Synziphosurina

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Synziphosurina
Temporal range: Jiangshanian–Mississippian
20200816 Synziphosurina Synziphosurine.png
Venustulus waukeshaensis (top left), Cyamocephalus loganensis (top right), Weinbergina opitzi (center), Limuloides limuloides (bottom left), and Legrandella lombardii (bottom right).
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Clade: Euchelicerata
Suborder:† Synziphosurina
Packard 1886
Genera [2] [3] [4]

Synziphosurina is a paraphyletic group of chelicerate arthropods previously thought to be basal horseshoe crabs (Xiphosura). [5] It was later identified as a grade composed of various basal euchelicerates, [5] [6] [7] [4] [3] eventually excluded from the monophyletic Xiphosura sensu stricto [5] and only regarded as horseshoe crabs under a broader sense ('Xiphosura' sensu lato). [4] [6] Synziphosurines survived at least since early Ordovician to early Carboniferous in ages, with most species are known from the in-between Silurian strata. [3]

Fossil of Weinbergina opitzi with preserved ventral appendages. Weinbergina opitzi.JPG
Fossil of Weinbergina opitzi with preserved ventral appendages.
Size comparison of various synziphosurines. 20200929 Synziphosurina Synziphosurine size comparison.png
Size comparison of various synziphosurines.

While Weinbergina and Willwerathia being exceptionally large, [8] most synziphosurines are small arthropods with body length ranging only about a few centimeters long. [9]

The body of synziphosurine composed of a prosoma covered by a dome-like carapace (prosomal dorsal shield) and an opisthosoma with usually unfused 9-11 segments expressed by tergites. [3] With the exception of Pseudoniscus [9] and Pasternakevia , [10] the last 3 opisthosomal segments precede the spine-like telson are specialized into a narrow postabdomen (pretelson), [3] while the remaining wider segments referred to as preabdomen. [9] A reduced anteriormost tergite (microtergite) originated from the first opisthosomal segment is observable at least in some genera. [9] [5] Most synziphosurines are possibly blind, with only a few species showing possible (e.g. Weinbergina opitzi) or clear (e.g. Legrandella lombardii) evidences of lateral compound eyes on their carapaces. [11] [3] Evidences of appendages are scarce, fragmentary known from Anderella parva, [12] Camanchia grovensis [13] and Venustulus waukeshaensis [14] while exceptionally well-documented in Weinbergina opitzi. [15] [3] The prosoma possess a pair of chelicerae and at least 5 pairs of walking legs while the opisthosoma probably has 6 pairs of plate-like opercula. [5] [16]

As of 2020, at least 13 genera and 20 species were considered to be synziphosurines. [3] The even basal euchelicerates Offacolus and Dibasterium , the questionable genus Borchgrevinkium , as well as the Dekatriata-related Houia and Winneshiekia , may also regarded as members of synziphosurines in some literatures. [17] [6] [7] [18] [3]

Related Research Articles

<span class="mw-page-title-main">Xiphosura</span> Order of marine chelicerates

Xiphosura is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs. They first appeared in the Hirnantian. Currently, there are only four living species. Xiphosura contains one suborder, Xiphosurida, and several stem-genera.

<span class="mw-page-title-main">Chasmataspidida</span> Order of arthropods

Chasmataspidids, sometime referred to as chasmataspids, are a group of extinct chelicerate arthropods that form the order Chasmataspidida. Chasmataspidids are probably related to horseshoe crabs (Xiphosura) and/or sea scorpions (Eurypterida), with more recent studies suggest that they form a clade (Dekatriata) with Eurypterida and Arachnida. Chasmataspidids are known sporadically in the fossil record through to the mid-Devonian, with possible evidence suggesting that they were also present during the late Cambrian. Chasmataspidids are most easily recognised by having an opisthosoma divided into a wide forepart (preabdomen) and a narrow hind part (postabdomen) each comprising 4 and 9 segments respectively. There is some debate about whether they form a natural group.

<i>Willwerathia</i> Genus of Devonian arthropod

Willwerathia is a genus of Devonian arthropod. It is sometimes classified as synziphosurine, a paraphyletic group of horseshoe crab-like fossil chelicerate arthropods, while some studies compare its morphology to an artiopod. Willwerathia known only by one species, Willwerathia laticeps, discovered in deposits of the Devonian period from the Klerf Formation, in the Rhenish Slate Mountains of Germany.

