Phylas: Hemichordata



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Spartobranchus tenuis

Artistic reconstruction of Spartobranchus tenuis. Marianne Collins © ROM

Taxonomy:

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

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

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

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

tenuis — from the Latin, meaning thin or delicate.

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

Burgess Shale and vicinity: None
Other deposits: None

Age & Localities:

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

Walcott Quarry

History of Research:

Brief history of research:

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

Description:

Morphology:

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

Abundance:

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

Maximum Size:
About 10 cm.

Ecology:

Life habits: Hemichordata
Feeding strategies: Hemichordata
Ecological Interpretations:

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

References:

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


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Gyaltsenglossus senis

Artistic reconstruction of Gyaltsenglossus senis. Emily Damstra © ROM

Taxonomy:

Kingdom: Hemichordata
Phylum: Hemichordata
Higher Taxonomic assignment: No subphylum assignment
Species name: Gyaltsenglossus senis
Remarks:

Gyaltsenglossus is currently considered a stem-group hemichordate. It has features of both the modern hemichordate groups in that it has the long proboscis and worm-shaped body of the Enteropneusta (acorn worms) and the crown of feeding tentacles of the Pterobranchia.

Described by: Nanglu et al. 2020
Description date: 2020
Etymology:

Gyaltsen (pronounced “GEN-zay”) in honour of the lead author’s father, and glossus from the Greek glossa, meaning tongue, a common generic suffix for hemichordates.

Senis from the Latin senex, meaning old.

Type Specimens: Holotype ROMIP 65606.1
Other species:

Burgess Shale and vicinity: None.
Other deposits: None

Age & Localities:

Age:
Middle Cambrian, Wuliuan Stage, upper part of the Burgess Shale Formation (around 507 million years old).
Principal localities:

Odaray Mountain, Yoho National Park.

History of Research:

Brief history of research:

Gyaltsenglossus was described in 2020 based on 33 specimens, all collected from Odaray Mountain. Only the holotype preserves all major anatomical features.

Description:

Morphology:

: Gyaltsenglossus is a worm roughly 2 cm long. At the anterior end, it has an elongate, ovoid, muscular proboscis. Behind the proboscis is a set of six arms which bore roughly 15 pairs of tentacles. These arms were roughly 1.5 times as long as the proboscis, based on measurements taken from the holotype. The tentacles give the arms an overall fuzzy or foliose appearance. Behind the feeding arms is a roughly cylindrical trunk, which tapers from the largest point at the anterior and becomes smaller towards the posterior end of the animal. On the dorsal side of the trunk, directly behind the feeding arms, an elevated area leads to a set of thin, thread-like appendages. Posterior to the trunk is a bulbous structure with internal features preserved more darkly than in the surrounding tissues. This bulbous structure may constitute thickened tissue. In some specimens, a gut ending prior to the posterior bulbous structure is preserved.

Abundance:

33 specimens were described.

Maximum Size:
About 2 cm.

Ecology:

Life habits: Hemichordata
Feeding strategies: Hemichordata
Ecological Interpretations:

The morphology of Gyaltsenglossus suggests that it had a two-part feeding ecology. The long proboscis could have been used to feed directly from the marine mud on which the animal would have lived, in a manner similar to that of modern-day acorn worms. The feeding arms could also have been used to filter food particles from the water above the organism, as done by pterobranchs. The posterior bulbous appendage may have been used to anchor Gyaltsenglossus to the seafloor, particularly when it was feeding on small particles from the water.

References:

  • NANGLU, K., J.-B. CARON, AND C. B. CAMERON. 2020. Cambrian tentaculate worms and the origin of the hemichordate body plan. Current Biology. 30 (21): 4238-4244
Other Links:


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Yuknessia simplex

3D animation of Yuknessia simplex.
© Phlesch Bubble

Taxonomy:

Kingdom: Hemichordata
Phylum: Hemichordata
Higher Taxonomic assignment: Pterobranchia
Species name: Yuknessia simplex
Remarks:

Yuknessia consists of the tubes of miniature colonial animals called pterobranchs (Hemichordata). The tubes were formed as clustered colonies, with the tubes themselves possessing the zig-zagging growth marks that are diagnostic of the Pterobranchia.

