Dinocaridida

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Dinocaridida
Temporal range: Cambrian–Early Devonian
20210730 Dinocaridida Dinocarida Dinocaridids AOPK group.png
Assembly of dinocaridids ( Anomalocaris , Opabinia , Pambdelurion and Kerygmachela )
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Stem group:† Dinocaridida
Collins, 1996
Subgroups

Dinocaridida [derivation 1] is a proposed fossil taxon of basal arthropods, [3] which flourished during the Cambrian period and survived up to Early Devonian. Characterized by a pair of frontal appendages and series of body flaps, the name of Dinocaridids (Greek for deinos "terrible" and Latin for caris "crab") refers to the suggested role of some of these members as the largest marine predators of their time. [3] Dinocaridids are occasionally referred to as the 'AOPK group' by some literatures, [4] [5] [6] as the group compose of Radiodonta ( Anomalocaris and relatives), Opabiniidae ( Opabinia and relatives), and the "gilled lobopodians" Pambdelurion and Kerygmachelidae. [7] It is most likely paraphyletic, with Kerygmachelidae and Pambdelurion more basal than the clade compose of Opabiniidae, Radiodonta and other arthropods. [4] [8] [9]

Contents

Anatomy

20191107 Radiodonta brain and digestive system.png
20191029 Kerygmachela brain and digestive system.png
20210809 Opabinia regalis digestive system.png
Eyes (deep blue and black), brain (light blue) and digestive system (yellow) of Radiodonta (left), Kerygmachela (Center) and Opabinia (Right)

Dinocaridids were bilaterally symmetrical, with a mostly non-mineralized cuticle and a body divided into two major groupings of tagmata (body-sections): head and trunk. The head apparently unsegmented [8] [9] and had a pair of specialized frontal appendages just in front of the mouth and eyes. The frontal appendages are either lobopodous (soft as in gilled lobopodians) or arthropodized (hardened and segmented as in Radiodonta) and usually paired, but highly fused into a nozzle-like structure in Opabiniidae. [7] Based on their preocular position and putative protocerebral origin, the frontal appendages are generally thought to be homologous to the labrum of euarthropods and primary antennae of onychophoran, [10] [9] while subsequent evidence also suggest a deutocerebral origin (homologous to the jaws of onychophora and great appendages/antennae/chelicerae of euarthropods). [11] [12] The trunk possessed multiple segments, each with its own gill branch and swimming flaps (lobes). [13] It is thought that these flaps moved in an up-and-down motion, in order to propel the animal forward [14] in a fashion similar to the cuttlefish. In gilled lobopodian genera, the trunk may have borne a lobopodous limb (lobopod) underneath each of the flaps. [13] The midgut of dinocaridids had paired digestive glands similar to those of siberiid lobopodians and Cambrian euarthropods. [15] The dinocaridid brain is relatively simple than those of a euarthropod (3-segmented), it is thought to be comprised either 1 (only protocerebrum [10] [16] ) or 2 cerebral ganglions (protocerebrum and deutocerebrum). [12]

Classification

Ecdysozoa
Dinocaridida

Although some authors may rather suggest different taxonomic affinities (e.g. as cycloneuralia n relatives [17] [7] ), most of the phylogenetic studies suggest that dinocaridids are stem group arthropods. [18] [19] [20] [21] [13] [8] [9] [22] [23] [24] Under this scenario, Dinocaridida is a paraphyletic grade in correspond to the arthropod crown group (Euarthropoda or Deuteropoda) and also suggest a lobopodian origin of the arthropod lineage. [25] [8] In general, the gilled lobopodian genera Pambdelurion and Kerygmachela which have lobopodian traits (e.g. lobopodous appendage, annulation) occupied the basal position; while Opabiniidae and Radiodonta are more derived and closely related to the arthropod crown group, with the latter even having significant arthropod affinities such as arthropodization and head sclerites. [24] [26] [8]

In the original description, Dinocaridida was composed of only Opabiniidae and Radiodonta. [3] With the exclusion of questionable taxa (e.g. the putative opabiniid Myoscolex [27] ), the former were known only by Opabinia, while all radiodont species were grouped under a single family: Anomalocarididae (hence the previous common name 'Anomalocaridids' [18] ). In later studies, the gilled lobopodians Pambdelurion and Kerygmachela were also regarded to be dinocaridids, [7] two new opabiniid genera, Utaurora and Mieridduryn were described, [28] [29] [30] other strange dinocaridids like Parvibellus (which might actually be a juvenile siberiid lobopodian), [31] [29] many radiodonts were reassigned to other new families (Amplectobeluidae, Tamisiocarididae and Hurdiidae), [21] and a new family, Kerygmachelidae, [29] was named.

