Hurdiidae

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Hurdiidae
Temporal range: Cambrian Stage 4–Lower Devonian
20220724 Hurdiidae.png
Stanleycaris (top left), Hurdia (top right), Aegirocassis (middle), Peytoia (bottom left), Cambroraster (bottom right)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class:† Dinocaridida
Order:† Radiodonta
Family:† Hurdiidae
Vinther et al., 2014
Genera

See text

Hurdiidae (synonymous with the previously named Peytoiidae [1] ) 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.

Contents

Description

Anatomy of the frontal appendage of a hurdiid. 20191213 Radiodonta frontal appendage Hurdiidae.png
Anatomy of the frontal appendage of a hurdiid.
Frontal appendages of various species of hurdiid. 20191229 Radiodonta frontal appendage Hurdiidae.png
Frontal appendages of various species of hurdiid.
Dorsal carapaces of various species of hurdiid. 20200803 Radiodonta Hurdiidae H-element.png
Dorsal carapaces of various species of hurdiid.

Hurdiidae is characterized by frontal appendages with distal region composed of 5 subequal blade-like endites, alongside the enlarged head carapaces and tetraradial mouthpart (oral cone). [2]

The frontal appendages of hurdiids have a distinctive morphology, with the appendage of most species bearing five equally-sized elongate blade-like ventral spines known as endites. [3] Subsequent podomeres were reduced in size and with only small endites or none. Each podomere bore only a single endite, unlike other radiodonts, in which the endites were paired. [3] In most species, the endites were curved medially, so that the appendages formed a basket-like structure. [2] Some hurdiids had greater numbers of endites, with Cordaticaris bearing seven endites of equal length. [4] Ursulinacaris is unique among hurdiids in bearing paired endites, which is likely a transitional form between the appendage of other radiodonts and that of hurdiids. [3]

Hurdiids exhibited a wide range of body size. The smallest known hurdiid specimen, of an unnamed species, is estimated to have had a body length of 6–15 millimetres (0.24–0.59 in), but it is not known whether this specimen was juvenile or adult. [5] Aegirocassis , the largest known hurdiid, was over 2 metres (6.6 ft) long, comparable in size to the largest known arthropods. [6]

Paleobiology

The majority of hurdiids appear to have been predators that fed by sifting sediment with their frontal appendages, but some members, like Aegirocassis , Pseudoangustidontus , and possibly Cambroraster were suspension feeders. [2] [7] [8]

Distribution

Hurdiids had a global distribution. [4] The earliest known hurdiid in the fossil record is Peytoia infercambriensis , which lived during the third age of the Cambrian in what is now the country of Poland. [9] The group increased in diversity during the Miaolingian epoch. [4] Post-Cambrian records of the group are rare, but the group lasted into the Devonian period, with the last known taxon being the Emsian Schinderhannes bartelsi from what is now Germany. [9] [5]

Classification

Hurdiidae is classified within Radiodonta, a clade of stem-group arthropods. Hurdiidae is defined phylogenetically as the most inclusive clade containing Hurdia victoria but not Amplectobelua symbrachiata , Anomalocaris canadensis , or Tamisiocaris borealis . [10] Some authors have argued that Peytoiidae, which was named by Conway Morris and Robison, 1982, has priority over Hurdiidae, and that Hurdiidae has "yet to be properly established following ICZN standards". [1]

The phylogeny of hurdiids, accompanying the description of the hurdiids Aegirocassis benmoulae , Titanokorys gainesii, and the analyzation of Stanleycaris hirpex as follows: [6]

Radiodonta

Tamisiocarididae 20191228 Radiodonta frontal appendage Tamisiocarididae Cetiocaridae.png

Anomalocarididae 20210626 Anomalocaris.png

Amplectobeluidae 20210912 Amplectobeluidae.png

Hurdiidae

Stanleycaris 20220716 Stanleycaris hirpex.png

Schinderhannes 20210708 Schinderhannes bartelsi diagrammatic reconstruction.png

Peytoia 20191021 Peytoia nathorsti Laggania cambria.png

Aegirocassis 20191205 Aegirocassis benmoulai Aegirocassis benmoulae.png

Hurdia 20210619 Hurdia.png

Pahvantia 20210516 Radiodonta head sclerites Pahvantia hastata.png

Cambroraster 20200329 Cambroraster falcatus.png

Titanokorys 20210909 Radiodonta head sclerites Titanokorys gainesi.png

Cordaticaris 20210516 Radiodonta head sclerites Cordaticaris striatus.png

Phylogenetic position of hurdiid radiodonts after Moysiuk & Caron 2022. [11]

Species include

Related Research Articles

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

Dinocaridida is a proposed fossil taxon of basal arthropods that flourished in the Cambrian period with occasional Ordovician and Devonian records. Characterized by a pair of frontal appendages and series of body flaps, the name of Dinocaridids refers to the suggested role of some of these members as the largest marine predators of their time. Dinocaridids are occasionally referred to as the 'AOPK group' by some literatures, as the group compose of Radiodonta, Opabiniidae, and the "gilled lobopodians" Pambdelurion and Kerygmachelidae. It is most likely paraphyletic, with Kerygmachelidae and Pambdelurion more basal than the clade compose of Opabiniidae, Radiodonta and other arthropods.