<i>Bembicosoma</i> Extinct genus of chelicerate

Bembicosoma is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Bembicosoma was regarded as part of the clade Planaterga. Fossils of the single and type species, B. pomphicus, have been discovered in deposits of the Silurian period in the Pentland Hills, Scotland. Bembicosoma had been tentatively assigned as an eurypterid before its synziphosurine affinities revealed.

Bunaia is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Bunaia was tentatively placed as part of the clade Planaterga, however a 2024 study found it to be within Offacolidae instead. The genus contains at least one species: Bunaia woodwardi from the Silurian period in Svalbard, Norway and the Bertie Group of Ontario

<i>Bunodes</i> Genus of horseshoe crab relatives

Bunodes is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Bunodes was regarded as part of the clade Planaterga. Fossils of the single and type species, B. lunula, have been discovered in deposits of the Silurian period in Ludlow, England. Bunodes is the type genus of the family Bunodidae, the other genera of the same family being Limuloides. There are 64 direct children of Bunodes.

<i>Cyamocephalus</i> Extinct genus of chelicerate

Cyamocephalus is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Cyamocephalus was regarded as part of the clade Planaterga. Fossils of the single and type species, C. loganensis, have been discovered in deposits of the Silurian-aged Patrick Burn Formation in Lesmahagow, Scotland. Cyamocephalus is one of the two members of the family Pseudoniscidae, the other being Pseudoniscus. Cyamocephalus differ from Pseudoniscus by the fused tergites of 6th and 7th opisthosomal segments.

<i>Legrandella</i> Extinct genus of chelicerate

Legrandella is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Legrandella was regarded as part of the clade Prosomapoda. Fossils of the single and type species, L. lombardii, have been discovered in deposits of the Devonian period in Cochabamba, Bolivia.

<i>Limuloides</i> Genus of horseshoe crab relatives

Limuloides is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Limuloides was regarded as part of the clade Planaterga. Fossils of the genus have been discovered in deposits of the Silurian period in the United Kingdom and potentially in the United States. Limuloides is one of the two genera of the family Bunodidae, the other being the type genus Bunodes. Limuloides is characterized by a carapace with radiated ridges and serrated lateral regions, and an opisthosoma with rows of nodes. Limuloides was once thought to have lateral compound eyes on its carapace, but later investigation did not find any evidence of it.

<i>Pasternakevia</i> Extinct genus of chelicerate

Pasternakevia is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Pasternakevia was regarded as part of the clade Planaterga. Fossils of the single and type species, P. podolica, have been discovered in deposits of the Silurian period in Podolia, Ukraine.

<i>Pseudoniscus</i> Extinct genus of chelicerate

Pseudoniscus is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Pseudoniscus was regarded as part of the clade Planaterga. Fossils of the genus have been discovered in deposits of the Silurian period in the United Kingdom, the United States and Estonia. Pseudoniscus is one of the two members of the family Pseudoniscidae, the other being Cyamocephalus.

<i>Weinbergina</i> Extinct genus of chelicerate

Weinbergina is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Fossils of the single and type species, W. opitzi, have been discovered in deposits of the Devonian period in the Hunsrück Slate, Germany.

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

Borchgrevinkium is an extinct genus of chelicerate arthropod. A fossil of the single and type species, B. taimyrensis, has been discovered in deposits of the Early Devonian period in the Krasnoyarsk Krai, Siberia, Russia. The name of the genus honors Carsten Borchgrevink, an Anglo-Norwegian explorer who participated in many expeditions to Antarctica. Borchgrevinkium represents a poorly known genus whose affinities are uncertain.

<span class="mw-page-title-main">Metastoma</span> Abdominal plate present in some anthropods

The metastoma is a ventral single plate located in the opisthosoma of non-arachnid dekatriatan chelicerates such as eurypterids, chasmataspidids and the genus Houia. The metastoma located between the base of 6th prosomal appendage pair and may had functioned as part of the animal's feeding structures. It most likely represented a fused appendage pair originated from somite 7, thus homologous to the chilaria of horseshoe crab and 4th walking leg pair of sea spider. In eurypterids, the plate was typically cordate (heart-shaped) in shape, though differed in shape in some genera, such as Megalograptus.

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

Prosomapoda is a clade of euchelicerates including the groups Xiphosura and Planaterga, as well as several basal synziphosurid genera. The clade is defined by the lack of exopods of prosomal appendage II-V in the adult instar, where in contrast the exopods of appendage II-V are well-developed in the non-prosomapod euchelicerates Offacolus and Dibasterium.

