Cephalon and pygidium of Lorrettina depressa, from Shergold (1980).

Belongs within: Ptychopariida.

The Dikelocephalacea are a group of medium-sized to large trilobites from the Cambrian period (Harrington et al. 1959).

Characters (from Harrington et al. 1959): Exoskeleton opisthoparian, medium-sized to large, ellipsoidal in outline, heteropygous to subisopygous. Cephalon mostly semicircular, with more or less broadly tapering glabella bearing two or three pairs of lateral glabellar furrows, posterior areas commonly complete; frontal area transversely and sagittally broad, anterior border furrow shallow to obsolete; palpebral lobes prominent, eyes usually medium-sized; librigenae bearing medium to long genal spine. Thorax with thirteen or fewer segments. Pygidium broadly ovate to transverse, with interpleural and pleural furrows tending to curve conspicuously backward across broad border, some forms with pair of short posterolateral spines. Surface smooth to finely granulose.

    |--Prosaukia Ulrich & Resser 1933 S80
    |    `--*P. misa (Hall 1863) [=Dikelocephalus misa] S80
    |--Idahoiidae S80
    |    |--Idahoia S80
    |    `--Maladioidella Endo 1937 S80
    |         |--*M. splendens Endo in Endo & Resser 1937 S80
    |         |--M. chinchiaensis (Endo in Endo & Resser 1937) [=Crepicephalus chinchiaensis] S80
    |         `--M. doylei Shergold 1980 S80
    `--Dokimocephalidae S80
         |--Dokimocephalinae S80
         |    |--Acrocephalites Wallerius 1895 S80
         |    |--Burnetiella Lochman 1958 [=Burnetia Walcott 1924 (preocc.)] S80
         |    |--Dokimocephalus Walcott 1924 S80
         |    |--Iddingsia Walcott 1924 S80
         |    |--Apachia Frederickson 1949 S80
         |    |--Kindbladia Frederickson 1948 S80
         |    |--Pseudosaratogia Wilson 1951 S80
         |    `--Elkia Walcott 1924 S80
         |         `--E. nasuta [incl. Parabriscoia dolichorachis Kobayashi 1935] S80
         `--Wuhuiinae S80
              |--Protemnites Whitehouse 1939 S80
              |--Saimachia Kobayashi 1937 S80
              |    `--‘Anomocare’ latelimbatum Dames 1883 [incl. Saimachia damesi Kobayashi 1937] S80
              |--Prismenaspis Henderson 1976 S80
              |    `--*P. propinquum (Whitehouse 1939) [=Eugonocare propinquum] S80
              |--Wuhuia Kobayashi 1933 S80
              |    |--*W. belus (Walcott 1905) [=Solenopleura belus, Conocephalina belus] S80
              |    |--W. dryope (Walcott 1905) S80
              |    `--W. silex Shergold 1980 S80
              `--Lorettina Shergold 1972 S80
                   |--*L. macrops Shergold 1972 S80
                   |--L. depressa Shergold 1980 S80
                   |--L. licina Shergold 1980 S80
                   `--‘Pagodia’ mina Endo 1944 [=Wuhuia mina] S80

Dikelocephalacea incertae sedis:
  Atratebiinae S80
    |--Atratebia Shergold 1975 S80
    |    `--A. nexosa Shergold 1975 S80
    |--Mendosina Shergold 1975 S80
    |    `--M. laciniosa Shergold 1972 S80
    `--Taishania Sun 1935 S80
         |--*T. taianensis Sun 1935 [=Mansuyia endoi Resser 1942] S80
         |--‘Mansuyia’ maladiformis Kobayashi 1935 S80
         |--‘Anomocare’ persicum King 1930 S80
         |--T. platyfrons Shergold 1980 S80
         `--‘Elrathia’ yentaiensis Endo 1944 S80
  Briscoia S80
    |--B. hartti S80
    `--B. septentrionalis S80
  Tellerina S80
  Dikelocephalus florentinensis Etheridge 1904 F71

*Type species of generic name indicated


[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

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.

No comments:

Post a Comment

Markup Key:
- <b>bold</b> = bold
- <i>italic</i> = italic
- <a href="http://www.fieldofscience.com/">FoS</a> = FoS