 50 mm. Specimen dry – polarized light. Walcott Quarry.

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

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Unranked clade (stem group arthropods)
Species name: Habelia? brevicauda
Affinity:

Habelia? brevicauda is too poorly known to definitively determine its affinities. It has been aligned in some studies with the arachnomorphs (a group including chelicerates and trilobites), and has been suggested to be closely related to lamellipedians such as Naraoia and the trilobites (Briggs and Fortey, 1989), or placed within Megacheira as a close relative of Leanchoilia (Wills et al., 1998).

Described by: Simonetta
Description date: 1964
Etymology:

Habelia – from Mount Habel (3,161 m), today known as Mount Des Poilus, at the head of Yoho Valley, named in 1900 by Norman Collie in honour of Jean Habel, a German mountaineer. The name Mount Habel is now applied to a peak north of Mount Des Poilus.

brevicauda – from the Latin brevis, “short,” and cauda, “tail.”

Type Specimens: Holotype –USNM144910 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Habelia optata from Walcott Quarry, Fossil Ridge and The Monarch in Kootenay National Park.

Other deposits: none.

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Habelia optata was first described by Walcott in 1912, to which Simonetta added the possible second species Habelia? brevicauda in 1964. This second species was later restudied by Whittington (1981). Phylogenetic analyses suggest a position within the arachnomorphs (Briggs and Fortey, 1989; Wills et al., 1998). If this is confirmed, Habelia probably represent a stem group of the Mandibulata, which includes crustaceans, myriapods, and hexapods (Scholtz and Edgecombe, 2006).

Description:

Morphology:

The body ranges in size from 1.8 – 5.4 cm and consists of a half-circle head shield and a trunk with twelve segments, the last of which bears a posterior spine. The head shield is smooth and featureless. The trunk segments have a broad, convex axial region, with blade-shaped elements (pleura) extending from either side. The pleura are short and round at the anterior of the body, but become progressively wider and have increasingly backward-pointing tips towards the posterior. The short, broad posterior spine tapers with a bluntly rounded tip.

In the type species, Habelia optata, the exoskeleton is covered in small tubercules , and appendages include a pair of antennae, two pairs of head appendages that are segmented and branch into two (biramous), and six pairs of possibly gnathobasic biramous trunk appendages (i.e., with a robust and spiny basal podomere or segment used for crushing food items). Tubercules and appendages have not been described in Habelia? brevicauda, which is why its placement in the genus is uncertain.

Abundance:

Habelia? brevicauda was originally described from fewer than ten specimens.

Maximum Size:
54 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

Habelia? brevicauda is assumed to have walked on trunk limbs, using its head appendages to manipulate food items. If gnathobases were present, they may have served to masticate food. The frontal antennae were presumably sensory. Considerable flexure of the head may have been possible, which may have allowed Habelia to use its cephalon to dig into the sediment in search of food. It walked along the sea floor while digging and scavenging food items.

References:

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

ELLIOTT, D. K. AND D. L. MARTIN. 1987. A new trace fossil from the Cambrian Bright Angel Shale, Grand Canyon, Arizona. Journal of Paleontology, 61: 641-648.

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.

SIMONETTA, A. M. 1964. Osservazioni sugli artropodi non trilobiti della ‘Burgess Shale’ (Cambriano medio). III conributo. Monitore Zoologico Italiano, 72: 215-231.

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

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.

WHITTINGTON, H. B. 1981. Rare arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 292: 329-357.

Other Links:

None

Habelia optata

Reconstruction of Habelia optata.

© Marianne Collins

Taxonomy:

Kingdom: Raymond Quarry
Phylum: Raymond Quarry
Higher Taxonomic assignment: Unranked clade (stem group arthropods)
Species name: Habelia optata
Remarks:

Habelia optata is an arthropod, but its exact relationships remain poorly understood. It has been aligned in some studies to the arachnomorphs (a group including chelicerates and trilobites), and has either been allied with lamellipedians such as Naraoia and the trilobites (Briggs and Fortey, 1989), or placed within Megacheira as closely related to Leanchoilia (Wills et al., 1998).

Described by: Walcott
Description date: 1912
Etymology:

Habelia – from Mount Habel (3,161 m), today known as Mount Des Poilus, at the head of Yoho Valley. Named in 1900 by Norman Collie in honour of Jean Habel, a German mountaineer. The name Mount Habel is now applied to a peak north of Mount Des Poilus.

optata – unspecified; may derive from the Latin optatus, “wish or desire.”

Type Specimens: Holotype –USNM57693 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Habelia? brevicauda from Walcott Quarry and Raymond Quarry, Fossil Ridge.

Other deposits: none.

Age & Localities:

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

The Walcott and Raymond Quarries on Fossil Ridge.

History of Research:

Brief history of research:

Habelia optata was first described by Walcott in 1912, and a possible second species Habelia? brevicauda was added to the genus by Simonetta in 1964. Habelia was later restudied by Whittington (1981). Habelia has been included in some phylogenetic analyses of arthropod relationships (Briggs and Fortey, 1989; Wills et al., 1998) and unusual zig-zag fossil tracks from the Middle Cambrian of the Grand Canyon have been ascribed to an arthropod similar to Habelia (Elliott and Martin, 1987).

Description:

Morphology:

Habelia optata is unusual in that its entire body is covered in tubercles (small, rounded nodules) that are particularly dense on the head shield and the axis of the body trunk. Its body consists of a convex head shield without eyes, and twelve body tergites with a long, jointed posterior spine projecting from the twelfth segment. The first three tergites have a thick median spine that bore tubercles. The head has a pair of multi-segmented setose antennae at the front, and two pairs of possibly biramous appendages with segmented walking limbs and dark sheets that may be filamentous branches.

The twelve body segments have a thick, blunt median spine on the dorsal surface. The first six body segments have appendages that are segmented and branch into two (biramous), including long stout segmented gnathobasic walking limbs (i.e., with a robust and spiny basal podomere or segment used for crushing food items) and a lobed outer branch with lamellae (small elongated structures) along the margin. The lobes are also present on the posterior segments, but no walking branches are associated with them. The tail is a long spine with a single joint midway along its length.

Abundance:

Extremely rare

Maximum Size:
41 mm

Ecology:

Life habits: Raymond Quarry
Feeding strategies: Raymond Quarry
Ecological Interpretations:

Habelia optata probably used its six trunk limbs for walking, reserving the head appendages for manipulating food items. It is likely that the frontal antennae were used to sense the environment since there are no obvious eyes. The size and shape of the posterior margin of the head suggests that there was considerable flexure possible between the head and the body, indicating that Habelia may have dug in the sediment for food items. It lived on the muddy seafloor and was heavily protected against predators by its thick body armor and pointed posterior spine, the latter of which would make it difficult for predators to attack from behind.

References:

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

ELLIOTT, D. K. AND D. L. MARTIN. 1987. A new trace fossil from the Cambrian Bright Angel Shale, Grand Canyon, Arizona. Journal of Paleontology, 61: 641-648.

SIMONETTA, A. M. 1964. Osservazioni sugli artropodi non trilobiti della ‘Burgess Shale’ (Cambriano medio). III conributo. Monitore Zoologico Italiano, 72: 215-231.

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

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.

WHITTINGTON, H. B. 1981. Rare arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 292: 329-357.

Other Links:

None