Chasmataspis

Last updated

Chasmataspis
Temporal range: Darriwilian
Chasmataspis laurencii USNM PAL 125099.jpg
Holotype specimen
20200606 Chasmataspis laurencii.png
Life reconstruction of C. laurencii
Scientific classification OOjs UI icon edit-ltr.svg
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

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]

Contents

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

  1. Dunlop, Penney & Jekel 2020, p. 16.
  2. Caster & Brooks 1956.
  3. 1 2 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. PMC   6325806 . PMID   30621579.
  4. 1 2 3 4 5 6 7 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" (PDF). Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 94 (3): 207–225. doi:10.1017/S0263593300000626. ISSN   1473-7116.

Cited bibliography