Distribution

The group was geographically widespread, and has been reported from Cambrian strata in Canada, United States, Greenland, China, Australia and Russia, [32] as well as the Early to Middle Ordovician of Morocco and Wales [33] [34] [30] and the Early Devonian of Germany. [35]

Notes

  1. ↑ Greek for deinos "terrible" and Latin for caris "crab" – sometimes informally spelt Dinocarida, but the second 'id' is linguistically correct – see 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.

Related Research Articles

<span class="mw-page-title-main">Lobopodia</span> Group of extinct worm-like animals with legs

Lobopodians are members of the informal group Lobopodia, or the formally erected phylum Lobopoda Cavalier-Smith (1998). They are panarthropods with stubby legs called lobopods, a term which may also be used as a common name of this group as well. While the definition of lobopodians may differ between literatures, it usually refers to a group of soft-bodied, marine worm-like fossil panarthropods such as Aysheaia and Hallucigenia. However, other genera like Kerygmachela and Pambdelurion are often referred to as “gilled lobopodians”.

<i>Anomalocaris</i> Extinct genus of cambrian radiodont

Anomalocaris is an extinct genus of radiodont, an order of early-diverging stem-group arthropods.

<span class="mw-page-title-main">Anomalocarididae</span> Clade of extinct arthropods

Anomalocarididae is an extinct family of Cambrian radiodonts, a group of stem-group arthropods.

<i>Kerygmachela</i> Extinct gilled lobopod

Kerygmachela kierkegaardi is a kerygmachelid gilled lobopodian from the Cambrian Stage 3 aged Sirius Passet Lagerstätte in northern Greenland. Its anatomy strongly suggests that it, along with its relative Pambdelurion whittingtoni, was a close relative of radiodont and euarthropods. The generic name "Kerygmachela" derives from the Greek words Kerygma (proclamation) and Chela (claw), in reference to the flamboyant frontal appendages. The specific name, "kierkegaardi" honors Danish philosopher Søren Kierkegaard.

<i>Pambdelurion</i> Extinct genus of Arthropod

Pambdelurion is an extinct genus of panarthropod from the Cambrian aged Sirius Passet site in northern Greenland. Like the morphologically similar Kerygmachela from the same locality, Pambdelurion is thought to be closely related to arthropods, combining characteristics of "lobopodians" with those of primitive arthropods.

<i>Parapeytoia</i> Extinct genus of arthropods

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

<span class="mw-page-title-main">Megacheira</span> Extinct class of arthropods

Megacheira is an extinct class of predatory arthropods defined by their possession of spined "great appendages". Their taxonomic position is controversial, with studies either considering them stem-group euarthropods, or stem-group chelicerates. The homology of the great appendages to the cephalic appendages of other arthropods is also controversial. Uncontested members of the group were present in marine environments worldwide from the lower Cambrian to the upper Ordovician.

<i>Schinderhannes bartelsi</i> Extinct species of radiodont

Schinderhannes bartelsi is a species of hurdiid radiodont (anomalocaridid), known from one specimen from the Lower Devonian Hunsrück Slates. Its discovery was astonishing because the latest definitive radiodonts were known only from the Early Ordovician, at least 66 million years earlier than this taxon.

<span class="mw-page-title-main">Radiodonta</span> Extinct order of basal arthropods

Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts are among the earliest large predators, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa Anomalocaris canadensis, Hurdia victoria, Peytoia nathorsti, Titanokorys gainesi, Cambroraster falcatus and Amplectobelua symbrachiata. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member Schinderhannes bartelsi from Germany.

