Reconstructed cranidium and pygidium of Connagnostus aversus, from Shergold (1980).

Belongs within: Agnostida.
Contains: Pseudagnostus.

The Diplagnostidae are a Middle Cambrian to Lower Ordovician group of agnostid trilobites.

Characters (from Harrington et al. 1959): Glabella with two main lobes, anterior one medially indented by longitudinal furrow; pygidial axis trilobed; surface of cephalon smooth, corrugated or rugose; surface of pygidium smooth.

    |--Connagnostus Öpik 1967 [Diplagnostinae] S80
    |    |--*C. venerabilis Öpik 1967 S80
    |    |--C. aversus Shergold 1980 S80
    |    |--C. conspectus Shergold 1975 S80
    |    `--C. junior Shergold 1972 S80
    `--Pseudagnostinae S80
         |--Pseudagnostus S80
         |--Rhaptagnostus Whitehouse 1936 S80
         |    |--*R. cyclopygeformis (Sun 1924) [=Agnostus cyclopygeformis] S80
         |    |--R. apsis Shergold 1980 S80
         |    |--R. auctor Shergold 1980 S80
         |    |--R. clarki (Kobayashi 1935) [=Pseudagnostus (Plethagnostus) clarki] S80
         |    |    |--R. c. clarki S80
         |    |    |--R. c. laevis Palmer 1955 S80
         |    |    |--R. c. patulus (Shergold 1975) S80
         |    |    `--R. c. prolatus Shergold 1975 S80
         |    |--R. convergens (Palmer 1955) [=Pseudagnostus convergens] S80
         |    `--R. impressus (Lermontova 1940) S80
         `--Neoagnostus Kobayashi 1955 (see below for synonymy) S80
              |--*N. aspidoides Kobayashi 1955 S80
              |--N. araneavelatus (Shaw 1951) [=Pseudagnostus araneavelatus] S80
              |--N. bilobus S80
              |--N. canadensis S80
              |--N. cavernosus (Rosova 1960) S80
              |--N. clavus (Shergold 1972) [=Pseudagnostus clavus] S80
              |--N. coronatus (Shergold 1975) S80
              |--N. denticulatus (Shergold 1975) S80
              |--N. felix Shergold 1980 S80
              |--N. greeni Shergold 1980 S80
              `--N. vulgaris (Rosova 1960) S80

Neoagnostus Kobayashi 1955 [incl. Euplethagnostus Lermontova 1940, Hyperagnostus Kobayashi 1955, Machairagnostus Harrington & Leanza 1957, Pseudorhaptagnostus Lermontova 1940] S80

*Type species of generic name indicated


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.

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