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

Offacolus is an extinct genus of euchelicerate, a group of chelicerate arthropods. Its only species, O. kingi, has been found in deposits from the Silurian period in the Wenlock Series Lagerstätte of Herefordshire, England. The genus is named after Offa, a king from the ancient kingdom of Mercia, and colus, a person who dwelled among the Offa's Dyke. The species name honors Robert Joseph King, a British mineralogist who found the fossils of Offacolus.

<i>Venustulus</i> Extinct genus of chelicerate from Wisconsin

Venustulus is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Venustulus was regarded as part of the clade Prosomapoda. Fossils of the single and type species, V. waukeshaensis, have been discovered in deposits of the Silurian period in Wisconsin, in the United States. Venustulus is one of the few synziphosurine genera with fossil showing evidence of appendages, the other ones being Weinbergina, Anderella and Camanchia. Despite often being aligned close to horseshoe crabs, it has been found that Venustulus and its relatives form a group made up of various basal euchelicerate arthropods more distant to the xiphosurans.

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

Camanchia is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Camanchia was regarded as part of the clade Prosomapoda. Fossils of the single and type species, C. grovensis, have been discovered in deposits of the Silurian period in Iowa, in the United States. Alongside Venustulus, Camanchia is one of the only Silurian synziphosurine with fossil showing evidence of appendages.

<i>Anderella</i> Extinct genus of chelicerate

Anderella is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Anderella was regarded as part of the clade Prosomapoda. Fossils of the single and type species, A. parva, have been discovered in deposits of the Carboniferous period in Montana, in the United States. Anderella is the first and so far the only Carboniferous synziphosurine being described, making it the youngest member of synziphosurines. Anderella is also one of the few synziphosurine genera with fossil showing evidence of appendages, but the details are obscure due to their poor preservation.

<i>Maldybulakia</i> Extinct arthropod genus

Maldybulakia is a genus of freshwater arthropod which lived during Late Silurian to Late Devonian. Maldybulakia is known from three species, M. angusi and M. malcolmi from Australia, M. mirabilis from Kazakhstan, and M. saierensis from China. Its classification is uncertain, it was originally described as a myriapod-like animal, and later considered related to the xiphosurans, or an artiopod.

