Olenus gibbosus, from here.

Belongs within: Libristoma.

The Olenacea are a group of trilobites known from the Middle Cambrian to the Upper Ordovician (Harrington et al. 1959).

Characters (from Harrington et al. 1959): Exoskeleton subovate to elongate, opisthoparian (exceptionally proparian), micropygous to (rarely)subisopygous, with rounded or spinose genal angles. Cephalon with narrow border, small to medium-sized eyes and in most forms distinct eye ridges; glabella tapering forward, with simple, sigmoidal, or bifurcate lateral furrows (if present); preglabellar field present or absent; librigenae separated by median suture or fused together. Hypostoma probably free. Thorax with 9 to 24 segments. Pygidium with or without marginal spines.

    |--Wentsuia Sun 1935 [Elviniidae, Elviniinae]S80
    |    |--*W. granulosa Sun 1935S80
    |    |--W. iota Shergold 1980S80
    |    `--‘Elrathia’ munda Resser & Endo in Endo & Resser 1937S80
    `--Olenidae [Olenina]S80
         |  i. s.: Hedinia regalis Troedsson 1937S80
         |         Porterfieldia punctataFO99
         |         Peltura scarabaeoidesFO99
         |         TriarthrusRC93
         |           |--T. beckiH04
         |           `--T. eatoniM79
         |         HypermecaspisF90
         |         BalnibarbiF90
         |--Leptoplastus Angelin 1854 [Leptoplastinae]S80
         |    |--*L. stenotus Angelin 1854S80
         |    |--L. paucisegmentatusWSB93
         |    `--L. rhaphidophorus Angelin 1854S80
              |--Plicatolina Shaw 1951S80
              |    |--*P. kindlei Shaw 1951S80
              |    |--P. changshanensisCT83
              |    |--P. lucida Lazarenko 1966S80
              |    |--P. perlata lazarenko 1966S80
              |    |--P. quadrata Pokrovskaya 1966S80
              |    |--P. scalpta Harrington & Leanza 1957S80
              |    `--P. yakutica Pokrovskaya 1966S80
                   |  i. s.: O. alpha Henningsmoen 1957RC93
                   |         O. cataractesRC93
                   |         O. sinensisCT83
                   |--*O. gibbosus (Wahlenberg 1821)F90, LN05
                   |--O. attenuatus (Boeck 1838)LN05
                   |--O. dentatus (Westergård 1922)LN05
                   `--+--O. transversusLN05
                      `--+--O. truncatus (Brünnich 1781)LN05
                         `--O. wahlenbergi (Wahlenberg 1821)LN05

*Type species of generic name indicated


[CT83] Chen J.-Y. & C. Teichert. 1983. Cambrian Cephalopoda of China. Palaeontographica Abteilung A: Paläozoologie—Stratigraphie 181 (1–3): 1–102.

[F90] Fortey, R. A. 1990. Ontogeny, hypostome attachment and trilobite classification. Palaeontology 33 (3): 529–576.

[FO99] Fortey, R. A. & R. M. Owens. 1999. Feeding habits in trilobites. Palaeontology 42 (3): 429–465.

[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.

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.

[LN05] Lauridsen, B. W., & A. T. Nielsen. 2005. The Upper Cambrian trilobite Olenus at Andrarum, Sweden: a case of iterative evolution? Palaeontology 48 (5): 1041–1056.

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[RC93] Romano, M., W. T. Chang, W. T. Dean, G. D. Edgecombe, R. A. Fortey, D. J. Holloway, P. D. Lane, A. W. Owen, R. M. Owens, A. R. Palmer, A. W. A. Rushton, J. H. Shergold, D. J. Siveter & M. A. Whyte. 1993. Arthropoda (Trilobita). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 279–296. Chapman & Hall: London.

[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.

[WSB93] Whatley, R. C., D. J. Siveter & I. D. Boomer. 1993. Arthropoda (Crustacea: Ostracoda). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 343–356. Chapman & Hall: London.

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