Biology:Chasmataspis
| Chasmataspis Temporal range: Early Ordovician
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| Holotype specimen | |
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| Life reconstruction of C. laurencii | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Clade: | Dekatriata |
| Order: | †Chasmataspidida |
| Family: | †Chasmataspididae Caster & Brooks, 1956 |
| Genus: | †Chasmataspis Caster & Brooks, 1956 |
| Type species | |
| †Chasmataspis laurencii Caster & Brooks, 1999
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Chasmataspis is a genus of chasmataspidid, a group of extinct aquatic chelicerate arthropods.[1][2] It was found in the Early Ordovician deposits of Tennessee , United States .[3]
Morphology
Just like other chasmataspidids, the body of Chasmataspis compose of a prosoma and a 13-segmented opisthosoma, with the latter subdivided into a 4-segmented preabdomen and a 9-segmented postabdomen.[4] Dorsal to the carapace were pairs of ridges, lateral eyes and median ocelli.[4] Chasmataspis characterized by a semicircular carapace (prosomal dorsal shield) with pointed genal spines and preabdomen with fused body segments.[4] Rows of tubercles and spines run through the axial and lateral regions of opisthosoma.[4] The body terminated with a spine-like telson.[4]
There is no body fossils of Chasmataspis with unambiguous appendages being discovered.[4] The only evidence were 2 specimens of disarticulated, claw-bearing appendages discovered from the same stratum which may represent the prosomal appendage (possibly appendage VI[3]) of Chasmastaspis.[4]
References
- ↑ Dunlop, Penney & Jekel 2020, p. 16.
- ↑ Caster & Brooks 1956.
- ↑ 3.0 3.1 Lamsdell, James C.; Gunderson, Gerald O.; Meyer, Ronald C. (2019-01-08). "A common arthropod from the Late Ordovician Big Hill Lagerstätte (Michigan) reveals an unexpected ecological diversity within Chasmataspidida". BMC Evolutionary Biology 19 (1): 8. doi:10.1186/s12862-018-1329-4. ISSN 1471-2148. PMID 30621579.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Dunlop, Jason A.; Anderson, Lyall I.; Braddy, Simon J. (2003). "A redescription of Chasmataspis laurencii Caster & Brooks, 1956 (Chelicerata: Chasmataspidida) from the Middle Ordovician of Tennessee, USA, with remarks on chasmataspid phylogeny" (in en). Earth and Environmental Science Transactions of the Royal Society of Edinburgh 94 (3): 207–225. doi:10.1017/S0263593300000626. ISSN 1473-7116. http://www.museunacional.ufrj.br/mndi/Aracnologia/Chasmataspidida/Dunlop%20et%20al%202007%20Chasmataspis.pdf.
Cited bibliography
- Caster, Kenneth E.; Brooks, H. K. (1956). "New fossils from the Canadian–Chazan (Ordovician) hiatus in Tennessee". Bulletins of American Paleontology 36 (157): 157–199. https://www.biodiversitylibrary.org/item/40434#page/189.
- Dunlop, Jason A.; Penney, D.; Jekel, D. (2020). "A summary list of fossil spiders and their relatives". World Spider Catalog. Natural History Museum Bern. http://www.wsc.nmbe.ch/resources/fossils/Fossils20.5.pdf.
Wikidata ☰ Q19832770 entry
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