Ceratopygidae

Somewhat distorted specimen of Proceratopyge, from here.

Belongs within: Ptychopariida.

The Ceratopygidae are a family of trilobites that lived from the Middle Cambrian to the Lower Ordovician. Members of the family possessed rear-pointing spines on both the cephalon and the pygidium.

Characters (from Harrington et al. 1959): Opisthoparian, ovate, slightly convex exoskeleton, heteropygous to almost isopygous. Cephalon approximately semicircular; glabella clavate to tapering forward, with median tubercle on posterior part; preglabellar field well developed, cephalic border furrow strongly impressed, adjoining narrow, convex border; librigenae fairly wide, with slender genal spines in direct continuation of lateral body or nearly so. Thorax (as far as known) of six to nine segments. Pygidium semicircular to subtriangular, with one or two pairs of lateral spines originating from anterior segments. Cephalic doublure, ventral sutures, and hypostoma imperfectly known.

<==Ceratopygidae [Ceratopygacea]
    |  i. s.: Pseudohysterolenus Harrington & Leanza 1957 S80
    |--Iwayaspidinae S80
    |    |--Pseudoyuepingia Chien 1961 S80
    |    |    `--P. modesta chien 1961 S80
    |    |--Cermatops Shergold 1980 S80
    |    |    `--C. vieta Shergold 1980 S80
    |    `--Iwayaspis Kobayashi 1962 S80
    |         |--I. asaphoides Kobayashi 1962 S80
    |         |--I. caelata Lazarenko in Datsenko et al. 1968 S80
    |         |--I. curta Lazarenko in Datsenko et al. 1968 S80
    |         `--I. longa Lazarenko in Datsenko et al. 1968 S80
    `--Proceratopyginae S80
         |--Aplotaspis Henderson 1976 S80
         |--Proceratopyge S80
         |    |--P. chuhsiensis Lu 1956 S80
         |    |--P. lata S80
         |    `--P. polita Whitehouse 1939 S80
         `--Haniwoides Kobayashi 1935 S80
              |--*H. longa Kobayashi 1935 S80
              |--H. concava Kobayashi 1935 S80
              |--H. longissima Kobayashi 1962 S80
              |--H. puteolata Kobayashi 1962 S80
              |--H. tenuis Kobayashi 1962 S80
              `--H. varia Shergold 1980 S80

*Type species of generic name indicated

REFERENCES

Harrington, H. J., G. Henningsmoen et al. 1959. Systematic descriptions. In Treatise on Invertebrate Paleontology pt O. Arthropoda 1 pp. O170-O540. Geological Society of America and University of Kansas Press.

[S80] Shergold, J. H. 1980. Late Cambrian trilobites from the Chatsworth Limestone, western Queensland. Bureau of Mineral Resources, Geology and Geophysics – Bulletin 186: 1-111.