Hymenocarina Explained

Hymenocarina is an order of extinct arthropods known from the Cambrian. They possess bivalved carapaces, typically with exposed posteriors. Members of the group are morphologically diverse and had a variety of ecologies, including as filter feeders and as predators. Recent research has generally considered them to be stem or crown group members of Mandibulata, due to the presence of mandibles in some species.

Taxonomy

Hymenocarines are characterized by the combination of following characters: bivalved, convex carapace covering cephalothoracic region; cephalothorax bearing multisegmented antennules and rounded mandibles, alongside post-maxillular limbs with spiny, subdivided basis and endopods with well-developed terminal claws; absence of appendages between antennules and mandibles; median sclerite and lobate protrusions located between compound eyes; posterior tagma (abdomen) with ring-like segments and terminated by a pair of well-developed caudal rami.

Based on the interpretation of simple head region that possess only a few segments and appendages, hymenocarine taxa were thought to be part of the upper stem-group euarthropods in early and mid 2010s.[1] [2] [3] [4] [5] [6] [7] [8] They later became widely accepted as mandibulates (jawed arthropods) after the discovery of their mandible-bearing mouthparts in late 2010s.[9] [10] Since then, most phylogenetic analysis suggest hymenocarines represent part of the mandibulate stem-group,[11] [12] [13] [14] [15] [16] [17] with some results suggest a rather crownward position such as stem-pancrustaceans,[18] [19] [20] stem-myriapods, stem-hexapods or somewhere in-between the former taxa.[21]

Several subgroups within the order are recognised, including Waptiidae and Protocarididae. The internal relationships of Hymenocarina are unstable, and it is unclear whether the group is monophyletic or paraphyletic.[22]

Cambrian bivalved arthropods are now recognised to be a polyphyletic group, with other groups of bivalved arthropods such as the Isoxyida, Bradoriida and Phosphatocopina only distantly related to Hymenocarina.[23] [24] Chuandianella a bivalved arthropod morphologically similar to Waptia and long thought to be closely related was reinterpreted as a non-hymenocarine euarthropod based on a restudy published in 2022, which found that it definitely lacked mandibles, characteristic of true hymenocarines.[25]

Diversity

The group was very diverse in shape, with some forms like Waptia somewhat resembling shrimp, and others like Odaraia having a large carapace and trifurcate tail.[26] The appendages showing various degrees of specialization across the group, ranging from the feathery gills of Waptia to the robust claws of Tokummia. They also had a wide range of sizes with some like Fibulacaris reaching a length of up to long,[27] while largest Balhuticaris reached long.[28] Hymenocarines are thought to have been ecologically diverse, with various forms occupying scavenging, predatory, deposit feeding and suspension feeding niches.

