Cnemidopyge

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Cnemidopyge
Temporal range: Ordovician
Cnemidopyge nuda CRF.jpg
Cnemidopyge nuda, Wales
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Trilobita
Order: Asaphida
Family: Raphiophoridae
Genus: Cnemidopyge
Whittard, 1955
Species
  • C. nuda(Muchison, 1839) (type) synonyms Trinucleus nudus, Ampyx nudus, A. latus

Cnemidopyge is a genus of trilobites that lived during the Ordovician. Like all Raphiophorids it is blind, with a cephalon that is subtriangular to subsemicircular, carrying genal spines and a forward directed rapier-like spine on the central raised area (or glabella), with the front of the glabella inflated and the natural fracture lines (or sutures) of the cephalon coinciding with its margin. It may be easily distinguished from other raphiophorids by the rectangular thorax with 6 segments, where other genera have a different number of segments and segments change in width over the length of the thorax. [1] Uniquely in this genus, the inner pleural region of the frontal segment is enlarged. [2] Also the axis (or rhachis) and pleural fields of the pygidium are strongly segmented. [1]

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<i>Orygmaspis</i>

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<i>Nanshanaspis</i> Extinct genus of trilobites

Nanshanaspis is a genus of asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. Like all raphiophorids it is blind, with a headshield that is subsemicircular, carrying genal spines and a forward directed spine on the central raised area, with the front of the glabella inflated and the natural fracture lines of the cephalon coinciding with its margin. It is easily distinguished from most other raphiophorids by the 3 thorax segments. Pseudampyxina, Taklamakania, and Kongqiangheia also have only 3 such segments, while all other raphiophorid genera have at least 5 thorax segments, leading to the erection of the subfamily "Taklamakaniinae" to contain these four genera. "Taklamakaniinae" was dissolved and its members absorbed into Raphiophorinae when further study showed the close similarities the "taklamakaniids" had to the juvenile forms of various raphiophorinids. Specimens of Nanshanaspis, for example, closely resemble juveniles of Globampyx trinucleoides.

References

  1. 1 2 Hughes, C.P. (1969). The Ordovician Trilobite Faunas of the Builth-Llandrindod Inlier Central Wales [Part 1]. Bulletin of the British Museum (Natural History), Geology. Vol. 18. pp. 41–103.
  2. Whittington, H. B. et al. (1997) Treatise on Invertebrate Paleontology. Part O, Revised, Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida.