Branchiocaris

Branchiocaris
Temporal range: Middle Cambrian
Fossil holotype of Branchiocaris pretiosa
Reconstruction of Branchiocaris pretiosa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Order: Hymenocarina
Family: Protocarididae
Genus: Branchiocaris
Briggs, 1976
Species
  • Branchiocaris pretiosa (Resser, 1929) (type)
  • Branchiocaris? yunnanensis Hou 1987
  • Branchiocaris malongensis Luo et al. 2008
  • Branchiocaris xundianensis Luo et al. 2008
  • Branchiocaris yiliangensis Luo et al. 2008

Branchiocaris is an extinct genus of Cambrian bivalved arthropod.[1] The type and best known species, Branchiocaris pretiosa, was described from the Burgess Shale of British Columbia, Canada, in 1929, originally placed in Protocaris, and was placed into its own distinct genus by Briggs in 1976.[2] Several other possible species have been described from Cambrian deposits in China,[3] and it is also possibly known from Cambrian deposits in Utah.[4]

Description

Branchiocaris pretiosa is around 80–90 millimetres (3.1–3.5 in) in length, with a highly segmented trunk, consisting of at least 44 ring-like segments, terminating in a forked tail telson. At the front of the animal is a pair of short segmented tapered antennules with at least 20 segments, as well as a pair of claw appendages. It was likely an active swimmer, and used the claw appendages to bring food to the mouth.[5]

Taxonomy

The discovery of Tokummia from the Burgess Shale, believed to be a close relative of Branchiocaris, has shed light on the evolutionary placement of Branchiocaris. The authors find both species to be arthropods at a stem position within Mandibulata, as part of the clade Hymenocarina. This is in part based on the clear presence of mandibles, characteristic of all mandibulates.[6]

Cladogram of Hymenocarina, following Izquierdo-López and Caron, (2024):[7]

References

  1. ^ Briggs, D. E. G.; Erwin, D. H.; Collier, F. J. (1995), Fossils of the Burgess Shale, Washington: Smithsonian Institution Press, ISBN 1-56098-659-X, OCLC 231793738
  2. ^ BRIGGS, D. E. G. 1976. The arthropod Branchiocaris n. gen. Middle Cambrian, Burgess Shale, British Columbia. Geological Survey of Canada Bulletin, 264: 1-29.
  3. ^ Yu, Wu; Dongjing, Fu; Xingliang, Zhang; Daley, Allison C.; Degan, Shu (June 2016). "Dimorphism of Bivalved Arthropod Branchiocaris? Yunnanensis from the Early Cambrian Chengjiang Biota, South China". Acta Geologica Sinica - English Edition. 90 (3): 818–826. Bibcode:2016AcGlS..90..818W. doi:10.1111/1755-6724.12725. S2CID 132558912.
  4. ^ Lerosey-Aubril, Rudy; Kimmig, Julien; Pates, Stephen; Skabelund, Jacob; Weug, Andries; Ortega-Hernández, Javier (November 2020). Zhang, Xi-Guang (ed.). "New exceptionally preserved panarthropods from the Drumian Wheeler Konservat-Lagerstätte of the House Range of Utah". Papers in Palaeontology. 6 (4): 501–531. Bibcode:2020PPal....6..501L. doi:10.1002/spp2.1307. ISSN 2056-2802. S2CID 218995462.
  5. ^ "Branchiocaris pretiosa". The Burgess Shale. Royal Ontario Museum. Retrieved 2022-10-28.
  6. ^ Aria, Cédric; Caron, Jean-Bernard (26 April 2017). "Burgess Shale fossils illustrate the origin of the mandibulate body plan". Nature. 545 (7652): 89–92. Bibcode:2017Natur.545...89A. doi:10.1038/nature22080. PMID 28445464. S2CID 4454526.
  7. ^ Izquierdo-López, Alejandro; Caron, Jean-Bernard (August 2024). "The Cambrian Odaraia alata and the colonization of nektonic suspension-feeding niches by early mandibulates". Proceedings of the Royal Society B: Biological Sciences. 291 (2027). doi:10.1098/rspb.2024.0622. ISSN 1471-2954. PMC 11463219. PMID 39043240.