Haikoucaris Explained

Haikoucaris is a genus of megacheiran arthropod that contains the single species Haikoucaris ercaiensis. It was discovered in the Cambrian Chengjiang biota of China.^[1]

Morphology

Haikoucaris measured about 38 mm in body length. The elongated body compose of a semicircular head shield, 13 trunk tergites and presumely a short, spine-like telson.^[2] The head possess a pair of unstalked eyes, a pair well-developed great appendages, as well as 3 more appendage pairs of unknown detail. Each of the great appendage consists of a 2-segmented peduncle and a 3-segmented claw. Each of the trunk segment possess a pair of biramus appendages that each comprising a leaf-shaped exopod and a possibly 7-segmented endopod.

Paleoecology

Haikoucaris may have been a predator, with its great appendages and exopod suggested to be used for hunting and swimming respectively.

Taxonomy

Within megacheirans, Haikoucaris is generally accepted to be a member of the clade Cheiromorpha alongside Yohoia and Leanchoiliidae.^{[3] [4] [5] [6]}

See also

• Cambrian explosion
• Chengjiang biota
  • List of Chengjiang Biota species by phylum

Notes and References

1. Chen. Junyuan. Waloszek. Dieter. Maas. Andreas. 2004. A new 'great-appendage' arthropod from the Lower Cambrian of China and homology of chelicerate chelicerae and raptorial antero-ventral appendages. Lethaia. en. 37. 1. 3–20. 10.1080/00241160410004764. 1502-3931.
2. Book: Xian-Guang. Hou. The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life. Siveter. David J.. Siveter. Derek J.. Aldridge. Richard J.. Pei-Yun. Cong. Gabbott. Sarah E.. Xiao-Ya. Ma. Purnell. Mark A.. Williams. Mark. 2017-03-08. John Wiley & Sons. 978-1-118-89631-0. en.
3. Aria. Cédric. Caron. Jean-Bernard. Gaines. Robert. 2015. A large new leanchoiliid from the Burgess Shale and the influence of inapplicable states on stem arthropod phylogeny. Palaeontology. en. 58. 4. 629–660. 10.1111/pala.12161. 86443516 . 1475-4983. free.
4. Izquierdo-López. Alejandro. Caron. Jean-Bernard. 2019. A possible case of inverted lifestyle in a new bivalved arthropod from the Burgess Shale. Royal Society Open Science. 6. 11. 191350. 10.1098/rsos.191350. 6894550. 31827867. 2019RSOS....691350I .
5. Aria. Cédric. Caron. Jean-Bernard. 2017-12-21. Mandibulate convergence in an armoured Cambrian stem chelicerate. BMC Evolutionary Biology. 17. 1. 261. 10.1186/s12862-017-1088-7. 1471-2148. 5738823. 29262772 . free .
6. Aria. Cédric. Zhao. Fangchen. Zeng. Han. Guo. Jin. Zhu. Maoyan. December 2020. Fossils from South China redefine the ancestral euarthropod body plan. BMC Evolutionary Biology. en. 20. 1. 4. 10.1186/s12862-019-1560-7. 1471-2148. 6950928. 31914921 . free .