Paranomalocaris

Paranomalocaris
Temporal range: Cambrian Stage 4
Frontal appendages of Paranomalocaris
Holotype of P. multisegmentalis
Scientific classification Edit this classification
Kingdom: Animalia
Stem group: Arthropoda
Class: †Dinocaridida
Order: †Radiodonta
Family: †Anomalocarididae (?)
Genus: †Paranomalocaris
Wang, Huang & Hu, 2013
Type species
Paranomalocaris multisegmentalis
Wang, Huang & Hu, 2013
Other species
  • Paranomalocaris simplex
    Jiao et al. 2021

Paranomalocaris is a genus of radiodont recovered from the Cambrian Stage 4 aged Wulongqing Formation, eastern Yunnan. It contains two species, Paranomalocaris multisegmentalis and P. simplex. It is only known from its frontal appendages.

Morphology

Fossil specimens of P. simplex

As the generic name suggest, Paranomalocaris frontal appendages resembling those of Anomalocaris at first glance, but distinctive by its excessive number of podomeres (segments), hence the specific name multisegmentalis for the type species. While most radiodont frontal appendages only have 16 (13 excluding the shaft/base region) or fewer podomeres, there are at least 17 segments in P. simplex and up to 22 segments in P. multisegmentalis.

The 2 species of Paranomalocaris differ by their endites (inner spines), where they are short and have many auxiliary spines in P. multisegmentalis, but simple and needle-like in P. simplex, hence the specific name. P. multisegmentalis also characterized by dorsal spines with serrated margin, a feature which is unique among radiodonts.

Paleobiology

Paranomalocaris may had been a predatory radiodont. The frontal appendages with excessive podomeres suggest a wide range of movement, and the many well developed endites imply a grasping and trapping function, specifically suitable for catching small and agile preys.

Taxonomy

Most phylogenetic analysis recovered Paranomalocaris as a member within the Anomalocarididae+Amplectobeluidae clade, but the deeper taxonomic position is uncertain. Some suggest it was part of Anomalocarididae, while others suggest it was basal than both families or closer to Ramskoeldia.

References

  1. 1 2 3 Jiao, De-guang; Pates, Stephen; Lerosey-Aubril, Rudy; Ortega-Hernandez, Javier; Yang, Jie; Lan, Tian; Zhang, Xi-guang (2021). "The endemic radiodonts of the Cambrian Stage 4 Guanshan biota of South China". Acta Palaeontologica Polonica. 66. doi:10.4202/app.00870.2020. ISSN 0567-7920. S2CID 236683029.
  2. 1 2 3 4 5 6 YuanYuan Wang; DiYing Huang; ShiXue Hu (2013). "New anomalocardid frontal appendages from the Guanshan biota, eastern Yunnan". Chinese Science Bulletin. 58 (32): 3937–3942. Bibcode:2013ChSBu..58.3937W. doi:10.1007/s11434-013-5908-x.
  3. ↑ Factor Trace (2026-04-11). Every Anomalocaridid-grade Radiodont, explained. Retrieved 2026-06-19 – via YouTube.
  4. ↑ Van Roy, Peter; Daley, Allison C.; Briggs, Derek E. G. (2015). "Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps". Nature. 522 (7554): 77–80. doi:10.1038/nature14256. ISSN 1476-4687.
  5. 1 2 Liu, Jianni; Lerosey-Aubril, Rudy; Steiner, Michael; Dunlop, Jason A; Shu, Degan; Paterson, John R (2018-11-01). "Origin of raptorial feeding in juvenile euarthropods revealed by a Cambrian radiodontan". National Science Review. 5 (6): 863–869. doi:10.1093/nsr/nwy057. ISSN 2095-5138.
  6. ↑ Vinther, Jakob; Stein, Martin; Longrich, Nicholas R.; Harper, David A. T. (2014). "A suspension-feeding anomalocarid from the Early Cambrian". Nature. 507 (7493): 496–499. doi:10.1038/nature13010. ISSN 1476-4687.
  7. ↑ Lerosey-Aubril, Rudy; Pates, Stephen (2018-09-14). "New suspension-feeding radiodont suggests evolution of microplanktivory in Cambrian macronekton". Nature Communications. 9 (1): 3774. doi:10.1038/s41467-018-06229-7. ISSN 2041-1723. PMC 6138677. PMID 30218075.
  8. ↑ Moysiuk, Joseph; Caron, Jean-Bernard (2021). "Exceptional multifunctionality in the feeding apparatus of a mid-Cambrian radiodont". Paleobiology. 47 (4): 704–724. doi:10.1017/pab.2021.19. ISSN 0094-8373.