// Workers AI · dad joke modeWhat did Surusicaris say when it ran into its friend? "Shell-abrate good times
| Surusicaris Temporal range: | |
|---|---|
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| Holotype and only known specimen | |
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| Life restoration | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Order: | †Isoxyida |
| Family: | †Isoxyidae |
| Genus: | †Surusicaris Aria and Caron, 2015 |
| Type species | |
| Surusicaris elegans Aria and Caron, 2015 | |
Surusicaris is an extinct genus of isoxyid bivalved arthropod, known from the Cambrian Burgess Shale of British Columbia, Canada. It is monotypic, containing a single species, Surusicaris elegans. It is considered to be closely related to Isoxys, and like it has spined grasping frontal appendages.
Description
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The only known specimen (ROM 62976), has a roughly semicircular bivalved carapace,[1] which is approximately 1.49 centimetres (0.59 in) long and 0.89 centimetres (0.35 in) tall. The head has a pair of rounded eyes, and a pair of upward-curling segmented frontal appendages with at least five segments, the second, third and fourth of which bear a spine, with three long spines and at least one short spine on the fifth and terminal segment. The head also has three pairs of other limbs, which are stubby, uniramous (single-part) and unsclerotized, with an annulated appearance, which are tipped with bifid claws. Along the trunk are 12 pairs of biramous (two-branched) limbs, which taper in size posteriorly. Their morphology is simple, the morphology of the endopod (the inner, leg-like limb branch) is similar to those of the three uniramous head limbs, while the exopod (the outer limb branch) is sub-lobate, elongate, and possibly flattened, with marginal setae (hair-like structures) and about the same length as the endopod. The posterior is poorly preserved but may be a tail-piece formed by two lobes or a fan.[2]
Taxonomy and ecology
[edit]Surusicaris has been placed as a member of Isoxyida and Isoxyidae, both of which contain only one other genus, Isoxys. Isoxyids are considered to be basal stem-group arthropods.[1][3] Isoxyids are thought to have been actively swimming predators.[2]
See also
[edit]References
[edit]- 1 2 Collantes, Luis; Pates, Stephen. "Isoxys carbonelli and the palaeoenvironmental disparity of Isoxys during Cambrian Stage 3". Historical Biology. 0 (0): 1–9. doi:10.1080/08912963.2025.2529395. ISSN 0891-2963.
- 1 2 Aria, Cédric; Caron, Jean-Bernard (2015-06-03). Friedman, Matt (ed.). "Cephalic and Limb Anatomy of a New Isoxyid from the Burgess Shale and the Role of "Stem Bivalved Arthropods" in the Disparity of the Frontalmost Appendage". PLOS ONE. 10 (6) e0124979. Bibcode:2015PLoSO..1024979A. doi:10.1371/journal.pone.0124979. ISSN 1932-6203. PMC 4454494. PMID 26038846.
- ↑ Zhang, Caixia; Liu, Yu; Ortega-Hernández, Javier; Wolfe, Joanna M.; Jin, Changfei; Mai, Huijuan; Hou, Xianguang; Guo, Jin; Zhai, Dayou (2023-04-26). "Three-dimensional morphology of the biramous appendages in Isoxys from the early Cambrian of South China, and its implications for early euarthropod evolution". Proceedings. Biological Sciences. 290 (1997) 20230335. doi:10.1098/rspb.2023.0335. ISSN 1471-2954. PMC 10113025. PMID 37072042.