Parapeytoia
Temporal range:
Holotype of Parapeytoia yunnanensis, part and counterpart
Ventral structures of the same species
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Megacheira
Family: Jianfengiidae
Genus: Parapeytoia
Hou, Bergström & Ahlberg, 1995[1]
Type species
Parapeytoia yunnanensis
Hou, Bergstrom & Ahlberg, 1995[1]

Parapeytoia is a genus of Cambrian arthropod. The type and only described species is Parapeytoia yunnanensis, lived over 518 million years ago[2] (Cambrian Stage 3) in the Maotianshan shales of Yunnan, China. Unidentified fossils from the same genus also had been discovered from the nearby Wulongqing Formation (Cambrian Stage 4).[3]

Classification

Initially, Parapeytoia was interpreted as a radiodont ("anomalocaridid" at that time) dinocaridid with legs alongside Cucumericrus,[1] purported to be an indicator that radiodonts might have legs underneath their body flaps in general, comparable to Pambdelurion.[4] With the combination of megacheiran and presumably radiodont features (see text), it was also suggest to be an intermediate form between the two taxa.[5][6] However, later studies reveal it most likely nested within megacheirans,[7][8][9][10][11][12][13][14] and megacheirans was no longer thought to be originated from radiodonts since than.[15] Within megacheirans, Parapeytoia possibly closest to the multisegmented (with over 20 trunk segments) taxa like Fortiforceps and Jianfengia, united under the family Jianfengiidae.[14]

Description

Interpretations on Parapeytoia yunnanensis as a radiodont (A) and jianfengiid megacheiran (B) respectively. Red parts indicating suggested radiodont-like features with questionable affinity. Dark grey indicating other structures unambiguously belong to this species.

Parapeytoia is known from a few incomplete fossil materials with part of its ventral structures preserved. The frontmost appendages were a pair of great appendages that form by a robust peduncle and 4 distal segments with serrated spine on each of them, a feature shared by some other megacheirans such as Yohoia and Fortiforceps.[16][17] Behind the great appendages were 2 or 3 pairs of short appendages, and numerous pairs of well-developed biramous appendages, each formed by a basipod with spiny gnathobase, lobe-like exopod and leg-like endopod with 8 segments. A narrow , hourglass-like sternite associated between each of those appendages.[1]

Some features originally interpreted as radiodont-like are more or less questionable, such as radial sclerites interpreted as its mouthparts (oral cone) have since been assigned to another genus of animal, Omnidens.[18] While some subsequent studies suggest those features are genuine, it most likely represent ancestral traits originated from more basal arthropods instead of any indicators of radiodont affinities.[19] The same goes with gnathobases,[20] and the presence of arthropodized endopods underneath the purported body flaps (exopods) conflict with the component of radiodont trunk appendages as well (the radiodont ventral body flaps are most likely homologous to euarthropod endopods).[13]

Parapeytoia was in all likelihood a benthic feeder, spending most of its time on the ocean floor hunting (or possibly scavenging) for prey.[12]