<i>Cucumericrus</i> Extinct genus of arthropod

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<i>Omnidens</i> Extinct genus of Cambrian animals

Omnidens, meaning "all-tooth", is an extinct genus of large Cambrian animal known only from a series of large mouth apparatus and sclerotized talon-like structures, originally mistaken as the mouthparts of anomalocaridids. When first named, it was interpreted as a giant priapulid, but is now considered a panarthropod. Its mouth apparatus closely resembles that of the smaller gilled lobopodian Pambdelurion, indicating it is likely to have been a close relative of that species, potentially even synonymous. With a maximum estimated body length of 1.5 metres (4.9 ft), Omnidens is suggested to have been the largest known free-living Cambrian organism. Omnidens fossils are found in the Maotianshan Shales.

<i>Caryosyntrips</i> Extinct genus of arthropod

Caryosyntrips ("nutcracker") is an extinct genus of stem-arthropod which known from Canada, United States and Spain during the middle Cambrian. It was first named by Allison C. Daley and Graham E. Budd in 2010, being the type species Caryosyntrips serratus.

<span class="mw-page-title-main">Amplectobeluidae</span> Extinct clade of Cambrian organisms

Amplectobeluidae is a clade of Cambrian radiodonts. It currently includes five definitive genera, Amplectobelua, Lyrarapax, Ramskoeldia, Guanshancaris and a currently unnamed genus from the lower Cambrian aged Sirius Passet site in Greenland. There is also a potential fifth genus, Houcaris, but that genus has become problematic in terms of its taxonomic placement.

<i>Lyrarapax</i> Extinct genus of Amplectobeluid radiodont

Lyrarapax is a radiodont genus of the family Amplectobeluidae that lived in the early Cambrian period 520 million years ago. Its neural tissue indicates that the radiodont frontal appendage is protocerebral, resolving parts of the arthropod head problem and showing that the frontal appendage is homologous to the antennae of Onychophorans and labrum of euarthropods. Its fossilized remains were found in Yunnan in southwestern China. A second species was described in 2016, differing principally in the morphology of its frontal appendages. It is a small animal, with L. unguispinus and L. trilobus measuring up to 8.3 cm (3.3 in) and 3.9 cm (1.5 in) in body length respectively.

<span class="mw-page-title-main">Hurdiidae</span> Extinct family of arthropods

Hurdiidae is an extinct cosmopolitan family of radiodonts, a group of stem-group arthropods, which lived during the Paleozoic Era. It is the most long-lived radiodont clade, lasting from the Cambrian period to the Devonian period.

<i>Houcaris</i> Genus of radiodonts

Houcaris is a possibly paraphyletic radiodont genus, tentatively assigned to either Amplectobeluidae, Anomalocarididae or Tamisiocarididae, known from Cambrian Series 2 of China and the United States. The type species is Houcaris saron which was originally described as a species of the related genus Anomalocaris. Other possible species include H. magnabasis and H. consimilis. The genus Houcaris was established for the two species in 2021 and honors Hou Xianguang, who had discovered and named the type species Anomalocaris saron in 1995 along with his colleagues Jan Bergström and Per E. Ahlberg.

<i>Erratus</i> Extinct genus of Cambrian arthropod

Erratus is an extinct genus of marine arthropod from the Cambrian of China. Its type and only species is Erratus sperare. Erratus is likely one of the most basal known arthropods, and its discovery has helped scientists understand the early evolution of arthropod trunk appendages. Some of the stem-arthropods like radiodonts did not have legs, instead they had flap like appendages that helped them swim. Erratus on the other hand had not only flaps but also a set of primitive legs. It also supported the theory that the gills of aquatic arthropods probably evolved into the wings and lungs of terrestrial arthropods later in the Paleozoic.

<i>Laminacaris</i> Genus of extinct arthropods

Laminacaris is a genus of extinct stem-group arthropods (Radiodonta) that lived during the Cambrian period. It is monotypic with a single species Laminacaris chimera, the fossil of which was described from the Chengjiang biota of China in 2018. Around the same time, two specimens that were similar or of the same species were discovered at the Kinzers Formation in Pennsylvania, USA. The first specimens from China were three frontal appendages, without the other body parts.

