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Ancalagon (worm)

April 15, 2024

Ancalagon minor is an extinct priapulid worm known from the Cambrian Burgess Shale.[3]

Ancalagon
Temporal range: Mid Cambrian
Reconstruction of Ancalagon minor
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Stem group: Priapulida (?)
Class: †Archaeopriapulida
Family: †Ancalagonidae
Conway Morris, 1977[1]
Genus: †Ancalagon
Conway Morris, 1977[1]
Species
  • †A. minor (Walcott, 1911) Conway Morris, 1977 (type)
Synonyms
  • Ottoia minor Walcott 1911[2]

Because it superficially resembles the modern-day internal parasites known as the acanthocephalids or "spiny-headed worms," A. minor was once thought to be, or once thought to resemble the hypothetical free-living ancestor of acanthocephalids.[3][4] Two specimens of Ancalagon (worm) are known from the Greater Phyllopod bed, where they comprise < 0.01% of the community.[5]

Along with the other Cambrian worms such as Ottoia, Selkirkia, Louisella, Fieldia, Scolecofurca, and Lecythioscopa, the organism may fall into a clade termed "Archaeopriapulida," a stem group to the Priapulids proper.[6] However, the morphological similarity of these organisms to their modern cousins is remarkable, especially for the Burgess Shale.[7] A phylogenetic analysis does not provide a great deal of resolution to the relationships between these basal worms.[8]

Etymology edit

The generic name is a homage to the dragon Ancalagon of J.R.R. Tolkien's Middle-earth legendarium, in reference to the worm's prominent rows of hooks on its proboscis.[9] The species was previously placed in the genus Ottoia, as Ottoia minor, but was removed by Simon Conway Morris, who noted morphological differences.[10]

Morphology edit

Ancalagon had a slender, cyndrical, radially symmetric body[10] averaging 6 centimeters in length. Its proboscis was armed with circum-oral hooks at the anterior. There were about 10 of these hooks, equal in size and with prominent bases. Directly posterior was an unarmed space, followed by posteriorly directed spinose hooks. The trunk is annulated with 0.2 to 0.25 millimeter spacing, and carried rows of setae possibly performing sensory functions. The apparent absence of retractor muscles correlates with Ancalagon's inability to significantly invert its proboscis. The organism was probably a burrowing predator.[1]

See also edit

References edit

  1. ^ a b c Conway Morris, S. "Fossil priapulid worms". Special Papers in Palaeontology. 20.
  2. ^ Haaramo, Mikko (2003). "Scalidophora – †palaeoscolecids, priapulids, mud dragons and brush heads". Mikko's Phylogeny Archive. from the original on 2023-04-22.
  3. ^ a b Conway Morris, S. (1979). "The Burgess Shale (Middle Cambrian) Fauna". Annual Review of Ecology and Systematics. 10: 327–349. doi:10.1146/annurev.es.10.110179.001551.
  4. ^ Conway Morris, S.; Crompton, D. W. T. (1982). "The Origins and Evolution of the Acanthocephala". Biological Reviews. 57: 85–115. doi:10.1111/j.1469-185X.1982.tb00365.x. S2CID 84098740.
  5. ^ Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. Bibcode:2006Palai..21..451C. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022. S2CID 53646959.
  6. ^ Por, F. D. (1983). "Class Seticoronaria and Phylogeny of the Phylum Priapulida". Zoologica Scripta. 12 (4): 267–272. doi:10.1111/j.1463-6409.1983.tb00510.x. S2CID 85091685.
  7. ^ Huang, D. Y.; Vannier, J.; Chen, J.Y. (2004). "Anatomy and lifestyles of Early Cambrian priapulid worms exemplified by Corynetis and Anningvermis from the Maotianshan Shale (SW China)". Lethaia. 37: 21–33. doi:10.1080/00241160410005088.
  8. ^ Wills, M. A. (1 April 1998). "Cambrian and Recent Disparity: the Picture from Priapulids". Paleobiology. 24 (2): 177–199. doi:10.1666/0094-8373(1998)024[0177:CARDTP]2.3.CO;2. JSTOR 2401237. S2CID 88647544.
  9. ^ "Ancalagon minor". Burgess Shale Fossil Gallery. Virtual Museum of Canada. from the original on 2023-03-21.
  10. ^ a b Whittington, H.B. (1911). "Middle Cambrian Annelids". Cambrian Geology and Paleontology. 2: 109–142.

External links edit

  • "Ancalagon minor". Burgess Shale Fossil Gallery. Virtual Museum of Canada. from the original on 2023-03-21.