Described by: Walcott
Description date: 1919
Etymology:

Yuknessia – from Yukness Mountain (2,847m), a Peak in Yoho National Park, east of the Burgess Shale.

simplex – from the Latin simplex, meaning “simple,” in reference to its simple morphology.

Type Specimens: Holotype –USNM35406 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: Yuknessia stephenensis from the Trilobite Beds on Mount Stephen (LoDuca et al. 2015)

Other deposits: Yuknessia stephenensis from the Wheeler Shale (Utah) and Spence Shale (Utah) (Conway Morris and Robison, 1988;  LoDuca et al. 2015). Yuknessia sp. from the Lower Cambrian Niutitan Formation in China (Yang et al., 2003).

Age & Localities:

Age:
Middle Cambrian, Wuliuan stage, Burgess Shale Formation (approximately 505 million years ago).
Principal localities:

Burgess Shale and vicinity: The Walcott Quarry on Fossil Ridge and the Trilobite Beds on Mount Stephen.

Other deposits: none

History of Research:

Brief history of research:

This genus was described by Charles Walcott (1919) as a possible green alga. It was redescribed by LoDuca et al. (2015) as the tubes of a hemichordate.

Description:

Morphology:

Yuknessia consists of a colony of branching tubes that were constructed by pterobranch individuals known as zooids. While the zooids themselves are not preserved, the growth mode of the tubes, in particular a series of zig-zagging growth marks known as fuselli, are diagnostic of the hemichordate class Pterobranchia. The tubes are thin, and range from 4mm-13mm, although 6mm is more common.

Abundance:

Yuknessia is very rare and represents only 0.04% of the Walcott Quarry community (Caron and Jackson, 2008).

Maximum Size:
30 mm

Ecology:

Life habits: Hemichordata
Feeding strategies: Hemichordata
Ecological Interpretations:

All pterobranchs, including Yuknessia, were suspension feeders. The zooids possessed tentacle-laden feeding arms which would have extended into the surrounding water. The tentacles would then trap passing food particles and transport them down to the mouth. The actual zooids themselves would have been attached to zooids in adjacent tubes with a system of tissues called the stolon system. In this way, Yuknessia actually represents a colony of related individuals rather than a single animal. The tubes of Yuknessia would have been attached directly to the seafloor or a hard substrate such as a rock or fragments of biomineralizing animals. While the zooids could move up and down within their individual tubes, the colony itself was immobile.

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. AND R. A. ROBISON. 1988. More soft-bodied animals from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions, 122 p.
  • WALCOTT, C. 1919. Cambrian Geology and Paleontology IV. Middle Cambrian Algae. Smithsonian Miscellaneous Collections, 67(5): 217-260.
  • YANG, R., W. ZHANG, L. JIANG AND H. GAO. 2003. Chengjiang biota from the Lower Cambrian Niutitang Formation, Zunyi County, Guizhou Province, China. Acta Palaeontologica Sinica, 77: 145-150.
Other Links:

None

Testing this Change


Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Chaunograptus scandens

Chaunograptus scandens (ROM 61106). A single stem with several small thecae on both sides, next to the arthropod Waptia fieldensis and the sponge Leptomitus lineatus. Specimen length = 14 mm. Specimen wet – direct light (both images). Walcott Quarry.

© Royal Ontario Museum. Photos: Jean-Bernard Caron

Taxonomy:

Kingdom: Hemichordata
Phylum: Hemichordata
Higher Taxonomic assignment: Graptolithina (Order: Dithecoidea, stem group hemichordates)
Species name: Chaunograptus scandens
Remarks:

This species belong to a primitive group of graptolites called the dithecoids, a sister group to dendroids and graptoloids (Rickards and Durman, 2006).

Described by: Ruedemann
Description date: 1931
Etymology:

Chaunograptus – from the Greek chaunos, “loose,” and graptos, “inscribed,” in reference to the general outline of the animal.

scandens – from the Latin scandens, “to climb,” in reference to the presence of this species on the surface of sponges.

Type Specimens: Holotype – UNSM 83484 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: Several species of this genus occur in the Cambrian (Rickards and Durman, 2006; Ruedemann, 1947).

Age & Localities:

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

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Described by Ruedemann in 1931, Chaunograptus was originally interpreted as a hydroid (which is now considered an obsolete group) within the Class Hydrozoa (see also Ruedemann, 1947). The hydrozoans include jellyfish and corals today. Graptolites are now convincingly interpreted as a primitive group of pterobranchs within Hemichordates (see references in Urbanek, 1986).