<i>Mieridduryn</i> An opabiniid-like panarthropod

Mieridduryn is a genus of extinct dinocaridid arthropod that lived during the Middle Ordovician of what is now the United Kingdom. This animal was described in 2022 based on a singular fossil found in Castle Bank, a Burgess shale type lagerstätte located in the country of Wales. This animal's taxonomic affinities are somewhat unclear, but there are some hypotheses. One is that this animal represents a new grade of stem-euarthropods that evolved features similar to the Cambrian aged opabiniids. Another is that if the features seen in Mieridduryn are convergent, and not homologous, to those seen in radiodonts, then this animal represents a late surviving opabiniid.

References

  1. ↑ Li, Wei; Yang, Jie; Yang, Xiaoyu; Dhungana, Alavya; Wang, Yu; Zhang, Xiguang; Smith, Martin R. (November 2024). "Omnidens appendages and the origin of radiodont mouthparts". Papers in Palaeontology. 10 (6). doi:10.1002/spp2.1600.
  2. ↑ Smith, Martin R.; Long, Emma J.; Dhungana, Alavya; Dobson, Katherine J.; Yang, Jie; Zhang, Xiguang (31 July 2024). "Organ systems of a Cambrian euarthropod larva". Nature. 633 (8028): 120–126. Bibcode:2024Natur.633..120S. doi: 10.1038/s41586-024-07756-8 . ISSN   1476-4687. PMC   11374701 . PMID   39085610.
  3. 1 2 3 Collins, D. (1996). "The "Evolution" of Anomalocaris and Its Classification in the Arthropod Class Dinocarida (nov.) and Order Radiodonta (nov.)". Journal of Paleontology. 70 (2): 280–293. Bibcode:1996JPal...70..280C. doi:10.1017/S0022336000023362. JSTOR   1306391. S2CID   131622496.
  4. 1 2 Budd, Graham E. (1998). "The morphology and phylogenetic significance of Kerygmachela kierkegaardi Budd (Buen Formation, Lower Cambrian, N Greenland)". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 89 (4): 249–290. doi:10.1017/S0263593300002418. ISSN   1473-7116. S2CID   85645934.
  5. ↑ Liu, Jianni (2004). "A rare lobopod with well-preserved eyes from Chengjiang Lagerstätte and its implications for origin of arthropods". Chinese Science Bulletin. 49 (10): 1063. Bibcode:2004ChSBu..49.1063L. doi:10.1360/04wd0052. ISSN   1001-6538.
  6. ↑ "Morpho-anatomy of the lobopod Magadictyon cf. haikouensis from the Early Cambrian Chengjiang Lagerstätte, South China". Acta Zoologica. 89 (2): 183. 2008. doi:10.1111/j.1463-6395.2007.00307.x. ISSN   1463-6395.
  7. 1 2 3 4 Xianguang, Hou; Jan, Jan Bergström; Jiayu, In Rong; Zongjie, Fang; Zhanghe, Zhou; Renbin, Zhan; Xiangdong, Wang; Xunlai, Yuan; Xianguang, Hou (2006). Dinocaridids – anomalous arthropods or arthropod-like worms?. CiteSeerX   10.1.1.693.5869 .
  8. 1 2 3 4 5 Ortega-Hernández, Javier (2016). "Making sense of 'lower' and 'upper' stem-group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848". Biological Reviews. 91 (1): 255–273. doi:10.1111/brv.12168. ISSN   1469-185X. PMID   25528950. S2CID   7751936.
  9. 1 2 3 4 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. Bibcode:2017ArtSD..46..354O. doi: 10.1016/j.asd.2016.10.011 . ISSN   1467-8039. PMID   27989966.
  10. 1 2 Cong, Peiyun; Ma, Xiaoya; Hou, Xianguang; Edgecombe, Gregory D.; Strausfeld, Nicholas J. (2014). "Brain structure resolves the segmental affinity of anomalocaridid appendages". Nature. 513 (7519): 538–542. Bibcode:2014Natur.513..538C. doi:10.1038/nature13486. ISSN   0028-0836. PMID   25043032. S2CID   4451239.