References

  1. 1 2 3 4 Xian-Guang, Hou; Bergström, Jan; Ahlberg, Per (1995-09-01). "Anomalocaris and other large animals in the lower Cambrian Chengjiang fauna of southwest China". GFF. 117 (3): 163–183. Bibcode:1995GFF...117..163X. doi:10.1080/11035899509546213. ISSN 1103-5897.
  2. Yang, Chuan; Li, Xian-Hua; Zhu, Maoyan; Condon, Daniel J.; Chen, Junyuan (2018). "Geochronological constraint on the Cambrian Chengjiang biota, South China". Journal of the Geological Society. 175 (4): 659–666. Bibcode:2018JGSoc.175..659Y. doi:10.1144/jgs2017-103. ISSN 0016-7649. S2CID 135091168.
  3. Hu, ShiXue; Zhu, MaoYan; Steiner, Michael; Luo, HuiLin; Zhao, FangChen; Liu, Qi (2010-12-01). "Biodiversity and taphonomy of the Early Cambrian Guanshan biota, eastern Yunnan". Science China Earth Sciences. 53 (12): 1765–1773. Bibcode:2010ScChD..53.1765H. doi:10.1007/s11430-010-4086-9. ISSN 1869-1897. S2CID 128882075.
  4. Xianguang, Hou; Jan, Jan Bergström; Jiayu, In Rong; Zongjie, Fang; Zhanghe, Zhou; Renbin, Zhan; Xiangdong, Wang; (eds, Yuan Xunlai et al. (2006). Dinocaridids - anomalous arthropods or arthropod-like worms?.
  5. Budd, Graham E. (2002). "A palaeontological solution to the arthropod head problem". Nature. 417 (6886): 271–275. Bibcode:2002Natur.417..271B. doi:10.1038/417271a. ISSN 1476-4687. S2CID 4310080.
  6. 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. 37 (1): 3–20. doi:10.1080/00241160410004764. ISSN 0024-1164.
  7. Daley, Allison C.; Budd, Graham E.; Caron, Jean-Bernard; Edgecombe, Gregory D.; Collins, Desmond (2009-03-20). "The Burgess Shale Anomalocaridid Hurdia and Its Significance for Early Euarthropod Evolution". Science. 323 (5921): 1597–1600. Bibcode:2009Sci...323.1597D. doi:10.1126/science.1169514. ISSN 0036-8075. PMID 19299617. S2CID 206517995.
  8. Stein, Martin (2010-03-01). "A new arthropod from the Early Cambrian of North Greenland, with a 'great appendage'-like antennula". Zoological Journal of the Linnean Society. 158 (3): 477–500. doi:10.1111/j.1096-3642.2009.00562.x. ISSN 0024-4082.
  9. Legg, David A.; Sutton, Mark D.; Edgecombe, Gregory D.; Caron, Jean-Bernard (2012). "Cambrian bivalved arthropod reveals origin of arthrodization". Proceedings of the Royal Society B: Biological Sciences. 279 (1748): 4699–4704. doi:10.1098/rspb.2012.1958. ISSN 0962-8452. PMC 3497099. PMID 23055069.
  10. Legg, David A.; Sutton, Mark D.; Edgecombe, Gregory D. (2013-09-30). "Arthropod fossil data increase congruence of morphological and molecular phylogenies". Nature Communications. 4 (1): 2485. Bibcode:2013NatCo...4.2485L. doi:10.1038/ncomms3485. ISSN 2041-1723. PMID 24077329.
  11. Daley, Allison C.; Edgecombe, Gregory D. (2014). "Morphology of Anomalocaris canadensis from the Burgess Shale". Journal of Paleontology. 88 (1): 68–91. Bibcode:2014JPal...88...68D. doi:10.1666/13-067. ISSN 0022-3360. S2CID 86683798.
  12. 1 2 Xian-Guang, Hou; Siveter, David J.; Siveter, Derek J.; Aldridge, Richard J.; Pei-Yun, Cong; Gabbott, Sarah E.; Xiao-Ya, Ma; Purnell, Mark A.; Williams, Mark (2017-04-24). The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life. John Wiley & Sons. ISBN 9781118896389.
  13. 1 2 Van Roy, Peter; Daley, Allison C.; Briggs, Derek E. G. (2015-06-04). "Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps". Nature. 522 (7554): 77–80. Bibcode:2015Natur.522...77V. doi:10.1038/nature14256. ISSN 1476-4687. PMID 25762145. S2CID 205242881.
  14. 1 2 Aria, Cédric; Zhao, Fangchen; Zeng, Han; Guo, Jin; Zhu, Maoyan (2020). "Fossils from South China redefine the ancestral euarthropod body plan". BMC Evolutionary Biology. 20 (1): 4. Bibcode:2020BMCEE..20....4A. doi:10.1186/s12862-019-1560-7. ISSN 1471-2148. PMC 6950928. PMID 31914921.
  15. Ortega-Hernández, Javier; Janssen, Ralf; Budd, Graham E. (2017-05-01). "Origin and evolution of the panarthropod head – A palaeobiological and developmental perspective". Arthropod Structure & Development. Evolution of Segmentation. 46 (3): 354–379. doi:10.1016/j.asd.2016.10.011. ISSN 1467-8039. PMID 27989966.
  16. Haug, Joachim T.; Waloszek, Dieter; Maas, Andreas; Liu, Yu; Haug, Carolin (March 2012). "Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian". Palaeontology. 55 (2): 369–399. Bibcode:2012Palgy..55..369H. doi:10.1111/j.1475-4983.2011.01124.x. S2CID 82841481.
  17. Zeng, Han; Zhao, Fangchen; Niu, Kecheng; Zhu, Maoyan; Huang, Diying (2020). "An early Cambrian euarthropod with radiodont-like raptorial appendages". Nature. 588 (7836): 101–105. Bibcode:2020Natur.588..101Z. doi:10.1038/s41586-020-2883-7. ISSN 1476-4687. PMID 33149303. S2CID 226248177.
  18. Hou, Xianguang; Bergström, Jan; Jie, Yang (2006). "Distinguishing anomalocaridids from arthropods and priapulids". Geological Journal. 41 (3–4): 259–269. Bibcode:2006GeolJ..41..259X. doi:10.1002/gj.1050. S2CID 83582128.
  19. Budd, Graham E. (2021-05-01). "The origin and evolution of the euarthropod labrum". Arthropod Structure & Development. 62: 101048. doi:10.1016/j.asd.2021.101048. ISSN 1467-8039.
  20. Cong, Peiyun; Daley, Allison C.; Edgecombe, Gregory D.; Hou, Xianguang (2017). "The functional head of the Cambrian radiodontan (stem-group Euarthropoda) Amplectobelua symbrachiata". BMC Evolutionary Biology. 17 (1): 208. Bibcode:2017BMCEE..17..208C. doi:10.1186/s12862-017-1049-1. ISSN 1471-2148. PMC 5577670. PMID 28854872.
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