<i>Anomalocaris</i> Extinct genus of anomalocaridid (also extinct)

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

<i>Peytoia</i> Genus of anomalocarids

Peytoia is a genus of hurdiid radiodont, an early diverging order of stem-group arthropods, that lived in the Cambrian period, containing two species, Peytoia nathorsti from the Miaolingian of Canada and Peytoia infercambriensis from Poland, dating to Cambrian Stage 3. Its two frontal appendages had long bristle-like spines, it had no fan tail, and its short stalked eyes were behind its large head.

<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>Peytoia infercambriensis</i> Extinct species of arthropod

Peytoia infercambriensis is a species of hurdiid radiodont in the genus Peytoia.

<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 to middle Cambrian.

<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 previously, radiodonts were known only from exceptionally well-preserved fossil beds (Lagerstätten) from the Cambrian, 100 million years earlier.

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

Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the last two originally refer to the family Anomalocarididae, which previously included all species of this order but is now restricted to only a few species. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts included the earliest large predators known, 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 gainessii, Cambroraster falcatus and Amplectobelua symbrachiata, the Ordovician Aegirocassis benmoulai and the Devonian Schinderhannes bartelsi.

<i>Hurdia</i> Extinct genus of radiodonts

Hurdia is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China and the Czech Republic.

<i>Stanleycaris</i> Extinct genus of radiodonts

Stanleycaris is an extinct, monotypic genus of hurdiid radiodont from the middle Cambrian (Miaolingian). The type species is Stanleycaris hirpex. Stanleycaris was described from the Stephen Formation near the Stanley Glacier and Burgess Shale locality of Canada, as well as Wheeler Formation of United States. The genus was characterized by the rake-like frontal appendages with robust inner spines.

<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>Aegirocassis</i> Extinct genus of radiodonts

Aegirocassis is an extinct genus of giant radiodont arthropod belonging to the family Hurdiidae that lived 480 million years ago during the early Ordovician in the Fezouata Formation of Morocco. It is known by a single species, Aegirocassis benmoulai. Van Roy initiated scientific study of the fossil, the earliest known of a "giant" filter-feeder discovered to date. Aegirocassis is considered to have evolved from early predatory radiodonts. This animal is characterized by its long, forward facing head sclerite, and the endites on its frontal appendages that bore copious amounts of baleen-like auxiliary spines. This animal evolving filter-feeding traits was most likely a result of the Great Ordovician Biodiversification Event, when environmental changes caused a diversification of plankton, which in turn allowed for the evolution of new suspension feeding lifeforms. Alongside the closely related Pseudoangustidontus, an unnamed hurdiid from Wales, the middle Ordovician dinocaridid Mieridduryn, and the Devonian hurdiid Schinderhannes this radiodont is one of the few known dinocaridids known from post-Cambrian rocks.

<i>Ramskoeldia</i>

Ramskoeldia is a genus of amplectobeluid radiodont described in 2018. It was the second genus of radiodont found to possess gnathobase-like structures and an atypical oral cone after Amplectobelua. It was discovered in the Chengjiang biota of China, the home of numerous radiodontids such as Amplectobelua and Lyrarapax.

<i>Ursulinacaris</i> Extinct genus of radiodonts

Ursulinacaris is a genus of hurdiid radiodont from the Cambrian of North America. It contains one known species, Ursulinacaris grallae. It was described in 2019, based on fossils of the frontal appendages discovered in the 1990s and thereafter. The endites of Ursulinacaris were very slender, unlike other hurdiids such as Peytoia or Hurdia. It was initially reported as the first hurdiid with paired endites, but Moysiuk & Caron (2021) suggested that it is actually the preservation of the fossils and thus no paired endites.

<i>Cambroraster</i> Extinct genus of radiodonts

Cambroraster is an extinct monotypic genus of hurdiid radiodont, dating to the middle Cambrian, and represented by the single formally described species Cambroraster falcatus. Hundreds of specimens were found in the Burgess Shale, and described in 2019. A large animal at up to 30 centimetres (12 in), it is characterized by a significantly enlarged horseshoe-shaped dorsal carapace (H-element), and presumably fed by sifting through the sediment with its well-developed tooth plates and short frontal appendages with hooked spines. It is named partially after the fictional Millennium Falcon, which its dorsal carapace resembles.

