Vetulicolia

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Vetulicolia
Temporal range: about 535–501 
Ma
 Fortunian—Drumian
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Superphylum: Deuterostomia
Phylum: †Vetulicolia
Shu et al. 2001
Type species
†Vetulicola cuneata
Hou, 1987
Classes

Vetulicolia

Cambrian period.[1][2] The phylum was created by Degan Shu and his research team in 2001,[3] and named after Vetulicola cuneata, the first species of the phylum described in 1987.[4]

The vetulicolian

body segments and functions as a tail. All vetulicolians lack preserved appendages of any kind, having no legs, feelers or even eye spots.[5] The area where the anterior and posterior parts join is constricted.[6]

Their

stem- and crown-group arthropods, stem-group vertebrates,[7] and early deuterostomes (a group which as a whole includes the vertebrates, other invertebrate chordates, echinoderms and hemichordates). The general scientific consensus before 2001 considered them early limbless arthropods but now considers them early deuterostomes.[8] Vetulicolian fossils examined in 2014 show the presence of notochord-like structures, and it was concluded that vetulicolians are crown-group chordates and probably related to modern tunicates.[9] Research from 2017 rather indicates vetulicolians are related to Saccorhytus, another basal deuterostome group,[10] although another study shows possibility that Saccorhytus is ecdysozoan instead of deuterostome.[11]

Taxonomy and evolution

See also:
List of bilaterial animal orders
Vetulicola cuneata fossil.

Vetulicolia as a phylum was created by Chinese palaeontologist Degan Shu and his research team at the

Xidazoon) and Vetulicolidae (Vetulicola, and Banffia) as a separate group of animals.[1][3] Other animals which may be related include the yunnanozoans.[3]

The taxonomic placement of the vetulicolians remains controversial. The original researcher Shu is of the opinion that the vetulicolians probably represent an early type of deuterostomes, and that this implies that segmentation in

cephalochordates and vertebrates may be derived from the common ancestor of protostomes and deuterostomes.[7] However, Derek Briggs of Yale University and his team who described Skeemella from the Middle Cambrian of Utah regard it as having affinity to protostomes with important arthropod features, thus confounding assignment of Vetulicolia to Deuterostomia.[12] Thurston C. Lacalli of the University of Saskatchewan, Saskatoon, Canada, agreed that the group are deuterostomes, but suggested that the animals were more likely related to tunicates.[13]

Dominguez and Jefferies have argued, based on

Nesonektris aldridgei, from Australia in 2014 supported a position close to urochordates for vetulicolians.[9]

The monophyly of Deuterostomia is not strongly evidenced.

pharyngeal slits.[16] If this is the case, banffids, which appear to lack pharyngeal slits, may be more closely related to crown-group protostomes than other vetulicolians.[16]

Ecology and lifestyle

Fossil of a Vetulicola rectangulata.

From their superficially tadpole-like forms, leaf or paddle-shaped tails, and various degrees of streamlining, it is assumed that all vetulicolians discovered to date were swimming animals that spent much, if not all, of their time living in water.[14] Some groups, like the genus Vetulicola, were more streamlined (complete with ventral keels) than other groups, such as the tadpole-like Didazoonidae.[14]

Because all vetulicolians had mouths which had no features for chewing or grasping, it is assumed that they were not predators.

planktivores. The sediment infills in the guts of their fossils have caused some to suggest that they were deposit feeders. This idea has been contested, as deposit feeders tend to have straight guts, whereas the hindguts of vetulicolians were spiral-shaped. Some researchers propose that the vetulicolians were "selective deposit-feeders" which actively swam from one region of the seafloor to another, while supplementing their nutrition with filter-feeding.[14]

Classification

Notes

  1. ^ The taxon name, Vetulocolia, is derived from the type genus, Vetulicola, which is a compound Latin word composed of vetuli "old" and cola "inhabitant".

References

  1. ^
    S2CID 86827605
    .
  2. ^
    ISSN 2076-3263
    .
  3. ^
    S2CID 4345484
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  4. ^
    S2CID 44066226
    .
  5. S2CID 128895860[dead link
    ]
  6. ^
    doi:10.3390/geosciences9080354
    .
  7. ^
    S2CID 85163902
    .
  8. ^ Dominguez, Patricio and Jeffries, Richard. (2003). Fossil evidence on the origin of appendicularians. Paper read at International Urochordate Meeting 2003. Abstract at [2] – URL retrieved June 22, 2006.
  9. ^
    PMID 25273382
    .
  10. S2CID 353780
    .
  11. S2CID 251646316
    .
  12. doi:10.1111/j.1475-4983.2005.00489.x
    .
  13. PMID 11891757
    .
  14. ^
    S2CID 85722738
    .
  15. PMID 31104936
    .
  16. ^
    bioRxiv 10.1101/2020.07.01.182915
    .
  17. S2CID 85602402
    .
  18. S2CID 128895860.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  19. S2CID 128851764
    .

External links

Wikispecies has information related to Vetulicolia.
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