Description:

Morphology:

Chaunograptus scandens is a small colonial organism comprised of several very slender and straight stems that branch near the base. Short conical structures (thecae) are attached to either side of each stem at regular intervals.

Abundance:

About a dozen specimens are known from the Walcott Quarry, comprising only 0.021% of the specimens counted (Caron and Jackson, 2008).

Maximum Size:
25 mm

Ecology:

Life habits: Hemichordata
Feeding strategies: Hemichordata
Ecological Interpretations:

Like modern rhabdopleurid forms, Chaunograptus was probably attached to substrates in order to filter the water for particulate organic matter. The original description suggests that Chaunograptus might have been climbing on the sponge Leptomitus lineata (“Tuponia lineata” in Ruedemann, 1931).

References:

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

RICKARDS, R. B. AND P. N. DURMAN, 2006. Evolution of the earliest graptolites and other hemichordates, p. 5-92. In M. G. Bassett and V. K. Deisler (eds.), Studies in Palaeozoic Palaeontology. National Museum of Wales Geological Series 25. National Museum of Wales, Cardiff.

RUEDEMANN, R. 1931. Some new Middle Cambrian fossils from British Columbia. Proceedings of the United States National Museum, 79: 1-25.

RUEDEMANN, R. 1947. Graptolites of North America. Geological Society of America Memoir, 19: 652.

URBANEK, A. 1986. The enigma of graptolite ancestry: lesson from a phylogenetic debate, p. 184-226. In A. Hoffman and M. H. Nitecki (eds.), Problematic Fossil Taxa (Oxford Monographs on Geology and Geophysics N°5). Oxford University Press and Clarendon Press, Oxford.

Other Links:

None



Mega Zoom & Pan Image Zoomer image with id 0 does not exist!

Mega Zoom & Pan Image Viewer with preset id 0 does not exist!

Oesia disjuncta

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

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

Taxonomy:

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

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

Described by: Walcott
Description date: 1911
Etymology:

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

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

Type Specimens: Lectotype –USNM57630 in the National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
Other species:

Burgess Shale and vicinity: none.

Other deposits: none.

Age & Localities:

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

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

History of Research:

Brief history of research:

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

Description:

Morphology:

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

Abundance:

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

Maximum Size:
120 mm.

Ecology:

Life habits: Hemichordata
Feeding strategies: Hemichordata
Ecological Interpretations:

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

References:

 

  • BRIGGS, D. E. G. AND S. CONWAY MORRIS. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia, p. 167-183. In A. Hoffman and M. H. Nitecki (eds.), Problematic fossil taxa (Oxford Monographs on Geology and Geophysics No. 5). Oxford University Press & Clarendon Press, New York.
  • CONWAY MORRIS, S. 1979. The Burgess Shale (Middle Cambrian) fauna. Annual Review of Ecology and Systematics, 10(1): 327-349.
  • CONWAY MORRIS, S. 2009. The Burgess Shale animal Oesia is not a chaetognath: A reply to Szaniawski (2005). Acta Palaeontologica Polonica, 54(1): 175-179.
  • LOHMANN, H. 1920. Oesia disjuncta Walcott, eine Appendicularie aus dem Kambrium. Mitteilungen aus dem Zoologischen Staatsinstitut und Zoologischen Museum in Hamburg, 38: 69-75.
  • NANGLU, K., CARON, J.-B., CONWAY MORRIS, S.C., AND C. B. CAMERON. 2016. Cambrian suspension-feeding tubicolous hemichordates. BMC Biology 14: 1-9.
  • NANGLU, K., J.-B. CARON, AND C. B. CAMERON. 2020a. Cambrian tentaculate worms and the origin of the hemichordate body plan. Current Biology 30 (21): 4238-4244
  • NANGLU, K., CARON, J.-B. and GAINES, R. R. 2020b. The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia. Paleobiology, 46, 58-81.
  • SZANIAWSKI, H. 2005. Cambrian chaetognaths recognized in Burgess Shale fossils. Acta Palaeontologica Polonica, 50(1): 1-8.
  • WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5): 109-145.
Other Links:

None