<i>Titanokorys</i> Extinct genus of giant hurdiid radiodont

Titanokorys is a genus of extinct hurdiid radiodont that existed during the mid Cambrian. It is the largest member of its family from the Cambrian, with a body length of 50 cm (20 in) long, making it one of the largest animals of the time. It bears a resemblance to the related genus Cambroraster. Fossils of T. gainesi were first found within Marble Canyon in 2018. The fossils were not named until 2021 because they were assumed to be giant specimens of Cambroraster.

<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>Pahvantia</i>

Pahvantia is an extinct genus of hurdiid radiodont from the Cambrian. It is known by a single species, Pahvantia hastata, described from Wheeler Shale and Marjum Formation in Utah. Although it was once considered as filter feeder using large number of putative setae, this structures are later considered as misidentification of trunk materials.

<i>Cordaticaris</i> Genus of extinct stem-group arthropods

Cordaticaris is a genus of extinct hurdiid radiodont that lived in what is now northern China during the middle Cambrian period. This animal was described in 2020 based off remains found in the Zhangxia Formation, located in the Shandong Province. It is differentiated from other members of its family by its unique heart-shaped frontal sclerite, and its frontal appendages bearing nine endites and seven more elongated subequal endites. This animal was important as it was the first Miaolingian aged hurdiid known from rock layers outside of laurentia, allowing paleontologists to get a better grasp of this families geographic range in life.

<i>Buccaspinea</i> Extinct genus of radiodont

Buccaspinea is an extinct genus of Cambrian peytoiid radiodont from the Marjum Formation, known from frontal appendages and a nearly complete albeit headless specimen with a preserved oral cone. Buccaspinea was described in January 2021, being the second-most recent hurdiid genus to be described.

References

  1. 1 2 McCall, Christian R.A. (2023-12-13). "A large pelagic lobopodian from the Cambrian Pioche Shale of Nevada". Journal of Paleontology: 1–16. doi:10.1017/jpa.2023.63. ISSN   0022-3360.
  2. 1 2 3 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.
  3. 1 2 3 4 5 Pates, Stephen; Daley, Allison C.; Butterfield, Nicholas J. (2019). "First report of paired ventral endites in a hurdiid radiodont". Zoological Letters. 5 (1): 18. doi: 10.1186/s40851-019-0132-4 . ISSN   2056-306X. PMC   6560863 . PMID   31210962.
  4. 1 2 3 Sun, Zhixin; Zeng, Han; Zhao, Fangchen (2020). "A new middle Cambrian radiodont from North China: Implications for morphological disparity and spatial distribution of hurdiids". Palaeogeography, Palaeoclimatology, Palaeoecology. 558: 109947. Bibcode:2020PPP...558j9947S. doi:10.1016/j.palaeo.2020.109947. ISSN   0031-0182. S2CID   224868404.
  5. 1 2 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.
  6. 1 2 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. PMID   25762145. S2CID   205242881.
  7. ↑ De Vivo, Giacinto; Lautenschlager, Stephan; Vinther, Jakob (2021-07-28). "Three-dimensional modelling, disparity and ecology of the first Cambrian apex predators". Proceedings of the Royal Society B: Biological Sciences. 288 (1955): 20211176. doi:10.1098/rspb.2021.1176. ISSN   0962-8452. PMC   8292756 . PMID   34284622.
  8. 1 2 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 .
  9. 1 2 Daley, Allison C.; Legg, David A. (2015). "A morphological and taxonomic appraisal of the oldest anomalocaridid from the Lower Cambrian of Poland". Geological Magazine. 152 (5): 949–955. Bibcode:2015GeoM..152..949D. doi:10.1017/S0016756815000412. S2CID   130745134.
  10. ↑ 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. PMID   24670770. S2CID   205237459.
  11. ↑ Moysiuk, Joseph; Caron, Jean-Bernard (2022-07-08). "A three-eyed radiodont with fossilized neuroanatomy informs the origin of the arthropod head and segmentation". Current Biology. 32 (15): 3302–3316.e2. doi: 10.1016/j.cub.2022.06.027 . ISSN   0960-9822. PMID   35809569. S2CID   250361698.
  12. ↑ Pates S, Lerosey-Aubril R, Daley AC, Kier C, Bonino E, Ortega-Hernández J. 2021. The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian) PeerJ 9:e10509 https://doi.org/10.7717/peerj.10509
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  14. ↑ Chlupač, Ivo; Kordule, Vratislav (2002). "Arthropods of Burgess Shale type from the Middle Cambrian of Bohemia (Czech Republic)". Bulletin of the Czech Geological Survey. 77 (3): 167–182.
  15. 1 2 Zhilin, Cui; Shicheng, Huo (1990). "鄂西下寒武统甲壳类化石新发现". Acta Palaeontologica Sinica.
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