  11. ↑ 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.
  12. 1 2 Moysiuk, Joseph; Caron, Jean-Bernard (2022-08-08). "A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation". Current Biology. 32 (15): 3302–3316.e2. Bibcode:2022CBio...32E3302M. doi: 10.1016/j.cub.2022.06.027 . ISSN   0960-9822. PMID   35809569. S2CID   250361698.
  13. 1 2 3 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. Bibcode:2015Natur.522...77V. doi:10.1038/nature14256. ISSN   1476-4687. PMID   25762145. S2CID   205242881.
  14. ↑ Usami, Y. (2006). "Theoretical study on the body form and swimming pattern of Anomalocaris based on hydrodynamic simulation". Journal of Theoretical Biology. 238 (1): 11–17. Bibcode:2006JThBi.238...11U. doi:10.1016/j.jtbi.2005.05.008. PMID   16002096.
  15. ↑ Vannier, Jean; Liu, Jianni; Lerosey-Aubril, Rudy; Vinther, Jakob; Daley, Allison C. (2014-05-02). "Sophisticated digestive systems in early arthropods". Nature Communications. 5 (1): 3641. Bibcode:2014NatCo...5.3641V. doi: 10.1038/ncomms4641 . ISSN   2041-1723. PMID   24785191.
  16. ↑ Park, Tae-Yoon S.; Kihm, Ji-Hoon; Woo, Jusun; Park, Changkun; Lee, Won Young; Smith, M. Paul; Harper, David A. T.; Young, Fletcher; Nielsen, Arne T.; Vinther, Jakob (2018-03-09). "Brain and eyes of Kerygmachela reveal protocerebral ancestry of the panarthropod head". Nature Communications. 9 (1): 1019. Bibcode:2018NatCo...9.1019P. doi: 10.1038/s41467-018-03464-w . ISSN   2041-1723. PMC   5844904 . PMID   29523785.
  17. ↑ 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.
  18. 1 2 Daley, A. C.; Budd, G. E.; Caron, J.-B.; Edgecombe, G. D.; Collins, D. (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.
  19. ↑ Edgecombe, Gregory D. (2010). "Arthropod phylogeny: an overview from the perspectives of morphology, molecular data and the fossil record". Arthropod Structure & Development. 39 (2–3): 74–87. Bibcode:2010ArtSD..39...74E. doi:10.1016/j.asd.2009.10.002. ISSN   1873-5495. PMID   19854297.
  20. ↑ Legg, David A.; Sutton, Mark D.; Edgecombe, Gregory D. (2013). "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.
  21. 1 2 Vinther, Jakob; Stein, Martin; Longrich, Nicholas R.; Harper, David A. T. (2014). "A suspension-feeding anomalocarid from the Early Cambrian" (PDF). Nature. 507 (7493): 496–499. Bibcode:2014Natur.507..496V. doi:10.1038/nature13010. ISSN   1476-4687. PMID   24670770. S2CID   205237459.
  22. ↑ Lerosey-Aubril, Rudy; Pates, Stephen (2018-09-14). "New suspension-feeding radiodont suggests evolution of microplanktivory in Cambrian macronekton". Nature Communications. 9 (1): 3774. Bibcode:2018NatCo...9.3774L. doi: 10.1038/s41467-018-06229-7 . ISSN   2041-1723. PMC   6138677 . PMID   30218075.
  23. ↑ Moysiuk, J.; Caron, J.-B. (2019-08-14). "A new hurdiid radiodont from the Burgess Shale evinces the exploitation of Cambrian infaunal food sources". Proceedings of the Royal Society B: Biological Sciences. 286 (1908): 20191079. doi:10.1098/rspb.2019.1079. PMC   6710600 . PMID   31362637.
