Primicaris

Primicaris is genus of Cambrian arthropod from the Chengjiang biota of China and the Burgess Shale of Canada. It contains a single described species, P. larvaformis.

Primicaris
Temporal range: Cambrian
Artist's reconstruction
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: †Marrellomorpha
Order: †Acercostraca
Genus: †Primicaris
Zhang et al 2003
Species:
†P. larvaformis
Binomial name
†Primicaris larvaformis
Zhang et al 2003

Description

Specimens range from 2.08 to 6.04 millimetres (3⁄32 to 1⁄4 in) in length, and 1.50 and 4.20 millimetres (1⁄16 and 5⁄32 in) in maximum width. The undivided subovate-shaped dorsal shield covered the entire body, and wrapped around the front edge of the carapace, forming a doublure structure. The midline of the carapace exhibited thickening. There is a pair of slender uniramous segmented antennae, as well as ten pairs of biramous limbs. The exopods of these limbs are flagellate and bear setae, with the exopods decreasing in size posteriorly. The endopods are poorly preserved.[1]

Taxonomy

Its specimens were once thought to be meraspids of Naraoia spinosa.[1] Although their phylogenetic position has been described as "problematic",[2] recent studies have suggested them to be marrellomorphs belonging to the subgroup Acercostraca.[3][4]

See also

References
  1. Zhang, Xing-Liang; Han, Jian; Zhang, Zhi-Fei; Liu, Hu-Qin; Shu, De-Gan (May 2003). "Reconsideration of the supposed naraoiid larva from the Early Cambrian Chengjiang Lagerstatte, South China". Palaeontology. 46 (3): 447–465. doi:10.1111/1475-4983.00307. ISSN 0031-0239.
  2. Caron, Jean-Bernard; Gaines, Robert R.; Aria, Cédric; Mángano, M. Gabriela; Streng, Michael (2014-02-11). "A new phyllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies". Nature Communications. 5 (1): 3210. Bibcode:2014NatCo...5.3210C. doi:10.1038/ncomms4210. ISSN 2041-1723. PMID 24513643.
  3. Legg, D.A. (2015-09-30). "The morphology and affinities of Skania fragilis (Arthropoda) from the middle Cambrian Burgess Shale". Bulletin of Geosciences: 509–518. doi:10.3140/bull.geosci.1532. ISSN 1802-8225.
  4. Moysiuk, Joseph; Izquierdo-López, Alejandro; Kampouris, George E.; Caron, Jean-Bernard (July 2022). "A new marrellomorph arthropod from southern Ontario: a rare case of soft-tissue preservation on a Late Ordovician open marine shelf". Journal of Paleontology. 96 (4): 859–874. doi:10.1017/jpa.2022.11. ISSN 0022-3360.


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