April 15, 2024
ancalagon, worm, ancalagon, minor, extinct, priapulid, worm, known, from, cambrian, burgess, shale, ancalagontemporal, range, cambrian, preꞒ, nreconstruction, ancalagon, minorscientific, classificationdomain, eukaryotakingdom, animaliastem, group, priapulida, . Ancalagon minor is an extinct priapulid worm known from the Cambrian Burgess Shale 3 AncalagonTemporal range Mid Cambrian PreꞒ Ꞓ O S D C P T J K Pg NReconstruction of Ancalagon minorScientific classificationDomain EukaryotaKingdom AnimaliaStem group Priapulida Class ArchaeopriapulidaFamily AncalagonidaeConway Morris 1977 1 Genus AncalagonConway Morris 1977 1 Species A minor Walcott 1911 Conway Morris 1977 type SynonymsOttoia minor Walcott 1911 2 Because it superficially resembles the modern day internal parasites known as the acanthocephalids or spiny headed worms A minor was once thought to be or once thought to resemble the hypothetical free living ancestor of acanthocephalids 3 4 Two specimens of Ancalagon worm are known from the Greater Phyllopod bed where they comprise lt 0 01 of the community 5 Along with the other Cambrian worms such as Ottoia Selkirkia Louisella Fieldia Scolecofurca and Lecythioscopa the organism may fall into a clade termed Archaeopriapulida a stem group to the Priapulids proper 6 However the morphological similarity of these organisms to their modern cousins is remarkable especially for the Burgess Shale 7 A phylogenetic analysis does not provide a great deal of resolution to the relationships between these basal worms 8 Contents 1 Etymology 2 Morphology 3 See also 4 References 5 External linksEtymology editThe generic name is a homage to the dragon Ancalagon of J R R Tolkien s Middle earth legendarium in reference to the worm s prominent rows of hooks on its proboscis 9 The species was previously placed in the genus Ottoia as Ottoia minor but was removed by Simon Conway Morris who noted morphological differences 10 Morphology editAncalagon had a slender cyndrical radially symmetric body 10 averaging 6 centimeters in length Its proboscis was armed with circum oral hooks at the anterior There were about 10 of these hooks equal in size and with prominent bases Directly posterior was an unarmed space followed by posteriorly directed spinose hooks The trunk is annulated with 0 2 to 0 25 millimeter spacing and carried rows of setae possibly performing sensory functions The apparent absence of retractor muscles correlates with Ancalagon s inability to significantly invert its proboscis The organism was probably a burrowing predator 1 See also editAnkalagon a mesonychid ungulate also named after Ancalagon the Black References edit a b c Conway Morris S Fossil priapulid worms Special Papers in Palaeontology 20 Haaramo Mikko 2003 Scalidophora palaeoscolecids priapulids mud dragons and brush heads Mikko s Phylogeny Archive Archived from the original on 2023 04 22 a b Conway Morris S 1979 The Burgess Shale Middle Cambrian Fauna Annual Review of Ecology and Systematics 10 327 349 doi 10 1146 annurev es 10 110179 001551 Conway Morris S Crompton D W T 1982 The Origins and Evolution of the Acanthocephala Biological Reviews 57 85 115 doi 10 1111 j 1469 185X 1982 tb00365 x S2CID 84098740 Caron Jean Bernard Jackson Donald A October 2006 Taphonomy of the Greater Phyllopod Bed community Burgess Shale PALAIOS 21 5 451 65 Bibcode 2006Palai 21 451C doi 10 2110 palo 2003 P05 070R JSTOR 20173022 S2CID 53646959 Por F D 1983 Class Seticoronaria and Phylogeny of the Phylum Priapulida Zoologica Scripta 12 4 267 272 doi 10 1111 j 1463 6409 1983 tb00510 x S2CID 85091685 Huang D Y Vannier J Chen J Y 2004 Anatomy and lifestyles of Early Cambrian priapulid worms exemplified by Corynetis and Anningvermis from the Maotianshan Shale SW China Lethaia 37 21 33 doi 10 1080 00241160410005088 Wills M A 1 April 1998 Cambrian and Recent Disparity the Picture from Priapulids Paleobiology 24 2 177 199 doi 10 1666 0094 8373 1998 024 0177 CARDTP 2 3 CO 2 JSTOR 2401237 S2CID 88647544 Ancalagon minor Burgess Shale Fossil Gallery Virtual Museum of Canada Archived from the original on 2023 03 21 a b Whittington H B 1911 Middle Cambrian Annelids Cambrian Geology and Paleontology 2 109 142 External links edit Ancalagon minor Burgess Shale Fossil Gallery Virtual Museum of Canada Archived from the original on 2023 03 21 Retrieved from https en wikipedia org w index php title Ancalagon worm amp oldid 1213048317, wikipedia, wiki, book, books, library,

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