Pasternakevia Explained

Pasternakevia is a genus of synziphosurine,^[1] a paraphyletic group of fossil chelicerate arthropods.^[2] Pasternakevia was regarded as part of the clade Planaterga.^{[3] [4] [5]} Fossils of the single and type species, P. podolica, have been discovered in deposits of the Silurian period in Podolia, Ukraine.^{[6] [7]}

The prosoma of Pasternakevia covered by a smooth, semicircular carapace with rounded genal cornua (posterolateral corner of carapace). Within the 10-segmented opisthosoma, tergite of the first segment is reduced and usually hidden under the preceding carapace, while the second one is significantly arched and well-developed. All but the first tergite possess well-developed pleurae (lateral extension). A complete telson is yet to be discovered.

Notes and References

1. Krzemiński. Wiesław. Krzemińska. Ewa. Wojciechowski. Dariusz. 2010. Silurian Synziphosurine Horseshoe Crab Pasternakevia Revisited. Acta Palaeontologica Polonica. en. 55. 1. 133–139. 10.4202/app.2008.0074. 0567-7920. free.
2. Bicknell. Russell D. C.. Pates. Stephen. 2020. Pictorial Atlas of Fossil and Extant Horseshoe Crabs, With Focus on Xiphosurida. Frontiers in Earth Science. en. 8. 98. 10.3389/feart.2020.00098. 2020FrEaS...8...98B. 2296-6463. free.
3. Selden. Paul A.. Lamsdell. James C.. Qi. Liu. An unusual euchelicerate linking horseshoe crabs and eurypterids, from the Lower Devonian (Lochkovian) of Yunnan, China. Zoologica Scripta. 2015 . en. 44. 6. 645–652. 10.1111/zsc.12124 . 55264483 . 0300-3256. free.
4. 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. en. 102. 9–10. 63. 10.1007/s00114-015-1312-5. 26391849. 2015SciNa.102...63L. 8153035. 0028-1042.
5. Bicknell. Russell D. C.. Lustri. Lorenzo. Brougham. Tom. 2019-12-01. Revision of "Bellinurus" carteri (Chelicerata: Xiphosura) from the Late Devonian of Pennsylvania, USA. Comptes Rendus Palevol. en. 18. 8. 967–976. 10.1016/j.crpv.2019.08.002. 1631-0683. free.
6. Book: http://www.wsc.nmbe.ch/resources/fossils/Fossils20.5.pdf. World Spider Catalog. Dunlop. J. A.. Penney. D.. Jekel. D.. Natural History Museum Bern. 2020. A summary list of fossil spiders and their relatives. 1–296.
7. Lamsdell. James C.. 2013. Revised systematics of Palaeozoic 'horseshoe crabs' and the myth of monophyletic Xiphosura. Zoological Journal of the Linnean Society. 167. 1. 1–27. 10.1111/j.1096-3642.2012.00874.x. 0024-4082. free.