Shumardiidae

Cranidia of Koldinioidia (Liriamnica) antyx, from Shergold (1980).

Belongs within: Ptychopariida.

The Shumardiidae are a Cambrian and Ordovician family of minute trilobites.

Characters (from Harrington et al. 1959): Minute, ovate, convex, heteropygous. Cephalon semicircular, without eyes and apparently without facial sutures; glabella delimited at sides by unusually deep axial furrows and in front by their narrower, shallower, (in some) almost effaced continuation; occipital ring well defined; convex preglabellar field usually well developed; almost evenly convex genae with acute genal angles or genal spines; posterior border furrows strongly impressed posterior border narrow. Thorax (as far as known) with six or seven segments. Pygidium greatly varying in shape, with four to seven axial rings. Cephalic doublure, ventral sutures and hypostoma unknown.

<==Shumardiidae
    |--Hospes S80
    |--Idiomesus S80
    |--Shumardia S80
    |--Shumardops S80
    |--Eoshumardia S80
    `--Koldinioidia Kobayashi 1931 S80
         |--K. (Koldinioida) S80
         |    |--*K. (K.) typicalis Kobayashi 1931 S80
         |    |--K. (K.) cylindrica (Shergold 1972) S80
         |    |--K. (K.) payntonensis Shergold 1975 S80
         |    `--K. (K.) sulcata Robison & Pantoja-Alor 1968 S80
         `--K. (Liriamnica Shergold 1980) S80
              `--K. (L.) antyx 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.