Sidneyia

Source: Wikipedia, the free encyclopedia.

Sidneyia
Temporal range: Cambrian Stage 3–Wuliuan
Reconstruction of Sidneyia minor
Fossil of S. inexpectans
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
(unranked): †Artiopoda
(unranked): †
Vicissicaudata
Genus: †Sidneyia
Walcott, 1911
Type species
†Sidneyia inexpectans
Walcott, 1911
Species
  • †S. inexpectans Walcott, 1911
  • †S. minor Du et al., 2023
  • †S. malongensis Zhu et al., 2023

Sidneyia is an extinct arthropod known from fossils found from the Early to the Mid Cambrian of China and the Mid Cambrian Burgess Shale of British Columbia, Canada.

Description

Size comparison of Sidneyia species
Biramous limb of Sidneyia inexpectans Key: gnathobasic basipod (pink, labelled pr) exopod (yellow, labelled ex), endopod (orange, with terminal podomere labelled pd7 in yellow)

Sidneyia inexpectans reached lengths of at least 160 millimetres (6.3 in).

exopod of these limbs is flattened and bears lamellae.[2] In S. inexpectans, the endopods of the biramous limbs have seven podomeres, with the first four of these each bearing a number of thin inward projecting spines, while the outer three podomeres bore more stout claw-like spines, with the fourth to ninth pairs of post antennal limbs bearing exopods with blade-like lamellae, which are thought to have been used as gills.[1] S. inexpectans had three pairs of digestive glands within the head shield and front of the thorax, adjacent to the central gut tube.[1]

Ecology

Sidneyia is thought to have been seafloor dwelling (

horseshoe crabs) to crush and shred prey items, including hard-shelled organisms like juvenile trilobites (which are abundantly preserved as stomach contents in S. inexpectans) and brachiopods (representing around 6% of the stomach contents of S. inexpectans), but possibly also softer animals like worms or soft bodied arthropods like bradoriids.[1][5]

Taxonomy

Sidneyia was discovered in 1910 during the first day of Charles Walcott's exploration of the Burgess Shale. He named it after his elder son, Sidney, who had helped to locate the site and collect the specimen. The species name, Sidneyia inexpectans, is derived from the meaning of "Sidney's surprise".[6]

144 specimens of Sidneyia are known from the Greater Phyllopod bed, where they comprise 0.27% of the community.[7]

Sidneyia sinica was named in 2002 from a specimen found in the

Chengjiang Biota of South China.[8] However, it has since been rejected from the genus, and other indeterminate specimens assigned to the genus from the Spence Shale and Sirius Passet lack key diagnostic characters. Specimens that can confidently assigned to the genus include Sidneyia cf. inexpectans, known from the Wuliuan Mantou Formation of North China,[9] Sidneyia minor from the Early Cambrian (Cambrian Stage 3) Xiaoshiba Biota of Yunnan, China,[2] and a valid species of Sidneyia from Chengjiang, Sidneyia malongensis.[3]

In 1923, Sidneyia, was placed, along with Emeraldella, as part of the group "Xenopoda". Today, both Sidneyia and Emeraldella are placed as part of the clade Vicissicaudata within Artiopoda, which includes trilobites and other arthropods with similar bodyforms. However, Sidneyia and Emeraldella are usually not recovered as each others closest relatives within Vicissicaudata, rendering "Xenopoda" invalid.[10]

See also

References

  1. ^
    S2CID 12638165
    .
  2. ^
    S2CID 257177978
    .
  3. ^
    doi:10.4202/app.01080.2023
    .
  4. S2CID 46830374
    .
  5. PMID 30355715
    .
  6. ISSN 0080-4622
    .
  7. S2CID 53646959
    .
  8. S2CID 129442308
    .
  9. S2CID 202899205
    .
  10. PMID 37538743
    .

External links

Further reading

  • D. L. Bruton (1981). "The arthropod Sidneyia inexpectans, Middle Cambrian, Burgess Shale, British Columbia".
    doi:10.1098/rstb.1981.0164
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Sidneyia&oldid=1187484302"