References

  1. ↑ Naimark, E. B.; Sizov, A. V.; Khubanov, V. B. (September 2023). "Kimiltei Is a New Late Cambrian Lagerstätte with the Faunistic Complex of Arthropods (Euthycarcinoidae, Synziphosurina, and Chasmataspidida) in the Irkutsk Region". Doklady Earth Sciences. 512 (1): 859–870. doi:10.1134/S1028334X2360127X.
  2. ↑ W. Krzemiński, E. Krzemińska, and D. Wojciechowski. 2010. Silurian synziphosurine horseshoe crab Pasternakevia revisited. Acta Palaeontologica Polonica 55(1):133-139 [A. Hendy/A. Hendy/J. Karr]
  3. 1 2 3 4 5 6 7 8 9 Bicknell, Russell D. C.; Pates, Stephen (2020). "Pictorial Atlas of Fossil and Extant Horseshoe Crabs, With Focus on Xiphosurida". Frontiers in Earth Science. 8: 98. Bibcode:2020FrEaS...8...98B. doi: 10.3389/feart.2020.00098 . ISSN   2296-6463.
  4. 1 2 3 Dunlop, J. A.; Penney, D.; Jekel, D. (2020). "A summary list of fossil spiders and their relatives" (PDF). World Spider Catalog. Natural History Museum Bern. pp. 1–296.
  5. 1 2 3 4 5 Lamsdell, James C. (2013-01-01). "Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura". Zoological Journal of the Linnean Society. 167 (1): 1–27. doi: 10.1111/j.1096-3642.2012.00874.x . ISSN   0024-4082.
  6. 1 2 3 Selden, Paul A.; Lamsdell, James C.; Qi, Liu (2015). "An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China". Zoologica Scripta. 44 (6): 645–652. doi: 10.1111/zsc.12124 . ISSN   0300-3256. S2CID   55264483.
  7. 1 2 Lamsdell, James C.; Briggs, Derek E. G.; Liu, Huaibao P.; Witzke, Brian J.; McKay, Robert M. (2015). "A new Ordovician arthropod from the Winneshiek Lagerstätte of Iowa (USA) reveals the ground plan of eurypterids and chasmataspidids". The Science of Nature. 102 (9–10): 63. Bibcode:2015SciNa.102...63L. doi:10.1007/s00114-015-1312-5. ISSN   0028-1042. PMID   26391849. S2CID   8153035.
  8. ↑ Anderson, Lyall I.; Poschmann, Markus; Brauckmann, Carsten (1998). "On the Emsian (Lower Devonian) arthropods of the Rhenish Slate Mountains: 2. The synziphosurine Willwerathia". Paläontologische Zeitschrift. 72 (3–4): 325–336. doi:10.1007/BF02988363. ISSN   0031-0220. S2CID   128464147.
  9. 1 2 3 4 Eldredge, Niles; Smith, LeGrande (1974). "Revision of the suborder Synziphosurina (Chelicerata, Merostomata) : with remarks on merostome phylogeny. American Museum novitates ; no. 2543". hdl:2246/2745.{{cite journal}}: Cite journal requires |journal= (help)
  10. ↑ Krzemiński, Wiesław; Krzemińska, Ewa; Wojciechowski, Dariusz (2010). "Silurian Synziphosurine Horseshoe Crab Pasternakevia Revisited". Acta Palaeontologica Polonica. 55 (1): 133–139. doi: 10.4202/app.2008.0074 . ISSN   0567-7920.
  11. ↑ Bicknell, Russell D. C.; Amati, Lisa; Ortega-Hernández, Javier (2019-11-14). "New insights into the evolution of lateral compound eyes in Palaeozoic horseshoe crabs". Zoological Journal of the Linnean Society. 187 (4): 1061–1077. doi:10.1093/zoolinnean/zlz065. ISSN   0024-4082.
  12. ↑ Moore, Rachel A.; McKENZIE, Scott C.; Lieberman, Bruce S. (2007). "A Carboniferous Synziphosurine (xiphosura) from the Bear Gulch Limestone, Montana, Usa". Palaeontology. 50 (4): 1013–1019. doi: 10.1111/j.1475-4983.2007.00685.x . ISSN   1475-4983. S2CID   59449700.
  13. ↑ MOORE, RACHEL A.; BRIGGS, DEREK E. G.; BRADDY, SIMON J.; SHULTZ, JEFFREY W. (2011). "Synziphosurines (Xiphosura: Chelicerata) from the Silurian of Iowa". Journal of Paleontology. 85 (1): 83–91. doi:10.1666/10-057.1. ISSN   0022-3360. JSTOR   23019501. S2CID   115132351.
  14. ↑ Moore, Rachel A.; Briggs, Derek E. G.; Braddy, Simon J.; Anderson, Lyall I.; Mikulic, Donald G.; Kluessendorf, Joanne (2005). "A new synziphosurine (Chelicerata : Xiphosura) from the Late Llandovery (Silurian) Waukesha Lagerstatte, Wisconsin, USA". Journal of Paleontology. 79 (2): 242–250. doi:10.1666/0022-3360(2005)079<0242:ANSCXF>2.0.CO;2. ISSN   0022-3360. S2CID   56570105.
  15. ↑ Moore, Rachel A.; Briggs, Derek E. G.; Bartels, Christoph (2005). "A new specimen ofWeinbergina opitzi (Chelicerata: Xiphosura) from the Lower Devonian Hunsriick Slate, Germany". Paläontologische Zeitschrift. 79 (3): 399–408. doi:10.1007/BF02991931. ISSN   0031-0220. S2CID   84994966.
  16. ↑ Dunlop, Jason A.; Lamsdell, James C. (2017). "Segmentation and tagmosis in Chelicerata". Arthropod Structure & Development. 46 (3): 395–418. doi:10.1016/j.asd.2016.05.002. ISSN   1467-8039. PMID   27240897.
  17. ↑ Briggs, Derek E. G.; Siveter, Derek J.; Siveter, David J.; Sutton, Mark D.; Garwood, Russell J.; Legg, David (2012-09-25). "Silurian horseshoe crab illuminates the evolution of arthropod limbs". Proceedings of the National Academy of Sciences. 109 (39): 15702–15705. Bibcode:2012PNAS..10915702B. doi: 10.1073/pnas.1205875109 . ISSN   0027-8424. PMC   3465403 . PMID   22967511.
  18. ↑ Bicknell, Russell D.C.; Lustri, Lorenzo; Brougham, Tom (2019). "Revision of "Bellinurus" carteri (Chelicerata: Xiphosura) from the Late Devonian of Pennsylvania, USA". Comptes Rendus Palevol. 18 (8): 967–976. doi: 10.1016/j.crpv.2019.08.002 .
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