Notes and References

  1. Legg . David A. . Sutton . Mark D. . Edgecombe . Gregory D. . Caron . Jean-Bernard . 2012-12-07 . Cambrian bivalved arthropod reveals origin of arthrodization . Proceedings of the Royal Society B: Biological Sciences . 279 . 1748 . 4699–4704 . 10.1098/rspb.2012.1958 . 3497099 . 23055069.
  2. Legg . David . 2013 . Multi-Segmented Arthropods from the Middle Cambrian of British Columbia (Canada) . Journal of Paleontology . en . 87 . 3 . 493–501 . 10.1666/12-112.1 . 86725173 . 0022-3360.
  3. Legg . David A. . Vannier . Jean . 2013-09-16 . The affinities of the cosmopolitan arthropod Isoxys and its implications for the origin of arthropods . Lethaia . 46 . 4 . 540–550 . 10.1111/let.12032 . 0024-1164.
  4. Legg . David A. . Sutton . Mark D. . Edgecombe . Gregory D. . 2013-09-30 . Arthropod fossil data increase congruence of morphological and molecular phylogenies . Nature Communications . en . 4 . 1 . 2485 . 10.1038/ncomms3485 . 24077329 . 2041-1723. free .
  5. Ortega-Hernández . Javier . 2014-12-21 . Making sense of 'lower' and 'upper' stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848 . Biological Reviews . en . 91 . 1 . 255–273. 10.1111/brv.12168 . 25528950 . 7751936 .
  6. 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 . en . 46 . 3 . 354–379 . 10.1016/j.asd.2016.10.011 . 27989966 . 1467-8039. free .
  7. Yang . Jie . Ortega-Hernández . Javier . Legg . David A. . Lan . Tian . Hou . Jin-bo . Zhang . Xi-guang . 2018-02-01 . Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods . Nature Communications . en . 9 . 1 . 470 . 10.1038/s41467-017-02754-z . 29391458 . 5794847 . 2018NatCo...9..470Y . 2041-1723.
  8. Daley . Allison C. . Antcliffe . Jonathan B. . Drage . Harriet B. . Pates . Stephen . 2018-05-22 . Early fossil record of Euarthropoda and the Cambrian Explosion . Proceedings of the National Academy of Sciences . en . 115 . 21 . 5323–5331 . 10.1073/pnas.1719962115 . 0027-8424 . 29784780. 6003487 . 2018PNAS..115.5323D . free .
  9. Giribet . Gonzalo . Edgecombe . Gregory D. . 2019-06-17 . The Phylogeny and Evolutionary History of Arthropods . Current Biology . English . 29 . 12 . R592–R602 . 10.1016/j.cub.2019.04.057 . 0960-9822 . 31211983. 189926344 . free .
  10. Edgecombe . Gregory D. . 2020-11-02 . Arthropod Origins: Integrating Paleontological and Molecular Evidence . Annual Review of Ecology, Evolution, and Systematics . 51 . 1 . 1–25 . 10.1146/annurev-ecolsys-011720-124437 . 225478171 . 1543-592X.
  11. Aria. Cédric. Caron. Jean-Bernard. 2017-04-26. Burgess Shale fossils illustrate the origin of the mandibulate body plan. Nature. 545. 7652. 89–92. 10.1038/nature22080. 28445464. 4454526. 0028-0836.
  12. 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 .
  13. Zeng . Han . Zhao . Fangchen . Niu . Kecheng . Zhu . Maoyan . Huang . Diying . 2020-12-03 . An early Cambrian euarthropod with radiodont-like raptorial appendages . Nature . 588 . 7836 . 101–105 . 10.1038/s41586-020-2883-7. 33149303 . 226248177 .
  14. Aria . Cédric . Zhao . Fangchen . Zhu . Maoyan . 2021-09-01 . Fuxianhuiids are mandibulates and share affinities with total-group Myriapoda . Journal of the Geological Society . en . 178 . 5 . 10.1144/jgs2020-246 . 233952670 . 0016-7649.
  15. Anderson . Evan P. . Schiffbauer . James D. . Jacquet . Sarah M. . Lamsdell . James C. . Kluessendorf . Joanne . Mikulic . Donald G. . 2021-04-19 . Stranger than a scorpion: a reassessment of Parioscorpio venator, a problematic arthropod from the Llandoverian Waukesha Lagerstätte . Palaeontology . 64 . 3 . 429–474 . 10.1111/pala.12534 . 234812878 . 0031-0239.
  16. Izquierdo‐López . Alejandro . Caron . Jean‐Bernard . 2021-06-15 . A Burgess Shale mandibulate arthropod with a pygidium: a case of convergent evolution . Papers in Palaeontology . 7 . 4 . 1877–1894 . 10.1002/spp2.1366 . 236284813 . 2056-2799.
  17. O'Flynn . Robert . Williams . Mark . Yu . Mengxiao . Harvey . Thomas . Liu . Yu . 2022-02-11 . A new euarthropod with large frontal appendages from the early Cambrian Chengjiang biota . Palaeontologia Electronica . 25 . a6 . 10.26879/1167. 246779634 . free .
  18. Vannier . Jean . Aria . Cédric . Taylor . Rod S. . Caron . Jean-Bernard . 2018 . Waptia fieldensis Walcott, a mandibulate arthropod from the middle Cambrian Burgess Shale . Royal Society Open Science . 5 . 6 . 172206 . 10.1098/rsos.172206 . 6030330 . 30110460 . free.
  19. Aria . Cédric . Caron . Jean-Bernard . 2019 . A middle Cambrian arthropod with chelicerae and proto-book gills . Nature . en . 573 . 7775 . 586–589 . 10.1038/s41586-019-1525-4 . 31511691 . 202550431 . 1476-4687.
  20. Aria . Cédric . Zhao . Fangchen . Zeng . Han . Guo . Jin . Zhu . Maoyan . 2020-01-08 . Fossils from South China redefine the ancestral euarthropod body plan . BMC Evolutionary Biology . 20 . 1 . 4 . 10.1186/s12862-019-1560-7 . 1471-2148 . 6950928 . 31914921 . free .
  21. Ou . Qiang . Vannier . Jean . Yang . Xianfeng . Chen . Aiiln . Huijuan . Mai . Shu . Degan . Han . Jian . Fu . Dongjing . Wang . Rong . Mayer . Georg . 2020-04-29 . Evolutionary trade-off in reproduction of Cambrian arthropods . Science Advances . 6 . 18 . 3376–3405 . 10.1126/sciadv.aaz3376. 32426476 . 7190318 . 218675348 . free .
  22. Izquierdo-López . Alejandro . Caron . Jean-Bernard . December 2022 . The problematic Cambrian arthropod Tuzoia and the origin of mandibulates revisited . Royal Society Open Science . en . 9 . 12 . 220933 . 10.1098/rsos.220933 . 2054-5703 . 9727825 . 36483757.
  23. 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.
  24. Zeng . Han . Zhao . Fang-Chen . Yin . Zong-Jun . Zhu . Mao-Yan . September 2021 . A new early Cambrian bivalved euarthropod from Yunnan, China and general interspecific morphological and size variations in Cambrian hymenocarines . Palaeoworld . en . 30 . 3 . 387–397 . 10.1016/j.palwor.2020.09.002.
  25. Zhai . Dayou . Williams . Mark . Siveter . David J. . Siveter . Derek J. . Harvey . Thomas H. P. . Sansom . Robert S. . Mai . Huijuan . Zhou . Runqing . Hou . Xianguang . 2022-02-22 . Chuandianella ovata: An early Cambrian stem euarthropod with feather-like appendages . Palaeontologia Electronica . English . 25 . 1 . 1–22 . 10.26879/1172 . 247123967 . 1094-8074. free .
  26. Briggs. D. E. G.. 1981. The Arthropod Odaraia alata Walcott, Middle Cambrian, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 291 . 1056 . 541–582 . 2395403 .
  27. Izquierdo-López . Alejandro . Caron . Jean-Bernard . A possible case of inverted lifestyle in a new bivalved arthropod from the Burgess Shale . Royal Society Open Science . 2019 . 6 . 11 . 191350 . 10.1098/rsos.191350 . 6894550 . 31827867.
  28. Izquierdo-López . Alejandro . Caron . Jean-Bernard . 2022-07-15 . Extreme multisegmentation in a giant bivalved arthropod from the Cambrian Burgess Shale . iScience . English . 25 . 7 . 104675 . 10.1016/j.isci.2022.104675 . 35845166 . 9283658 . 250057171 . 2589-0042. free .

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