Kootenayscolex

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Kootenayscolex
Temporal range: Cambrian Stage 5
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Kootenayscolex ROMIP62972.png
Paratype specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Annelida
Genus: Kootenayscolex
Nanglu & Caron, 2018
Species:
K. barbarensis
Binomial name
Kootenayscolex barbarensis
Nanglu & Caron, 2018

Kootenayscolex is the extinct genus of annelid resembling a bristle worm, found in Burgess Shale, British Columbia. [1] It appears to have been an aquatic worm with about 56 chaetae (bristles) on each of up to 25 segments, serving to propel it through mud or water.

The only one known species in the genus, Kootenayscolex barbarensis, is thought to exhibit primitive traits that show the foundation for the evolution of modern annelids, like "head" segment that still has traits of simply being another generic body segment, for example having bristles poking out of it, which no modern annelid shares. [2]

Description

The genus name Kootenascolex, means "worm from Kootenay National Park" (in British Columbia, where its fossils were found) and species name barbarensis is from Barbara Polk Milstein, a researcher on the burgess shale fossils. Over 500 specimen are known, and length ranges 1–30 mm (0.039–1.181 in). [1] They appear to have been bottom feeders, sifting sediment from the seafloor in their mouths. [2]

Related Research Articles

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Polychaeta is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm and the sandworm or clam worm Alitta.

<i>Hallucigenia</i> Genus of Cambrian animals

Hallucigenia is a genus of lobopodian known from Cambrian aged fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual appearance and eccentric history of study; when it was erected as a genus, H. sparsa was reconstructed as an enigmatic animal upside down and back to front. Lobopodians are a grade of Paleozoic panarthropods from which the velvet worms, water bears, and arthropods arose.

<i>Opabinia</i> Extinct stem-arthropod species found in Cambrian fossil deposits

Opabinia regalis is an extinct, stem group arthropod found in the Middle Cambrian Burgess Shale Lagerstätte of British Columbia. Opabinia was a soft-bodied animal, measuring up to 7 cm in body length, and its segmented trunk had flaps along the sides and a fan-shaped tail. The head shows unusual features: five eyes, a mouth under the head and facing backwards, and a clawed proboscis that probably passed food to the mouth. Opabinia probably lived on the seafloor, using the proboscis to seek out small, soft food. Fewer than twenty good specimens have been described; 3 specimens of Opabinia are known from the Greater Phyllopod bed, where they constitute less than 0.1% of the community.

<i>Marrella</i> Extinct genus of Arthropods

Marrella is an extinct genus of marrellomorph arthropod known from the Middle Cambrian of North America and Asia. It is the most common animal represented in the Burgess Shale of British Columbia, Canada, with tens of thousands of specimens collected. Much rarer remains are also known from deposits in China.

<i>Aysheaia</i> Extinct genus of soft-bodied animals

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<i>Wiwaxia</i> Genus of Cambrian animals

Wiwaxia is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. Wiwaxia fossils—mainly isolated scales, but sometimes complete, articulated fossils—are known from early Cambrian and middle Cambrian fossil deposits across the globe. The living animal would have measured up to 5 centimetres (2 in) when fully grown, although a range of juvenile specimens are known, the smallest being 2 millimetres (0.08 in) long.

<i>Sidneyia</i> Extinct genus of arthropods

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<i>Odontogriphus</i> Genus of soft-bodied animals from middle Cambrian

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<i>Orthrozanclus</i> Extinct genus of Cambrian animals

Orthrozanclus is a genus of sea creatures known from two species, O. reburrus from the Middle Cambrian Burgess shale and O. elongata from Early Cambrian Maotianshan Shales. Animals in this genus were one to two centimeters long, with spikes protruding from their armored bodies. The placement of this genus into a specific family is not universally accepted.

<i>Olenoides</i> Genus of trilobites

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<span class="mw-page-title-main">Halwaxiida</span> Proposed clade of extinct Lophotrochozoa

Halwaxiida or halwaxiids is a proposed clade equivalent to the older orders Sachitida He 1980 and Thambetolepidea Jell 1981, loosely uniting scale-bearing Cambrian animals, which may lie in the stem group to molluscs or lophotrochozoa. Some palaeontologists question the validity of the Halwaxiida clade.

<i>Burgessochaeta</i> Cambrian Annelid

Burgessochaeta is an extinct genus of polychaete annelids from the Middle Cambrian. Its fossils have been found in the Burgess Shale in British Columbia, Canada. A total of 189 specimens of Burgessochaeta are known from the Greater Phyllopod bed, where they comprise 0.36% of the community. Specimens have also been found at Marble Canyon. The genus was described by Conway Morris (1979) and re-examined by Eibye-Jacobsen (2004).

<i>Canadia spinosa</i> Species of annelid (fossil)

Canadia is a genus of extinct annelid worm present in Burgess Shale type Konservat-Lagerstätte. It is found in strata dating back to the Delamaran stage of the Middle Cambrian around 505 million years ago, during the time of the Cambrian explosion. It was about 3 centimeters in length. Charles Doolittle Walcott named Canadia in 1911 after Canada, the country from which its remains have been found. 28 specimens of Canadia are known from the Greater Phyllopod bed, where they comprise 0.05% of the community.

The fossils of the Burgess Shale, like the Burgess Shale itself, are fossils that formed around 505 million years ago in the mid-Cambrian period. They were discovered in Canada in 1886, and Charles Doolittle Walcott collected over 65,000 specimens in a series of field trips up to the alpine site from 1909 to 1924. After a period of neglect from the 1930s to the early 1960s, new excavations and re-examinations of Walcott's collection continue to reveal new species, and statistical analysis suggests that additional discoveries will continue for the foreseeable future. Stephen Jay Gould's 1989 book Wonderful Life describes the history of discovery up to the early 1980s, although his analysis of the implications for evolution has been contested.

<span class="mw-page-title-main">Annelid</span> Phylum of segmented worms

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<i>Balhuticaris</i> Extinct genus of arthropods

Balhuticaris is a genus of extinct bivalved hymenocarine arthropod that lived in the Cambrian aged Burgess Shale in what is now British Columbia around 506 million years ago. This extremely multisegmented arthropod is the largest member of the group, and it was even one of the largest animals of the Cambrian, with individuals reaching lengths of 245 mm (9 in). Fossils of this animal suggests that gigantism occurred in more groups of Arthropoda than had been previously thought. It also presents the possibility that bivalved arthropods were very diverse, and filled in a lot of ecological niches.

The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 538 and 485 million years ago. The first Cambrian chordate known is Pikaia gracilens, a lancelet-like animal from the Burgess Shale in British Columbia, Canada. The discoverer, Charles Doolittle Walcott, described it as a kind of worm (annelid) in 1911, but it was later identified as a chordate. Subsequent discoveries of other Cambrian fossils from the Burgess Shale in 1991, and from the Chengjiang biota of China in 1991, which were later found to be of chordates, several Cambrian chordates are known, with some fossils considered as putative chordates.

References

  1. 1 2 Nanglu, Karma; Caron, Jean-Bernard (2018). "A New Burgess Shale Polychaete and the Origin of the Annelid Head Revisited". Current Biology. 28 (2): 319–326.e1. doi: 10.1016/j.cub.2017.12.019 . ISSN   0960-9822. PMID   29374441.
  2. 1 2 "New 508-million-year-old bristle worm species from British Columbia's Burgess Shale wiggles into evolutionary history". phys.org. Retrieved 2018-01-22.