  24. 1 2 Chipman, Ariel D.; Edgecombe, Gregory D. (2019-10-09). "Developing an integrated understanding of the evolution of arthropod segmentation using fossils and evo-devo". Proceedings of the Royal Society B: Biological Sciences. 286 (1912): 20191881. doi:10.1098/rspb.2019.1881. PMC   6790758 . PMID   31575373.
  25. ↑ Budd, G. E. (1996). "The morphology of Opabinia regalis and the reconstruction of the arthropod stem-group". Lethaia. 29 (1): 1–14. Bibcode:1996Letha..29....1B. doi:10.1111/j.1502-3931.1996.tb01831.x.
  26. ↑ Ortega-Hernández, Javier (2015-06-15). "Homology of Head Sclerites in Burgess Shale Euarthropods". Current Biology. 25 (12): 1625–1631. Bibcode:2015CBio...25.1625O. doi: 10.1016/j.cub.2015.04.034 . ISSN   0960-9822. PMID   25959966.
  27. ↑ Briggs, Derek E. G.; Nedin, Christopher (1997). "The taphonomy and affinities of the problematic fossil Myoscolex from the Lower Cambrian Emu Bay Shale of South Australia". Journal of Paleontology. 71 (1): 22–32. Bibcode:1997JPal...71...22B. doi:10.1017/S0022336000038919. ISSN   0022-3360. S2CID   131851540.
  28. ↑ Pates, Stephen; Wolfe, Joanna M.; Lerosey-Aubril, Rudy; Daley, Allison C.; Ortega-Hernández, Javier (2022-02-09). "New opabiniid diversifies the weirdest wonders of the euarthropod stem group". Proceedings of the Royal Society B: Biological Sciences. 289 (1968): 20212093. doi:10.1098/rspb.2021.2093. PMC   8826304 . PMID   35135344.
  29. 1 2 3 McCall, C. R. A. (2023). "A large pelagic lobopodian from the Cambrian Pioche Shale of Nevada". Journal of Paleontology. 97 (5): 1009–1024. Bibcode:2023JPal...97.1009M. doi:10.1017/jpa.2023.63.
  30. 1 2 Pates, S.; Botting, J. P.; Muir, L. A.; Wolfe, J. M. (2022). "Ordovician opabiniid-like animals and the role of the proboscis in euarthropod head evolution". Nature Communications. 13 (1). 6969. Bibcode:2022NatCo..13.6969P. doi: 10.1038/s41467-022-34204-w . PMC   9666559 . PMID   36379946.
  31. ↑ Liu, Jianni; Dunlop, Jason A.; Steiner, Michael; Shu, Degan (2022-07-22). "A Cambrian fossil from the Chengjiang fauna sharing characteristics with gilled lobopodians, opabiniids and radiodonts". Frontiers in Earth Science. 10: 861934. doi: 10.3389/feart.2022.861934 . ISSN   2296-6463.
  32. ↑ Ponomarenko, A. G. (2010). "First record of Dinocarida from Russia". Paleontological Journal. 44 (5): 503–504. Bibcode:2010PalJ...44..503P. doi:10.1134/S0031030110050047. S2CID   128957999.
  33. ↑ Potin, G. J.-M.; Gueriau, P.; Daley, A. C. (2023). "Radiodont frontal appendages from the Fezouata Biota (Morocco) reveal high diversity and ecological adaptations to suspension-feeding during the Early Ordovician". Frontiers in Ecology and Evolution. 11. 1214109. doi: 10.3389/fevo.2023.1214109 .
  34. ↑ Pates, Stephen; Botting, Joseph P.; McCobb, Lucy M. E.; Muir, Lucy A. (2020). "A miniature Ordovician hurdiid from Wales demonstrates the adaptability of Radiodonta". Royal Society Open Science. 7 (6): 200459. Bibcode:2020RSOS....700459P. doi: 10.1098/rsos.200459 . PMC   7353989 . PMID   32742697.
  35. ↑ Kühl, G.; Briggs, D. E. G.; Rust, J. (Feb 2009). "A Great-Appendage Arthropod with a Radial Mouth from the Lower Devonian Hunsrück Slate, Germany". Science. 323 (5915): 771–3. Bibcode:2009Sci...323..771K. doi:10.1126/science.1166586. ISSN   0036-8075. PMID   19197061. S2CID   47555807.
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