Vetulicola cuneata

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Vetulicola cuneata
Temporal range: Cambrian Stage 3
Reconstruction of V. cuneata
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: †Vetulicolia
Class: †Vetulicolida
Order: †Vetulicolata
Family: †Vetulicolidae
Genus: †Vetulicola
Species:
†V. cuneata
Binomial name
†Vetulicola cuneata
Hou, 1987

Vetulicola cuneata ("wedged-shaped ancient dweller") is a species of extinct animal from the Early

Chiungchussu Formation,[1][2] and became the first animal (type species) under an eponymous phylum Vetulicolia.[3]

Remarked as "enigmatic creatures"

Vetulicolata), family (Vetulicolidae) and ultimately a new phylum were created based on its name.[3][5]

Discovery and taxonomy

In 1984, Hou Xian-guang of the Nanjing Institute of Geology and Palaeontology,

Chengjiang biota.[8]

Among Hou's earliest collections were a group of bivalved arthropods, which he described in the journal Acta Palaeontologica Sinica in 1987.[2] One group which he categorised "larger bivalved arthropods" included five distinct species, one of which he named Vetulicola cuneata,[1] for its obvious ancient nature (Latin vetuli means "old" and cola, "inhabitant") and wedge-shaped beak-like body (cuneata for wedge-shaped).[4] Although Hou classified V. cuneata as a species of the phylum Arthopoda for its prominent body covering called carapace, a common feature among arthropods, he immediately noticed some issues. The Vetulicola body was divided into two separate parts, dorsal and ventral carapace, by clear longitudinal groove, which he realised was an odd feature for an arthropod that should normally lack such demarcating groove. He also mistakenly identified a short tail-like projection at the posterior region as consisting of two segments and attached to the ventral side of the body.[9]

In 1991, with the help of Jan Bergström (of the Swedish Museum of Natural History), Hou re-analysed the species from more than 100 specimens and resolved that the posterior projection typically consists of seven segments and arose (after turning upside-down the specimens) from the dorsal surface of the body.[10] Palaeontologists continued to consider the species as an arthropod although they understood the anomaly and missing features of Arthropoda.[11][12][13]

In 1997, Hou's colleagues Jun-yuan Chen and Guiqing Zhou extensively reviewed and re-eaxmined the Chengjian fossils. Among the new species they identified was

Annelida for its apparent segmented worm-like body.[16] When Chen and Zhou compared B. confusa with V. cuneata, they realised the close relationship between the two specimens, having shared most defining features, so that they created a new class Vetulicolida for the two genus under Arthropoda.[9][17]

In 1999, Huilin Luo and his colleagues at the Yunnan Institute of Geological Sciences described a new species

Didazoon haoae, they revised the entire classification adopting the class Vetulicolida and introduced the phylum Vetulicolia for all species of Vetulicola, Banffia, Pomatrum, Xidazoon and Didazoon. The new phylum was classified as member of the "primitive deuterostomes," a group that consists of animals ancestral to chordates.[5][20]

Description

Fossil of Vetulicola cuneata

Vetulicola cuneata has a body composed of two distinct parts of approximately equal length.

dorsally.[1] It is made up of seven segments.[9] Paired openings connecting the pharynx to the outside run down the sides. These features are interpreted as possible primitive gill slits.[21] The entire body could be up to 7 cm long.[22]

Lifestyle

It is assumed that V. cuneata spent most or all of its time swimming in the water column. Sediment found within the gut suggest that it was a deposit-feeder, possibly swimming to and from favorable feeding sites. Some specimens that had individuals of the putative

Cotyledion tyloides attached to the terminal tail segment indicate that V. cuneata lay buried in the sediment, with only its terminal segment exposed, but, nothing about its anatomy, or the taphonomy of its fossils, suggest that it was a burrower. Rather, it was more likely that larval C. tyloides would occasionally settle on the terminal segment, then take advantage of serendipity to feed whenever their host discharged nutrient-rich fecal matter.[23]

V. cuneata and V. rectangulata have symbiotic association with a worm called Vermilituus gregarius. The worms are attached on the internal surface of the plates as a kind of endosymbionts. The nature of the symbiosis is not clear, as it could be either useful (commensal) or harmful (parasitic).[24]

References

  1. ^ a b c d Hou, Xian-guang (1987). "Early Cambrian large bivalved arthropods from Chengjiang, Eastern Yunnan". Acta Palaeontologica Sinica. 26 (3): 272–285 – via China Knowledge Network.
  2. ^
    S2CID 44066226
    .
  3. ^
    S2CID 86827605
    .
  4. ^
    ISSN 2076-3263
    .
  5. ^
    S2CID 4345484
    .
  6. ISSN 1342-8144
    .
  7. ^ Zhang, T.W.; Hou, X.-G. (1985). "Preliminary notes on the occurrence of the unusual trilobite Naraoia in Asia". Acta Palaeontologica Sinica. 24 (6): 591–595.
  8. PMID 25750235
    .
  9. ^
    S2CID 85722738
    .
  10. ISBN 978-0-521-11158-4
    .
  11. S2CID 85077111
    .
  12. ISBN 978-1-4899-2429-2
    , retrieved 2023-03-18
  13. ISBN 978-1-4899-2429-2
    , retrieved 2023-03-18
  14. ISSN 1726-2038
    .
  15. ^ Walcott, Charles D. (1911). "Cambrian Geology and Paleontology II: No.5--Middle Cambrian Annelids" (PDF). Smithsonian Miscellaneous Collections. 57 (5): 109–144.
  16. S2CID 10491968
    .
  17. ^ Chen, Junyuan; Zhou, Guiqing (1997). "Biology of the Chengjiang Fauna". In Iten, H.V. (ed.). The Cambrian Explosion and the Fossil Record. National Museum of Natural Science. pp. 11, 95.
  18. S2CID 133363305
    .
  19. S2CID 204995356
    .
  20. S2CID 86827605
    .
  21. PMID 23031545
    .
  22. ISSN 1871-174X
    .
  23. PMID 23336066
    .
  24. PMID 32948820
    .

External links
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